"use client";

import { useCallback, useEffect, useMemo, useState, type ReactNode } from "react";
import {
  AlertCircle,
  Check,
  ChevronDown,
  Clapperboard,
  Download,
  ExternalLink,
  LoaderCircle,
  Lock,
  RotateCcw,
  X,
} from "lucide-react";
import { cn } from "@/lib/utils";
import { AnswerTrustFooter, EvidenceBadge } from "@/components/dashboard/EvidenceBadge";
import { useJobPolling } from "@/hooks/useJobPolling";
import { normalizeApiError, resolveMediaUrl } from "@/lib/api/client";
import {
  createStudyVideoJob,
  getVideoJob,
  renderStudyVideoPreview,
} from "@/lib/api/video";
import type {
  StudyVideoJobResponse,
  StudyVideoMode,
  StudyVideoPlan,
  StudyVideoScene,
  StudyVideoPreviewResponse,
  VideoRenderJob,
} from "@/lib/api/types";
import {
  VIDEO_DURATION_OPTIONS,
  type VideoDurationMinutes,
  videoDurationOption,
} from "@/lib/video/durations";

type WizardStage =
  | "setup"
  | "planning"
  | "script_ready"
  | "preview_rendering"
  | "preview_ready"
  | "failed";

type JobViewState = {
  id: string;
  status: string;
  current_step?: string | null;
  progress?: number | null;
  output_url?: string | null;
  evidence_label?: string | null;
  error_message?: string | null;
};

type MaterialType =
  | "notes"
  | "chapter"
  | "textbook"
  | "question_paper"
  | "handwritten_notes"
  | "syllabus"
  | "resume_or_personal_doc"
  | "unknown";

export type StudyVideoWizardSource = {
  id: string;
  title: string;
  subject?: string;
  status?: string;
  materialType?: MaterialType | null;
  material_type?: MaterialType | null;
  evidenceLabel?: string | null;
  evidence_label?: string | null;
};

type StudyVideoWizardProps = {
  isOpen: boolean;
  source: StudyVideoWizardSource;
  onClose: () => void;
  onUploadClick?: () => void;
};

const validVideoMaterialTypes = new Set<MaterialType>([
  "notes",
  "chapter",
  "textbook",
  "handwritten_notes",
  "question_paper",
  "syllabus",
]);

const materialLabels: Record<MaterialType, string> = {
  notes: "Notes",
  chapter: "Chapter",
  textbook: "Textbook",
  question_paper: "Question paper",
  handwritten_notes: "Handwritten notes",
  syllabus: "Syllabus",
  resume_or_personal_doc: "Personal document",
  unknown: "Unknown source",
};

const specialModeOptions: {
  value: StudyVideoMode;
  label: string;
  helper: string;
  target: number;
  durationMinutes: VideoDurationMinutes;
}[] = [
  {
    value: "last_night_revision",
    label: "Last-night revision",
    helper: "Quick recall and scoring points.",
    target: 600,
    durationMinutes: 10,
  },
  {
    value: "pyq_review",
    label: "PYQ review",
    helper: "Only for uploaded question paper sources.",
    target: 600,
    durationMinutes: 10,
  },
];

const languageOptions = ["English", "Malayalam", "Mixed"];
const formatOptions = [
  { value: "16:9", label: "Landscape" },
  { value: "9:16", label: "Vertical" },
];
const visualStyleOptions = [
  { value: "clean_explainer", label: "Clean explainer" },
  { value: "anime_visual_explainer", label: "Anime visual explainer" },
];
const voiceOptions = [
  { value: "", label: "Default" },
  { value: "calm_teacher", label: "Calm teacher" },
  { value: "malayalam_english_teacher", label: "Malayalam + English teacher" },
];
const previewPollingTimeoutMs = 10 * 60 * 1000;
const previewTimeoutCopy = "Preview is still rendering. You can close this and check Recent videos later.";

function getMaterialType(source: StudyVideoWizardSource) {
  return source.materialType ?? source.material_type ?? null;
}

function defaultModeForSource(source: StudyVideoWizardSource): StudyVideoMode {
  if (getMaterialType(source) === "question_paper") return "pyq_review";
  return "exam_study_video";
}

function targetForMode(mode: StudyVideoMode, durationMinutes: VideoDurationMinutes) {
  const special = specialModeOptions.find((option) => option.value === mode);
  if (special) return special.target;
  return videoDurationOption(durationMinutes).targetSeconds;
}

function modeForDuration(durationMinutes: VideoDurationMinutes, materialType: MaterialType | null | undefined): StudyVideoMode {
  if (materialType === "question_paper") return "pyq_review";
  return videoDurationOption(durationMinutes).studyMode;
}

function getSourceEvidenceLabel(source: StudyVideoWizardSource) {
  return source.evidenceLabel ?? source.evidence_label ?? null;
}

function getEligibility(source: StudyVideoWizardSource) {
  const materialType = getMaterialType(source);
  if (!source.id) {
    return {
      canCreate: false,
      title: "Upload material to create a study video.",
      body: "Choose a readable PDF or TXT source containing notes, a chapter, syllabus, textbook, or question paper before creating a video.",
      cta: "Upload material",
    };
  }
  if (source.status === "processing" || source.status === "uploaded") {
    return {
      canCreate: false,
      title: "This source is still processing.",
      body: "Create the video after DocDoe finishes reading the source.",
      cta: null,
    };
  }
  if (source.status === "failed") {
    return {
      canCreate: false,
      title: "This source is no longer eligible for study videos.",
      body: "DocDoe could not read this file. Upload another copy or use another source.",
      cta: "Upload material",
    };
  }
  if (materialType === "resume_or_personal_doc") {
    return {
      canCreate: false,
      title: "Use study material to create a video.",
      body: "Personal documents are blocked from exam video generation.",
      cta: null,
    };
  }
  if (materialType === "unknown" || !materialType) {
    return {
      canCreate: false,
      title: "Classify this source to create a video.",
      body: "Use readable notes, a chapter, syllabus, textbook, or question paper to create a study video.",
      cta: null,
    };
  }
  if (!validVideoMaterialTypes.has(materialType)) {
    return {
      canCreate: false,
      title: "This source is no longer eligible for study videos.",
      body: "Use readable notes, a chapter, syllabus, textbook, or question paper to create a study video.",
      cta: null,
    };
  }
  return { canCreate: true, title: "", body: "", cta: null };
}

function sourceHeader(source: StudyVideoWizardSource) {
  const materialType = getMaterialType(source);
  if (materialType === "question_paper") return `Analyzing paper: ${source.title}`;
  if (
    materialType === "notes" ||
    materialType === "chapter" ||
    materialType === "textbook" ||
    materialType === "handwritten_notes" ||
    materialType === "syllabus"
  ) {
    return `Working from: ${source.title}`;
  }
  return null;
}

// The "verified" note is only earned by the real evidence marker: the backend
// evidence contract emits a "verified" label solely when 8+ distinct years of
// reviewed papers are uploaded (backend/app/services/evidence_contract.py).
// A marketing span like "10-year" must never mint this state, and a label that
// explicitly denies verification ("not verified", "unverified") must not be
// read as its opposite.
function hasVerifiedEvidence(text: string): boolean {
  return text.includes("verified") && !text.includes("not verified") && !text.includes("unverified");
}

function evidenceContextNote(label: string | null | undefined) {
  if (!label) return null;
  const text = label.toLowerCase();
  if (text.includes("uploaded material only") || text.includes("material only")) {
    return "Video will be based on uploaded material only. Upload question papers to unlock PYQ-based video signals.";
  }
  if (text.includes("1 uploaded") || text.includes("one uploaded")) {
    return "Video will analyze this paper only. Upload more papers for trend analysis.";
  }
  if (hasVerifiedEvidence(text)) {
    return "Verified PYQ evidence is available for this context.";
  }
  return null;
}

function isTerminalStatus(status: string | null | undefined) {
  return status === "complete" || status === "ready" || status === "failed";
}

function isCompleteStatus(status: string | null | undefined) {
  return status === "complete" || status === "ready";
}

function fallbackProgress(status: string | null | undefined) {
  if (status === "audio_generating") return 35;
  if (status === "rendering" || status === "running" || status === "uploading") return 65;
  if (isCompleteStatus(status)) return 100;
  if (status === "script_ready") return 25;
  return 10;
}

function progressFor(job: JobViewState | null, stage: WizardStage) {
  if (!job) return stage === "planning" ? 18 : 0;
  return Math.max(0, Math.min(job.progress ?? fallbackProgress(job.status), 100));
}

function toJobState(job: StudyVideoJobResponse | StudyVideoPreviewResponse | VideoRenderJob): JobViewState {
  const record = job as Partial<VideoRenderJob & StudyVideoJobResponse & StudyVideoPreviewResponse>;
  return {
    id: job.id,
    status: job.status,
    current_step: job.current_step,
    progress: record.progress ?? null,
    output_url: record.output_url ?? record.public_url ?? record.download_url ?? null,
    evidence_label: record.evidence_label ?? null,
    error_message: record.error_message ?? null,
  };
}

function safeVideoError(error: unknown) {
  const message = normalizeApiError(error);
  const lower = message.toLowerCase();

  if (lower.includes("sign in")) return "Please sign in again.";
  if (lower.includes("offline") || lower.includes("unreachable") || lower.includes("failed to fetch")) {
    return "DocDoe is temporarily offline. Check your connection and try again.";
  }
  if (lower.includes("pyq") && lower.includes("question")) {
    return "PYQ review needs a question paper source.";
  }
  if (lower.includes("script") && lower.includes("ready")) {
    return "Preview render can only start after the study video script is ready.";
  }
  if (lower.includes("scene plan") || lower.includes("missing")) {
    return "Scene plan is missing. Create the study video plan again.";
  }
  if (lower.includes("source") || lower.includes("eligible") || lower.includes("material")) {
    return "Use readable notes, a chapter, syllabus, textbook, or question paper to create a study video.";
  }
  if (message.includes("Traceback") || message.includes("{") || message.length > 180) {
    return "Preview render failed.";
  }
  return message || "Preview render failed.";
}

function materialLabel(source: StudyVideoWizardSource) {
  const materialType = getMaterialType(source);
  return materialType ? materialLabels[materialType] : "Unknown source";
}

function jobTitle(plan: StudyVideoPlan | null, source: StudyVideoWizardSource) {
  if (plan?.title) return plan.title;
  const materialType = getMaterialType(source);
  if (materialType === "question_paper") return "PYQ review video";
  if (materialType === "syllabus") return "Syllabus map video";
  return "Study video";
}

function isStudyVideoPlan(value: unknown): value is StudyVideoPlan {
  if (!value || typeof value !== "object") return false;
  const record = value as Partial<StudyVideoPlan>;
  return typeof record.title === "string" && Array.isArray(record.scenes);
}

function normalizeScene(scene: Partial<StudyVideoScene>, index: number): StudyVideoScene {
  const id = typeof scene.id === "string" && scene.id.trim() ? scene.id : `scene_${index + 1}`;
  const title = typeof scene.title === "string" && scene.title.trim() ? scene.title : `Scene ${index + 1}`;
  const narration = typeof scene.narration === "string" ? scene.narration : "";
  return {
    id,
    type: typeof scene.type === "string" && scene.type.trim() ? scene.type : "explanation",
    title,
    narration,
    duration_seconds: typeof scene.duration_seconds === "number" && Number.isFinite(scene.duration_seconds)
      ? scene.duration_seconds
      : 30,
    visual_hint: typeof scene.visual_hint === "string" ? scene.visual_hint : "",
    on_screen_text: typeof scene.on_screen_text === "string" && scene.on_screen_text.trim()
      ? scene.on_screen_text
      : title,
    keywords: Array.isArray(scene.keywords) ? scene.keywords.filter((keyword): keyword is string => typeof keyword === "string") : [],
    evidence_note: typeof scene.evidence_note === "string" ? scene.evidence_note : null,
    animation_style: typeof scene.animation_style === "string" && scene.animation_style.trim()
      ? scene.animation_style
      : "clean_explainer",
    subtitle_segments: Array.isArray(scene.subtitle_segments) ? scene.subtitle_segments : [],
  };
}

function normalizeStudyVideoPlan(value: unknown): StudyVideoPlan | null {
  if (!isStudyVideoPlan(value)) return null;
  const rawScenes = value.scenes as unknown[];
  const scenes = rawScenes
    .filter((scene): scene is Partial<StudyVideoScene> => Boolean(scene) && typeof scene === "object")
    .map(normalizeScene);
  if (scenes.length === 0) return null;
  return { ...value, scenes };
}

export function StudyVideoWizard({ isOpen, source, onClose, onUploadClick }: StudyVideoWizardProps) {
  const [stage, setStage] = useState<WizardStage>("setup");
  const [durationMinutes, setDurationMinutes] = useState<VideoDurationMinutes>(10);
  const [mode, setMode] = useState<StudyVideoMode>("exam_study_video");
  const [language, setLanguage] = useState("English");
  const [format, setFormat] = useState("16:9");
  const [visualStyle, setVisualStyle] = useState("clean_explainer");
  const [voice, setVoice] = useState("");
  const [planResponse, setPlanResponse] = useState<StudyVideoJobResponse | null>(null);
  const [job, setJob] = useState<JobViewState | null>(null);
  const [error, setError] = useState<string | null>(null);
  const [pollTimedOut, setPollTimedOut] = useState(false);
  const [expandedScenes, setExpandedScenes] = useState<Record<string, boolean>>({});

  const eligibility = useMemo(() => getEligibility(source), [source]);
  const sourceEvidenceLabel = getSourceEvidenceLabel(source);
  const plan = useMemo(() => normalizeStudyVideoPlan(planResponse?.plan), [planResponse?.plan]);
  const currentEvidenceLabel = job?.evidence_label ?? plan?.evidence_label ?? planResponse?.evidence_label ?? sourceEvidenceLabel;
  const sourceContextHeader = sourceHeader(source);
  const evidenceNote = evidenceContextNote(currentEvidenceLabel);
  const previewUrl = resolveMediaUrl(job?.output_url);
  const progress = progressFor(job, stage);
  const selectedDuration = videoDurationOption(durationMinutes);
  const selectedSpecialMode = specialModeOptions.find((option) => option.value === mode);
  const jobId = job?.id ?? null;

  useEffect(() => {
    if (!isOpen) return;
    const resetTimeoutId = window.setTimeout(() => {
      const nextMode = defaultModeForSource(source);
      setStage("setup");
      setDurationMinutes(nextMode === "pyq_review" ? 10 : 10);
      setMode(nextMode);
      setLanguage("English");
      setFormat("16:9");
      setVisualStyle("clean_explainer");
      setVoice("");
      setPlanResponse(null);
      setJob(null);
      setError(null);
      setPollTimedOut(false);
      setExpandedScenes({});
    }, 0);
    return () => window.clearTimeout(resetTimeoutId);
  }, [isOpen, source]);

  const pollFetcher = useCallback(async () => {
    if (!jobId) throw new Error("No preview job is running.");
    return getVideoJob(jobId);
  }, [jobId]);

  const onPollData = useCallback((nextJob: VideoRenderJob) => {
    const nextState = toJobState(nextJob);
    setJob(nextState);

    if (nextState.status === "failed") {
      setStage("failed");
      setError(nextState.error_message ? safeVideoError(new Error(nextState.error_message)) : "Preview render failed.");
      setPollTimedOut(false);
      return;
    }

    if (isCompleteStatus(nextState.status)) {
      setStage("preview_ready");
      setPollTimedOut(false);
      return;
    }

    setStage("preview_rendering");
    setPollTimedOut(false);
  }, []);

  const shouldContinuePolling = useCallback((nextJob: VideoRenderJob) => {
    return !isTerminalStatus(nextJob.status);
  }, []);

  const onPollingError = useCallback((caughtError: unknown) => {
    setStage("failed");
    setError(safeVideoError(caughtError));
    setPollTimedOut(false);
  }, []);

  const onPollingTimeout = useCallback(() => {
    setPollTimedOut(true);
  }, []);

  useJobPolling({
    enabled: isOpen && stage === "preview_rendering" && Boolean(jobId) && !pollTimedOut,
    fetcher: pollFetcher,
    intervalMs: 2500,
    timeoutMs: previewPollingTimeoutMs,
    shouldContinue: shouldContinuePolling,
    onData: onPollData,
    onError: onPollingError,
    onTimeout: onPollingTimeout,
  });

  if (!isOpen) return null;

  async function handleCreatePlan() {
    const latestEligibility = getEligibility(source);
    if (!latestEligibility.canCreate) {
      setError("This source is no longer eligible for study videos.");
      return;
    }
    if (mode === "pyq_review" && getMaterialType(source) !== "question_paper") {
      setError("PYQ review needs a question paper source.");
      return;
    }

    setStage("planning");
    setError(null);
    setPollTimedOut(false);
    setPlanResponse(null);
    setJob(null);
    setExpandedScenes({});

    try {
      const response = await createStudyVideoJob({
        document_id: source.id,
        video_mode: mode,
        target_duration_seconds: targetForMode(mode, durationMinutes),
        language,
        voice: voice || null,
        visual_style: visualStyle,
        format,
        preview_quality: true,
      });

      if (!normalizeStudyVideoPlan(response.plan)) {
        throw new Error("Scene plan is missing. Create the study video plan again.");
      }

      setPlanResponse(response);
      setJob(toJobState(response));
      setStage("script_ready");
    } catch (caughtError) {
      setStage("failed");
      setError(safeVideoError(caughtError));
    }
  }

  async function handleRenderPreview() {
    const latestEligibility = getEligibility(source);
    if (!latestEligibility.canCreate) {
      setError("This source is no longer eligible for study videos.");
      return;
    }
    if (!planResponse?.id) {
      setStage("failed");
      setError("Scene plan is missing. Create the study video plan again.");
      return;
    }
    if (job?.status !== "script_ready") {
      setError("Preview render can only start after the study video script is ready.");
      return;
    }

    setStage("preview_rendering");
    setError(null);
    setPollTimedOut(false);

    try {
      const response = await renderStudyVideoPreview(planResponse.id);
      const nextState = toJobState(response);
      setJob(nextState);
      if (nextState.status === "failed") {
        setStage("failed");
        setError("Preview render failed.");
        setPollTimedOut(false);
      } else if (isCompleteStatus(nextState.status)) {
        setStage("preview_ready");
        setPollTimedOut(false);
      }
    } catch (caughtError) {
      setStage("failed");
      setError(safeVideoError(caughtError));
      setPollTimedOut(false);
    }
  }

  function handleRetrySetup() {
    setStage("setup");
    setError(null);
    setPollTimedOut(false);
    setJob(null);
  }

  function toggleScene(sceneId: string) {
    setExpandedScenes((current) => ({ ...current, [sceneId]: !current[sceneId] }));
  }

  return (
    <div className="fixed inset-0 z-[110] flex items-end justify-center p-2 sm:items-center sm:p-4">
      <button
        type="button"
        aria-label="Close study video wizard"
        className="absolute inset-0 bg-black/72 backdrop-blur-sm"
        onClick={onClose}
      />
      <section
        aria-modal="true"
        role="dialog"
        className="relative flex max-h-[94dvh] w-full max-w-4xl flex-col overflow-hidden rounded-[22px] border border-white/[0.1] bg-[#050507] shadow-[0_32px_120px_rgba(0,0,0,0.68)] sm:max-h-[88dvh]"
      >
        <header className="flex shrink-0 items-center justify-between gap-3 border-b border-white/[0.08] bg-white/[0.025] px-4 py-3 sm:px-5">
          <div className="flex min-w-0 items-center gap-3">
            <span className="grid size-9 shrink-0 place-items-center rounded-2xl border border-white/[0.08] bg-white/[0.04] text-white/72">
              <Clapperboard className="size-4.5" strokeWidth={1.8} />
            </span>
            <div className="min-w-0">
              <p className="text-[10px] font-semibold uppercase text-white/36">Study video</p>
              <h2 className="truncate text-[15px] font-bold text-white">Create study video</h2>
            </div>
          </div>
          <div className="flex items-center gap-2">
            <StagePill stage={stage} />
            <button
              type="button"
              onClick={onClose}
              className="grid size-9 shrink-0 place-items-center rounded-2xl border border-white/[0.08] bg-white/[0.035] text-white/48 transition hover:bg-white/[0.07] hover:text-white"
              aria-label="Close wizard"
            >
              <X className="size-4" strokeWidth={2} />
            </button>
          </div>
        </header>

        <div className="min-h-0 flex-1 overflow-y-auto px-4 py-4 [scrollbar-color:rgba(255,255,255,0.14)_transparent] [scrollbar-width:thin] sm:px-5">
          <div className="space-y-4">
            <SourceSummaryCard
              source={source}
              sourceContextHeader={sourceContextHeader}
              evidenceLabel={currentEvidenceLabel}
            />

            {!eligibility.canCreate ? (
              <BlockedPanel
                title={eligibility.title}
                body={eligibility.body}
                cta={eligibility.cta}
                onUploadClick={onUploadClick}
              />
            ) : null}

            {error ? (
              <div className="rounded-2xl border border-rose-300/16 bg-rose-500/[0.06] px-4 py-3 text-[12px] leading-5 text-rose-50/78">
                <div className="flex gap-2.5">
                  <AlertCircle className="mt-0.5 size-4 shrink-0 text-rose-100/70" strokeWidth={1.8} />
                  <span>{error}</span>
                </div>
              </div>
            ) : null}

            {stage === "setup" || stage === "planning" ? (
              <SetupStep
                canCreate={eligibility.canCreate}
                durationMinutes={durationMinutes}
                mode={mode}
                language={language}
                format={format}
                visualStyle={visualStyle}
                voice={voice}
                selectedDuration={selectedDuration}
                selectedSpecialMode={selectedSpecialMode}
                materialType={getMaterialType(source)}
                evidenceNote={evidenceNote}
                isPlanning={stage === "planning"}
                onDurationChange={(minutes) => {
                  setDurationMinutes(minutes);
                  setMode(modeForDuration(minutes, getMaterialType(source)));
                }}
                onModeChange={setMode}
                onLanguageChange={setLanguage}
                onFormatChange={setFormat}
                onVisualStyleChange={setVisualStyle}
                onVoiceChange={setVoice}
                onCreatePlan={() => void handleCreatePlan()}
              />
            ) : null}

            {stage === "script_ready" && plan ? (
              <PlanReadyStep
                plan={plan}
                warnings={planResponse?.warnings ?? []}
                evidenceLabel={currentEvidenceLabel}
                evidenceNote={evidenceNote}
                canRender={eligibility.canCreate && job?.status === "script_ready"}
                expandedScenes={expandedScenes}
                onToggleScene={toggleScene}
                onRenderPreview={() => void handleRenderPreview()}
                onBackToSettings={handleRetrySetup}
              />
            ) : null}

            {stage === "preview_rendering" ? (
              <PreviewProgressStep
                title={jobTitle(plan, source)}
                job={job}
                progress={progress}
                evidenceLabel={currentEvidenceLabel}
                hasTimedOut={pollTimedOut}
              />
            ) : null}

            {stage === "preview_ready" ? (
              <PreviewReadyStep
                title={jobTitle(plan, source)}
                previewUrl={previewUrl}
                evidenceLabel={currentEvidenceLabel}
                onRetryLater={handleRetrySetup}
              />
            ) : null}

            {stage === "failed" ? (
              <FailedStep
                message={error ?? "Preview render failed."}
                onBackToSettings={handleRetrySetup}
              />
            ) : null}
          </div>
        </div>
      </section>
    </div>
  );
}

function StagePill({ stage }: { stage: WizardStage }) {
  const label: Record<WizardStage, string> = {
    setup: "Setup",
    planning: "Planning",
    script_ready: "Scene plan ready",
    preview_rendering: "Rendering",
    preview_ready: "Preview ready",
    failed: "Failed",
  };
  return (
    <span className="hidden rounded-full border border-white/[0.1] bg-white/[0.035] px-2.5 py-1 text-[10px] font-semibold text-white/55 sm:inline-flex">
      {label[stage]}
    </span>
  );
}

function SourceSummaryCard({
  source,
  sourceContextHeader,
  evidenceLabel,
}: {
  source: StudyVideoWizardSource;
  sourceContextHeader: string | null;
  evidenceLabel: string | null | undefined;
}) {
  return (
    <div className="rounded-2xl border border-white/[0.08] bg-white/[0.025] p-3.5">
      <div className="flex min-w-0 flex-wrap items-start justify-between gap-3">
        <div className="min-w-0">
          {sourceContextHeader ? (
            <p className="mb-1 truncate text-[11px] font-semibold text-white/46">{sourceContextHeader}</p>
          ) : null}
          <h3 className="break-words text-[14px] font-bold text-white/88">{source.title}</h3>
          <div className="mt-2 flex flex-wrap items-center gap-2">
            <span className="rounded-full border border-white/[0.08] bg-black/30 px-2.5 py-1 text-[10px] font-semibold text-white/50">
              {materialLabel(source)}
            </span>
            {source.subject ? (
              <span className="rounded-full border border-white/[0.08] bg-black/30 px-2.5 py-1 text-[10px] font-semibold text-white/50">
                {source.subject}
              </span>
            ) : null}
            <span className="rounded-full border border-white/[0.08] bg-black/30 px-2.5 py-1 text-[10px] font-semibold text-white/50">
              {source.status === "ready" || !source.status
                ? "Ready"
                : source.status.charAt(0).toUpperCase() + source.status.slice(1)}
            </span>
          </div>
        </div>
        <EvidenceBadge label={evidenceLabel} />
      </div>
    </div>
  );
}

function BlockedPanel({
  title,
  body,
  cta,
  onUploadClick,
}: {
  title: string;
  body: string;
  cta: string | null;
  onUploadClick?: () => void;
}) {
  return (
    <div className="rounded-2xl border border-white/[0.08] bg-white/[0.025] p-4">
      <div className="flex gap-3">
        <span className="grid size-9 shrink-0 place-items-center rounded-2xl border border-white/[0.08] bg-black/30 text-white/46">
          <Lock className="size-4" strokeWidth={1.8} />
        </span>
        <div className="min-w-0">
          <h3 className="text-[14px] font-bold text-white/86">{title}</h3>
          <p className="mt-1 text-[12px] leading-5 text-white/46">{body}</p>
          {cta && onUploadClick ? (
            <button
              type="button"
              onClick={onUploadClick}
              className="mt-3 inline-flex h-9 items-center justify-center rounded-2xl border border-white/[0.12] bg-white/[0.06] px-3 text-[12px] font-bold text-white/74 transition hover:bg-white/[0.1] hover:text-white"
            >
              {cta}
            </button>
          ) : null}
        </div>
      </div>
    </div>
  );
}

function SetupStep({
  canCreate,
  durationMinutes,
  mode,
  language,
  format,
  visualStyle,
  voice,
  selectedDuration,
  selectedSpecialMode,
  materialType,
  evidenceNote,
  isPlanning,
  onDurationChange,
  onModeChange,
  onLanguageChange,
  onFormatChange,
  onVisualStyleChange,
  onVoiceChange,
  onCreatePlan,
}: {
  canCreate: boolean;
  durationMinutes: VideoDurationMinutes;
  mode: StudyVideoMode;
  language: string;
  format: string;
  visualStyle: string;
  voice: string;
  selectedDuration: (typeof VIDEO_DURATION_OPTIONS)[number];
  selectedSpecialMode?: (typeof specialModeOptions)[number];
  materialType?: MaterialType | null;
  evidenceNote: string | null;
  isPlanning: boolean;
  onDurationChange: (minutes: VideoDurationMinutes) => void;
  onModeChange: (mode: StudyVideoMode) => void;
  onLanguageChange: (language: string) => void;
  onFormatChange: (format: string) => void;
  onVisualStyleChange: (style: string) => void;
  onVoiceChange: (voice: string) => void;
  onCreatePlan: () => void;
}) {
  return (
    <div className="space-y-4">
      <div>
        <h3 className="text-[18px] font-bold text-white">Create study video</h3>
        <p className="mt-1 max-w-2xl text-[12px] leading-5 text-white/48">
          DocDoe will turn this source into a short exam-focused video plan, then render a low-quality preview.
        </p>
      </div>

      {evidenceNote ? (
        <p className="rounded-2xl border border-white/[0.08] bg-black/28 px-3.5 py-3 text-[12px] leading-5 text-white/50">
          {evidenceNote}
        </p>
      ) : null}

      <div>
        <p className="mb-2 text-[11px] font-semibold uppercase text-white/36">Video length</p>
        <div className="grid gap-2 sm:grid-cols-3">
          {VIDEO_DURATION_OPTIONS.map((option) => {
            const active = durationMinutes === option.minutes && !selectedSpecialMode;
            return (
              <button
                key={option.minutes}
                type="button"
                onClick={() => onDurationChange(option.minutes)}
                className={cn(
                  "min-h-[88px] rounded-2xl border p-3 text-left transition",
                  active
                    ? "border-white/[0.22] bg-white/[0.09] text-white"
                    : "border-white/[0.08] bg-white/[0.025] text-white/66 hover:border-white/[0.14] hover:bg-white/[0.045]",
                )}
              >
                <span className="block text-[1.35rem] font-bold">{option.minutes} min</span>
                <span className="mt-1 block text-[11px] leading-4 text-white/42">{option.helper}</span>
              </button>
            );
          })}
        </div>
      </div>

      <div>
        <p className="mb-2 text-[11px] font-semibold uppercase text-white/36">Special formats</p>
        <div className="grid gap-2 sm:grid-cols-2">
          {specialModeOptions.map((option) => {
            const disabled = option.value === "pyq_review" && materialType !== "question_paper";
            const active = mode === option.value;
            return (
              <button
                key={option.value}
                type="button"
                disabled={disabled}
                onClick={() => onModeChange(option.value)}
                className={cn(
                  "min-h-[72px] rounded-2xl border p-3 text-left transition disabled:cursor-not-allowed disabled:opacity-45",
                  active
                    ? "border-white/[0.22] bg-white/[0.09] text-white"
                    : "border-white/[0.08] bg-white/[0.025] text-white/66 hover:border-white/[0.14] hover:bg-white/[0.045]",
                )}
              >
                <span className="block text-[12.5px] font-bold">{option.label}</span>
                <span className="mt-1 block text-[11px] leading-4 text-white/42">
                  {disabled ? "PYQ review needs a question paper source." : option.helper}
                </span>
              </button>
            );
          })}
        </div>
      </div>

      <div className="grid gap-3 sm:grid-cols-2">
        <SettingGroup label="Language">
          <SegmentedControl value={language} options={languageOptions} onChange={onLanguageChange} />
        </SettingGroup>
        <SettingGroup label="Format">
          <SegmentedControl
            value={format}
            options={formatOptions.map((option) => option.value)}
            labels={Object.fromEntries(formatOptions.map((option) => [option.value, option.label]))}
            onChange={onFormatChange}
          />
        </SettingGroup>
        <SettingGroup label="Visual style">
          <SelectControl
            value={visualStyle}
            options={visualStyleOptions}
            onChange={onVisualStyleChange}
          />
        </SettingGroup>
        <SettingGroup label="Voice">
          <SelectControl
            value={voice}
            options={voiceOptions}
            onChange={onVoiceChange}
          />
        </SettingGroup>
      </div>

      <div className="flex flex-col gap-3 rounded-2xl border border-white/[0.08] bg-white/[0.025] p-3 sm:flex-row sm:items-center sm:justify-between">
        <div>
          <p className="text-[12px] font-bold text-white/78">
            {selectedSpecialMode?.label ?? selectedDuration.label}
          </p>
          <p className="mt-1 text-[11px] text-white/38">
            Target duration: {Math.round((selectedSpecialMode?.target ?? selectedDuration.targetSeconds) / 60)} minutes
          </p>
        </div>
        <button
          type="button"
          disabled={!canCreate || isPlanning}
          onClick={onCreatePlan}
          className="inline-flex h-10 items-center justify-center gap-2 rounded-2xl border border-white/[0.14] bg-white/[0.08] px-4 text-[12px] font-bold text-white/84 transition hover:bg-white/[0.13] disabled:cursor-not-allowed disabled:opacity-45"
        >
          {isPlanning ? (
            <>
              <LoaderCircle className="size-4 animate-spin" strokeWidth={1.8} />
              Building video plan...
            </>
          ) : (
            "Create scene plan"
          )}
        </button>
      </div>
    </div>
  );
}

function SettingGroup({ label, children }: { label: string; children: ReactNode }) {
  return (
    <div className="min-w-0 rounded-2xl border border-white/[0.08] bg-white/[0.025] p-3">
      <p className="mb-2 text-[10px] font-semibold uppercase text-white/34">{label}</p>
      {children}
    </div>
  );
}

function SegmentedControl({
  value,
  options,
  labels,
  onChange,
}: {
  value: string;
  options: string[];
  labels?: Record<string, string>;
  onChange: (value: string) => void;
}) {
  return (
    <div className="flex min-w-0 flex-wrap gap-1.5">
      {options.map((option) => (
        <button
          key={option}
          type="button"
          onClick={() => onChange(option)}
          className={cn(
            "min-h-9 rounded-xl border px-2.5 text-[11px] font-semibold transition",
            value === option
              ? "border-white/[0.18] bg-white/[0.1] text-white"
              : "border-white/[0.08] bg-black/24 text-white/50 hover:bg-white/[0.05] hover:text-white/72",
          )}
        >
          {labels?.[option] ?? option}
        </button>
      ))}
    </div>
  );
}

function SelectControl({
  value,
  options,
  onChange,
}: {
  value: string;
  options: { value: string; label: string }[];
  onChange: (value: string) => void;
}) {
  return (
    <label className="relative block">
      <select
        value={value}
        onChange={(event) => onChange(event.target.value)}
        className="h-10 w-full appearance-none rounded-xl border border-white/[0.08] bg-black/36 px-3 pr-9 text-[12px] font-semibold text-white/72 outline-none transition focus:border-white/[0.18]"
      >
        {options.map((option) => (
          <option key={option.value} value={option.value}>
            {option.label}
          </option>
        ))}
      </select>
      <ChevronDown className="pointer-events-none absolute right-3 top-1/2 size-4 -translate-y-1/2 text-white/36" strokeWidth={1.8} />
    </label>
  );
}

function PlanReadyStep({
  plan,
  warnings,
  evidenceLabel,
  evidenceNote,
  canRender,
  expandedScenes,
  onToggleScene,
  onRenderPreview,
  onBackToSettings,
}: {
  plan: StudyVideoPlan;
  warnings: string[];
  evidenceLabel: string | null | undefined;
  evidenceNote: string | null;
  canRender: boolean;
  expandedScenes: Record<string, boolean>;
  onToggleScene: (sceneId: string) => void;
  onRenderPreview: () => void;
  onBackToSettings: () => void;
}) {
  return (
    <div className="space-y-4">
      <div className="rounded-2xl border border-white/[0.08] bg-white/[0.025] p-4">
        <div className="flex flex-wrap items-start justify-between gap-3">
          <div className="min-w-0">
            <p className="text-[10px] font-semibold uppercase text-white/34">Scene plan ready</p>
            <h3 className="mt-1 break-words text-[18px] font-bold text-white">{plan.title}</h3>
          </div>
          <EvidenceBadge label={evidenceLabel} />
        </div>
        <div className="mt-3 grid gap-2 sm:grid-cols-3">
          <Metric label="Target" value={`${Math.round(plan.target_duration_seconds / 60)} min`} />
          <Metric label="Scene time" value={`${plan.total_duration_seconds}s`} />
          <Metric label="Scenes" value={String(plan.scenes.length)} />
        </div>
        {plan.caution_note ? (
          <p className="mt-3 rounded-xl border border-white/[0.08] bg-black/28 px-3 py-2 text-[12px] leading-5 text-white/50">
            {plan.caution_note}
          </p>
        ) : null}
        {evidenceNote ? (
          <p className="mt-3 text-[12px] leading-5 text-white/46">{evidenceNote}</p>
        ) : null}
        <p className="mt-3 text-[12px] leading-5 text-white/52">
          Next: {plan.next_study_action}
        </p>
        {warnings.length > 0 ? (
          <div className="mt-3 space-y-1.5">
            {warnings.map((warning) => (
              <p key={warning} className="text-[11px] leading-4 text-amber-100/70">
                {warning}
              </p>
            ))}
          </div>
        ) : null}
      </div>

      <div className="space-y-2.5">
        {plan.scenes.map((scene, index) => (
          <article
            key={scene.id}
            className="rounded-2xl border border-white/[0.08] bg-white/[0.025] p-3.5"
          >
            <div className="flex flex-wrap items-start justify-between gap-3">
              <div className="min-w-0">
                <p className="text-[10px] font-semibold uppercase text-white/34">
                  Scene {index + 1} - {scene.type.replace(/_/g, " ")}
                </p>
                <h4 className="mt-1 break-words text-[13px] font-bold text-white/84">{scene.title}</h4>
              </div>
              <span className="rounded-full border border-white/[0.08] bg-black/28 px-2.5 py-1 text-[10px] font-semibold text-white/50">
                {scene.duration_seconds}s
              </span>
            </div>
            <p className="mt-3 break-words rounded-xl border border-white/[0.06] bg-black/26 px-3 py-2 text-[12px] leading-5 text-white/58">
              {scene.on_screen_text}
            </p>
            {scene.evidence_note ? (
              <p className="mt-2 text-[11px] leading-4 text-white/40">{scene.evidence_note}</p>
            ) : null}
            {scene.keywords && scene.keywords.length > 0 ? (
              <div className="mt-3 flex flex-wrap gap-1.5">
                {scene.keywords.slice(0, 8).map((keyword) => (
                  <span
                    key={keyword}
                    className="rounded-full border border-white/[0.08] bg-black/24 px-2 py-0.5 text-[10px] font-semibold text-white/42"
                  >
                    {keyword}
                  </span>
                ))}
              </div>
            ) : null}
            <button
              type="button"
              onClick={() => onToggleScene(scene.id)}
              className="mt-3 inline-flex h-8 items-center gap-1.5 rounded-xl border border-white/[0.08] bg-white/[0.025] px-3 text-[11px] font-bold text-white/54 transition hover:bg-white/[0.06] hover:text-white/74"
            >
              {expandedScenes[scene.id] ? "Hide narration" : "View narration"}
            </button>
            {expandedScenes[scene.id] ? (
              <p className="mt-2 whitespace-pre-wrap break-words rounded-xl border border-white/[0.06] bg-black/30 px-3 py-2 text-[12px] leading-5 text-white/50">
                {scene.narration}
              </p>
            ) : null}
          </article>
        ))}
      </div>

      <div className="flex flex-col-reverse gap-2 sm:flex-row sm:items-center sm:justify-end">
        <button
          type="button"
          onClick={onBackToSettings}
          className="inline-flex h-10 items-center justify-center rounded-2xl border border-white/[0.09] bg-white/[0.025] px-4 text-[12px] font-bold text-white/58 transition hover:bg-white/[0.06] hover:text-white/78"
        >
          Back to settings
        </button>
        <button
          type="button"
          disabled={!canRender}
          onClick={onRenderPreview}
          className="inline-flex h-10 items-center justify-center gap-2 rounded-2xl border border-white/[0.16] bg-white/[0.09] px-4 text-[12px] font-bold text-white/88 transition hover:bg-white/[0.14] disabled:cursor-not-allowed disabled:opacity-45"
        >
          Render preview
        </button>
      </div>
      <AnswerTrustFooter />
    </div>
  );
}

function Metric({ label, value }: { label: string; value: string }) {
  return (
    <div className="rounded-xl border border-white/[0.07] bg-black/24 px-3 py-2">
      <p className="text-[10px] font-semibold uppercase text-white/32">{label}</p>
      <p className="mt-1 text-[13px] font-bold text-white/78">{value}</p>
    </div>
  );
}

// Friendly render pipeline. Each stage maps to a backend status so the student
// sees real movement (and which step is live) instead of one vague bar.
const RENDER_STAGES: { key: string; label: string; statuses: string[] }[] = [
  { key: "script", label: "Writing the script", statuses: ["queued", "script_ready", "planning"] },
  { key: "audio", label: "Recording the narration", statuses: ["audio_generating"] },
  { key: "render", label: "Drawing the video", statuses: ["rendering", "running", "visuals_generating"] },
  { key: "finish", label: "Finishing up", statuses: ["uploading"] },
];

function renderStageIndex(status: string | null | undefined): number {
  const s = (status ?? "").toLowerCase();
  if (isCompleteStatus(s)) return RENDER_STAGES.length; // all done
  const found = RENDER_STAGES.findIndex((stage) => stage.statuses.includes(s));
  return found === -1 ? 0 : found;
}

function ElapsedTime() {
  const [seconds, setSeconds] = useState(0);
  useEffect(() => {
    const t = window.setInterval(() => setSeconds((value) => value + 1), 1000);
    return () => window.clearInterval(t);
  }, []);
  const mm = String(Math.floor(seconds / 60)).padStart(2, "0");
  const ss = String(seconds % 60).padStart(2, "0");
  return <span className="tabular-nums">{mm}:{ss}</span>;
}

function PreviewProgressStep({
  title,
  job,
  progress,
  evidenceLabel,
  hasTimedOut,
}: {
  title: string;
  job: JobViewState | null;
  progress: number;
  evidenceLabel: string | null | undefined;
  hasTimedOut: boolean;
}) {
  const activeIndex = renderStageIndex(job?.status);
  return (
    <div className="rounded-2xl border border-white/[0.08] bg-white/[0.025] p-4">
      <div className="flex flex-wrap items-start justify-between gap-3">
        <div>
          <p className="text-[10px] font-semibold uppercase text-white/34">Building your video</p>
          <h3 className="mt-1 text-[18px] font-bold text-white">{title}</h3>
        </div>
        <EvidenceBadge label={evidenceLabel} />
      </div>

      <div className="mt-3 flex items-center gap-2 text-[11px] font-semibold text-white/42">
        <span className="inline-flex size-1.5 rounded-full bg-white/50 animate-pulse" />
        <span>Working for <ElapsedTime /></span>
        <span className="ml-auto tabular-nums text-white/30">{progress}%</span>
      </div>

      <div className="mt-3 h-1.5 overflow-hidden rounded-full bg-white/[0.06]">
        <div
          className="h-full rounded-full bg-white/60 transition-[width] duration-700"
          style={{ width: `${progress}%` }}
        />
      </div>

      {/* Live stage checklist */}
      <ol className="mt-5 space-y-2.5">
        {RENDER_STAGES.map((stage, index) => {
          const done = index < activeIndex;
          const active = index === activeIndex;
          return (
            <li key={stage.key} className="flex items-center gap-3">
              <span
                className={cn(
                  "grid size-5 shrink-0 place-items-center rounded-full border",
                  done
                    ? "border-white/40 bg-white/85 text-black"
                    : active
                    ? "border-white/35 bg-white/[0.06]"
                    : "border-white/12 bg-transparent",
                )}
              >
                {done ? (
                  <Check className="size-3" strokeWidth={3} />
                ) : active ? (
                  <LoaderCircle className="size-3 animate-spin text-white/80" strokeWidth={2.4} />
                ) : (
                  <span className="size-1 rounded-full bg-white/25" />
                )}
              </span>
              <span
                className={cn(
                  "text-[13px]",
                  done ? "font-medium text-white/55" : active ? "font-bold text-white" : "text-white/35",
                )}
              >
                {stage.label}
              </span>
            </li>
          );
        })}
      </ol>

      <p className="mt-4 text-[11px] leading-4 text-white/38">
        {hasTimedOut
          ? previewTimeoutCopy
          : "Keep this open. A short video takes about a minute; longer ones take a few."}
      </p>
    </div>
  );
}

function PreviewReadyStep({
  title,
  previewUrl,
  evidenceLabel,
  onRetryLater,
}: {
  title: string;
  previewUrl: string | null;
  evidenceLabel: string | null | undefined;
  onRetryLater: () => void;
}) {
  const durationLabel = "Preview";
  return (
    <div className="space-y-4">
      <div className="rounded-2xl border border-white/[0.08] bg-white/[0.025] p-4">
        <div className="flex flex-wrap items-start justify-between gap-3">
          <div>
            <p className="text-[10px] font-semibold uppercase text-white/34">{durationLabel}</p>
            <h3 className="mt-1 text-[18px] font-bold text-white">Preview video ready</h3>
            <p className="mt-1 max-w-xl text-[12px] leading-5 text-white/46">{title}</p>
          </div>
          <EvidenceBadge label={evidenceLabel} />
        </div>
        {previewUrl ? (
          <div className="mt-4 overflow-hidden rounded-2xl border border-white/[0.09] bg-black">
            <video
              className="aspect-video w-full max-h-[400px] bg-black object-contain sm:max-h-[480px]"
              controls
              playsInline
              preload="metadata"
              src={previewUrl}
            />
          </div>
        ) : (
          <div className="mt-4 rounded-2xl border border-white/[0.08] bg-black/30 p-4 text-[12px] leading-5 text-white/52">
            <p>Preview finished, but no video file was returned.</p>
            <button
              type="button"
              onClick={onRetryLater}
              className="mt-3 inline-flex h-9 items-center justify-center rounded-2xl border border-white/[0.1] bg-white/[0.04] px-3 text-[12px] font-bold text-white/62 transition hover:bg-white/[0.08] hover:text-white"
            >
              Try again later
            </button>
          </div>
        )}
        <p className="mt-3 text-[12px] leading-5 text-white/44">
          This is a low-quality preview. Final render comes later.
        </p>
        <div className="mt-3 flex flex-wrap gap-2">
          {previewUrl ? (
            <>
              <a
                href={previewUrl}
                target="_blank"
                rel="noreferrer"
                className="inline-flex h-9 items-center gap-2 rounded-2xl border border-white/[0.1] bg-white/[0.04] px-3 text-[12px] font-bold text-white/64 transition hover:bg-white/[0.08] hover:text-white"
              >
                <ExternalLink className="size-3.5" strokeWidth={1.8} />
                Open
              </a>
              <a
                href={previewUrl}
                download
                className="inline-flex h-9 items-center gap-2 rounded-2xl border border-white/[0.1] bg-white/[0.04] px-3 text-[12px] font-bold text-white/64 transition hover:bg-white/[0.08] hover:text-white"
              >
                <Download className="size-3.5" strokeWidth={1.8} />
                Download
              </a>
            </>
          ) : null}
          <button
            type="button"
            disabled
            aria-disabled="true"
            className="inline-flex h-9 cursor-not-allowed items-center justify-center rounded-2xl border border-white/[0.07] bg-white/[0.02] px-3 text-[12px] font-bold text-white/32"
          >
            Final render coming next
          </button>
        </div>
      </div>
      <AnswerTrustFooter />
    </div>
  );
}

function FailedStep({
  message,
  onBackToSettings,
}: {
  message: string;
  onBackToSettings: () => void;
}) {
  return (
    <div className="rounded-2xl border border-white/[0.08] bg-white/[0.025] p-4">
      <div className="flex gap-3">
        <span className="grid size-10 shrink-0 place-items-center rounded-2xl border border-white/[0.08] bg-black/30 text-white/50">
          <AlertCircle className="size-5" strokeWidth={1.8} />
        </span>
        <div className="min-w-0">
          <h3 className="text-[16px] font-bold text-white">Preview render failed</h3>
          <p className="mt-1 text-[12px] leading-5 text-white/48">{message}</p>
          <button
            type="button"
            onClick={onBackToSettings}
            className="mt-4 inline-flex h-9 items-center gap-2 rounded-2xl border border-white/[0.1] bg-white/[0.045] px-3 text-[12px] font-bold text-white/68 transition hover:bg-white/[0.08] hover:text-white"
          >
            <RotateCcw className="size-3.5" strokeWidth={1.8} />
            Back to settings
          </button>
        </div>
      </div>
    </div>
  );
}