// scripts/storyboard.mjs — 分镜脚本
//
// 输入：work/song.json（产线A）或口播稿（产线B）
// 输出：work/storyboard.json，结构见 templates/storyboard.schema.json
//
// 分镜是整条链路的枢纽：后面的 keyframe / video / lipsync / assemble 全部读它。

import {
  parseArgs, writeJSON, readJSON, paths, ensureWork, log, chatJSON,
} from '../lib/index.mjs';
import {
  buildStoryboardPrompt, buildTalkStoryboardPrompt, DEFAULT_ANCHOR,
} from '../lib/prompts.mjs';

const SYSTEM_A = `你是顶级音乐 MV 导演兼 AI 视频提示词工程师，服务于「全程 AI 生成、无实拍」的 MV 制作。
你的核心职责是：把一首歌拆成一个可被 AI 逐个执行的镜头清单，并保证跨镜头的人物/场景一致性。
只输出 JSON，不要任何解释文字与 markdown 围栏。`;

const SYSTEM_B = `你是顶级口播讲解视频导演兼 AI 视频提示词工程师，服务于「全程 AI 生成、无实拍」的讲解视频。
你的核心职责是：把口播稿拆成镜头清单，让每一句口播都有对应的、语义相关的画面，并保持讲者形象一致。
只输出 JSON，不要任何解释文字与 markdown 围栏。`;

const SCHEMA_A = `严格输出如下 JSON（字段名不可改）：
{
  "title": "与歌曲同名",
  "aspect": "16:9",
  "totalDuration": 180,
  "appearanceAnchor": "英文，主角外貌锚点（性别/年龄/发型/服装/气质），逐镜头复述用",
  "styleKeywords": "英文，全片统一影像风格关键词",
  "shots": [
    {
      "id": 1,
      "type": "broll | perf",
      "start": 0,
      "duration": 6,
      "section": "Intro",
      "description": "中文画面描述",
      "imagePrompt": "英文，完整可独立投喂文生图的提示词",
      "videoPrompt": "英文，图生视频的运镜/动作描述",
      "lipSync": false,
      "subtitle": "该镜头对应的歌词（用于字幕，可留空）",
      "notes": "可选，中文备注"
    }
  ]
}`;

const SCHEMA_B = `严格输出如下 JSON（字段名不可改）：
{
  "title": "标题",
  "aspect": "16:9",
  "totalDuration": 90,
  "appearanceAnchor": "英文，讲者外貌锚点",
  "styleKeywords": "英文，全片统一影像风格关键词",
  "shots": [
    {
      "id": 1,
      "type": "talking | broll",
      "start": 0,
      "duration": 8,
      "section": "开场钩子",
      "narration": "该镜头对应的口播原文",
      "subtitle": "字幕文本（≤20字）",
      "description": "中文画面描述",
      "imagePrompt": "英文，完整可独立投喂文生图的提示词",
      "videoPrompt": "英文，图生视频运镜描述",
      "lipSync": false,
      "notes": ""
    }
  ]
}`;

/** 归一化分镜，保证下游字段齐全 */
export function normalizeStoryboard(sb, { aspect = '16:9', anchor = '', minShot = 3, maxShot = 10 } = {}) {
  const shots = (sb.shots || []).map((s, i) => {
    const dur = Number(s.duration) || 6;
    const start = s.start !== undefined && s.start !== null ? Number(s.start) : null;
    return {
      id: Number(s.id) || i + 1,
      type: s.type === 'perf' || s.type === 'talking' ? s.type : 'broll',
      start,
      duration: dur,
      section: s.section || '',
      description: s.description || s.prompt || '',
      imagePrompt: s.imagePrompt || s.description || '',
      videoPrompt: s.videoPrompt || 'subtle natural motion, slow cinematic push in',
      lipSync: !!s.lipSync && ['perf', 'talking'].includes(s.type === 'perf' ? 'perf' : s.type),
      subtitle: s.subtitle ?? s.narration ?? '',
      narration: s.narration ?? '',
      section: s.section || '',
      notes: s.notes || '',
    };
  });
  // 时长约束：AI 图生视频单段现实上限约 8~10 秒，模型常给出 30s+ 的不可能值。
  // 这里按规格（每段 5~8 秒）夹取，并如实记录被夹取的镜头，绝不偷偷改。
  let clamped = 0;
  for (const s of shots) {
    const before = s.duration;
    s.duration = Math.min(maxShot, Math.max(minShot, s.duration));
    if (Math.abs(s.duration - before) > 0.01) {
      s._durationClampedFrom = before;
      clamped++;
    }
  }

  // 补齐 start，保证时间轴连续
  let t = 0;
  for (const s of shots) {
    if (s.start === null || Number.isNaN(s.start)) s.start = +t.toFixed(3);
    t = s.start + s.duration;
  }
  const totalDuration = shots.length ? +(shots[shots.length - 1].start + shots[shots.length - 1].duration).toFixed(3) : 0;
  return {
    title: sb.title || '',
    aspect: sb.aspect || aspect,
    totalDuration,
    appearanceAnchor: sb.appearanceAnchor || anchor,
    styleKeywords: sb.styleKeywords || '',
    shots,
    _meta: {
      createdBy: 'fmode-mv/storyboard',
      generatedAt: new Date().toISOString(),
      durationClamped: clamped,
    },
  };
}

/** 产线A：从歌曲生成 MV 分镜 */
export async function buildStoryboardFromSong(song, opts = {}) {
  const { shotCount = 8, aspect = '16:9', perShot = 6, model, project = '' } = opts;
  const prompt = buildStoryboardPrompt({ song, shotCount, aspect, perShot, project }) + '\n\n' + SCHEMA_A;
  const res = await chatJSON({
    model,
    system: SYSTEM_A,
    messages: [{ role: 'user', content: prompt }],
    temperature: 0.85,
    max_tokens: 12000,
  });
  const sb = normalizeStoryboard(res.json, { aspect });
  sb._meta = { ...sb._meta, model: res.model, maxTokensUsed: res.maxTokensUsed, repaired: !!res.repaired };
  return sb;
}

/** 产线B：从口播稿生成讲解分镜 */
export async function buildStoryboardFromScript(script, opts = {}) {
  const { durationSec = 90, aspect = '16:9', shotCount = 8, model, project = '', hostAnchor = '' } = opts;
  const prompt =
    buildTalkStoryboardPrompt({ script, durationSec, aspect, shotCount, project, hostAnchor }) + '\n\n' + SCHEMA_B;
  const res = await chatJSON({
    model,
    system: SYSTEM_B,
    messages: [{ role: 'user', content: prompt }],
    temperature: 0.8,
    max_tokens: 12000,
  });
  const sb = normalizeStoryboard(res.json, { aspect, anchor: DEFAULT_ANCHOR.talk });
  sb._meta = { ...sb._meta, model: res.model, maxTokensUsed: res.maxTokensUsed, repaired: !!res.repaired };
  return sb;
}

export async function main(argv = process.argv.slice(2)) {
  const { _, flags } = parseArgs(argv);

  if (flags.help || (!_.length && !flags.from && !flags.script)) {
    console.log(`
fmode-mv storyboard — 分镜脚本（chat 通道）

产线A（歌曲 MV）:
  fmode-mv storyboard --from work/song.json [--shots 8] [--aspect 16:9] [--per-shot 6]

产线B（口播视频）:
  fmode-mv storyboard --script work/script.md [--duration 90] [--shots 8]

选项:
  --from <file>     歌曲 JSON（产线A）
  --script <file>   口播稿文本文件（产线B）
  --shots <n>       镜头数（默认 8）
  --per-shot <s>    单镜头秒数，仅产线A（默认 6）
  --duration <s>    口播总时长，仅产线B（默认 90）
  --aspect <r>      16:9 | 9:16 | 1:1（默认 16:9）
  --project "..."   项目背景，帮助模型贴合语境
  --model <name>    覆盖 LLM 模型
  --out <file>      输出（默认 work/storyboard.json）
  --json            只打印 JSON
`);
    return 0;
  }

  ensureWork();
  const aspect = flags.aspect || '16:9';
  let sb;

  if (flags.script) {
    const { readFileSync } = await import('node:fs');
    const script = readFileSync(String(flags.script), 'utf8');
    if (!script.trim()) throw new Error(`口播稿为空：${flags.script}`);
    log.step('生成口播分镜（产线B）');
    log.key('口播稿', `${script.length} 字`);
    sb = await buildStoryboardFromScript(script, {
      durationSec: Number(flags.duration) || 90,
      aspect,
      shotCount: Number(flags.shots) || 8,
      project: flags.project || '',
      model: flags.model,
    });
  } else {
    const from = typeof flags.from === 'string' ? flags.from : paths.song;
    const song = readJSON(from);
    if (!song) throw new Error(`未找到歌曲文件 ${from}。先跑：fmode-mv lyrics "主题"`);
    log.step(`生成 MV 分镜（产线A）：《${song.title}》`);
    sb = await buildStoryboardFromSong(song, {
      shotCount: Number(flags.shots) || 8,
      aspect,
      perShot: Number(flags.per_shot) || 6,
      project: flags.project || '',
      model: flags.model,
    });
  }

  const outFile = typeof flags.out === 'string' ? flags.out : paths.storyboard;
  writeJSON(outFile, sb);
  const { writeFileSync } = await import('node:fs');
  const { join } = await import('node:path');
  writeFileSync(join(paths.work, 'storyboard.md'), renderStoryboardMd(sb), 'utf8');

  if (flags.json) {
    console.log(JSON.stringify(sb, null, 2));
    return 0;
  }

  console.log(renderStoryboardMd(sb));
  log.ok(`已写入 ${outFile} 与 work/storyboard.md`);

  if (sb._meta?.durationClamped) {
    log.warn(
      `${sb._meta.durationClamped} 个镜头的时长超出合理区间（${3}~${10}s）已被夹取 —— ` +
        'AI 图生视频单段现实上限约 8~10 秒，模型给出的几十秒镜头无法直接生成。'
    );
  }
  const perfs = sb.shots.filter((s) => s.lipSync).length;
  const brolls = sb.shots.filter((s) => !s.lipSync).length;
  log.key('镜头', `${sb.shots.length} 个（空镜/场景 ${brolls} + 唇形 ${perfs}）`);
  log.key('总时长', `${sb.totalDuration}s`);
  if (!sb.appearanceAnchor) log.warn('缺少 appearanceAnchor（人物一致性锚点），跨镜头可能换脸');
  return 0;
}

export function renderStoryboardMd(sb) {
  const lines = [];
  lines.push(`# 分镜表 · ${sb.title}`);
  lines.push('');
  lines.push(`- 画面比例：${sb.aspect}`);
  lines.push(`- 总时长：${sb.totalDuration}s`);
  lines.push(`- 影像风格：${sb.styleKeywords || '-'}`);
  lines.push(`- 人物锚点：${sb.appearanceAnchor || '-'}`);
  lines.push('');
  lines.push('| # | 时间码 | 时长 | 类型 | 段落 | 画面 | 唇形 |');
  lines.push('|---|--------|------|------|------|------|------|');
  for (const s of sb.shots) {
    const tc = `${fmt(s.start)}–${fmt(s.start + s.duration)}`;
    lines.push(
      `| ${s.id} | ${tc} | ${s.duration}s | ${s.type} | ${s.section || '-'} | ${oneLine(s.description)} | ${s.lipSync ? '✓' : ''} |`
    );
  }
  lines.push('');
  lines.push('## 镜头明细');
  for (const s of sb.shots) {
    lines.push('');
    lines.push(`### #${s.id} · ${fmt(s.start)}–${fmt(s.start + s.duration)} · ${s.type}`);
    lines.push(`- 画面：${s.description}`);
    if (s.narration) lines.push(`- 口播：${s.narration}`);
    if (s.subtitle) lines.push(`- 字幕：${s.subtitle}`);
    lines.push(`- 图 prompt：\`${s.imagePrompt}\``);
    lines.push(`- 运镜 prompt：\`${s.videoPrompt}\``);
  }
  return lines.join('\n') + '\n';
}

function fmt(sec) {
  const s = Math.max(0, Number(sec) || 0);
  const m = Math.floor(s / 60);
  const r = (s % 60).toFixed(1).padStart(4, '0');
  return `${String(m).padStart(2, '0')}:${r}`;
}

function oneLine(s, n = 34) {
  const t = String(s || '').replace(/[\r\n|]/g, ' ').trim();
  return t.length > n ? t.slice(0, n) + '…' : t;
}

if (import.meta.url === `file://${process.argv[1]}`) {
  main().then((c) => process.exit(Number(c) || 0)).catch((e) => {
    console.error(`✗ ${e.message}`);
    process.exit(1);
  });
}