import type { StudioToolId } from "@/components/dashboard/studioTools";
import {
  generateBrainAnswerCorrection,
  generateBrainExamAnswer,
  generateBrainFlashcards,
  generateBrainLastNightPlan,
  generateBrainNotes,
  generateBrainQuiz,
  generateBrainVideoPlan,
  generateStudyPath,
} from "@/lib/api/brain";
import { getStudyPath, getWhatToStudy } from "@/lib/api/intelligence";
import {
  normalizeExamAnswer,
  normalizeFlashcards,
  normalizeNotes,
  normalizePYQAnalysis,
  normalizeQuiz,
  normalizeStudyPlan,
  normalizeVideoPlan,
} from "@/lib/api/normalizers";
import { analyzeStructuredPreviousPapers, listPreviousPapers } from "@/lib/api/previous-papers";
import { createVideoScenePlan } from "@/lib/api/video";
import type {
  BrainAnswerCorrectionOutput,
  BrainGeneratePayload,
  ExamModeAnswer,
  ExamModeFourMarkAnswer,
  ExamModeTwoMarkAnswer,
  StudentLevel,
  StudyPathPlanType,
  VideoScene,
} from "@/lib/api/types";

type SourceValidationError = {
  valid: false;
  error: string;
};

type SourceValidationResult = { valid: true } | SourceValidationError;

type SourceWithStatus = {
  id: string;
  status?: "uploaded" | "processing" | "ready" | "failed";
};

export type AnswerCorrectionInput = {
  question: string;
  studentAnswer: string;
  marks: "1" | "2" | "3" | "4" | "5" | "6" | "not_sure";
  subject?: string;
  chapter?: string;
};

function validateSourceForTool(documents: SourceWithStatus[], sourceIds: string[]): SourceValidationResult {
  if (sourceIds.length === 0) {
    return { valid: false, error: "Choose a source first so I can make this from your material." };
  }

  const selectedDocuments = documents.filter((doc) => sourceIds.includes(doc.id));
  if (selectedDocuments.length === 0) {
    return { valid: false, error: "Selected source not found. Please choose a valid source." };
  }

  const processingSources = selectedDocuments.filter((doc) => doc.status === "processing" || doc.status === "uploaded");
  if (processingSources.length > 0) {
    return { valid: false, error: "This source is still being read. I'll unlock source-based tools when it's ready." };
  }

  const failedSources = selectedDocuments.filter((doc) => doc.status === "failed");
  if (failedSources.length > 0) {
    return { valid: false, error: "I couldn't read this file properly. Try retrying extraction or upload a clearer file." };
  }

  // If any source has no status, treat it as potentially not ready
  const unknownStatusSources = selectedDocuments.filter((doc) => !doc.status);
  if (unknownStatusSources.length > 0 && unknownStatusSources.length === selectedDocuments.length) {
    return { valid: false, error: "Source status unknown. Please wait for the source to finish processing." };
  }

  return { valid: true };
}

export type StudioRunSection = {
  title: string;
  items: string[];
  variant?: "default" | "caution" | "action" | "keywords";
};

export type StudioRunResult = {
  toolId: StudioToolId;
  title: string;
  summary: string;
  sections: StudioRunSection[];
  status: "ready" | "empty" | "fallback";
  generationTimeMs?: number | null;
  cacheHit?: boolean;
  raw?: unknown;
  evidenceLabel?: string | null;
};

type RunStudioToolInput = {
  toolId: StudioToolId;
  documentId: string;
  sourceIds?: string[];
  sourceTitle: string;
  language?: string;
  studentLevel?: StudentLevel;
  weakAreas?: string[];
  goal?: string;
  timeLeft?: string;
  topic?: string;
  studyProfileId?: string | null;
  quizQuestionCount?: number;
  documents?: SourceWithStatus[] | undefined;
  answerCorrection?: AnswerCorrectionInput;
};

const toolTitles: Record<StudioToolId, string> = {
  "smart-notes": "Teach this syllabus topic",
  "pyq-intelligence": "Show exam pattern from uploaded PYQs",
  "ai-quiz": "Test me on this topic",
  flashcards: "Lock exam keywords",
  "study-videos": "Teach with a visual lesson",
  "exam-answer": "Make board-answer version",
  "answer-correction": "Correct my answer",
  "last-night-prep": "Tell me what to study tonight",
  "study-plan": "Build my chapter roadmap",
  "what-to-study": "What To Study First",
  "check-level": "Check My Level",
  "exam-war-mode": "Exam War Mode",
};

function baseResult(input: RunStudioToolInput, summary: string, sections: StudioRunSection[], raw?: unknown, evidenceLabel?: string | null): StudioRunResult {
  return {
    toolId: input.toolId,
    title: `${toolTitles[input.toolId]}: ${input.sourceTitle}`,
    summary,
    sections,
    status: "ready",
    raw,
    evidenceLabel: evidenceLabel ?? null,
  };
}

function answerToLine(answer: ExamModeAnswer | ExamModeTwoMarkAnswer | ExamModeFourMarkAnswer | { question?: string; answer?: string }) {
  if ("question" in answer && "answer" in answer) return `${answer.question}: ${answer.answer}`;
  return "Mark-wise answer outline";
}

function planTypeForTool(toolId: StudioToolId): StudyPathPlanType {
  if (toolId === "last-night-prep") return "1h";
  if (toolId === "exam-war-mode") return "5h";
  return "7d";
}

function evidenceLabelFromRaw(raw: unknown): string | null {
  if (raw && typeof raw === "object" && "evidence_label" in raw) {
    const label = (raw as { evidence_label?: unknown }).evidence_label;
    return typeof label === "string" ? label : null;
  }
  return null;
}

// The title must describe what the analysis actually did, never a span the data
// does not establish. The analyzer is upload-gated: it compares only the user's
// uploaded and verified papers and refuses pattern analysis below 2 years
// (backend/app/services/pyq_pattern_analyzer.py). "10-year" must not appear
// unless a genuine verified evidence label (8+ distinct years) is present.
function pyqTitleFromEvidence(label: string | null, paperCount: number) {
  const text = label?.toLowerCase() ?? "";
  const hasVerifiedEvidence =
    text.includes("verified") && !text.includes("not verified") && !text.includes("unverified");
  if (hasVerifiedEvidence) return "Verified multi-year PYQ signals";
  if (paperCount === 1) return "Signals from this paper";
  return "Signals across uploaded papers";
}

function uploadedPaperEvidenceLabel(paperCount: number) {
  return `Based on ${paperCount} uploaded question paper${paperCount !== 1 ? "s" : ""}`;
}

export async function runStudioTool(input: RunStudioToolInput): Promise<StudioRunResult> {
  const language = input.language ?? "English";
  const sourceIds = input.sourceIds?.length ? input.sourceIds : [input.documentId];

  // Validate sources if documents are provided
  if (input.documents && input.documents.length > 0) {
    const validation = validateSourceForTool(input.documents, sourceIds);
    if (!validation.valid) {
      return {
        toolId: input.toolId,
        title: `${toolTitles[input.toolId]}: ${input.sourceTitle}`,
        summary: validation.error,
        sections: [{ title: "Error", items: [validation.error], variant: "caution" as const }],
        status: "empty",
      };
    }
  }

  const topic = input.topic || input.sourceTitle.replace(/^\d+\s+selected\s+sources$/i, "selected sources");
  const brainPayload: BrainGeneratePayload = {
    topic,
    subject: undefined,
    source_id: input.documentId,
    source_ids: sourceIds,
    study_profile_id: input.studyProfileId ?? null,
    level: input.studentLevel ?? "intermediate",
    goal: input.goal ?? "good marks",
    language_preference: language,
    options: { tool: input.toolId, weak_areas: input.weakAreas ?? [] },
  };
  if (input.toolId === "smart-notes") {
    const result = await generateBrainNotes({ ...brainPayload, options: { mode: "smart_notes" } });
    const notes = normalizeNotes(result.output);
    const sections: StudioRunSection[] = [
      { title: "Key points", items: notes.key_points },
      { title: "Exam focus", items: notes.exam_focus ?? notes.exam_keywords ?? [] },
      ...(notes.scoring_keywords?.length ? [{ title: "Scoring keywords", items: notes.scoring_keywords, variant: "keywords" as const }] : []),
      ...(notes.common_mistakes?.length ? [{ title: "Common mistakes", items: notes.common_mistakes }] : []),
      { title: "Last-minute revision", items: notes.last_minute_revision ?? [] },
      ...(notes.ten_minute_revision?.length ? [{ title: "10-min revision", items: notes.ten_minute_revision }] : []),
      ...(notes.caution_note ? [{ title: "Caution", items: [notes.caution_note], variant: "caution" as const }] : []),
      ...(notes.next_study_action ? [{ title: "Next move", items: [notes.next_study_action], variant: "action" as const }] : []),
    ];
    return baseResult(
      input,
      notes.source_summary ?? notes.summary ?? notes.student_level_summary ?? "DocDoe created source-based revision notes.",
      sections,
      result,
      result.evidence_label,
    );
  }

  if (input.toolId === "ai-quiz") {
    const questionCount = input.quizQuestionCount ?? 5;
    const result = await generateBrainQuiz({
      ...brainPayload,
      options: {
        ...(brainPayload.options ?? {}),
        difficulty: "exam",
        num_questions: questionCount,
        question_count: questionCount,
      },
    });
    const questions = normalizeQuiz(result.output);
    const traps = questions.map((q) => q.common_trap).filter((t): t is string => Boolean(t));
    const quizSections: StudioRunSection[] = [
      { title: "Practice questions", items: questions.map((question) => question.question) },
      ...(traps.length ? [{ title: "Common traps", items: traps, variant: "caution" as const }] : []),
    ];
    const quizResult = baseResult(
      input,
      questions.length > 0
        ? result.cache_hit
          ? "DocDoe reused your recent quiz instantly."
          : questionCount >= 10
            ? `DocDoe created a ${questionCount}-question practice set from your selected source.`
            : "DocDoe created a short practice quiz from the active source."
        : "DocDoe could not create quiz questions from this source yet.",
      quizSections,
      result,
      result.evidence_label,
    );
    return {
      ...quizResult,
      generationTimeMs: result.generation_time_ms ?? null,
      cacheHit: Boolean(result.cache_hit),
    };
  }

  if (input.toolId === "flashcards") {
    const result = await generateBrainFlashcards({ ...brainPayload, options: { card_count: 8 } });
    const cards = normalizeFlashcards(result.output);
    const hooks = cards.map((c) => c.memory_hook).filter((h): h is string => Boolean(h));
    const examUses = cards.map((c) => c.exam_use).filter((u): u is string => Boolean(u));
    const flashSections: StudioRunSection[] = [
      { title: "Cards", items: cards.map((card) => `${card.front} — ${card.back}`) },
      ...(hooks.length ? [{ title: "Memory hooks", items: hooks }] : []),
      ...(examUses.length ? [{ title: "Exam use", items: examUses }] : []),
    ];
    return baseResult(
      input,
      cards.length > 0
        ? "DocDoe created active-recall cards for quick revision."
        : "DocDoe could not create flashcards from this source yet.",
      flashSections,
      result,
      result.evidence_label,
    );
  }

  if (input.toolId === "exam-answer") {
    const result = await generateBrainExamAnswer(brainPayload);
    const output = normalizeExamAnswer(result.output);
    const answers = [
      ...(output?.one_mark ?? []),
      ...(output?.two_mark ?? []),
      ...(output?.four_mark ?? []),
      ...result.output.six_mark,
      ...(output?.one_mark_answers ?? []),
      ...(output?.two_mark_answers ?? []),
      ...(output?.four_mark_answers ?? []),
    ];
    const examSections: StudioRunSection[] = [
      { title: "Mark-wise answers", items: answers.map(answerToLine).slice(0, 6) },
      { title: "Keywords", items: output?.keywords_to_use ?? output?.important_keywords ?? result.output.keywords_to_underline ?? [] },
      ...(result.output.scoring_keywords?.length ? [{ title: "Scoring keywords", items: result.output.scoring_keywords, variant: "keywords" as const }] : []),
      { title: "Common mistakes", items: output?.mistakes_to_avoid ?? [result.output.common_mistake] },
      { title: "Examiner tip", items: [result.output.examiner_tip, ...(result.output.answer_writing_formula ?? [])] },
      ...(result.output.caution_note ? [{ title: "Caution", items: [result.output.caution_note], variant: "caution" as const }] : []),
      ...(result.output.next_study_action ? [{ title: "Next move", items: [result.output.next_study_action], variant: "action" as const }] : []),
    ];
    return baseResult(
      input,
      "DocDoe shaped this into mark-wise exam answers.",
      examSections,
      result,
      result.evidence_label,
    );
  }

  if (input.toolId === "answer-correction") {
    const correction = input.answerCorrection;
    if (!correction?.question.trim() || !correction.studentAnswer.trim()) {
      return {
        toolId: input.toolId,
        title: `${toolTitles[input.toolId]}: ${input.sourceTitle}`,
        summary: "Paste the question and your answer before correction.",
        sections: [{ title: "Missing input", items: ["Paste the question and your answer before correction."], variant: "caution" as const }],
        status: "empty",
      };
    }
    const result = await generateBrainAnswerCorrection({
      ...brainPayload,
      topic: correction.question,
      subject: correction.subject || brainPayload.subject,
      options: {
        ...(brainPayload.options ?? {}),
        mode: "answer_correction",
        question: correction.question,
        student_answer: correction.studentAnswer,
        marks: correction.marks,
        subject: correction.subject,
        chapter: correction.chapter,
      },
    });
    const output = result.output as BrainAnswerCorrectionOutput;
    const isSourceMismatch = output.source_truth.toLowerCase().includes("not found");
    const correctionSections: StudioRunSection[] = [
      { title: "Syllabus position", items: [output.syllabus_position, output.mark_scheme_assumption, output.score] },
      { title: "What you wrote correctly", items: output.what_correct },
      { title: "Marks lost", items: output.marks_lost, variant: isSourceMismatch ? "caution" : "default" },
      { title: "Missing keywords", items: output.missing_keywords, variant: "keywords" },
      { title: "Corrected board-answer version", items: [output.corrected_board_answer] },
      { title: "How to improve next time", items: output.how_to_improve },
      { title: "Quick retry task", items: [output.quick_retry_task], variant: "action" },
      ...(output.source_evidence?.length ? [{ title: "Source evidence", items: output.source_evidence, variant: "keywords" as const }] : []),
      { title: "Source truth", items: [output.source_truth], variant: isSourceMismatch ? "caution" : "default" },
    ];
    return baseResult(
      input,
      isSourceMismatch
        ? output.source_truth
        : `${output.score}. DocDoe found the marks lost and rewrote the answer in board format.`,
      correctionSections,
      result,
      result.evidence_label,
    );
  }

  if (input.toolId === "pyq-intelligence") {
    const papers = await listPreviousPapers();
    if (papers.length === 0) {
      return {
        toolId: input.toolId,
        title: "Upload question papers to unlock PYQ signals",
        summary: "DocDoe can explain this material, but PYQ trends need actual previous papers. Add past papers for this subject to compare patterns.",
        sections: [
          { title: "Upload question paper", items: ["Upload question papers to unlock PYQ signals."] },
          { title: "Continue with material-only questions", items: ["Likely questions from this material"] },
        ],
        status: "empty",
        evidenceLabel: "Based on uploaded material only",
      };
    }
    const result = await analyzeStructuredPreviousPapers({
      paper_ids: papers.map((paper) => paper.id),
      subject: papers[0]?.subject ?? "Study",
      syllabus: papers[0]?.syllabus ?? "Indian Board Exams",
      target_exam: "Board exam",
    });
    const analysis = normalizePYQAnalysis(result);
    const pyqSections: StudioRunSection[] = [
      {
        title: "Repeated topics",
        items: analysis?.repeated_topics.map((topic) => `${topic.topic}: ${topic.reason}`) ?? [],
      },
      {
        title: "High probability",
        items: analysis?.high_probability_topics.map((topic) => `${topic.topic}: ${topic.reason}`) ?? [],
      },
      { title: "Study priority", items: analysis?.study_priority ?? [] },
      ...(analysis?.one_paper_limit_note ? [{ title: "Note", items: [analysis.one_paper_limit_note], variant: "caution" as const }] : []),
      ...(analysis?.next_study_action ? [{ title: "Next move", items: [analysis.next_study_action], variant: "action" as const }] : []),
      ...(analysis?.caution_note ? [{ title: "Caution", items: [analysis.caution_note], variant: "caution" as const }] : []),
    ];
    const evidenceLabel = evidenceLabelFromRaw(result) ?? uploadedPaperEvidenceLabel(papers.length);
    const pyqResult = baseResult(
      input,
      analysis?.summary ?? "DocDoe checked available previous papers for patterns.",
      pyqSections,
      result,
      evidenceLabel,
    );
    return {
      ...pyqResult,
      title: pyqTitleFromEvidence(evidenceLabel, papers.length),
      evidenceLabel,
    };
  }

  if (input.toolId === "what-to-study") {
    const result = await getWhatToStudy(input.documentId, input.studentLevel ?? "intermediate", "good marks");
    return baseResult(
      input,
      "DocDoe prioritized the chapter from your source, goal, and current level.",
      [
        { title: "Study first", items: result.must_study_topics.map((topic) => `${topic.topic}: ${topic.reason}`) },
        { title: "Quick wins", items: result.easy_marks.map((topic) => `${topic.topic}: ${topic.reason}`) },
        { title: "Skip for now", items: result.skip_for_now_topics.map((topic) => `${topic.topic}: ${topic.reason}`) },
      ],
      result,
      result.evidence_label ?? null,
    );
  }

  if (input.toolId === "study-plan" || input.toolId === "last-night-prep" || input.toolId === "exam-war-mode") {
    if (input.toolId === "last-night-prep") {
      const result = await generateBrainLastNightPlan({
        ...brainPayload,
        time_left: input.timeLeft ?? "5 hours",
      });
      const plan = result.output;
      const lnpSections: StudioRunSection[] = [
        ...(plan.do_first?.length ? [{ title: "Do first", items: plan.do_first }] : []),
        { title: "Time blocks", items: plan.time_blocks.map((block) => `${block.label}: ${block.minutes} min`) },
        ...(plan.if_30_minutes?.length ? [{ title: "If 30 minutes", items: plan.if_30_minutes }] : []),
        ...(plan.if_2_hours?.length ? [{ title: "If 2 hours", items: plan.if_2_hours }] : []),
        ...(plan.if_half_day?.length ? [{ title: "If half day", items: plan.if_half_day }] : []),
        { title: "Must study", items: plan.must_study },
        { title: "Skip for now", items: plan.skip_now },
        ...(plan.skip_or_skim?.length ? [{ title: "Skip or skim", items: plan.skip_or_skim }] : []),
        ...(plan.quick_recall_questions?.length ? [{ title: "Quick recall", items: plan.quick_recall_questions }] : []),
        { title: "Final checklist", items: plan.final_checklist },
        ...(plan.final_check_before_sleep?.length ? [{ title: "Final check before sleep", items: plan.final_check_before_sleep }] : []),
        ...(plan.caution_note ? [{ title: "Caution", items: [plan.caution_note], variant: "caution" as const }] : []),
        { title: "Trust note", items: [result.trust_note ?? plan.trust_note ?? "Using your selected source and study goal."] },
      ];
      return baseResult(
        input,
        plan.calming_note ?? "DocDoe built a calm last-night plan with scoring priorities.",
        lnpSections,
        result,
        result.evidence_label,
      );
    }
    const planType = planTypeForTool(input.toolId);
    const goal = input.toolId === "exam-war-mode" ? "pass" : "good marks";
    const result = sourceIds.length > 1
      ? await generateStudyPath({
          source_id: input.documentId,
          source_ids: sourceIds,
          topic,
          goal,
          level: input.studentLevel ?? "intermediate",
          language_preference: language,
          use_my_profile: true,
        })
      : await getStudyPath(input.documentId, planType, input.studentLevel ?? "intermediate", goal);
    const plan = "study_timeline" in result
      ? {
          blocks: result.study_timeline.map((item) => ({
            time_block: `${item.duration_minutes} min`,
            topic: item.title,
            reason: item.reason,
            task: item.task,
            output_expected: item.expected_output,
            revision_checkpoint: item.actions.join(", "),
          })),
        }
      : normalizeStudyPlan(result);
    const studyPathEvidenceLabel = "evidence_label" in result && typeof (result as { evidence_label?: unknown }).evidence_label === "string"
      ? (result as { evidence_label: string }).evidence_label
      : null;
    return baseResult(
      input,
      `DocDoe built a ${planType} plan with checkpoints and revision blocks.`,
      [
        {
          title: "Time blocks",
          items: plan?.blocks.map((block) => `${block.time_block}: ${block.task}`) ?? [],
        },
        {
          title: "Why this order",
          items: plan?.blocks.map((block) => `${block.topic}: ${block.reason}`) ?? [],
        },
      ],
      result,
      studyPathEvidenceLabel,
    );
  }

  if (input.toolId === "study-videos") {
    const brainPlan = await generateBrainVideoPlan({
      topic,
      video_mode: "exam_focus",
      teaching_style: "visual_tutor",
      language_preference: language,
      format: "16:9",
      source_id: input.documentId,
      source_ids: sourceIds,
      level: input.studentLevel ?? "intermediate",
      goal: input.goal ?? "good marks",
    });
    if (brainPlan.planning_only || !brainPlan.render_supported) {
      return baseResult(
        input,
        "DocDoe created a study video plan. This long video is planned first. Rendering support will be added later.",
        [
          { title: "Duration", items: [brainPlan.target_duration_range, `${brainPlan.estimated_duration_minutes} minutes estimated`] },
          { title: "Scene plan", items: brainPlan.scenes.map((scene) => `${scene.title}: ${scene.on_screen_text}`) },
          { title: "Trust note", items: [brainPlan.trust_note] },
        ],
        brainPlan,
        brainPlan.evidence_label,
      );
    }
    const result = await createVideoScenePlan({
      document_id: input.documentId,
      title: input.sourceTitle,
      language,
      duration_minutes: 5,
      visual_style: "clean_explainer",
      video_format: "16:9",
    });
    const plan = normalizeVideoPlan(result);
    const scenes = "scenes" in (plan ?? {}) ? (plan as { scenes: VideoScene[] }).scenes : [];
    return baseResult(
      input,
      "DocDoe created a teachable scene plan. Long videos can take more time to prepare.",
      [{ title: "Scene plan", items: scenes.map((scene) => `${scene.screen_text}: ${scene.visual_hint}`) }],
      result,
      result.evidence_label ?? null,
    );
  }

  return {
    toolId: input.toolId,
    title: `${toolTitles[input.toolId]}: ${input.sourceTitle}`,
    summary: "Choose this tool from Studio to continue.",
    sections: [{ title: "Next step", items: ["DocDoe is ready when you are."] }],
    status: "fallback",
  };
}