#!/usr/bin/env node
/**
 * P0-2 Patch: Hook Session-Once
 * - session-start-mcp-probe.js: 追加 session-once early-exit + markRun
 * - session-start-memory-audit.js: 追加 session-once early-exit + markRun
 * 幂等: sentinel [P0-2] SESSION_ONCE_v1
 */
'use strict';
const fs = require('fs');
const path = require('path');

const HOOKS = path.resolve(__dirname, '..', '..', 'hooks');
const SENTINEL = '[P0-2] SESSION_ONCE_v1';

function patchFile(name, fn) {
  const fp = path.join(HOOKS, name);
  if (!fs.existsSync(fp)) { process.stderr.write('[SKIP] ' + name + ' not found\n'); return false; }
  const src = fs.readFileSync(fp, 'utf8');
  if (src.includes(SENTINEL)) { process.stderr.write('[SKIP] ' + name + ' already patched\n'); return false; }
  fs.writeFileSync(fp + '.bak-p02.' + Date.now(), src);
  const out = fn(src);
  const tmp = fp + '.tmp.' + process.pid;
  fs.writeFileSync(tmp, out, 'utf8');
  fs.renameSync(tmp, fp);
  process.stderr.write('[DONE] ' + name + '\n');
  return true;
}

// --- session-start-mcp-probe.js ---
function patchMcpProbe(src) {
  // early-exit 插在 feature flag 检查之前 (main 函数第一行)
  const marker = '  // Feature flag 检查';
  if (!src.includes(marker)) throw new Error('marker not found in mcp-probe');

  const earlyExit = [
    '  // ' + SENTINEL + ' — 会话级去重 (<1ms)',
    '  try { if (require(\'./lib/session-once.js\').hasRun(\'mcp-probe\')) return safeExit(); } catch {}',
    '',
    marker,
  ].join('\n');
  let result = src.replace(marker, earlyExit);

  // markRun 插在原子写成功之后
  const writeMarker = "    fs.renameSync(tmp, HEALTH_FILE);";
  if (!result.includes(writeMarker)) throw new Error('write marker not found');

  result = result.replace(
    writeMarker,
    writeMarker + '\n    // ' + SENTINEL + '\n    try { require(\'./lib/session-once.js\').markRun(\'mcp-probe\'); } catch {}'
  );
  return result;
}

// --- session-start-memory-audit.js ---
function patchMemoryAudit(src) {
  // early-exit 插在 feature flag 之前
  const marker = '    // Feature flag';
  if (!src.includes(marker)) throw new Error('marker not found in memory-audit');

  const earlyExit = [
    '    // ' + SENTINEL + ' — 会话级去重 (<1ms)',
    '    try { if (require(\'./lib/session-once.js\').hasRun(\'memory-audit\')) return safeExit(); } catch {}',
    '',
    marker,
  ].join('\n');
  let result = src.replace(marker, earlyExit);

  // markRun 插在 stamp 更新之后
  const stampMarker = "      fs.writeFileSync(STAMP_FILE, TODAY);";
  if (!result.includes(stampMarker)) throw new Error('stamp marker not found');

  result = result.replace(
    stampMarker,
    stampMarker + '\n      // ' + SENTINEL + '\n      try { require(\'./lib/session-once.js\').markRun(\'memory-audit\'); } catch {}'
  );
  return result;
}

// --- Execute ---
let count = 0;
if (patchFile('session-start-mcp-probe.js', patchMcpProbe)) count++;
if (patchFile('session-start-memory-audit.js', patchMemoryAudit)) count++;
process.stderr.write('\nP0-2 Session-Once: ' + count + '/2 files patched\n');