#!/usr/bin/env node
'use strict';
/**
 * /mcp-prune — MCP 剪枝分析工具 (Phase 1 · T1.4)
 * sentinel: PHASE1_T1_4_MCP_PRUNE_2026_04_24
 *
 * 职责:
 *   - 基于 mcp-usage-tracker 的数据识别低频 MCP
 *   - 交叉 mcp-critical-allowlist.json 保护救命 MCP
 *   - 生成剪枝 plan 文件 (JSON)
 *   - 输出用户手动 apply 的指令
 *
 * 用法:
 *   node scripts/mcp-prune.js            # 默认: 只报告
 *   node scripts/mcp-prune.js --days 30  # 用 30 天窗口
 *   node scripts/mcp-prune.js --plan     # 写入 mcp-prune-plan-<date>.json
 *   node scripts/mcp-prune.js --confirm  # 输出用户 apply 的完整步骤
 *
 * 安全:
 *   - 永不修改 ~/.claude.json (用户核心配置)
 *   - 永不自动删除 MCP
 *   - --confirm 只打印操作指南，用户自行执行
 */

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 TRACKER_PATH = path.join(CLAUDE_ROOT, 'scripts', 'mcp-usage-tracker.js');
const ALLOWLIST_FILE = path.join(CLAUDE_ROOT, 'mcp-critical-allowlist.json');
const GLOBAL_CONFIG = path.join(HOME, '.claude.json');

function parseArgs(argv) {
  const args = { days: 30, plan: false, confirm: false };
  for (let i = 2; i < argv.length; i++) {
    const a = argv[i];
    if (a === '--days' && argv[i + 1]) { args.days = parseInt(argv[++i], 10) || 30; }
    else if (a === '--plan') { args.plan = true; }
    else if (a === '--confirm') { args.confirm = true; }
    else if (a === '-h' || a === '--help') { args.help = true; }
  }
  return args;
}

function safeReadJson(file, fallback) {
  try { return JSON.parse(fs.readFileSync(file, 'utf8')); }
  catch { return fallback; }
}

function runAnalysis(days) {
  const tracker = require(TRACKER_PATH);
  const allowlist = safeReadJson(ALLOWLIST_FILE, { critical: [] });
  const criticalSet = new Set((allowlist.critical || []).map(c => c.name));
  const cfg = safeReadJson(GLOBAL_CONFIG, { mcpServers: {} });
  const allServers = Object.keys(cfg.mcpServers || {});

  const events = tracker.collectMcpEvents(days);
  const stats = tracker.aggregate(events, allServers);
  const candidates = tracker.identifyPruneCandidates(stats, criticalSet);

  return { stats, candidates, criticalSet, allServers, cfg, days, events };
}

function report(result) {
  console.log('');
  console.log('═══════════════════════════════════════════════════════════');
  console.log('  /mcp-prune — 剪枝分析 · ' + result.days + '天窗口');
  console.log('═══════════════════════════════════════════════════════════');
  console.log('');
  console.log('总 MCP 数:           ' + result.allServers.length);
  console.log('★critical (永不剪枝): ' + result.criticalSet.size);
  console.log('活跃 MCP (>0 调用):   ' + Object.values(result.stats).filter(s => s.totalCalls > 0).length);
  console.log('剪枝候选 (0 调用):   ' + result.candidates.length);
  console.log('');

  if (result.candidates.length === 0) {
    console.log('✅ 没有剪枝候选。所有 MCP 都在最近 ' + result.days + ' 天被使用或在 critical 清单。');
    return;
  }

  console.log('剪枝候选清单:');
  console.log('─'.repeat(60));
  for (const c of result.candidates) {
    console.log('  - ' + c.server.padEnd(24) + '  ' + c.reason);
  }
  console.log('');

  const estTokens = result.candidates.length * 200;
  console.log('预估节省 (tokens/cold start): ≈ ' + estTokens + ' tokens');
  console.log('  (每 MCP schema 均值 200 tokens × ' + result.candidates.length + ')');
}

function writePlan(result, planFile) {
  const plan = {
    schema_version: 1,
    generated: new Date().toISOString(),
    tool: 'mcp-prune',
    windowDays: result.days,
    totalMcps: result.allServers.length,
    critical: Array.from(result.criticalSet),
    candidates: result.candidates.map(c => ({
      server: c.server,
      reason: c.reason,
      recommendedAction: 'REMOVE from ~/.claude.json mcpServers (manual)',
      backupHint: 'cp ~/.claude.json ~/.claude.json.bak-before-prune-' + new Date().toISOString().slice(0, 10)
    })),
    note: '此 plan 仅供参考，mcp-prune 绝不自动修改 .claude.json。用户需人工 apply。'
  };

  const tmp = planFile + '.tmp';
  fs.writeFileSync(tmp, JSON.stringify(plan, null, 2), 'utf8');
  fs.renameSync(tmp, planFile);
  console.log('');
  console.log('✅ Plan 写入: ' + planFile);
  return plan;
}

function printApplyInstructions(plan) {
  console.log('');
  console.log('═══════════════════════════════════════════════════════════');
  console.log('  用户 Apply 步骤 (请人工执行)');
  console.log('═══════════════════════════════════════════════════════════');
  console.log('');
  console.log('1. 备份原配置:');
  console.log('   Copy-Item ~/.claude.json ~/.claude.json.bak-$(Get-Date -Format yyyy-MM-dd)');
  console.log('');
  console.log('2. 用编辑器打开 ~/.claude.json，在 mcpServers 下删除以下键:');
  for (const c of plan.candidates) {
    console.log('     • ' + c.server);
  }
  console.log('');
  console.log('3. 重启 Claude Code 使改动生效');
  console.log('');
  console.log('4. 若需恢复某个 MCP, 从备份文件找回对应 JSON 片段即可');
  console.log('');
  console.log('⚠ 本工具不会自动修改 .claude.json — 这是故意设计的安全边界。');
}

function main() {
  const args = parseArgs(process.argv);
  if (args.help) {
    console.log('用法: node scripts/mcp-prune.js [--days N] [--plan] [--confirm]');
    console.log('  默认:     只报告');
    console.log('  --plan:   生成 mcp-prune-plan-<date>.json');
    console.log('  --confirm: 打印用户手动 apply 的完整步骤');
    process.exit(0);
  }

  if (!fs.existsSync(TRACKER_PATH)) {
    console.error('错误: mcp-usage-tracker.js 不存在，需先完成 Phase 1 T1.1');
    process.exit(2);
  }

  const result = runAnalysis(args.days);
  report(result);

  if (result.candidates.length === 0) {
    process.exit(0);
  }

  if (args.plan || args.confirm) {
    const planFile = path.join(CLAUDE_ROOT, 'mcp-prune-plan-' + new Date().toISOString().slice(0, 10) + '.json');
    const plan = writePlan(result, planFile);

    if (args.confirm) {
      printApplyInstructions(plan);
    }
  } else {
    console.log('');
    console.log('提示: 运行 \'--plan\' 生成 plan 文件, \'--confirm\' 查看完整 apply 步骤');
  }

  process.exit(0);
}

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