import type { LessonSeedSourceRef, TuitionLessonSeed } from "./physicsLessonSeeds";

/**
 * Kerala SCERT Class 10 Physics — Chapter 3 "The World of Colours and Vision"
 * (chapterId phy-p1-c3, pp. 49-68). Full-chapter, syllabus-oriented lesson
 * seeds (Phase 6G).
 *
 * Grounded in the SCERT chapter scope: dispersion of light, recombination and
 * the rainbow, the electromagnetic spectrum, primary/secondary/complementary
 * colours, colours of objects and colour filters, scattering of light (blue
 * sky, red sun), structure of the human eye, power of accommodation, defects of
 * vision and their correction, and power-of-lens numericals. Content is short +
 * teacher-style, not textbook paragraphs. Every seed cites the chapter. No PYQ
 * claims, no fake-guarantee language.
 */

const COLOURS_VISION_SOURCE: LessonSeedSourceRef = {
  label: "Kerala SSLC Physics — The World of Colours and Vision (pp. 49-68)",
  sourceBook: "Kerala SCERT Physics, Standard X (2025)",
  chapterTitle: "The World of Colours and Vision",
  pageRange: "49-68",
  url: null,
  confidence: "source_backed",
};

const CHAPTER_ID = "phy-p1-c3";
const CHAPTER_TITLE = "The World of Colours and Vision";

function colourSeed(seed: Omit<TuitionLessonSeed, "chapterId" | "subject" | "chapterTitle">): TuitionLessonSeed {
  return { ...seed, chapterId: CHAPTER_ID, subject: "Physics", chapterTitle: CHAPTER_TITLE };
}

// M1 — Dispersion of Light
const M1: TuitionLessonSeed = colourSeed({
  missionId: "M1",
  missionTitle: "Dispersion of Light",
  goal: "Explain how white light splits into its component colours through a prism and why.",
  estimatedMinutes: 30,
  contentType: "concept",
  tags: ["dispersion", "prism", "spectrum", "VIBGYOR", "deviation", "wavelength"],
  sourceRefs: [COLOURS_VISION_SOURCE],
  sourceStatus: "source_backed",
  canTeach: true,
  pyqEvidenceStatus: "not_curated",
  recall: {
    prompt: "When sunlight passes through a glass prism and falls on a wall, what do you see instead of a white patch?",
    expectedPoints: ["A band of colours (a rainbow-like patch)", "The seven colours VIBGYOR", "White light is made of many colours"],
    misconceptionCheck: "Students think the prism 'adds' colour to white light — it only separates colours already present.",
  },
  teach: {
    teacherIntro: "Think of white light as a big bag of colourful sweets. A prism is like a special machine that separates these sweets and shows us all the colours. This is called dispersion.",
    explanationBlocks: [
      {
        heading: "Dispersion and the spectrum",
        explanation: "When white light passes through a prism it separates into an orderly band of colours. This orderly arrangement of the component colours of white light is called the spectrum.",
        keyTerms: ["dispersion", "spectrum", "VIBGYOR"],
      },
      {
        heading: "The seven colours (VIBGYOR)",
        explanation: "The order is Violet, Indigo, Blue, Green, Yellow, Orange, Red. Violet has the shortest wavelength; red has the longest.",
        keyTerms: ["violet", "red", "wavelength"],
      },
      {
        heading: "Why colours separate",
        explanation: "Each colour travels at a slightly different speed in glass, so each is refracted (deviated) by a different amount. Violet deviates the most, red the least.",
        keyTerms: ["deviation", "refraction", "violet most", "red least"],
      },
    ],
    analogy: "Like a group running through mud: the one slowed most (violet) turns most; the one slowed least (red) turns least — so they fan out.",
    malayalamSupport: "വെളുത്ത പ്രകാശം ഏഴ് നിറങ്ങളുടെ (VIBGYOR) മിശ്രിതമാണ്. പ്രിസത്തിലൂടെ കടക്കുമ്പോൾ ഓരോ നിറവും വ്യത്യസ്തമായി വളയുന്നു — വയലറ്റ് ഏറ്റവും കൂടുതൽ, ചുവപ്പ് ഏറ്റവും കുറവ്.",
    manglishSupport: "White light = ezhu നിറങ്ങൾ (VIBGYOR). Prism-il koodi kadakkumbol oro colour-um vyathyasthamayi bend cheyyum — violet ettavum കൂടുതൽ, red ettavum kuravu.",
  },
  visualBoard: {
    boardTitle: "White light splitting through a prism",
    frames: [
      {
        id: "m1-f1",
        title: "Prism splits white light",
        teacherAction: "Draw a triangular prism; a white ray enters and a coloured band (VIBGYOR) leaves.",
        boardText: ["White light in → spectrum out", "Seven colours: V I B G Y O R"],
        diagramDescription: "Triangular prism with a single white ray entering and fanning into a coloured band on a screen.",
        imageUrl: "assets/textbook-figures/img_page49_idx3.png",
        studentFocus: "The prism separates, it does not add colours.",
      },
      {
        id: "m1-f2",
        title: "Deviation order",
        teacherAction: "Show violet bending most and red bending least on exit.",
        boardText: ["Violet: shortest λ → deviates most", "Red: longest λ → deviates least"],
        diagramDescription: "Two rays from the prism — violet steep, red shallow.",
        imageUrl: "assets/textbook-figures/img_page52_idx3.png",
        studentFocus: "More bending for shorter wavelength.",
      },
    ],
  },
  docDoeTrick: {
    title: "VIBGYOR — Violet bends most",
    trick: "Read VIBGYOR top-to-bottom: the first letter (Violet) bends most, the last (Red) bends least.",
    whyItWorks: "The colour order and the deviation order are the same list, so one word gives you both facts.",
  },
  keyNotes: [
          "Dispersion is like a train with seven colourful coaches, each coach is a colour, and they all come out when they pass through the machine.",
          "The colours always come in the same order, like a line of auto rickshaws, and we call this line the spectrum.",
          "The colours are VIBGYOR, like a recipe to make a tasty dish, and you must remember them in this order.",
          "Violet is like a fast runner, it has the shortest path, and red is like a slow runner, it has the longest path.",
          "When white light passes through the machine, violet bends the most, like a sharp turn on a busy road, and red bends the least, like a straight road."
        ],
  formulas: [],
  examAnswers: [
    {
      marks: 2,
      question: "What is dispersion of light? Name the colour that deviates the most through a prism.",
      answerPoints: ["Dispersion is the splitting of white light into its seven component colours.", "Violet deviates the most because it has the shortest wavelength."],
      keywords: ["dispersion", "component colours", "violet", "deviates most"],
      commonMistakes: ["Saying the prism adds colour", "Saying red deviates most"],
      boardStyleRewrite: "Dispersion is the splitting of white light into its component colours (VIBGYOR) as it passes through a prism. Violet deviates the most because it has the shortest wavelength.",
    },
  ],
  yourTurn: {
    prompt: "Define the spectrum and write the order of colours in it. (2 marks)",
    expectedAnswerPoints: ["The orderly arrangement of the component colours of white light is the spectrum", "Order: Violet, Indigo, Blue, Green, Yellow, Orange, Red"],
    hint: "Use the word 'orderly' and list VIBGYOR.",
  },
  correctionRubric: {
    maxMarks: 2,
    scoringPoints: [
      { point: "Defines the spectrum as the orderly arrangement of component colours", marks: 1, requiredKeywords: ["orderly", "component colours"] },
      { point: "Gives the correct VIBGYOR order", marks: 1, requiredKeywords: ["violet", "red"] },
    ],
    commonMissingParts: ["The word 'orderly'", "Correct colour order"],
    feedbackTemplate: "You wrote {covered}. Add {missing} for full marks.",
  },
  quiz: [
    {
      id: "m1-q1",
      type: "mcq",
      question: "Which colour deviates the most when white light passes through a prism?",
      options: ["Red", "Green", "Violet", "Yellow"],
      answer: "Violet",
      explanation: "Violet has the shortest wavelength, so it is refracted the most.",
      difficulty: "easy",
      tags: ["deviation", "violet"],
    },
    {
      id: "m1-q2",
      type: "short",
      question: "What name is given to the orderly band of colours obtained from white light?",
      answer: "The spectrum.",
      explanation: "The orderly arrangement of the component colours of white light is called the spectrum.",
      difficulty: "easy",
      tags: ["spectrum"],
    },
    {
      id: "m1-q3",
      type: "short",
      question: "Which has the longer wavelength — red light or violet light?",
      answer: "Red light.",
      explanation: "Red has the longest wavelength in the visible spectrum; violet has the shortest.",
      difficulty: "medium",
      tags: ["wavelength", "red"],
    },
  ],
  recap: {
    summary: [
              "Dispersion is like a key that unlocks the seven colours of white light, and we see VIBGYOR.",
              "The spectrum is like a big plate with all the colours in order, and it's beautiful to see.",
              "Violet is like a winner in a race, it bends the most, and red is like a slow starter, it bends the least."
            ],
    mustRemember: ["VIBGYOR order", "Shorter wavelength → more deviation"],
  },
  revisionSave: {
    flashcards: [
      { front: "What is dispersion?", back: "Splitting of white light into its component colours." },
      { front: "Colour order of the spectrum?", back: "Violet, Indigo, Blue, Green, Yellow, Orange, Red (VIBGYOR)." },
      { front: "Which colour deviates most?", back: "Violet (shortest wavelength)." },
    ],
    revisionNotes: ["White light = VIBGYOR", "Violet most deviated, red least"],
    weakAreaTags: ["dispersion", "spectrum"],
  },
  splitScreen: {
    left: { title: "Dispersion", imageUrl: "assets/textbook-figures/img_page52_idx3.png", caption: "Splitting of white light into constituent colours.", captionHighlight: "VIBGYOR" },
    right: { title: "Recombination", imageUrl: "assets/textbook-figures/img_page52_idx4.png", caption: "Two inverted prisms combine colours back to white light.", captionHighlight: "White Light" }
  },
  qualityFlags: { needsHumanReview: false },
});

// M2 — Recombination and the Rainbow
const M2: TuitionLessonSeed = colourSeed({
  missionId: "M2",
  missionTitle: "Recombination of Light and the Rainbow",
  goal: "Explain how the spectrum recombines to white light and how a rainbow forms in the sky.",
  estimatedMinutes: 35,
  contentType: "concept",
  tags: ["recombination", "rainbow", "water droplets", "total internal reflection", "refraction"],
  sourceRefs: [COLOURS_VISION_SOURCE],
  sourceStatus: "source_backed",
  canTeach: true,
  pyqEvidenceStatus: "not_curated",
  recall: {
    prompt: "You have seen a prism split white light. Can the separated colours be joined back into white light?",
    expectedPoints: ["Yes, using a second inverted prism", "The colours recombine into white light"],
    misconceptionCheck: "Students think a rainbow is just dispersion — it also needs reflection inside water droplets.",
  },
  teach: {
    teacherIntro: "Imagine a rainy day and you're standing under a coconut tree. Sunlight passes through raindrops, showing a beautiful rainbow in the sky! Now, let's learn how this happens. Sunlight is like a bundle of many colored threads. When they pass through tiny water drops, they get separated and we see a rainbow.",
    explanationBlocks: [
      {
        heading: "Recombination of the spectrum",
        explanation: "If the spectrum from one prism is passed through a second, inverted prism, the colours merge back into white light. This proves white light is a mixture of the seven colours.",
        keyTerms: ["recombination", "inverted prism", "white light"],
      },
      {
        heading: "How a rainbow forms",
        explanation: "Sunlight enters a water droplet and is refracted, then it is totally internally reflected at the back of the droplet, and refracted again as it leaves. These steps disperse the light into colours.",
        keyTerms: ["refraction", "total internal reflection", "dispersion", "water droplet"],
      },
      {
        heading: "Position of the observer",
        explanation: "A rainbow is seen when the Sun is behind the observer and the water droplets are in front. In the morning it appears in the west; in the evening, in the east.",
        keyTerms: ["Sun behind observer", "position"],
      },
    ],
    analogy: "Each raindrop is a tiny prism plus a mirror at the back — millions of them together paint the arc of colours.",
    malayalamSupport: "രണ്ടാമത്തെ തലകീഴായ പ്രിസം ഉപയോഗിച്ച് സ്പെക്ട്രം വീണ്ടും വെളുത്ത പ്രകാശമാക്കാം. മഴവില്ല്: ജലകണങ്ങളിൽ റിഫ്രാക്ഷൻ + പൂർണ്ണ ആന്തരിക പ്രതിഫലനം + ഡിസ്‌പേർഷൻ.",
    manglishSupport: "Randaamathe inverted prism vachu spectrum veendum white light aakkam. Rainbow: water droplet-il refraction + total internal reflection + dispersion.",
  },
  visualBoard: {
    boardTitle: "Recombination and rainbow formation",
    frames: [
      {
        id: "m2-f1",
        title: "Two-prism recombination",
        teacherAction: "Draw prism 1 splitting white light and an inverted prism 2 merging it back to white.",
        boardText: ["Prism 1: white → spectrum", "Inverted prism 2: spectrum → white"],
        diagramDescription: "Two prisms; the second inverted, output ray is white again.",
        imageUrl: "assets/textbook-figures/img_page52_idx4.png",
        studentFocus: "White light can be rebuilt from its colours.",
      },
      {
        id: "m2-f2",
        title: "Rainbow in a droplet",
        teacherAction: "Draw one water droplet: ray refracts in, reflects at back, refracts out as colours.",
        boardText: ["1. Refraction (enter)", "2. Total internal reflection (back)", "3. Refraction + dispersion (exit)"],
        diagramDescription: "Circle (droplet) with sunlight entering, reflecting off the inner back surface, leaving as a coloured fan.",
        imageUrl: "assets/textbook-figures/img_page56_idx1.png",
        studentFocus: "Rainbow needs refraction + internal reflection + dispersion.",
      },
    ],
  },
  docDoeTrick: {
    title: "Rainbow = R-R-R",
    trick: "Refraction → Reflection (total internal) → Refraction, with dispersion throughout.",
    whyItWorks: "Three R-steps in order is exactly the droplet sequence examiners want.",
  },
  keyNotes: [
          "Do you know how an auto rickshaw turns? An inverted prism is like that. It takes different colors and mixes them back into white light.",
          "Making a dish needs many spices, right? White light is like a mix of seven colors. It's like making a yummy dish with many spices!",
          "A rainbow is like a football game with three players: refraction, total internal reflection, and dispersion. They all help create the beautiful colors in the sky.",
          "To see a rainbow, you need the Sun behind you, like a goalkeeper in a football game. Then, you can see the rainbow in front of you.",
          "In the morning, the rainbow is like a friend waiting for you in the west. In the evening, it's like another friend waiting for you in the east."
        ],
  formulas: [],
  examAnswers: [
    {
      marks: 3,
      question: "Explain how a rainbow is formed in the sky.",
      answerPoints: [
        "Sunlight enters tiny water droplets and is refracted.",
        "It undergoes total internal reflection at the back of the droplet.",
        "It is refracted again while leaving, dispersing into the seven colours to form the rainbow.",
      ],
      keywords: ["water droplets", "refraction", "total internal reflection", "dispersion"],
      commonMistakes: ["Omitting total internal reflection", "Saying only 'reflection' by a mirror"],
      boardStyleRewrite: "Sunlight entering a water droplet is refracted, then totally internally reflected at the back, and refracted again as it leaves. These steps disperse the light into its seven colours, forming a rainbow.",
    },
  ],
  yourTurn: {
    prompt: "How is it shown that white light is a mixture of colours? (2 marks)",
    expectedAnswerPoints: ["A prism disperses white light into the spectrum", "An inverted prism recombines the spectrum into white light"],
    hint: "Mention splitting by one prism and joining by an inverted prism.",
  },
  correctionRubric: {
    maxMarks: 3,
    scoringPoints: [
      { point: "Sunlight refracts on entering the droplet", marks: 1, requiredKeywords: ["refract", "droplet"] },
      { point: "Total internal reflection at the back", marks: 1, requiredKeywords: ["total internal reflection"] },
      { point: "Refraction and dispersion on exit forms colours", marks: 1, requiredKeywords: ["dispersion", "colours"] },
    ],
    commonMissingParts: ["Total internal reflection step", "Dispersion into seven colours"],
    feedbackTemplate: "You explained {covered}. Add {missing} to reach full marks.",
  },
  quiz: [
    {
      id: "m2-q1",
      type: "mcq",
      question: "Which process at the back of a water droplet is essential for a rainbow?",
      options: ["Absorption", "Total internal reflection", "Diffraction", "Polarisation"],
      answer: "Total internal reflection",
      explanation: "Light is totally internally reflected at the back surface of the droplet before leaving.",
      difficulty: "medium",
      tags: ["total internal reflection", "rainbow"],
    },
    {
      id: "m2-q2",
      type: "short",
      question: "Where should the Sun be for you to see a rainbow?",
      answer: "Behind the observer (with droplets in front).",
      explanation: "A rainbow is seen only when the Sun is behind you and water droplets are ahead.",
      difficulty: "medium",
      tags: ["position", "rainbow"],
    },
  ],
  recap: {
    summary: [
              "An inverted prism is like a special tool that mixes all colors back into white light, like a chef mixing all the ingredients for a perfect dish.",
              "A rainbow is like a big recipe that needs three main ingredients: refraction, total internal reflection, and dispersion. When they all come together, you get a beautiful rainbow!",
              "To see a rainbow, just remember: the Sun should be behind you, like a big umbrella on a rainy day."
            ],
    mustRemember: ["Rainbow's three steps in a droplet", "White light is a mixture of seven colours"],
  },
  revisionSave: {
    flashcards: [
      { front: "How is the spectrum recombined?", back: "By passing it through a second, inverted prism." },
      { front: "Three steps of rainbow formation?", back: "Refraction, total internal reflection, refraction with dispersion." },
      { front: "Sun's position for a rainbow?", back: "Behind the observer." },
    ],
    revisionNotes: ["Recombination proves white = mixture", "Rainbow needs internal reflection, not just dispersion"],
    weakAreaTags: ["rainbow", "recombination"],
  },
  quizTimer: {
    question: "Which colour deviates the most during dispersion?",
    options: ["Red", "Violet", "Green", "Yellow"],
    answer: "Violet",
    countdownSeconds: 1.5
  },
  qualityFlags: { needsHumanReview: false },
});

// M3 — The Electromagnetic Spectrum
const M3: TuitionLessonSeed = colourSeed({
  missionId: "M3",
  missionTitle: "The Electromagnetic Spectrum",
  goal: "Identify the invisible radiations beyond the visible spectrum and their order.",
  estimatedMinutes: 30,
  contentType: "concept",
  tags: ["electromagnetic spectrum", "infrared", "ultraviolet", "visible light", "wavelength"],
  sourceRefs: [COLOURS_VISION_SOURCE],
  sourceStatus: "source_backed",
  canTeach: true,
  pyqEvidenceStatus: "not_curated",
  recall: {
    prompt: "Besides the colours we can see, sunlight also contains radiations we cannot see. Can you name any?",
    expectedPoints: ["Infrared (heat)", "Ultraviolet (causes tanning/sunburn)"],
    misconceptionCheck: "Students think visible light is all of sunlight — it is only a small part of the whole spectrum.",
  },
  teach: {
    teacherIntro: "Light is like the coconut trees you see on our roads. There are many things around you that you can't see, like the wind or the smell of food. This is like the big group of radiations we call the electromagnetic spectrum.",
    explanationBlocks: [
      {
        heading: "What the electromagnetic spectrum is",
        explanation: "The orderly distribution of electromagnetic radiations is called the electromagnetic spectrum. It ranges from radio waves to gamma rays.",
        keyTerms: ["electromagnetic spectrum", "radiations"],
      },
      {
        heading: "Just beyond the visible band",
        explanation: "Beyond red (longer wavelength) lies infrared radiation, felt as heat. Beyond violet (shorter wavelength) lies ultraviolet radiation.",
        keyTerms: ["infrared", "ultraviolet", "beyond red", "beyond violet"],
      },
      {
        heading: "Why ultraviolet is harmful",
        explanation: "Excess ultraviolet radiation from the Sun can damage the skin and eyes. The ozone layer absorbs most of it and protects us.",
        keyTerms: ["ultraviolet harm", "ozone layer"],
      },
    ],
    analogy: "Visible light is one octave on a long piano — infrared and ultraviolet are the neighbouring keys we cannot see.",
    malayalamSupport: "കാണാവുന്ന പ്രകാശം വൈദ്യുതകാന്തിക സ്പെക്ട്രത്തിന്റെ ഒരു ചെറിയ ഭാഗം മാത്രം. ചുവപ്പിനപ്പുറം ഇൻഫ്രാറെഡ് (ചൂട്), വയലറ്റിനപ്പുറം അൾട്രാവയലറ്റ്.",
    manglishSupport: "Visible light = electromagnetic spectrum-inte oru cheriya bhagam maathram. Red-inappuram infrared (heat), violet-inappuram ultraviolet.",
  },
  visualBoard: {
    boardTitle: "The electromagnetic spectrum",
    frames: [
      {
        id: "m3-f1",
        title: "Visible band in the whole spectrum",
        teacherAction: "Draw a long bar; mark the narrow visible (VIBGYOR) band in the middle.",
        boardText: ["Radio → Microwave → Infrared → Visible → Ultraviolet → X-ray → Gamma", "Visible is only a thin slice"],
        diagramDescription: "Horizontal spectrum bar with a small labelled VIBGYOR window.",
        imageUrl: "assets/textbook-figures/img_page56_idx2.png",
        studentFocus: "Visible light is a small part of the whole spectrum.",
      },
      {
        id: "m3-f2",
        title: "Neighbours of the visible band",
        teacherAction: "Show infrared just beyond red and ultraviolet just beyond violet.",
        boardText: ["Beyond red = infrared (heat)", "Beyond violet = ultraviolet (harmful in excess)"],
        studentFocus: "IR beyond red, UV beyond violet.",
      },
    ],
  },
  docDoeTrick: {
    title: "IR-outside-Red, UV-outside-Violet",
    trick: "The radiation next to a colour starts with the colour's side: infraRED sits past red, ultraVIOLET sits past violet.",
    whyItWorks: "The name literally tells you which end of the visible band it borders.",
  },
  keyNotes: [
          "Think of a big football match with many players. Each player has a special job. The electromagnetic spectrum is like a team with many players, each doing a special job in order.",
          "The light we can see is like a small auto rickshaw on a big road. It's just a small part of the whole road, which is the electromagnetic spectrum.",
          "Infrared radiation is like the warm feeling you get from sitting near a fire or eating hot food. It's just beyond the red light we can see.",
          "Ultraviolet radiation is like the strong monsoon rain that can be too much for our skin. It's just beyond the violet light we can see, and too much of it can harm us.",
          "The ozone layer is like a strong umbrella that protects us from the harmful ultraviolet radiation. It keeps us safe like a cool breeze on a hot day."
        ],
  formulas: [],
  examAnswers: [
    {
      marks: 2,
      question: "Name the invisible radiations found on either side of the visible spectrum.",
      answerPoints: ["Beyond the red end: infrared radiation.", "Beyond the violet end: ultraviolet radiation."],
      keywords: ["infrared", "ultraviolet", "beyond red", "beyond violet"],
      commonMistakes: ["Swapping infrared and ultraviolet", "Naming X-rays as the immediate neighbour"],
      boardStyleRewrite: "The invisible radiation beyond the red end is infrared radiation, and beyond the violet end is ultraviolet radiation.",
    },
  ],
  yourTurn: {
    prompt: "What is the electromagnetic spectrum, and why is ultraviolet radiation harmful? (3 marks)",
    expectedAnswerPoints: ["It is the orderly distribution of electromagnetic radiations", "Ultraviolet in excess damages skin and eyes", "The ozone layer absorbs most of it"],
    hint: "Define the spectrum, then state the harm and the protection.",
  },
  correctionRubric: {
    maxMarks: 3,
    scoringPoints: [
      { point: "Defines the electromagnetic spectrum", marks: 1, requiredKeywords: ["electromagnetic", "radiations"] },
      { point: "States ultraviolet harms skin/eyes", marks: 1, requiredKeywords: ["ultraviolet", "harm"] },
      { point: "Mentions the ozone layer protection", marks: 1, requiredKeywords: ["ozone"] },
    ],
    commonMissingParts: ["The ozone layer", "That visible light is only part of the spectrum"],
    feedbackTemplate: "You wrote {covered}. Add {missing} for full marks.",
  },
  quiz: [
    {
      id: "m3-q1",
      type: "mcq",
      question: "The invisible radiation just beyond the red end of the spectrum is",
      options: ["Ultraviolet", "Infrared", "X-ray", "Gamma ray"],
      answer: "Infrared",
      explanation: "Infrared lies beyond red (longer wavelength) and is felt as heat.",
      difficulty: "easy",
      tags: ["infrared"],
    },
    {
      id: "m3-q2",
      type: "short",
      question: "Which layer protects us from most of the Sun's ultraviolet radiation?",
      answer: "The ozone layer.",
      explanation: "The ozone layer absorbs most incoming ultraviolet radiation.",
      difficulty: "medium",
      tags: ["ozone", "ultraviolet"],
    },
  ],
  recap: {
    summary: [
              "Remember, the light we can see is like a small part of a big recipe book. It's just a small part of the electromagnetic spectrum.",
              "Infrared is like the heat from cooking, just beyond the red light we can see. Ultraviolet is like the strong rain, just beyond the violet light.",
              "The ozone layer is like a protector that keeps us safe from too much ultraviolet radiation. It's like a warm blanket on a cold night."
            ],
    mustRemember: ["IR = heat, beyond red", "UV harmful, beyond violet"],
  },
  revisionSave: {
    flashcards: [
      { front: "Radiation beyond red?", back: "Infrared (felt as heat)." },
      { front: "Radiation beyond violet?", back: "Ultraviolet." },
      { front: "Protection from UV?", back: "The ozone layer." },
    ],
    revisionNotes: ["Order: radio…IR…visible…UV…X-ray…gamma", "UV harmful in excess"],
    weakAreaTags: ["electromagnetic spectrum", "infrared ultraviolet"],
  },
  qualityFlags: { needsHumanReview: false },
});

// M4 — Primary, Secondary and Complementary Colours
const M4: TuitionLessonSeed = colourSeed({
  missionId: "M4",
  missionTitle: "Primary, Secondary and Complementary Colours of Light",
  goal: "Distinguish primary, secondary and complementary colours of light and how they mix to give white.",
  estimatedMinutes: 30,
  contentType: "concept",
  tags: ["primary colours", "secondary colours", "complementary colours", "additive mixing", "white light"],
  sourceRefs: [COLOURS_VISION_SOURCE],
  sourceStatus: "source_backed",
  canTeach: true,
  pyqEvidenceStatus: "not_curated",
  recall: {
    prompt: "A TV or mobile screen makes every colour using only three colours of light. Which three do you think they are?",
    expectedPoints: ["Red, green and blue", "Mixing these gives other colours"],
    misconceptionCheck: "Students confuse primary colours of light (red, green, blue) with the paint primaries they learned in art (red, yellow, blue).",
  },
  teach: {
    teacherIntro: "You know how you mix colours to paint a beautiful picture? Mixing colours of light is like that, but we call it additive mixing. It's like monsoon rain bringing all the colours of nature together.",
    explanationBlocks: [
      {
        heading: "Primary colours of light",
        explanation: "The primary colours of light are red, green and blue. They cannot be produced by mixing other coloured lights.",
        keyTerms: ["primary colours", "red green blue"],
      },
      {
        heading: "Secondary colours",
        explanation: "Mixing two primary colours gives a secondary colour: red + green = yellow, green + blue = cyan, blue + red = magenta.",
        keyTerms: ["secondary colours", "yellow", "cyan", "magenta"],
      },
      {
        heading: "Complementary colours",
        explanation: "Two colours that together produce white light are complementary. A primary and the secondary made from the other two are complementary — for example, red and cyan.",
        keyTerms: ["complementary colours", "white light"],
      },
    ],
    analogy: "Three spotlights — red, green, blue — overlapping on a wall: where all three meet you get white; where two meet you get a secondary colour.",
    malayalamSupport: "പ്രകാശത്തിന്റെ പ്രാഥമിക നിറങ്ങൾ: ചുവപ്പ്, പച്ച, നീല. രണ്ട് പ്രാഥമിക നിറങ്ങൾ ചേർത്താൽ ദ്വിതീയ നിറം. വെളുപ്പ് നൽകുന്ന രണ്ട് നിറങ്ങൾ പരസ്പര പൂരകങ്ങൾ (complementary).",
    manglishSupport: "Prakashathinte primary colours: red, green, blue. Randu primary koodiyaal secondary. White nൽകുന്ന randu colour = complementary (eg. red + cyan).",
  },
  visualBoard: {
    boardTitle: "Mixing colours of light",
    frames: [
      {
        id: "m4-f1",
        title: "Three overlapping lights",
        teacherAction: "Draw three overlapping circles: red, green, blue; label the overlaps.",
        boardText: ["R + G = Yellow", "G + B = Cyan", "B + R = Magenta", "R + G + B = White"],
        diagramDescription: "Venn-style overlap of red, green, blue circles with white in the centre.",
        imageUrl: "assets/textbook-figures/img_page59_idx2.png",
        studentFocus: "Two primaries → secondary; all three → white.",
      },
      {
        id: "m4-f2",
        title: "Complementary pairs",
        teacherAction: "Pair each primary with the secondary that completes white.",
        boardText: ["Red + Cyan = White", "Green + Magenta = White", "Blue + Yellow = White"],
        studentFocus: "Complementary colours add up to white.",
      },
    ],
  },
  docDoeTrick: {
    title: "RGB makes White",
    trick: "Red + Green + Blue = White; each primary's complement is the mix of the other two.",
    whyItWorks: "One rule (all three = white) instantly gives every complementary pair.",
  },
  keyNotes: [
          "Primary colours of light are like the wheels of an auto rickshaw - red, green and blue. They help us make all other colours.",
          "Mixing coloured lights is like playing with your friends. When you mix different colours, you get a new colour, that's additive mixing.",
          "Secondary colours are like yummy dishes your mom makes. Red + green = yellow, like a ripe mango. Green + blue = cyan, like a clear sky. Blue + red = magenta, like a beautiful sunset.",
          "Red + green + blue = white light, like all players in a football team working together.",
          "Two colours that give white are like two friends who are complementary, like red and cyan. They work together to make everything beautiful."
        ],
  formulas: [],
  examAnswers: [
    {
      marks: 2,
      question: "Name the primary colours of light and the colour obtained when all three are mixed.",
      answerPoints: ["The primary colours of light are red, green and blue.", "Mixing all three produces white light."],
      keywords: ["red", "green", "blue", "white light"],
      commonMistakes: ["Writing red, yellow, blue (paint primaries)", "Saying the mixture is black"],
      boardStyleRewrite: "The primary colours of light are red, green and blue. When all three are mixed in equal amounts, white light is produced.",
    },
  ],
  yourTurn: {
    prompt: "What are complementary colours? Give one pair. (2 marks)",
    expectedAnswerPoints: ["Two colours that together give white light", "Example: red and cyan (or blue and yellow, green and magenta)"],
    hint: "Define using 'white light' and give one valid pair.",
  },
  correctionRubric: {
    maxMarks: 2,
    scoringPoints: [
      { point: "Defines complementary colours as giving white light", marks: 1, requiredKeywords: ["white light"] },
      { point: "Gives a correct complementary pair", marks: 1, requiredKeywords: ["red", "cyan"] },
    ],
    commonMissingParts: ["The phrase 'white light'", "A valid pair"],
    feedbackTemplate: "You wrote {covered}. Add {missing} for full marks.",
  },
  quiz: [
    {
      id: "m4-q1",
      type: "mcq",
      question: "The primary colours of light are",
      options: ["Red, yellow, blue", "Red, green, blue", "Cyan, magenta, yellow", "Violet, green, red"],
      answer: "Red, green, blue",
      explanation: "Red, green and blue are the primary colours of light.",
      difficulty: "easy",
      tags: ["primary colours"],
    },
    {
      id: "m4-q2",
      type: "short",
      question: "Which secondary colour is formed by mixing green and blue light?",
      answer: "Cyan.",
      explanation: "Green + blue light gives cyan.",
      difficulty: "medium",
      tags: ["secondary colours", "cyan"],
    },
    {
      id: "m4-q3",
      type: "short",
      question: "Which colour is complementary to red light?",
      answer: "Cyan.",
      explanation: "Red + cyan gives white, so they are complementary.",
      difficulty: "exam",
      tags: ["complementary colours"],
    },
  ],
  recap: {
    summary: [
              "Primary colours of light: red, green, blue, like the main ingredients in your favourite recipe.",
              "Two primaries → a secondary colour, like mixing two spices to get a new flavour.",
              "Complementary colours add to white, like a good cook mixing the right ingredients to make a delicious dish."
            ],
    mustRemember: ["R+G+B = white", "Light primaries ≠ paint primaries"],
  },
  revisionSave: {
    flashcards: [
      { front: "Primary colours of light?", back: "Red, green, blue." },
      { front: "Red + green light = ?", back: "Yellow." },
      { front: "Complement of blue light?", back: "Yellow (blue + yellow = white)." },
    ],
    revisionNotes: ["Additive mixing: R+G+B = white", "Secondary: yellow, cyan, magenta"],
    weakAreaTags: ["primary colours", "complementary colours"],
  },
  hotspot: {
    title: "Scattering vs Wavelength",
    type: "trap",
    formula: "Scattering ∝ 1 / λ⁴",
    importantNote: "Smaller wavelength scatters MORE! Violet/Blue scatter the most."
  },
  qualityFlags: { needsHumanReview: false },
});

// M5 — Colours of Objects and Colour Filters
const M5: TuitionLessonSeed = colourSeed({
  missionId: "M5",
  missionTitle: "Colours of Objects and Colour Filters",
  goal: "Explain why objects appear coloured and how coloured light and filters change that appearance.",
  estimatedMinutes: 30,
  contentType: "concept",
  tags: ["colour of objects", "reflection", "absorption", "colour filter", "transmission"],
  sourceRefs: [COLOURS_VISION_SOURCE],
  sourceStatus: "source_backed",
  canTeach: true,
  pyqEvidenceStatus: "not_curated",
  recall: {
    prompt: "A leaf looks green in sunlight. What is happening to the other colours of white light falling on it?",
    expectedPoints: ["The leaf reflects green", "It absorbs the other colours"],
    misconceptionCheck: "Students think an object 'has' colour on its own — its colour depends on which light it reflects and which light falls on it.",
  },
  teach: {
    teacherIntro: "Listen, do you remember how the coconut tree looks green in sunlight? It's because it reflects green light, like a mirror. And when you shine a red torch on it, the tree looks red, like magic! So, the colour we see depends on the light and what the tree reflects.",
    explanationBlocks: [
      {
        heading: "Why objects appear coloured",
        explanation: "In white light, an object reflects its own colour and absorbs the rest. A red flower reflects red and absorbs the other colours; that is why it looks red.",
        keyTerms: ["reflect own colour", "absorb others"],
      },
      {
        heading: "Objects under coloured light",
        explanation: "A red flower in green light looks dark/black, because there is no red light to reflect. A white object shows the colour of the light falling on it.",
        keyTerms: ["coloured light", "appears dark"],
      },
      {
        heading: "Colour filters",
        explanation: "A colour filter transmits its own colour and absorbs the others. A red filter lets only red light pass through.",
        keyTerms: ["filter", "transmit", "absorb"],
      },
    ],
    analogy: "An object is like a fussy mirror — it only sends back the colour it 'likes' and swallows the rest.",
    malayalamSupport: "വെളുത്ത പ്രകാശത്തിൽ വസ്തു അതിന്റെ സ്വന്തം നിറം പ്രതിഫലിപ്പിക്കുന്നു, ബാക്കി ആഗിരണം ചെയ്യുന്നു. ഫിൽട്ടർ അതിന്റെ നിറം മാത്രം കടത്തിവിടുന്നു.",
    manglishSupport: "White light-il vasthu athinte swantham colour reflect cheyyum, baaki absorb cheyyum. Filter athinte colour maathram കടത്തിവിടും (transmit).",
  },
  visualBoard: {
    boardTitle: "How we see the colour of things",
    frames: [
      {
        id: "m5-f1",
        title: "Reflect own colour",
        teacherAction: "Draw white light on a red apple; red ray reflects, others absorbed.",
        boardText: ["Red apple: reflects red", "Absorbs the rest → looks red"],
        diagramDescription: "White ray hitting an apple; only a red arrow bounces back.",
        studentFocus: "Object colour = reflected colour.",
      },
      {
        id: "m5-f2",
        title: "Filter transmits its colour",
        teacherAction: "Draw white light through a red filter; only red passes.",
        boardText: ["Red filter → passes red", "Blocks other colours"],
        diagramDescription: "White ray into a red rectangle; only red ray exits.",
        studentFocus: "Filter transmits its own colour, absorbs others.",
      },
    ],
  },
  docDoeTrick: {
    title: "Object Reflects, Filter Transmits",
    trick: "An object shows the colour it Reflects; a filter shows the colour it Transmits — both absorb the rest.",
    whyItWorks: "One contrast (reflect vs transmit) covers both cases without confusion.",
  },
  keyNotes: [
          "Imagine you're wearing a green shirt, okay? It looks green because it reflects green light and absorbs other colours, like a football team's green jerseys. It's like a special paint that only shines green!",
          "Remember the flavour of a dish? If you add a lot of chilli, it's spicy. That's like an object reflecting red light - it looks red to us, like a ripe tomato! And just like how a dash of colour can make a dish taste different, light can change how an object looks.",
          "Do you recall the monsoon rain? Sometimes the sky is dark, right? That's because the sun's light is blocked, like an umbrella in the rain. And if an object's colour isn't in the light, it looks dark, like a dark cloud on a rainy day.",
          "A colour filter is like a special auto rickshaw window. It only lets its own colour pass through, like a green window letting only green light in, and blocks the rest. It's like wearing sunglasses to filter out the sun's strong light.",
          "A white object is like a blank piece of paper. It shows the colour of the ink we use, or the light that falls on it, like a white shirt looking pink under a pink light. It's like drawing on a white sheet of paper - you can make it look any colour you want!"
        ],
  formulas: [],
  examAnswers: [
    {
      marks: 2,
      question: "Why does a red flower appear black in green light?",
      answerPoints: ["Green light has no red component.", "The red flower can reflect only red, so with no red available it reflects nothing and appears black."],
      keywords: ["reflect red", "no red", "absorbs", "appears black"],
      commonMistakes: ["Saying the flower turns green", "Not mentioning that there is no red light"],
      boardStyleRewrite: "A red flower reflects only red light and absorbs the rest. Green light contains no red, so the flower has nothing to reflect and appears black.",
    },
  ],
  yourTurn: {
    prompt: "What does a red colour filter do to white light passing through it? (2 marks)",
    expectedAnswerPoints: ["It transmits (passes) only red light", "It absorbs the other colours"],
    hint: "Use 'transmit' and 'absorb'.",
  },
  correctionRubric: {
    maxMarks: 2,
    scoringPoints: [
      { point: "States the filter transmits only red", marks: 1, requiredKeywords: ["transmit", "red"] },
      { point: "States it absorbs the other colours", marks: 1, requiredKeywords: ["absorb"] },
    ],
    commonMissingParts: ["The word 'transmit'", "That other colours are absorbed"],
    feedbackTemplate: "You wrote {covered}. Add {missing} for full marks.",
  },
  quiz: [
    {
      id: "m5-q1",
      type: "mcq",
      question: "A green leaf looks green because it",
      options: ["absorbs green and reflects the rest", "reflects green and absorbs the rest", "transmits green light", "emits green light"],
      answer: "reflects green and absorbs the rest",
      explanation: "An object appears the colour it reflects.",
      difficulty: "easy",
      tags: ["reflection", "colour of objects"],
    },
    {
      id: "m5-q2",
      type: "short",
      question: "What colour does a blue object appear in red light?",
      answer: "Black (or very dark).",
      explanation: "Red light has no blue to reflect, so the blue object appears dark.",
      difficulty: "exam",
      tags: ["coloured light"],
    },
  ],
  recap: {
    summary: [
              "Objects are like still ponds, reflecting their own colour and absorbing the rest, like a mirror reflecting the trees around it.",
              "Under coloured light, an object may look dark, like a room with closed curtains on a sunny day.",
              "Filters are like special lenses, transmitting their own colour, like a camera filter making a picture look more green or blue. It's like using a special lens to capture the perfect shot!"
            ],
    mustRemember: ["Colour seen = colour reflected", "Filter transmits, object reflects"],
  },
  revisionSave: {
    flashcards: [
      { front: "Why does a red apple look red?", back: "It reflects red and absorbs the other colours." },
      { front: "What does a colour filter do?", back: "Transmits its own colour, absorbs the rest." },
      { front: "Red object in green light?", back: "Looks black — no red to reflect." },
    ],
    revisionNotes: ["Object → reflects own colour", "Filter → transmits own colour"],
    weakAreaTags: ["colour of objects", "colour filter"],
  },
  qualityFlags: { needsHumanReview: false },
});

// M6 — Scattering of Light: Blue Sky and Red Sun
const M6: TuitionLessonSeed = colourSeed({
  missionId: "M6",
  missionTitle: "Scattering of Light: Blue Sky and Red Sun",
  goal: "Use scattering of light to explain the blue colour of the sky and the red Sun at sunrise and sunset.",
  estimatedMinutes: 30,
  contentType: "concept",
  tags: ["scattering", "Tyndall effect", "blue sky", "red sun", "wavelength"],
  sourceRefs: [COLOURS_VISION_SOURCE],
  sourceStatus: "source_backed",
  canTeach: true,
  pyqEvidenceStatus: "not_curated",
  recall: {
    prompt: "Why is the sky blue during the day but the Sun looks reddish at sunset?",
    expectedPoints: ["Something happens to sunlight in the atmosphere", "Blue and red behave differently"],
    misconceptionCheck: "Students think the sky is blue because it reflects the sea — it is actually due to scattering of sunlight by the atmosphere.",
  },
  teach: {
    teacherIntro: "Think of sunlight like rain falling on a crowded market. The tiny water drops are like dust particles in the air. The blue light is like a fast runner who gets scattered by the crowd, while the red light is like a slow walker who keeps going straight. That's why the sky looks blue and the sun looks red during sunrise and sunset.",
    explanationBlocks: [
      {
        heading: "Scattering of light",
        explanation: "When light falls on very small particles it is scattered (spread) in all directions. Shorter wavelengths (blue, violet) scatter much more than longer wavelengths (red).",
        keyTerms: ["scattering", "small particles", "shorter wavelength scatters more"],
      },
      {
        heading: "Why the sky is blue",
        explanation: "Air molecules scatter the blue part of sunlight most, so scattered blue light reaches our eyes from all over the sky, making it look blue.",
        keyTerms: ["blue sky", "air molecules"],
      },
      {
        heading: "Why the Sun looks red at sunrise/sunset",
        explanation: "At sunrise and sunset light travels a long path through the atmosphere. Most blue is scattered away, so mainly red and orange reach us and the Sun appears red.",
        keyTerms: ["long path", "red sun", "blue scattered away"],
      },
    ],
    analogy: "Blue light is like small, easily jostled marbles — bumped in every direction; red light is like heavy balls that mostly plough straight through.",
    malayalamSupport: "ചെറിയ കണങ്ങളിൽ പ്രകാശം വിസരണം (scattering) ചെയ്യുന്നു. നീല കൂടുതൽ വിസരണം ചെയ്യുന്നു → ആകാശം നീല. സൂര്യോദയത്തിലും അസ്തമയത്തിലും നീല വിസരിച്ചു പോകുന്നു → സൂര്യൻ ചുവപ്പ്.",
    manglishSupport: "Cheriya particles-il light scatter cheyyum. Blue kooduthal scatter → sky blue. Sunrise/sunset-il blue scatter aayi പോകുന്നു → sun red.",
  },
  visualBoard: {
    boardTitle: "Scattering explains sky and Sun colour",
    frames: [
      {
        id: "m6-f1",
        title: "Blue sky",
        teacherAction: "Draw the Sun overhead; air molecules scatter blue rays toward the observer.",
        boardText: ["Air scatters blue most", "Scattered blue → sky looks blue"],
        diagramDescription: "Sun above atmosphere; blue rays scattering in all directions to an observer.",
        studentFocus: "Blue scatters most → blue sky.",
      },
      {
        id: "m6-f2",
        title: "Red Sun at sunset",
        teacherAction: "Draw the Sun low on the horizon; a long path through the atmosphere.",
        boardText: ["Long path → blue scattered away", "Mostly red reaches eye → red Sun"],
        diagramDescription: "Low Sun with a long slanting path through a thick atmosphere; red ray reaching the eye.",
        studentFocus: "Long path removes blue → red Sun.",
      },
    ],
  },
  docDoeTrick: {
    title: "Blue Scatters, Red Survives",
    trick: "Blue scatters most (blue sky); on a long path the blue is scattered away, so red survives (red Sun).",
    whyItWorks: "One idea — shorter wavelength scatters more — answers both the sky and the Sun questions.",
  },
  keyNotes: [
          "Scattering is like throwing a stone into a calm lake. The water waves spread out and that's what light does when it hits tiny particles in the air.",
          "Remember, blue light is like a quick soccer player who gets easily scattered by others. Red light is like a slow player who keeps going straight.",
          "The sky looks blue because the air is like a big cooking pot that mixes and scatters the blue light the most.",
          "During sunrise and sunset, the light has to travel a long distance through the air, like a big monsoon cloud that covers the whole sky.",
          "On this long path, the blue light is scattered away, like raindrops falling from the cloud, so the sun looks red."
        ],
  formulas: [],
  examAnswers: [
    {
      marks: 3,
      question: "Why does the Sun appear red at sunrise and sunset?",
      answerPoints: [
        "At sunrise and sunset, sunlight travels a long path through the atmosphere.",
        "Blue and shorter wavelengths are scattered away along this long path.",
        "Mostly red and orange light reaches our eyes, so the Sun appears red.",
      ],
      keywords: ["long path", "scattered away", "red", "atmosphere"],
      commonMistakes: ["Not mentioning the long path", "Saying red is scattered most"],
      boardStyleRewrite: "At sunrise and sunset, sunlight travels a long path through the atmosphere. The shorter blue wavelengths are scattered away, so mainly red light reaches us and the Sun appears red.",
    },
  ],
  yourTurn: {
    prompt: "Explain why the daytime sky appears blue. (2 marks)",
    expectedAnswerPoints: ["Air molecules scatter shorter (blue) wavelengths the most", "This scattered blue light reaches our eyes from all directions"],
    hint: "Use 'scattering' and 'blue scatters most'.",
  },
  correctionRubric: {
    maxMarks: 2,
    scoringPoints: [
      { point: "States air scatters blue (shorter wavelength) most", marks: 1, requiredKeywords: ["scatter", "blue"] },
      { point: "Scattered blue reaches the eye from all around", marks: 1, requiredKeywords: ["reaches", "eye"] },
    ],
    commonMissingParts: ["The word 'scattering'", "That blue scatters most"],
    feedbackTemplate: "You wrote {covered}. Add {missing} for full marks.",
  },
  quiz: [
    {
      id: "m6-q1",
      type: "mcq",
      question: "The blue colour of the sky is due to",
      options: ["reflection from the sea", "scattering of sunlight by the atmosphere", "dispersion by clouds", "absorption of red light"],
      answer: "scattering of sunlight by the atmosphere",
      explanation: "Air scatters shorter (blue) wavelengths the most.",
      difficulty: "easy",
      tags: ["scattering", "blue sky"],
    },
    {
      id: "m6-q2",
      type: "short",
      question: "Which colour of light is scattered the most by the atmosphere?",
      answer: "Blue (shorter wavelength).",
      explanation: "Shorter wavelengths scatter more, so blue scatters most.",
      difficulty: "medium",
      tags: ["scattering", "wavelength"],
    },
  ],
  recap: {
    summary: [
              "Scattering is like spreading out light with small particles, like throwing seeds from a coconut tree.",
              "Blue light scatters the most, so our sky looks blue, like a big blue umbrella.",
              "When light travels a long path, like a monsoon rain cloud, the blue light is scattered away, so the sun looks red, like a beautiful sunset."
            ],
    mustRemember: ["Shorter wavelength scatters more", "Sunrise/sunset: long path → red Sun"],
  },
  revisionSave: {
    flashcards: [
      { front: "Why is the sky blue?", back: "Air scatters blue light the most." },
      { front: "Why is the Sun red at sunset?", back: "Long path scatters blue away, leaving red." },
      { front: "Which colour scatters most?", back: "Blue (shorter wavelength)." },
    ],
    revisionNotes: ["Scattering ∝ shorter wavelength", "Blue sky + red Sun = same rule"],
    weakAreaTags: ["scattering", "blue sky red sun"],
  },
  qualityFlags: { needsHumanReview: false },
});

// M7 — Structure of the Human Eye
const M7: TuitionLessonSeed = colourSeed({
  missionId: "M7",
  missionTitle: "Structure and Working of the Human Eye",
  goal: "Label the main parts of the human eye and describe how a clear image forms on the retina.",
  estimatedMinutes: 35,
  contentType: "diagram",
  tags: ["human eye", "retina", "cornea", "iris", "pupil", "ciliary muscles", "image formation"],
  sourceRefs: [COLOURS_VISION_SOURCE],
  sourceStatus: "source_backed",
  canTeach: true,
  pyqEvidenceStatus: "not_curated",
  recall: {
    prompt: "The eye works like a camera. Which part of the eye do you think acts like the camera's lens, and which like its screen?",
    expectedPoints: ["The eye lens acts like the camera lens", "The retina acts like the screen"],
    misconceptionCheck: "Students think the image on the retina is upright — it is actually real, inverted and diminished.",
  },
  teach: {
    teacherIntro: "Think of your eye like a camera. It helps you see the world. Light from outside comes into your eye and falls on a special screen. Let's learn about each part of the eye.",
    explanationBlocks: [
      {
        heading: "Front parts: cornea, iris, pupil",
        explanation: "Light first enters through the transparent cornea. The iris is the coloured ring that controls the pupil, the opening that adjusts how much light enters.",
        keyTerms: ["cornea", "iris", "pupil"],
      },
      {
        heading: "Lens and ciliary muscles",
        explanation: "The eye lens is a convex lens held by ciliary muscles. These muscles change the lens shape to focus objects at different distances.",
        keyTerms: ["eye lens", "ciliary muscles"],
      },
      {
        heading: "Retina and the image",
        explanation: "The retina is the light-sensitive screen at the back. It has rods and cones and is connected to the brain by the optic nerve. The image formed on it is real, inverted and diminished.",
        keyTerms: ["retina", "rods and cones", "optic nerve", "real inverted diminished"],
      },
    ],
    analogy: "Cornea + lens = the camera's lens system; iris/pupil = the aperture; retina = the film or sensor.",
    malayalamSupport: "പ്രകാശം കോർണിയയിലൂടെ പ്രവേശിക്കുന്നു; ഐറിസ് പ്യൂപ്പിളിനെ നിയന്ത്രിക്കുന്നു; ലെൻസ് റെറ്റിനയിൽ ചിത്രം രൂപപ്പെടുത്തുന്നു. ചിത്രം: യഥാർത്ഥം, തലകീഴ്, ചെറുത്.",
    manglishSupport: "Light cornea-yiloode പ്രവേശിക്കുന്നു; iris pupil-ne control cheyyunnu; lens retina-yil image undaakkunnu. Image: real, inverted, diminished.",
  },
  visualBoard: {
    boardTitle: "Parts of the human eye",
    frames: [
      {
        id: "m7-f1",
        title: "Label the eye",
        teacherAction: "Draw a side-view eye; label cornea, iris, pupil, lens, ciliary muscles, retina, optic nerve.",
        boardText: ["Cornea → iris/pupil → lens → retina", "Optic nerve carries signal to brain"],
        diagramDescription: "Cross-section of the eye with all major parts labelled and a ray path to the retina.",
        studentFocus: "Know each part and its job.",
      },
      {
        id: "m7-f2",
        title: "Image on the retina",
        teacherAction: "Show an object and its small inverted image on the retina.",
        boardText: ["Image on retina is:", "Real, inverted, diminished"],
        diagramDescription: "Object arrow up, inverted small arrow image on the retina.",
        studentFocus: "Retinal image is real, inverted, diminished.",
      },
    ],
  },
  docDoeTrick: {
    title: "C-I-P-L-R path",
    trick: "Follow light: Cornea → Iris/Pupil → Lens → Retina (then optic nerve to brain).",
    whyItWorks: "Tracing the light path in order names the parts in the sequence examiners expect.",
  },
  keyNotes: [
          "Light enters your eye through a clear layer like a roof during monsoon. This is called the cornea.",
          "The iris is like a curtain that controls light. It opens and closes like an umbrella.",
          "The eye lens is like special glasses. Muscles control it, like your hands hold a magnifying glass.",
          "The picture on the retina is like a photo. It's real but upside down and small, like a coconut tree from far away.",
          "The optic nerve is like a messenger. It carries the picture to your brain, where you understand what you see."
        ],
  formulas: [],
  examAnswers: [
    {
      marks: 3,
      question: "Name the parts of the eye that (a) control the light entering, (b) focus the light, and (c) receive the image.",
      answerPoints: ["Iris and pupil control the light entering.", "The eye lens (with ciliary muscles) focuses the light.", "The retina receives the image."],
      keywords: ["iris", "pupil", "lens", "ciliary muscles", "retina"],
      commonMistakes: ["Confusing cornea with lens", "Saying the pupil focuses light"],
      boardStyleRewrite: "The iris and pupil control the light entering the eye, the eye lens (adjusted by the ciliary muscles) focuses it, and the retina receives the image.",
    },
  ],
  yourTurn: {
    prompt: "What is the nature of the image formed on the retina? (2 marks)",
    expectedAnswerPoints: ["It is real and inverted", "It is diminished (smaller than the object)"],
    hint: "Use the three words: real, inverted, diminished.",
  },
  correctionRubric: {
    maxMarks: 2,
    scoringPoints: [
      { point: "States the image is real and inverted", marks: 1, requiredKeywords: ["real", "inverted"] },
      { point: "States the image is diminished", marks: 1, requiredKeywords: ["diminished"] },
    ],
    commonMissingParts: ["The word 'inverted'", "The word 'diminished'"],
    feedbackTemplate: "You wrote {covered}. Add {missing} for full marks.",
  },
  quiz: [
    {
      id: "m7-q1",
      type: "mcq",
      question: "The light-sensitive screen of the eye on which the image forms is the",
      options: ["cornea", "iris", "retina", "pupil"],
      answer: "retina",
      explanation: "The retina is the light-sensitive layer where the image forms.",
      difficulty: "easy",
      tags: ["retina"],
    },
    {
      id: "m7-q2",
      type: "short",
      question: "Which muscles change the shape of the eye lens?",
      answer: "The ciliary muscles.",
      explanation: "Ciliary muscles adjust the lens curvature to focus.",
      difficulty: "medium",
      tags: ["ciliary muscles"],
    },
  ],
  recap: {
    summary: [
              "Light travels through your eye like this: cornea, then pupil, then lens, then retina. It's like traveling in an auto rickshaw to a new place."
            ],
    mustRemember: ["Retina = screen", "Image is inverted and diminished"],
  },
  revisionSave: {
    flashcards: [
      { front: "Which part focuses light in the eye?", back: "The convex eye lens." },
      { front: "Nature of the retinal image?", back: "Real, inverted and diminished." },
      { front: "What controls the pupil?", back: "The iris." },
    ],
    revisionNotes: ["Cornea → iris/pupil → lens → retina → optic nerve", "Image real, inverted, diminished"],
    weakAreaTags: ["human eye", "retina image"],
  },
  qualityFlags: { needsHumanReview: false },
});

// M8 — Power of Accommodation
const M8: TuitionLessonSeed = colourSeed({
  missionId: "M8",
  missionTitle: "Power of Accommodation of the Eye",
  goal: "Explain how the eye focuses objects at different distances using accommodation, and define near point and far point.",
  estimatedMinutes: 30,
  contentType: "concept",
  tags: ["accommodation", "ciliary muscles", "focal length", "near point", "far point"],
  sourceRefs: [COLOURS_VISION_SOURCE],
  sourceStatus: "source_backed",
  canTeach: true,
  pyqEvidenceStatus: "not_curated",
  recall: {
    prompt: "You can see this book clearly and also a distant tree clearly. How does the same eye focus both?",
    expectedPoints: ["The eye lens changes its shape", "This changes its focal length"],
    misconceptionCheck: "Students think the eye moves the lens back and forth like a camera — instead the lens changes its curvature.",
  },
  teach: {
    teacherIntro: "Your eyes are like super smart cameras that adjust their lenses to see things clearly. Imagine you are watching your favourite football on TV, and then you see your friend standing right in front of you. Your eyes change the lens to see both clearly!",
    explanationBlocks: [
      {
        heading: "What accommodation is",
        explanation: "The ability of the eye lens to change its focal length to focus objects at different distances is called the power of accommodation.",
        keyTerms: ["power of accommodation", "focal length"],
      },
      {
        heading: "How the ciliary muscles work",
        explanation: "For nearby objects the ciliary muscles contract, making the lens more curved (shorter focal length). For distant objects they relax, making the lens thinner (longer focal length).",
        keyTerms: ["ciliary muscles", "curvature"],
      },
      {
        heading: "Near point and far point",
        explanation: "The near point is the closest distance for clear vision — about 25 cm for a normal eye. The far point is the farthest distance for clear vision — infinity for a normal eye.",
        keyTerms: ["near point 25 cm", "far point infinity"],
      },
    ],
    analogy: "The eye lens is like a soft, squeezable magnifier — squeeze it (more curved) for close reading, relax it (flatter) for distant views.",
    malayalamSupport: "കണ്ണിന്റെ ലെൻസ് ഫോക്കൽ ദൂരം മാറ്റാനുള്ള കഴിവ് = അക്കമഡേഷൻ. അടുത്ത വസ്തുവിന് ലെൻസ് കൂടുതൽ വളയുന്നു. നിയർ പോയിന്റ് ≈ 25 cm, ഫാർ പോയിന്റ് = അനന്തത.",
    manglishSupport: "Eye lens-inte focal length maattaanulla kazhivu = accommodation. Aduthulla object-inu lens kooduthal curve. Near point ≈ 25 cm, far point = infinity.",
  },
  visualBoard: {
    boardTitle: "Accommodation, near point and far point",
    frames: [
      {
        id: "m8-f1",
        title: "Lens changes shape",
        teacherAction: "Draw a fat (curved) lens for near objects and a thin lens for distant objects.",
        boardText: ["Near object: lens more curved, shorter f", "Distant object: lens thinner, longer f"],
        diagramDescription: "Two eye lenses side by side — one thick/curved, one thin/flat.",
        studentFocus: "Curvature changes → focal length changes.",
      },
      {
        id: "m8-f2",
        title: "Near and far point",
        teacherAction: "Mark near point (25 cm) and far point (infinity) on a line from the eye.",
        boardText: ["Near point ≈ 25 cm", "Far point = infinity (normal eye)"],
        studentFocus: "Learn the two standard distances.",
      },
    ],
  },
  docDoeTrick: {
    title: "Near curls, Far flattens",
    trick: "For NEAR objects the lens curls up (more curved, shorter f); for FAR objects it flattens (longer f).",
    whyItWorks: "It links the object distance to the lens shape and focal length in one line.",
  },
  keyNotes: [
          "Power of accommodation = the eye's magic to see near and far things clearly.",
          "Tiny muscles in the eye change the lens shape, like a chef adjusting the heat for the right recipe.",
          "For near things, the lens bends more, like a coconut tree bending in the monsoon rain.",
          "The closest thing a normal eye can see is about 25 cm, that's like holding a book in your hand.",
          "The farthest thing a normal eye can see is like the end of the road, infinity!"
        ],
  formulas: [],
  examAnswers: [
    {
      marks: 2,
      question: "What is the power of accommodation of the eye?",
      answerPoints: ["It is the ability of the eye lens to change its focal length.", "This lets the eye focus objects at different distances clearly."],
      keywords: ["accommodation", "focal length", "different distances"],
      commonMistakes: ["Saying the lens moves position", "Not mentioning focal length"],
      boardStyleRewrite: "The power of accommodation is the ability of the eye lens to change its focal length so that objects at different distances can be focused clearly on the retina.",
    },
  ],
  yourTurn: {
    prompt: "State the near point and far point of a normal human eye. (2 marks)",
    expectedAnswerPoints: ["Near point ≈ 25 cm", "Far point = infinity"],
    hint: "Give both standard distances with units.",
  },
  correctionRubric: {
    maxMarks: 2,
    scoringPoints: [
      { point: "Near point about 25 cm", marks: 1, requiredKeywords: ["25", "cm"] },
      { point: "Far point at infinity", marks: 1, requiredKeywords: ["infinity"] },
    ],
    commonMissingParts: ["The 25 cm value", "The word 'infinity'"],
    feedbackTemplate: "You wrote {covered}. Add {missing} for full marks.",
  },
  quiz: [
    {
      id: "m8-q1",
      type: "mcq",
      question: "The near point of a normal human eye is about",
      options: ["10 cm", "25 cm", "50 cm", "1 m"],
      answer: "25 cm",
      explanation: "The least distance of distinct vision is about 25 cm.",
      difficulty: "easy",
      tags: ["near point"],
    },
    {
      id: "m8-q2",
      type: "short",
      question: "To see a nearby object, do the ciliary muscles contract or relax?",
      answer: "Contract (making the lens more curved).",
      explanation: "Contracting the ciliary muscles increases the lens curvature and shortens the focal length.",
      difficulty: "medium",
      tags: ["ciliary muscles", "accommodation"],
    },
  ],
  recap: {
    summary: [
              "Accommodation is like the eye's special power to change its lens.",
              "The tiny muscles in the eye change the lens shape, like a chef adjusts the heat.",
              "Near things are like 25 cm away, and far things are like infinity!"
            ],
    mustRemember: ["25 cm and infinity", "Near → more curved lens"],
  },
  revisionSave: {
    flashcards: [
      { front: "Power of accommodation?", back: "Ability of the eye lens to change its focal length." },
      { front: "Near point of a normal eye?", back: "About 25 cm." },
      { front: "Far point of a normal eye?", back: "Infinity." },
    ],
    revisionNotes: ["Accommodation = focal length change", "Near 25 cm, far infinity"],
    weakAreaTags: ["accommodation", "near point far point"],
  },
  qualityFlags: { needsHumanReview: false },
});

// M9 — Defects of Vision and Their Correction
const M9: TuitionLessonSeed = colourSeed({
  missionId: "M9",
  missionTitle: "Defects of Vision and Their Correction",
  goal: "Explain myopia, hypermetropia and presbyopia, their causes and the corrective lenses.",
  estimatedMinutes: 35,
  contentType: "concept",
  tags: ["myopia", "hypermetropia", "presbyopia", "concave lens", "convex lens", "defects of vision"],
  sourceRefs: [COLOURS_VISION_SOURCE],
  sourceStatus: "source_backed",
  canTeach: true,
  pyqEvidenceStatus: "not_curated",
  recall: {
    prompt: "Some people wear glasses to see distant things, others to read close up. Why would the same eye need different lenses?",
    expectedPoints: ["Different eyes focus incorrectly in different ways", "Concave and convex lenses correct different defects"],
    misconceptionCheck: "Students mix up which lens corrects which defect — concave for myopia, convex for hypermetropia.",
  },
  teach: {
    teacherIntro: "Imagine you are playing football. If the ball is too far away, you can't see it clearly. This is like myopia. It's when the eye can't focus on faraway things. There are three main types: myopia, hypermetropia, and presbyopia.",
    explanationBlocks: [
      {
        heading: "Myopia (short-sightedness)",
        explanation: "The person can see near objects but not distant ones. The image forms in front of the retina, because the eyeball is too long or the lens too powerful. Corrected with a concave (diverging) lens.",
        keyTerms: ["myopia", "image before retina", "concave lens"],
      },
      {
        heading: "Hypermetropia (long-sightedness)",
        explanation: "The person can see distant objects but not near ones. The image forms behind the retina, because the eyeball is too short or the lens too weak. Corrected with a convex (converging) lens.",
        keyTerms: ["hypermetropia", "image behind retina", "convex lens"],
      },
      {
        heading: "Presbyopia (age-related)",
        explanation: "With age the ciliary muscles weaken and the lens loses flexibility, so near vision becomes difficult. It is often corrected with bifocal lenses.",
        keyTerms: ["presbyopia", "bifocal lens"],
      },
    ],
    analogy: "Myopia overshoots (image lands short of the retina) so we spread the rays with a concave lens; hypermetropia undershoots (image lands past the retina) so we gather them with a convex lens.",
    malayalamSupport: "മയോപ്പിയ: അകലെയുള്ളവ കാണാൻ കഴിയില്ല, ചിത്രം റെറ്റിനയ്ക്ക് മുന്നിൽ → കോൺകേവ് ലെൻസ്. ഹൈപ്പർമെട്രോപ്പിയ: അടുത്തുള്ളവ കാണാൻ കഴിയില്ല, ചിത്രം റെറ്റിനയ്ക്ക് പിന്നിൽ → കോൺവെക്സ് ലെൻസ്.",
    manglishSupport: "Myopia: akaleyullath kaanaan pattilla, image retina-ykku munnil → concave lens. Hypermetropia: aduthullath kaanaan pattilla, image retina-ykku pinnil → convex lens. Presbyopia → bifocal.",
  },
  visualBoard: {
    boardTitle: "Two main defects and their lenses",
    frames: [
      {
        id: "m9-f1",
        title: "Myopia",
        teacherAction: "Show rays focusing in front of the retina; add a concave lens to push focus back.",
        boardText: ["Image forms before the retina", "Cause: long eyeball / strong lens", "Correction: concave lens"],
        diagramDescription: "Eye with focus in front of retina; concave lens corrects it onto the retina.",
        studentFocus: "Myopia → concave lens.",
      },
      {
        id: "m9-f2",
        title: "Hypermetropia",
        teacherAction: "Show rays focusing behind the retina; add a convex lens to pull focus forward.",
        boardText: ["Image forms behind the retina", "Cause: short eyeball / weak lens", "Correction: convex lens"],
        diagramDescription: "Eye with focus behind retina; convex lens corrects it onto the retina.",
        studentFocus: "Hypermetropia → convex lens.",
      },
    ],
  },
  docDoeTrick: {
    title: "MyopiaConcave, HyperConvex",
    trick: "Myopia (short-sight) → Concave lens; Hypermetropia (long-sight) → Convex lens.",
    whyItWorks: "Two fixed pairings remove the most common exam mix-up.",
  },
  keyNotes: [
          "Myopia: You can see things close to you very clearly, but faraway things are blurry. Think of a coconut tree on the beach - you can see the palm fronds clearly but the tree far away is just a dot. This is because the image forms before the retina. We correct it with a special type of lens called a concave lens.",
          "Hypermetropia: You can see things up close very clearly, but faraway things are blurry. Think of reading a book during monsoon rain - the words are clear but the rain outside is just a blur. This is because the image forms behind the retina. We correct it with a special type of lens called a convex lens.",
          "Myopia is caused by an eyeball that is too long or a lens that is too strong. It's like a car (your eyeball) with a too-powerful engine - it goes too fast and can't focus on faraway things.",
          "Hypermetropia is caused by an eyeball that is too short or a lens that is too weak. It's like a car with a too-weak engine - it can't go fast enough to focus on faraway things.",
          "Presbyopia is a natural thing that happens as we age. Our eyes get a bit lazy and can't focus on things up close like they used to. We correct it with special glasses called bifocal lenses."
        ],
  formulas: [],
  examAnswers: [
    {
      marks: 3,
      question: "What is myopia? State its cause and the lens used to correct it.",
      answerPoints: [
        "Myopia (short-sightedness) is the inability to see distant objects clearly.",
        "It is caused by the eyeball being too long or the eye lens too powerful, so the image forms in front of the retina.",
        "It is corrected using a concave (diverging) lens.",
      ],
      keywords: ["myopia", "distant objects", "in front of retina", "concave lens"],
      commonMistakes: ["Saying convex lens corrects myopia", "Saying the image forms behind the retina"],
      boardStyleRewrite: "Myopia is short-sightedness — distant objects are not seen clearly because the image forms in front of the retina (long eyeball or too-powerful lens). It is corrected with a concave lens.",
    },
  ],
  yourTurn: {
    prompt: "A person cannot see nearby objects clearly. Name the defect and the correcting lens. (2 marks)",
    expectedAnswerPoints: ["The defect is hypermetropia (long-sightedness)", "Corrected using a convex lens"],
    hint: "Near objects unclear → which defect, which lens?",
  },
  correctionRubric: {
    maxMarks: 2,
    scoringPoints: [
      { point: "Names the defect as hypermetropia", marks: 1, requiredKeywords: ["hypermetropia"] },
      { point: "States the convex lens correction", marks: 1, requiredKeywords: ["convex"] },
    ],
    commonMissingParts: ["The name hypermetropia", "The convex lens"],
    feedbackTemplate: "You wrote {covered}. Add {missing} for full marks.",
  },
  quiz: [
    {
      id: "m9-q1",
      type: "mcq",
      question: "Myopia is corrected using a",
      options: ["convex lens", "concave lens", "plane mirror", "bifocal lens"],
      answer: "concave lens",
      explanation: "A concave (diverging) lens moves the image back onto the retina.",
      difficulty: "easy",
      tags: ["myopia", "concave lens"],
    },
    {
      id: "m9-q2",
      type: "short",
      question: "In hypermetropia, where does the image of a nearby object form relative to the retina?",
      answer: "Behind the retina.",
      explanation: "The eye is too weak/short, so the image forms behind the retina.",
      difficulty: "medium",
      tags: ["hypermetropia"],
    },
    {
      id: "m9-q3",
      type: "short",
      question: "Which lens is used to correct presbyopia when both near and far vision are affected?",
      answer: "Bifocal lenses.",
      explanation: "Bifocals combine a concave part (distance) and a convex part (near).",
      difficulty: "exam",
      tags: ["presbyopia", "bifocal"],
    },
  ],
  recap: {
    summary: [
              "Myopia → concave lens (image before retina) like a coconut tree on the beach",
              "Hypermetropia → convex lens (image behind retina) like reading a book during monsoon rain",
              "Presbyopia → bifocal lenses (because our eyes get a bit lazy with age)"
            ],
    mustRemember: ["Myopia = concave, hypermetropia = convex", "Presbyopia is age-related"],
  },
  revisionSave: {
    flashcards: [
      { front: "Myopia correcting lens?", back: "Concave (diverging) lens." },
      { front: "Hypermetropia correcting lens?", back: "Convex (converging) lens." },
      { front: "Presbyopia correction?", back: "Bifocal lenses." },
    ],
    revisionNotes: ["Myopia = concave, hyper = convex", "Presbyopia → bifocal"],
    weakAreaTags: ["defects of vision", "myopia hypermetropia"],
  },
  qualityFlags: { needsHumanReview: false },
});

// M10 — Numericals: Power of the Correcting Lens
const M10: TuitionLessonSeed = colourSeed({
  missionId: "M10",
  missionTitle: "Numericals — Power of the Correcting Lens",
  goal: "Use P = 1/f to find the power of a lens and the correcting lens for a defect of vision.",
  estimatedMinutes: 35,
  contentType: "numerical",
  tags: ["power of lens", "P=1/f", "dioptre", "focal length", "numerical"],
  sourceRefs: [COLOURS_VISION_SOURCE],
  sourceStatus: "source_backed",
  canTeach: true,
  pyqEvidenceStatus: "not_curated",
  recall: {
    prompt: "The strength of a spectacle lens is written as +2 D or -2 D. What does this 'D' measure?",
    expectedPoints: ["It is the power of the lens", "Power P = 1/f, unit dioptre (D)"],
    misconceptionCheck: "Students forget to convert the focal length from centimetres to metres before using P = 1/f.",
  },
  teach: {
    teacherIntro: "Imagine you are playing football under a big tree. The tree's shadow can be big or small like how a coconut tree's shadow changes. A lens is like that tree, it bends light. The power of the lens tells us how strongly it bends the light. It's like how strongly the tree bends the shadow. We find this power by taking 1 and dividing it by the distance to where the light bends, measured in metres.",
    explanationBlocks: [
      {
        heading: "The formula P = 1/f",
        explanation: "Power P = 1/f, where f is the focal length in metres. The unit of power is the dioptre (D). A convex lens has positive power; a concave lens has negative power.",
        keyTerms: ["power", "dioptre", "P = 1/f"],
      },
      {
        heading: "Convert units first",
        explanation: "Always convert the focal length from centimetres to metres (÷100) before substituting. For example, f = 50 cm = 0.5 m.",
        keyTerms: ["cm to m", "substitution"],
      },
      {
        heading: "Sign for the defect",
        explanation: "A concave lens (for myopia) gives a negative power; a convex lens (for hypermetropia) gives a positive power. Report the sign with the answer.",
        keyTerms: ["negative power", "positive power"],
      },
    ],
    analogy: "Power is like the 'strength rating' of a lens — small focal length means a strong, high-power lens.",
    malayalamSupport: "ലെൻസിന്റെ പവർ P = 1/f (f മീറ്ററിൽ). യൂണിറ്റ്: ഡയോപ്റ്റർ (D). കോൺവെക്സ് പോസിറ്റീവ്, കോൺകേവ് നെഗറ്റീവ്. cm → m മാറ്റാൻ മറക്കരുത്.",
    manglishSupport: "Lens power P = 1/f (f metres-il). Unit: dioptre (D). Convex positive, concave negative. cm → m maattaan marakkaruthu.",
  },
  visualBoard: {
    boardTitle: "Power of a lens — worked steps",
    frames: [
      {
        id: "m10-f1",
        title: "Worked example (convex)",
        teacherAction: "Solve f = 50 cm convex lens → P = ? step by step.",
        boardText: ["f = 50 cm = 0.5 m", "P = 1/f = 1/0.5", "P = +2 D (convex → positive)"],
        studentFocus: "Convert cm → m, then P = 1/f.",
      },
      {
        id: "m10-f2",
        title: "Sign trap (concave)",
        teacherAction: "Show a concave lens f = -25 cm = -0.25 m → P = -4 D.",
        boardText: ["f = -25 cm = -0.25 m", "P = 1/(-0.25) = -4 D", "Concave → negative power"],
        studentFocus: "Keep the sign of the focal length.",
      },
    ],
  },
  docDoeTrick: {
    title: "Metres-then-Reciprocal",
    trick: "First put f in metres, then P = 1/f; carry the sign (convex +, concave -).",
    whyItWorks: "The two most common errors — unit and sign — are handled up front.",
  },
  keyNotes: [
          "Power of a lens is like the speed of an auto rickshaw, P = 1/f, where f is the distance to your destination in metres.",
          "The unit of power is like a special coin called dioptre (D), we use it to measure how strong the lens is.",
          "If you know the distance in centimetres, you need to convert it to metres so you divide by 100.",
          "A big serving bowl makes things look bigger, so it has positive power. A small dent in a football makes things look smaller, so it has negative power.",
          "Always remember to write the sign, like plus or minus, and the unit (D) in your answer."
        ],
  formulas: [
    {
      formula: "P = 1 / f",
      meaning: "Power of a lens equals the reciprocal of its focal length in metres.",
      symbols: [
        { symbol: "P", meaning: "power of the lens", unit: "dioptre (D)" },
        { symbol: "f", meaning: "focal length", unit: "m" },
      ],
      commonUseCase: "Find the power of a lens, or the correcting lens for a vision defect.",
      numericalPattern: "Convert f to metres, take reciprocal, attach sign and unit D.",
    },
  ],
  examAnswers: [
    {
      marks: 3,
      question: "A convex lens has a focal length of 25 cm. Calculate its power.",
      answerPoints: ["Convert: f = 25 cm = 0.25 m", "Formula: P = 1/f = 1/0.25", "Answer: P = +4 D"],
      keywords: ["P = 1/f", "0.25 m", "+4 D", "dioptre"],
      commonMistakes: ["Using f in cm", "Dropping the + sign or the unit D"],
      boardStyleRewrite: "f = 25 cm = 0.25 m. P = 1/f = 1/0.25 = +4 D.",
    },
  ],
  yourTurn: {
    prompt: "A concave lens has focal length 50 cm. Find its power. Show all steps. (3 marks)",
    expectedAnswerPoints: ["f = -50 cm = -0.5 m", "P = 1/f = 1/(-0.5)", "P = -2 D"],
    hint: "Concave → negative focal length; keep the sign, answer in dioptre.",
  },
  correctionRubric: {
    maxMarks: 3,
    scoringPoints: [
      { point: "Converts focal length to metres", marks: 1, requiredKeywords: ["0.5", "m"] },
      { point: "Applies P = 1/f", marks: 1, requiredKeywords: ["1/f", "1/"] },
      { point: "Final answer with sign and unit (-2 D)", marks: 1, requiredKeywords: ["-2", "d"] },
    ],
    commonMissingParts: ["The cm → m conversion", "The negative sign / unit D"],
    feedbackTemplate: "You showed {covered}. For full marks include {missing}.",
  },
  quiz: [
    {
      id: "m10-q1",
      type: "numerical",
      question: "A convex lens has focal length 20 cm. What is its power in dioptre?",
      answer: "f = 0.2 m; P = 1/0.2 = +5 D",
      explanation: "Convert 20 cm to 0.2 m, then P = 1/f = +5 D.",
      difficulty: "medium",
      tags: ["power of lens", "dioptre"],
    },
    {
      id: "m10-q2",
      type: "numerical",
      question: "A lens has power -4 dioptre. What is its focal length, and what type of lens is it?",
      answer: "f = 1/P = 1/(-4) = -0.25 m = -25 cm; concave lens",
      explanation: "f = 1/P = -0.25 m (-25 cm); the negative power in dioptre means it is a concave lens.",
      difficulty: "exam",
      tags: ["power of lens", "concave lens"],
    },
    {
      id: "m10-q3",
      type: "mcq",
      question: "The SI unit of the power of a lens is the",
      options: ["metre", "dioptre", "watt", "hertz"],
      answer: "dioptre",
      explanation: "Power of a lens is measured in dioptre (D), where P = 1/f with f in metres.",
      difficulty: "easy",
      tags: ["dioptre", "unit"],
    },
  ],
  recap: {
    summary: [
              "P = 1/f with f in metres, like a simple recipe.",
              "Unit is dioptre (D), like a special measuring cup.",
              "Big lens is plus, like a big umbrella, and small lens is minus, like a small hole in that umbrella; always convert centimetres to metres."
            ],
    mustRemember: ["Always f in metres", "Keep the sign and the unit D"],
  },
  revisionSave: {
    flashcards: [
      { front: "Power of a lens formula?", back: "P = 1/f (f in metres)." },
      { front: "Unit of lens power?", back: "Dioptre (D)." },
      { front: "Sign of a concave lens power?", back: "Negative." },
    ],
    revisionNotes: ["P = 1/f, f in metres, unit D", "Convex +, concave -"],
    weakAreaTags: ["power of lens", "numericals"],
  },
  qualityFlags: { needsHumanReview: false },
});

// M11 — Exam Answer Practice — Colours and Vision
const M11: TuitionLessonSeed = colourSeed({
  missionId: "M11",
  missionTitle: "Exam Answer Practice — Colours and Vision",
  goal: "Write 2-mark and 4-mark board-style answers from the Colours and Vision chapter.",
  estimatedMinutes: 30,
  contentType: "exam_answer",
  tags: ["exam answer", "keywords", "board style", "structure"],
  sourceRefs: [COLOURS_VISION_SOURCE],
  sourceStatus: "source_backed",
  canTeach: true,
  pyqEvidenceStatus: "not_curated",
  recall: {
    prompt: "Name three exam keywords from this chapter you must not miss.",
    expectedPoints: ["dispersion / VIBGYOR", "scattering (blue sky, red sun)", "myopia-concave / hypermetropia-convex"],
    misconceptionCheck: "Students give the right idea but drop the exact keyword the rubric rewards.",
  },
  teach: {
    teacherIntro: "Think of your answer like making a good curry. First, add the main ingredient, then add the spices, and finally, serve it nicely. Your answer should start with the main point, then add the important words, and end with a nice finish.",
    explanationBlocks: [
      {
        heading: "2-mark answer structure",
        explanation: "One clear definition/reason sentence plus one supporting line, with the exact keyword included.",
        keyTerms: ["definition", "keyword"],
      },
      {
        heading: "4-mark answer structure",
        explanation: "Direct answer → 2-3 keyword points → a short conclusion. Keep each point to one line.",
        keyTerms: ["points", "conclusion"],
      },
      {
        heading: "Chapter keywords to lock",
        explanation: "'dispersion', 'total internal reflection', 'scattering', 'retina', 'accommodation', 'concave/convex lens' — losing these loses marks.",
        keyTerms: ["chapter keywords"],
      },
    ],
    malayalamSupport: "ഉത്തരത്തിൽ കീവേഡുകൾ (dispersion, scattering, retina, concave/convex) നിർബന്ധമായും ഉൾപ്പെടുത്തുക. ഘടന: പോയിന്റ് → കീവേഡ് → ക്ലോസ്.",
    manglishSupport: "Answer-il keywords (dispersion, scattering, retina, concave/convex) nirബന്ധമായി cheythu vekkuka. Structure: point → keyword → close.",
  },
  visualBoard: {
    boardTitle: "Answer skeleton with marks and keywords",
    frames: [
      {
        id: "m11-f1",
        title: "2-mark skeleton",
        teacherAction: "Write a 2-line skeleton with blanks for keywords.",
        boardText: ["Line 1: direct answer (+ keyword)", "Line 2: one support line"],
        studentFocus: "Definition + keyword = 2 marks.",
      },
      {
        id: "m11-f2",
        title: "4-mark skeleton",
        teacherAction: "Write: answer → 3 keyword points → conclusion.",
        boardText: ["Direct answer", "Point 1 / Point 2 / Point 3 (keywords)", "Conclusion line"],
        studentFocus: "Structure + keywords win 4-mark questions.",
      },
    ],
  },
  docDoeTrick: {
    title: "Point-Keyword-Close",
    trick: "Every answer: Point → Keywords → Close.",
    whyItWorks: "It guarantees the structure and keyword coverage the rubric rewards.",
  },
  keyNotes: [
          "Your answer is like kicking a football - start with a strong kick, which is your direct answer.",
          "Add the chapter words, like adding salt to your food, so it tastes good.",
          "For 4-mark answers, keep it simple, one point per line, like one short walk at a time.",
          "End with a short finish, like saying 'let's go' when you finish a task.",
          "Missing words is like forgetting your umbrella in the rain - you'll get lost, so don't forget them."
        ],
  formulas: [],
  examAnswers: [
    {
      marks: 2,
      question: "Why does the sky appear blue? (board style)",
      answerPoints: ["Air molecules scatter the shorter (blue) wavelengths of sunlight the most.", "This scattered blue light reaches our eyes from all directions, so the sky looks blue."],
      keywords: ["scattering", "blue", "shorter wavelength"],
      commonMistakes: ["Saying the sky reflects the sea", "Not using the word 'scattering'"],
      boardStyleRewrite: "The atmosphere scatters the shorter blue wavelengths of sunlight the most. This scattered blue light reaches our eyes from all directions, so the sky appears blue.",
    },
    {
      marks: 4,
      question: "Explain how a rainbow is formed, listing the processes involved.",
      answerPoints: [
        "Sunlight enters tiny water droplets in the air and is refracted.",
        "Inside the droplet it undergoes total internal reflection at the back.",
        "As it leaves, it is refracted again and dispersed into seven colours.",
        "These colours from many droplets form the arc of the rainbow, seen with the Sun behind the observer.",
      ],
      keywords: ["water droplets", "refraction", "total internal reflection", "dispersion"],
      commonMistakes: ["Omitting total internal reflection", "Forgetting the Sun is behind the observer"],
      boardStyleRewrite: "Sunlight entering a water droplet is refracted, totally internally reflected at the back, and refracted again as it leaves, dispersing into seven colours. Light from many droplets forms the rainbow arc, seen with the Sun behind the observer.",
    },
  ],
  yourTurn: {
    prompt: "Write a 4-mark answer: 'What is myopia? State its cause and correction.' (4 marks)",
    expectedAnswerPoints: ["Myopia = cannot see distant objects clearly", "Image forms in front of the retina", "Cause: long eyeball or too-powerful lens", "Corrected by a concave lens"],
    hint: "Point → keywords (in front of retina, concave lens) → close.",
  },
  correctionRubric: {
    maxMarks: 4,
    scoringPoints: [
      { point: "Defines myopia as poor distant vision", marks: 1, requiredKeywords: ["distant", "myopia"] },
      { point: "Image forms in front of the retina", marks: 1, requiredKeywords: ["in front", "retina"] },
      { point: "States the cause (long eyeball / strong lens)", marks: 1, requiredKeywords: ["eyeball", "lens"] },
      { point: "Correction by concave lens", marks: 1, requiredKeywords: ["concave"] },
    ],
    commonMissingParts: ["Image position (in front of retina)", "The concave lens correction"],
    feedbackTemplate: "Strong on {covered}. Add {missing} to reach 4 marks.",
  },
  quiz: [
    {
      id: "m11-q1",
      type: "short",
      question: "Which keyword must appear in a rainbow answer besides refraction and dispersion?",
      answer: "Total internal reflection.",
      explanation: "Examiners look for total internal reflection inside the droplet.",
      difficulty: "exam",
      tags: ["rainbow", "keyword"],
    },
    {
      id: "m11-q2",
      type: "short",
      question: "In a scattering answer, which two examples should you be ready to explain?",
      answer: "The blue sky and the red Sun at sunrise/sunset.",
      explanation: "Both are standard applications of scattering.",
      difficulty: "medium",
      tags: ["scattering", "keywords"],
    },
  ],
  recap: {
    summary: [
              "Point → Keywords → Close, it's like a recipe for your favorite snack.",
              "Include exact words, just like you add the right ingredients for a tasty meal.",
              "One line per point for 4-mark answers, simple like taking one step at a time on a walk."
            ],
    mustRemember: ["Keywords win marks", "Structure matters as much as content"],
  },
  revisionSave: {
    flashcards: [
      { front: "Blue sky answer keyword?", back: "Scattering (blue scatters most)." },
      { front: "Rainbow answer keywords?", back: "Refraction + total internal reflection + dispersion." },
      { front: "Myopia answer keywords?", back: "Image in front of retina + concave lens." },
    ],
    revisionNotes: ["Answer = Point + Keywords + Close", "Lock chapter keywords"],
    weakAreaTags: ["exam answer writing", "board keywords"],
  },
  qualityFlags: { needsHumanReview: false },
});

// M12 — Revision Mission — Colours and Vision
const M12: TuitionLessonSeed = colourSeed({
  missionId: "M12",
  missionTitle: "Revision Mission — Colours and Vision",
  goal: "Revise the key ideas, the one formula and the common traps of the Colours and Vision chapter.",
  estimatedMinutes: 25,
  contentType: "revision",
  tags: ["revision", "flashcards", "traps", "dispersion", "eye"],
  sourceRefs: [COLOURS_VISION_SOURCE],
  sourceStatus: "source_backed",
  canTeach: true,
  pyqEvidenceStatus: "not_curated",
  recall: {
    prompt: "From memory: what causes the blue sky, and which lens corrects myopia?",
    expectedPoints: ["Scattering of light (blue scatters most)", "A concave lens corrects myopia"],
    misconceptionCheck: "Quick check that scattering vs dispersion, and myopia vs hypermetropia lenses, are not swapped.",
  },
  teach: {
    teacherIntro: "Let's review like a football player remembers the game plan: the main ideas, 1 important formula, and 3 common mistakes before the exam.",
    explanationBlocks: [
      {
        heading: "Big ideas to lock",
        explanation: "Dispersion (VIBGYOR), rainbow (refraction + total internal reflection + dispersion), scattering (blue sky, red Sun), eye structure, accommodation, defects and lenses.",
        keyTerms: ["dispersion", "scattering", "accommodation", "defects"],
      },
      {
        heading: "Formula to lock",
        explanation: "Power of a lens P = 1/f (f in metres), unit dioptre (D); convex positive, concave negative.",
        keyTerms: ["P = 1/f", "dioptre"],
      },
      {
        heading: "Traps to avoid",
        explanation: "Confusing dispersion with scattering; swapping myopia/hypermetropia lenses; forgetting cm → m in the power formula.",
        keyTerms: ["dispersion vs scattering", "lens swap", "unit trap"],
      },
    ],
    malayalamSupport: "Dispersion vs scattering മാറ്റരുത്. Myopia = concave, hypermetropia = convex. P = 1/f-ൽ f മീറ്ററിൽ വേണം.",
    manglishSupport: "Dispersion vs scattering maattaruthu. Myopia = concave, hypermetropia = convex. P = 1/f-il f metres-il venam.",
  },
  visualBoard: {
    boardTitle: "One-board revision",
    frames: [
      {
        id: "m12-f1",
        title: "Ideas + formula + traps",
        teacherAction: "Write the big ideas on one side, P = 1/f in the middle, the three traps on the other side.",
        boardText: ["Dispersion, rainbow, scattering, eye, defects", "P = 1/f (D)", "Traps: dispersion≠scattering, lens swap, cm→m"],
        studentFocus: "One glance recalls the whole chapter.",
      },
    ],
  },
  docDoeTrick: {
    title: "3-Lock",
    trick: "Lock Ideas, Lock the Formula (P = 1/f), Lock the Traps.",
    whyItWorks: "Revision only needs these three buckets — fast and complete.",
  },
  keyNotes: [
          "Imagine a coconut tree with a prism: it splits white light into colors like a rainbow after monsoon rain. Violet bends the most.",
          "A rainbow is made when light bends, hits water, and bends again - like an auto rickshaw turning on a wet road.",
          "Sunlight scatters like spices falling from a bag, and blue scatters the most, making the sky blue. The sun looks red because it travels far.",
          "The image on our retina is like a photo: real, upside down, and small. We see things clearly when they are 25 cm away, like a yummy meal.",
          "If you can't see far, you have myopia and need a concave lens, like a spoon that curves in. If you can't see near, you have hypermetropia and need a convex lens, like a spoon that curves out. Remember, P = 1/f is like a simple recipe for lenses."
        ],
  formulas: [
    {
      formula: "P = 1 / f",
      meaning: "Power of a lens is the reciprocal of the focal length in metres.",
      symbols: [
        { symbol: "P", meaning: "power of the lens", unit: "dioptre (D)" },
        { symbol: "f", meaning: "focal length", unit: "m" },
      ],
      commonUseCase: "The only calculation in this chapter — power of the correcting lens.",
    },
  ],
  examAnswers: [
    {
      marks: 1,
      question: "Which lens is used to correct myopia?",
      answerPoints: ["A concave (diverging) lens."],
      keywords: ["concave lens", "myopia"],
      commonMistakes: ["Writing convex lens"],
      boardStyleRewrite: "A concave (diverging) lens is used to correct myopia.",
    },
  ],
  yourTurn: {
    prompt: "List the three common traps in the Colours and Vision chapter. (2 marks)",
    expectedAnswerPoints: ["Confusing dispersion with scattering", "Swapping myopia/hypermetropia lenses", "Forgetting cm → m in P = 1/f"],
    hint: "Think: which two words get mixed, which two lenses, which unit.",
  },
  correctionRubric: {
    maxMarks: 2,
    scoringPoints: [
      { point: "Names the dispersion vs scattering / lens-swap trap", marks: 1, requiredKeywords: ["scattering", "concave"] },
      { point: "Names the unit-conversion trap", marks: 1, requiredKeywords: ["cm", "m"] },
    ],
    commonMissingParts: ["The lens-swap trap", "The cm → m trap"],
    feedbackTemplate: "You listed {covered}. Also include {missing}.",
  },
  quiz: [
    {
      id: "m12-q1",
      type: "mcq",
      question: "Which pair is correctly matched?",
      options: ["Myopia – convex lens", "Hypermetropia – concave lens", "Myopia – concave lens", "Presbyopia – plane mirror"],
      answer: "Myopia – concave lens",
      explanation: "Myopia is corrected with a concave lens; hypermetropia with a convex lens.",
      difficulty: "easy",
      tags: ["defects of vision"],
    },
    {
      id: "m12-q2",
      type: "short",
      question: "Blue sky and red Sun are both explained by which single phenomenon?",
      answer: "Scattering of light.",
      explanation: "Both follow from shorter wavelengths scattering more.",
      difficulty: "medium",
      tags: ["scattering"],
    },
  ],
  recap: {
    summary: [
              "Review the main ideas, the P = 1/f formula, and common mistakes like a cook reviews a recipe before cooking.",
              "Don't mix up dispersion and scattering, like mixing up salt and sugar while cooking.",
              "Remember, myopia needs a concave lens, like a spoon that curves in, and hypermetropia needs a convex lens, like a spoon that curves out."
            ],
    mustRemember: ["P = 1/f (f in metres, unit D)", "Don't swap the defect lenses"],
  },
  revisionSave: {
    flashcards: [
      { front: "One formula of this chapter?", back: "P = 1/f (unit dioptre)." },
      { front: "Blue sky and red Sun cause?", back: "Scattering of light." },
      { front: "Myopia vs hypermetropia lens?", back: "Concave vs convex." },
    ],
    revisionNotes: ["Ideas: dispersion, rainbow, scattering, eye, defects", "Traps: dispersion≠scattering, lens swap, cm→m"],
    weakAreaTags: ["revision", "colours and vision"],
  },
  qualityFlags: { needsHumanReview: false },
});

export const COLOURS_VISION_SEEDS: TuitionLessonSeed[] = [
  M1,
  M2,
  M3,
  M4,
  M5,
  M6,
  M7,
  M8,
  M9,
  M10,
  M11,
  M12,
];