export const reviewModules = [
  'api',
  'database',
  'api-database',
  'tasks',
  'redis',
  'docker',
  'linux',
  'troubleshooting',
  'distributed',
];
const nonempty = (value) =>
  typeof value === 'string' && value.trim().length > 0;
const strings = (value, min) =>
  Array.isArray(value) && value.length >= min && value.every(nonempty);

export function verifyReview(lesson, index, sources) {
  const errors = [];
  const at = `review/${lesson?.id || index + 1}`;
  const fail = (message) => errors.push(`${at}: ${message}`);
  if (
    lesson.kind !== 'review' ||
    lesson.id !== String(index + 1).padStart(2, '0') ||
    lesson.sourceModule !== reviewModules[index]
  )
    fail('invalid review identity or source module');
  for (const key of ['title', 'summary', 'group'])
    if (!nonempty(lesson[key])) fail(`missing ${key}`);
  if (
    !nonempty(lesson.intro?.scenario) ||
    !nonempty(lesson.intro?.outcome) ||
    !strings(lesson.intro?.startingPoint, 2)
  )
    fail('missing self-test preparation');
  for (const key of [
    'steps',
    'production',
    'interview',
    'demo',
    'code',
    'concepts',
  ])
    if (key in lesson)
      fail(`review must not contain teaching-only field ${key}`);
  const source = sources.get(lesson.sourceModule);
  if (!source) fail('missing source lessons');
  for (const [key, count, prefix] of [
    ['questions', 6, 'q'],
    ['challenges', 2, 'c'],
  ]) {
    if (!Array.isArray(lesson[key]) || lesson[key].length !== count) {
      fail(`expected ${count} ${key}`);
      continue;
    }
    for (const [i, item] of lesson[key].entries()) {
      if (item.id !== `${prefix}${i + 1}`) fail(`invalid ${key} ID`);
      if (
        !nonempty(item.title) ||
        !nonempty(item.prompt) ||
        !strings(item.checkpoints, 3) ||
        !nonempty(item.misconception)
      )
        fail(`incomplete ${item.id}`);
      if (
        !Array.isArray(item.revisit) ||
        item.revisit.length < 1 ||
        item.revisit.length > 2
      ) {
        fail(`${item.id} needs one or two return links`);
        continue;
      }
      const seen = new Set();
      for (const link of item.revisit) {
        const original = source?.find((entry) => entry.id === link.lessonId);
        if (
          !original ||
          original.title !== link.label ||
          seen.has(link.lessonId)
        )
          fail(`${item.id}: invalid or duplicate return link ${link.lessonId}`);
        seen.add(link.lessonId);
      }
    }
  }
  if (!Array.isArray(lesson.mastery) || lesson.mastery.length !== 4)
    fail('expected four mastery criteria');
  else
    lesson.mastery.forEach((item, i) => {
      if (
        item.id !== `m${i + 1}` ||
        !nonempty(item.text) ||
        !nonempty(item.evidence) ||
        item.text === item.evidence
      )
        fail(`incomplete mastery evidence ${item.id}`);
    });
  return errors;
}

const bullets = (items) => items.map((item) => `- ${item}`).join('\n');
function links(lesson, item) {
  return item.revisit
    .map((link) => {
      const route =
        lesson.sourceModule === 'api'
          ? `lesson=${link.lessonId}`
          : `module=${lesson.sourceModule}&lesson=${link.lessonId}`;
      return `[${link.lessonId} · ${link.label}](../?${route})`;
    })
    .join('；');
}
export function reviewMarkdown(lessons) {
  let result =
    '# 复盘与自测\n\n术核 AI · 后端工程课件\n\n每个单元对应一个已学模块。先独立回答，再看文末参考要点；合上答案后仍能解释原因、推演条件变化，并拿出四项掌握证据，才达到本轮标准。记录反映学员自评，不自动判定文字答案的正确性。\n\n';
  for (const lesson of lessons) {
    result += `## ${lesson.id} ${lesson.title}\n\n${lesson.summary}\n\n### 如何自测\n\n${lesson.intro.scenario}\n\n${bullets(lesson.intro.startingPoint)}\n\n本轮目标：${lesson.intro.outcome}\n\n原模块讲义：[${lesson.sourceModule}-lessons.md](./${lesson.sourceModule}-lessons.md)。离线阅读时按题目下的课号查找。\n\n`;
    for (const [title, items] of [
      ['核心理解问题', lesson.questions],
      ['情境推演', lesson.challenges],
    ]) {
      result += `### ${title}\n\n先写下判断、原因与验证方式，再对照本单元末尾的参考要点。\n\n`;
      for (const item of items)
        result += `#### ${item.id.toUpperCase()} ${item.title}\n\n${item.prompt}\n\n我的回答：\n\n自评：□ 还需要回学　□ 合上要点后能独立回答并举例或推演\n\n需要时回学：${links(lesson, item)}\n\n`;
    }
    result += '### 掌握标准与证据\n\n';
    for (const item of lesson.mastery)
      result += `- [ ] ${item.text}\n\n  证据：${item.evidence}\n\n`;
    result +=
      '### 本轮结果与回学计划\n\n八项问题均能独立回答，且四项证据均已核对，才达到本轮标准。未完成的题按回学链接补课，再闭卷重答；已经完成的题，隔一天换个条件再次推演。\n\n需要回学的题号：\n\n尚缺的证据：\n\n下次复测时准备改变的条件：\n\n### 参考要点与易错点\n\n完成自己的回答后再阅读。表述可以不同，要核对的是推理、边界和验证依据。\n\n';
    for (const item of [...lesson.questions, ...lesson.challenges])
      result += `#### ${item.id.toUpperCase()} ${item.title}\n\n${bullets(item.checkpoints)}\n\n容易误判：${item.misconception}\n\n`;
    result += '---\n\n';
  }
  return result;
}