#!/usr/bin/env node
/**
 * auto-git-sync.js — 自动 Git 同步模块
 *
 * pullLatest()  → 会话启动时调用，拉取最新代码
 * pushChanges() → 会话结束时调用，提交并推送变更
 *
 * 设计原则:
 *   - fail-open: 任何错误只写日志，不抛出，不阻断主流程
 *   - 幂等: 无变更时静默跳过
 *   - 安全: 使用 spawnSync 数组参数，无 shell 注入风险
 */
'use strict';

const fs   = require('fs');
const path = require('path');
const { spawnSync } = require('child_process');

let ROOT;
try { ROOT = require('./paths.config.js').PATHS.root; }
catch (_) { ROOT = path.join(require('os').homedir(), '.claude'); }

const CONF_PATH  = path.join(ROOT, 'config', 'auto-sync-repos.json');
const LOG_PATH   = path.join(ROOT, 'debug', 'auto-git-sync.log');
const STATE_PATH = path.join(ROOT, 'session-state', 'git-sync-state.json');

// ─── 工具函数 ───────────────────────────────────────────────
function log(msg) {
  try { fs.appendFileSync(LOG_PATH, `${new Date().toISOString()} ${msg}\n`, 'utf8'); }
  catch (_) {}
}

/**
 * 安全执行 git 命令，使用数组参数（无 shell 拼接）
 * @param {string[]} args  命令参数数组，如 ['git', 'pull', 'origin', 'main']
 * @param {string}   cwd   工作目录
 */
function git(args, cwd) {
  const result = spawnSync('git', args, {
    cwd,
    timeout: 20000,
    encoding: 'utf8',
    env: Object.assign({}, process.env, { GIT_TERMINAL_PROMPT: '0' }),
  });
  if (result.status !== 0) {
    throw new Error((result.stderr || result.stdout || 'git error').trim().slice(0, 300));
  }
  return (result.stdout || '').trim();
}

function loadConf() {
  if (!fs.existsSync(CONF_PATH)) return null;
  try { return JSON.parse(fs.readFileSync(CONF_PATH, 'utf8')); }
  catch (e) { log(`[CONF ERROR] ${e.message}`); return null; }
}

function loadState() {
  try { return JSON.parse(fs.readFileSync(STATE_PATH, 'utf8')); }
  catch (_) { return {}; }
}

function saveState(state) {
  try {
    fs.mkdirSync(path.dirname(STATE_PATH), { recursive: true });
    fs.writeFileSync(STATE_PATH, JSON.stringify(state, null, 2), 'utf8');
  } catch (_) {}
}

// ─── Pull: 会话启动时拉取最新代码 ───────────────────────────
function pullLatest() {
  const conf = loadConf();
  if (!conf) return [];

  const state  = loadState();
  const minGap = (conf.minPullIntervalMinutes || 30) * 60 * 1000;
  const now    = Date.now();
  const msgs   = [];

  for (const repo of (conf.repos || [])) {
    if (!repo.pullOnStart) continue;
    const gitDir = path.join(repo.path, '.git');
    if (!fs.existsSync(gitDir)) continue;

    const stateKey = 'pull:' + repo.path;
    if (now - (state[stateKey] || 0) < minGap) continue; // 冷却中

    const remote = repo.remote || 'origin';
    const branch = repo.branch || 'main';

    try {
      // 有未提交改动先 stash
      const dirty = git(['status', '--porcelain'], repo.path);
      if (dirty) git(['stash', 'push', '-m', 'auto-sync-stash'], repo.path);

      const before = git(['rev-parse', 'HEAD'], repo.path);
      git(['pull', remote, branch, '--ff-only'], repo.path);
      const after  = git(['rev-parse', 'HEAD'], repo.path);

      if (dirty) {
        try { git(['stash', 'pop'], repo.path); } catch (_) {}
      }

      state[stateKey] = now;

      if (before !== after) {
        const diffStat = git(['diff', '--stat', before + '..' + after], repo.path)
          .split('\n').pop().trim();
        msgs.push('[git-pull] ' + path.basename(repo.path) + ': ' + diffStat);
        log('[PULL OK] ' + repo.path + ' ' + before.slice(0, 7) + '->' + after.slice(0, 7));
      } else {
        log('[PULL SKIP] ' + repo.path + ' already up to date');
      }
    } catch (e) {
      log('[PULL ERROR] ' + repo.path + ': ' + e.message);
      msgs.push('[git-pull] WARN ' + path.basename(repo.path) + ': ' + e.message.slice(0, 60));
    }
  }

  saveState(state);
  return msgs; // 注入 systemMessage（有更新才非空）
}

// ─── Push: 会话结束时提交并推送 ─────────────────────────────
function pushChanges() {
  const conf = loadConf();
  if (!conf) return;
  if (conf.dryRun) { log('[PUSH DRY-RUN] skipping'); return; }

  for (const repo of (conf.repos || [])) {
    if (!repo.pushOnStop) continue;
    const gitDir = path.join(repo.path, '.git');
    if (!fs.existsSync(gitDir)) continue;

    const remote  = repo.remote || 'origin';
    const branch  = repo.branch || 'main';
    const prefix  = repo.commitPrefix || 'chore:';
    const maxFiles = repo.maxFilesPerCommit || 80;

    try {
      // stage 配置的路径（安全：每个 pattern 独立调用）
      for (const p of (repo.stagePatterns || ['.'])) {
        const fullP = path.join(repo.path, p);
        if (fs.existsSync(fullP)) {
          try { git(['add', p], repo.path); } catch (_) {}
        }
      }

      const staged = git(['diff', '--cached', '--name-only'], repo.path);
      if (!staged) { log('[PUSH SKIP] ' + repo.path + ' no staged changes'); continue; }

      const fileList = staged.split('\n').filter(Boolean);
      if (fileList.length > maxFiles) {
        log('[PUSH SKIP] ' + repo.path + ' too many files: ' + fileList.length);
        continue;
      }

      const ts      = new Date().toISOString().slice(0, 16).replace('T', ' ');
      const preview = fileList.slice(0, 3).join(', ')
        + (fileList.length > 3 ? ' +' + (fileList.length - 3) : '');
      const msg = prefix + ' auto-sync ' + ts + ' — ' + preview;

      git(['commit', '-m', msg], repo.path);
      git(['push', remote, 'HEAD:' + branch], repo.path);

      log('[PUSH OK] ' + repo.path + ' -> ' + remote + '/' + branch + ' | ' + fileList.length + ' files');
    } catch (e) {
      log('[PUSH ERROR] ' + repo.path + ': ' + e.message);
      // fail-open: 不阻断 stop-dispatcher
    }
  }
}

module.exports = { pullLatest, pushChanges };