/**
 * git 操作：状态、发布（提交 + 推两端）、同步。
 *
 * 所有 git 调用串行化——两个并发的 commit/push 撞在一起会互相踩工作区，
 * 单用户场景下也值得防一手（用户手快连点两次「发布」就会遇到）。
 */
import { execFile } from 'node:child_process';

function run(cwd, args, { allowFailure = false } = {}) {
  return new Promise((resolve, reject) => {
    execFile('git', args, { cwd, maxBuffer: 8 * 1024 * 1024 }, (err, stdout, stderr) => {
      const out = (stdout || '') + (stderr || '');
      if (err && !allowFailure) {
        const e = new Error(out.trim() || err.message);
        e.stdout = stdout;
        e.stderr = stderr;
        e.code = err.code;
        reject(e);
        return;
      }
      resolve({ ok: !err, code: err ? (typeof err.code === 'number' ? err.code : 1) : 0, out, stdout, stderr });
    });
  });
}

export function makeGit(cfg) {
  const { repoRoot, branch, pushRemotes, authorName, authorEmail, paths } = cfg;

  // 串行队列
  let tail = Promise.resolve();
  function serial(task) {
    const next = tail.then(task, task);
    tail = next.catch(() => {});
    return next;
  }

  const identity = [
    '-c', 'user.name=' + authorName,
    '-c', 'user.email=' + authorEmail,
    // 容器里通常没有 GPG，且我们不需要签名
    '-c', 'commit.gpgsign=false',
  ];

  /**
   * scope 语义（编辑角色 = 只提交自己的文章）：
   *   undefined  → 全量 cfg.paths（content / static），管理员用
   *   string[]   → 只用这些 pathspec（编辑自己的文章目录）
   *   []         → 编辑名下还没有文章目录：什么都不做（不能退化成全量！）
   *
   * ★ 空数组必须显式拦掉。`git add -- ` 后面不跟 pathspec 就等于 `git add -A`，
   *   会把仓库里所有人未提交的改动一起提交进去 —— 那正是要避免的事。
   */
  function resolvePaths(scope) {
    if (Array.isArray(scope)) return scope;
    return paths;
  }

  async function status(scope) {
    const usePaths = resolvePaths(scope);
    const scoped = Array.isArray(scope);

    const head = await run(repoRoot, ['log', '-1', '--pretty=%h%x09%ad%x09%s', '--date=format:%Y-%m-%d %H:%M']);
    const br = await run(repoRoot, ['rev-parse', '--abbrev-ref', 'HEAD']);
    const base = {
      branch: br.out.trim(),
      scoped,
      lastCommit: head.out.trim(),
    };

    if (scoped && !usePaths.length) {
      return { ...base, dirty: false, changed: 0, files: [] };
    }

    // core.quotepath=false：不把中文文件名转成 \346\265\213 那种八进制转义，
    // 否则发布弹层里满屏都是看不懂的编码
    const st = await run(repoRoot, ['-c', 'core.quotepath=false', 'status', '--porcelain', '--', ...usePaths]);
    const files = st.out.split('\n').map((l) => l.trim()).filter(Boolean);
    return {
      ...base,
      dirty: files.length > 0,
      changed: files.length,
      files: files.slice(0, 50),
    };
  }

  async function publish(message, scope) {
    return serial(async () => {
      const log = [];
      const usePaths = resolvePaths(scope);
      const scoped = Array.isArray(scope);

      if (scoped && !usePaths.length) {
        return { ok: true, pushed: [], scoped: true, warning: null, log: '（你名下还没有文章目录，没有需要发布的内容）' };
      }

      const add = await run(repoRoot, ['add', '--', ...usePaths]);
      log.push(add.out.trim());

      // 先提交（没有暂存内容就跳过）
      const diff = await run(repoRoot, ['diff', '--cached', '--quiet'], { allowFailure: true });
      if (diff.code === 1) {
        const msg = message || ('编辑: ' + new Date().toISOString().slice(0, 16).replace('T', ' '));
        const c = await run(repoRoot, [...identity, 'commit', '-m', msg]);
        log.push(c.out.trim());
      } else if (diff.code !== 0) {
        throw new Error('检查暂存区失败: ' + diff.out.trim());
      } else {
        log.push('（没有需要提交的改动）');
      }

      // 先拉再推，减少被拒概率
      const pull = await run(repoRoot, ['pull', '--rebase', '--autostash', 'origin', branch], { allowFailure: true });
      log.push(pull.out.trim());
      if (!pull.ok && /conflict|CONFLICT|nothing to rebase|Automatic merge failed/i.test(pull.out)) {
        await run(repoRoot, ['rebase', '--abort'], { allowFailure: true });
        return { ok: false, conflict: true, log: log.join('\n'), error: '远程有冲突，已放弃合并。请先「同步」后手动处理。' };
      }

      const pushed = [];
      const failed = [];
      for (const remote of pushRemotes) {
        const p = await run(repoRoot, ['push', remote, 'HEAD:' + branch], { allowFailure: true });
        log.push(p.out.trim());
        if (p.ok) pushed.push(remote);
        else failed.push(remote + ': ' + p.out.trim().split('\n').slice(-2).join(' '));
      }

      if (!pushed.length) {
        return { ok: false, log: log.join('\n'), error: '推送失败：' + failed.join(' | ') };
      }

      return {
        ok: true,
        pushed,
        scoped,
        // 备份远端推失败不算发布失败（主仓成了就算成），但如实说明
        warning: failed.length ? '以下远端推送失败（不影响上线）: ' + failed.join(' | ') : null,
        log: log.join('\n'),
      };
    });
  }

  async function sync() {
    return serial(async () => {
      const pull = await run(repoRoot, ['pull', '--rebase', '--autostash', 'origin', branch], { allowFailure: true });
      if (pull.ok) return { ok: true, log: pull.out.trim() };
      if (/conflict|CONFLICT|Automatic merge failed/i.test(pull.out)) {
        await run(repoRoot, ['rebase', '--abort'], { allowFailure: true });
        return { ok: false, conflict: true, error: '存在冲突，已放弃合并' };
      }
      return { ok: false, error: pull.out.trim() };
    });
  }

  return { status, publish, sync };
}