import { readFileSync, writeFileSync, mkdirSync } from 'node:fs';
import { resolve } from 'node:path';
const root = process.cwd();
const catalog = [
  ['api', 'API 服务开发', 16],
  ['database', '数据库开发', 12],
  ['api-database', 'API + 数据库', 12],
  ['tasks', '异步任务开发', 16],
  ['redis', 'Redis 缓存', 10],
  ['docker', 'Docker 容器化', 10],
  ['linux', 'Linux 部署', 10],
  ['troubleshooting', '线上问题排查', 12],
];
const errors = [];
let total = 0;
const report = [];
mkdirSync(resolve(root, 'public/downloads'), { recursive: true });
const text = (value) => typeof value === 'string' && value.trim().length > 0;
const list = (value, min = 1) => Array.isArray(value) && value.length >= min;
function verify(l, slug, index) {
  const prefix = `${slug}/${l?.id || index}`;
  if (l?.id !== String(index + 1).padStart(2, '0'))
    errors.push(`${prefix}: invalid lesson ID`);
  for (const key of ['group', 'title', 'summary'])
    if (!text(l?.[key])) errors.push(`${prefix}: missing ${key}`);
  if ('minutes' in l)
    errors.push(`${prefix}: instructor duration metadata is not allowed`);
  for (const key of [
    'objectives',
    'concepts',
    'steps',
    'checks',
    'pitfalls',
    'refs',
  ])
    if (!list(l?.[key])) errors.push(`${prefix}: missing ${key}`);
  for (const c of l.concepts || [])
    if (!text(c.title) || !text(c.body))
      errors.push(`${prefix}: incomplete concept`);
  for (const s of l.steps || [])
    if (!text(s.title) || !text(s.body))
      errors.push(`${prefix}: incomplete step`);
  for (const p of l.pitfalls || [])
    if (!text(p.symptom) || !text(p.cause) || !text(p.fix))
      errors.push(`${prefix}: incomplete troubleshooting`);
  for (const key of ['task', 'hint', 'answer'])
    if (!text(l.exercise?.[key]))
      errors.push(`${prefix}: missing exercise ${key}`);
  for (const ref of l.refs || []) {
    try {
      if (!text(ref.label) || new URL(ref.url).protocol !== 'https:')
        throw new Error();
    } catch {
      errors.push(`${prefix}: invalid reference ${ref.url}`);
    }
  }
  if (slug !== 'api') {
    if (
      !list(l.objectives, 3) ||
      !list(l.steps, 4) ||
      !list(l.concepts, 3) ||
      !list(l.checks, 3) ||
      !list(l.pitfalls, 2) ||
      !list(l.refs, 2)
    )
      errors.push(`${prefix}: insufficient practical lesson detail`);
    if (
      !text(l.production?.scenario) ||
      !list(l.production?.decisions) ||
      !text(l.production?.failureDrill) ||
      !list(l.production?.acceptance)
    )
      errors.push(`${prefix}: incomplete production exercise`);
  }
}
const bullets = (items) => items.map((s) => `- ${s}`).join('\n');
function markdown(title, lessons) {
  return (
    `# ${title}\n\n术核 AI · 后端工程课件\n\n` +
    lessons
      .map((l) => {
        let out = `## ${l.id} ${l.title}\n\n${l.summary}\n\n### 本节目标\n\n${bullets(l.objectives)}\n\n### 必要概念\n\n`;
        out += l.concepts
          .map((c) => `#### ${c.title}\n\n${c.body}\n`)
          .join('\n');
        out +=
          '\n### 动手实现\n\n' +
          l.steps
            .map(
              (s, i) =>
                `#### ${i + 1}. ${s.title}\n\n${s.body}\n${s.code ? `\n文件：${s.filename || '终端 / 当前课时'}\n\n\`\`\`\`${s.lang || 'text'}\n${s.code}\n\`\`\`\`\n` : ''}`,
            )
            .join('\n');
        out += `\n### 验收结果\n\n${bullets(l.checks)}\n`;
        if (l.production) {
          const p = l.production;
          out += `\n### 生产约束与故障演练\n\n${p.scenario}\n\n#### 实现决策\n\n${bullets(p.decisions)}\n\n#### 隔离环境演练\n\n${p.failureDrill}\n\n#### 恢复验收\n\n${bullets(p.acceptance)}\n`;
        }
        out +=
          '\n### 常见错误\n\n' +
          l.pitfalls
            .map(
              (p) =>
                `#### ${p.symptom}\n\n原因：${p.cause}\n\n处理：${p.fix}\n`,
            )
            .join('\n');
        out += `\n### 扩展练习\n\n${l.exercise.task}\n\n提示：${l.exercise.hint}\n\n参考答案：\n\n${l.exercise.answer}\n\n### 技术文档\n\n${l.refs.map((r) => `- [${r.label}](${r.url})`).join('\n')}\n`;
        return out;
      })
      .join('\n---\n\n')
  );
}
for (const [slug, title, count] of catalog) {
  const path = resolve(
    root,
    slug === 'api' ? 'app/lessons.json' : `public/content/${slug}.json`,
  );
  let lessons;
  try {
    lessons = JSON.parse(readFileSync(path, 'utf8').replace(/^\uFEFF/, ''));
  } catch (error) {
    errors.push(`${slug}: ${error.message}`);
    continue;
  }
  if (!Array.isArray(lessons) || lessons.length !== count) {
    errors.push(`${slug}: expected ${count} lessons`);
    continue;
  }
  lessons.forEach((l, i) => verify(l, slug, i));
  total += lessons.length;
  writeFileSync(
    resolve(root, `public/downloads/${slug}-lessons.md`),
    markdown(title, lessons),
  );
  report.push({
    slug,
    lessons: lessons.length,
    steps: lessons.reduce((n, l) => n + l.steps.length, 0),
    codeBlocks: lessons.reduce(
      (n, l) => n + l.steps.filter((s) => s.code).length,
      0,
    ),
  });
}
if (errors.length) {
  console.error(errors.join('\n'));
  process.exit(1);
}
console.log(
  JSON.stringify(
    { modules: report.length, lessons: total, details: report },
    null,
    2,
  ),
);