#!/usr/bin/env node
'use strict';
/**
 * SessionStart MCP Probe (Phase 1 · T1.2)
 * sentinel: PHASE1_T1_2_MCP_PROBE_HOOK_2026_04_24
 *
 * 事件: UserPromptSubmit (Bookworm 无 SessionStart 键，用 UserPromptSubmit + 日期守卫替代)
 * 目的: 每日首次会话轻量探测 MCP 配置健康度，结果写 logs/mcp-health-<date>.json
 *
 * 预算:
 *   - 今日 snapshot 已存在: <5ms (fs.existsSync 快速返回)
 *   - 首次运行: <500ms (22 个 MCP 的命令存在性检查)
 *
 * 容错:
 *   - Feature flag 关闭: 立即 exit 0
 *   - 任何异常: exit 0 (fail-open，永不阻断用户输入)
 *
 * 不做的事:
 *   - 不 spawn MCP 子进程 (太慢，交给 /mcp-probe 技能)
 *   - 不做实际 HTTP 请求
 *   - 不修改 .claude.json
 */

const fs = require('fs');
const path = require('path');
const os = require('os');

const HOME = process.env.USERPROFILE || process.env.HOME || os.homedir();
const CLAUDE_ROOT = process.env.CLAUDE_HOME ||
  (fs.existsSync(path.join(HOME, '.claude')) ? path.join(HOME, '.claude') : HOME);
const LOGS_DIR = path.join(CLAUDE_ROOT, 'logs');
const FEATURE_FLAGS_FILE = path.join(CLAUDE_ROOT, '.bookworm-features.json');
const TODAY = new Date().toISOString().slice(0, 10);
const HEALTH_FILE = path.join(LOGS_DIR, 'mcp-health-' + TODAY + '.json');
const CONFIG_FILE = path.join(HOME, '.claude.json');

function safeExit() { process.exit(0); }

// 已知在 PATH 上的命令（避免 which 调用开销）
const WELL_KNOWN_CMDS = /^(npx|node|python|python3|bash|sh|pnpm|yarn|uvx|go|deno|bun)$/;

function commandPlausible(cmd) {
  if (!cmd || typeof cmd !== 'string') return false;
  if (path.isAbsolute(cmd)) return fs.existsSync(cmd);
  // Windows 可能配置带 .cmd/.exe/.bat 后缀 (e.g. npx.cmd)，剥离后比对已知命令
  const stripped = cmd.replace(/\.(exe|cmd|bat)$/i, '');
  if (WELL_KNOWN_CMDS.test(stripped)) return true;
  // 回退: 按 PATH 扫描 (受限于 PATH 数量，10-30 次 existsSync 可接受)
  const PATH_DIRS = (process.env.PATH || process.env.Path || '').split(path.delimiter).filter(Boolean);
  const candidates = [cmd, cmd + '.exe', cmd + '.cmd', cmd + '.bat'];
  for (const dir of PATH_DIRS) {
    for (const c of candidates) {
      try { if (fs.existsSync(path.join(dir, c))) return true; } catch {}
    }
  }
  return false;
}

function probeMcp(name, cfg) {
  try {
    if (cfg && (cfg.type === 'http' || cfg.type === 'sse')) {
      const hasUrl = !!cfg.url && /^https?:\/\//.test(cfg.url);
      return {
        kind: cfg.type,
        url: cfg.url || null,
        urlValid: hasUrl,
        reachable: hasUrl
      };
    }
    // 默认 stdio
    const command = (cfg && cfg.command) || '';
    const exists = commandPlausible(command);
    return {
      kind: 'stdio',
      command,
      commandExists: exists,
      reachable: exists
    };
  } catch (e) {
    return { error: String(e.message || e), reachable: false };
  }
}

function main() {
  // Feature flag 检查
  try {
    if (fs.existsSync(FEATURE_FLAGS_FILE)) {
      const flags = JSON.parse(fs.readFileSync(FEATURE_FLAGS_FILE, 'utf8'));
      if (flags && flags.mcp_probe === false) return safeExit();
    }
  } catch {}

  // 今日 snapshot 已存在 → 跳过 (日级守卫)
  if (fs.existsSync(HEALTH_FILE)) return safeExit();

  // 读取 MCP 配置
  let mcpServers = {};
  try {
    const cfg = JSON.parse(fs.readFileSync(CONFIG_FILE, 'utf8'));
    mcpServers = cfg.mcpServers || {};
  } catch {
    return safeExit();
  }

  const results = {};
  let reachable = 0;
  let unreachable = 0;
  const unreachableList = [];

  for (const name of Object.keys(mcpServers)) {
    const r = probeMcp(name, mcpServers[name]);
    results[name] = r;
    if (r.reachable) reachable++;
    else { unreachable++; unreachableList.push(name); }
  }

  const snapshot = {
    schema_version: 1,
    date: TODAY,
    probedAt: new Date().toISOString(),
    probeKind: 'lightweight-static',
    totalMcps: Object.keys(mcpServers).length,
    reachable,
    unreachable,
    unreachableList,
    results
  };

  // 确保 logs 目录
  try { fs.mkdirSync(LOGS_DIR, { recursive: true }); } catch {}

  // 原子写
  try {
    const tmp = HEALTH_FILE + '.tmp';
    fs.writeFileSync(tmp, JSON.stringify(snapshot, null, 2), 'utf8');
    fs.renameSync(tmp, HEALTH_FILE);
  } catch {}

  safeExit();
}

if (require.main === module) main();

module.exports = { probeMcp, commandPlausible };