#!/usr/bin/env node
/**
 * 汇总 parts/00-preamble.md + parts/NN-*.md 为最终提示词文件。
 * 用法：node scripts/assemble.mjs [--split]
 * 输出：ClassIsland-给ChatGPT的完整提示词.md（工作区根目录）；--split 额外输出 out/ 下的分卷。
 */
import { readdirSync, readFileSync, writeFileSync, mkdirSync, copyFileSync } from 'node:fs';
import { join, dirname } from 'node:path';
import { fileURLToPath } from 'node:url';

const root = join(dirname(fileURLToPath(import.meta.url)), '..');
const partsDir = join(root, 'parts');
const outFile = join(root, 'ClassIsland-给ChatGPT的完整提示词.md');

const files = readdirSync(partsDir)
  .filter((f) => /^\d{2}-.+\.md$/.test(f))
  .sort((a, b) => a.localeCompare(b, 'en'));

if (!files.some((f) => f.startsWith('00-'))) throw new Error('缺少 parts/00-preamble.md');
if (files.length !== 20) console.warn(`警告：part 数量为 ${files.length}，预期 20`);

const sections = [];
const toc = [];
const stats = [];
let preamble = '';

for (const file of files) {
  const content = readFileSync(join(partsDir, file), 'utf8').replace(/\r\n/g, '\n').trimEnd();
  if (file.startsWith('00-')) {
    preamble = content;
    for (const line of content.split('\n')) {
      if (/^## /.test(line)) toc.push(`- ${line.replace(/^##\s+/, '').trim()}`);
    }
    continue;
  }
  for (const line of content.split('\n')) {
    if (/^## /.test(line)) toc.push(`- ${line.replace(/^##\s+/, '').trim()}`);
    else if (/^### /.test(line)) toc.push(`  - ${line.replace(/^###\s+/, '').trim()}`);
  }
  const chars = [...content.replace(/\s/g, '')].length;
  const cjk = (content.match(/[\u4e00-\u9fff]/g) || []).length;
  stats.push({ file, chars, cjk, lines: content.split('\n').length });
  sections.push(content);
}

if (!preamble.includes('<!-- TOC -->')) throw new Error('preamble 缺少 <!-- TOC --> 占位符');
const tocBlock = ['## 目录', '', ...toc, ''].join('\n');
const body = [preamble.replace('<!-- TOC -->', tocBlock), ...sections].join('\n\n---\n\n');

writeFileSync(outFile, body + '\n', 'utf8');

const totalChars = [...body.replace(/\s/g, '')].length;
const totalCjk = (body.match(/[\u4e00-\u9fff]/g) || []).length;
const lines = body.split('\n').length;
console.log(`输出：${outFile}`);
console.log(`总字符（去空白）：${totalChars}；汉字：${totalCjk}；行数：${lines}`);
console.log(`粗略 token 估算：${Math.round(totalCjk * 0.9 + (totalChars - totalCjk) * 0.3)}（仅参考）`);
console.log('各 part：');
for (const s of stats) console.log(`  ${s.file.padEnd(28)} ${String(s.chars).padStart(7)} 字符  ${String(s.cjk).padStart(6)} 汉字`);
console.log(`  00-preamble.md               ${String([...preamble.replace(/\s/g, '')].length).padStart(7)} 字符  ${String((preamble.match(/[\u4e00-\u9fff]/g) || []).length).padStart(6)} 汉字`);

if (process.argv.includes('--split')) {
  const outDir = join(root, 'out');
  const sectionsDir = join(outDir, 'sections');
  mkdirSync(sectionsDir, { recursive: true });
  const volumes = [
    { name: 'vol1-总纲与技术栈（00-02）', nums: [0, 1, 2] },
    { name: 'vol2-设计系统与主界面组件（03-05）', nums: [3, 4, 5] },
    { name: 'vol3-课表提醒自动化（06-08）', nums: [6, 7, 8] },
    { name: 'vol4-主题设置窗口系统与数据（09-13）', nums: [9, 10, 11, 12, 13] },
    { name: 'vol5-动画资源验收与结语（14-19）', nums: [14, 15, 16, 17, 18, 19] },
  ];
  for (const v of volumes) {
    const chunks = [];
    if (v.nums.includes(0)) chunks.push(preamble.replace('<!-- TOC -->', tocBlock));
    for (const n of v.nums) {
      if (n === 0) continue;
      const f = files.find((x) => Number(x.slice(0, 2)) === n);
      if (f) chunks.push(readFileSync(join(partsDir, f), 'utf8').replace(/\r\n/g, '\n').trimEnd());
      else console.warn(`警告：缺少 part ${n}`);
    }
    const p = join(outDir, `${v.name}.md`);
    writeFileSync(p, chunks.join('\n\n---\n\n') + '\n', 'utf8');
    const c = readFileSync(p, 'utf8');
    console.log(`分卷：${p}（${[...c.replace(/\s/g, '')].length} 字符，${(c.match(/[\u4e00-\u9fff]/g) || []).length} 汉字）`);
  }
  // 逐节文件（适合按章节投喂）
  let copied = 0;
  for (const f of files) {
    if (f.startsWith('00-')) continue;
    copyFileSync(join(partsDir, f), join(sectionsDir, f));
    copied += 1;
  }
  copyFileSync(join(partsDir, '00-preamble.md'), join(sectionsDir, '00-preamble.md'));
  console.log(`逐节文件：${sectionsDir}（${copied + 1} 个）`);
}