#!/usr/bin/env node
/**
 * post-edit-snapshot.js · Phase α 冲刺 3 · 2026-04-25
 * PostToolUse:Edit|Write hook - snapshot edited file to staging/
 * Dormant until feature-flag staging-pipeline.mode != 'off'
 */
'use strict';
const fs = require('fs');
const path = require('path');
const crypto = require('crypto');
const { spawn } = require('child_process');

const ROOT = path.resolve(__dirname, '..');
const FLAG_FILE = path.join(ROOT, 'feature-flags.json');
const PIPELINE_DIR = path.join(ROOT, 'ai-delivery-pipeline');
const STAGING_DIR = path.join(PIPELINE_DIR, 'staging');
const MANIFEST = path.join(PIPELINE_DIR, 'manifest.jsonl');
const VALIDATOR = path.join(__dirname, 'staging-validator.js');
const MAX_FILE_BYTES = 5 * 1024 * 1024;
const HASH_LEN = 12;

function readFlag() {
  try {
    const f = JSON.parse(fs.readFileSync(FLAG_FILE, 'utf8'));
    return f.features && f.features['staging-pipeline'] || { mode: 'off', enabled: false };
  } catch (_) { return { mode: 'off', enabled: false }; }
}
function readStdin() {
  try { const d = fs.readFileSync(0, 'utf8'); return d ? JSON.parse(d) : {}; }
  catch (_) { return {}; }
}
function ensureDir(d) { try { fs.mkdirSync(d, { recursive: true }); } catch (_) {} }
function appendManifest(entry) {
  try { fs.appendFileSync(MANIFEST, JSON.stringify(entry) + '\n', 'utf8'); } catch (_) {}
}
function getSessionId(input) {
  return input.session_id || process.env.CLAUDE_SESSION_ID || 'no-session';
}

function main() {
  const t0 = Date.now();
  const flag = readFlag();
  if (flag.mode === 'off') process.exit(0);
  const input = readStdin();
  const tool = input.tool_name || '';
  if (!/^(Edit|Write|NotebookEdit)$/.test(tool)) process.exit(0);
  const filePath = (input.tool_input && input.tool_input.file_path) || '';
  if (!filePath) process.exit(0);
  if (filePath.includes('ai-delivery-pipeline')) process.exit(0);
  let stat;
  try { stat = fs.statSync(filePath); } catch (_) { process.exit(0); }
  if (!stat.isFile()) process.exit(0);
  if (stat.size > MAX_FILE_BYTES) {
    appendManifest({ ts: new Date().toISOString(), event: 'skip-oversize', sessionId: getSessionId(input), originalPath: filePath, size: stat.size, cap: MAX_FILE_BYTES });
    process.exit(0);
  }
  let content;
  try { content = fs.readFileSync(filePath); } catch (_) { process.exit(0); }
  const hash = crypto.createHash('sha256').update(content).digest('hex').slice(0, HASH_LEN);
  const sessionId = getSessionId(input);
  const stagingAbsDir = path.join(STAGING_DIR, sessionId, hash);
  ensureDir(stagingAbsDir);
  const stagingPath = path.join(stagingAbsDir, path.basename(filePath));
  try { fs.writeFileSync(stagingPath, content); }
  catch (e) {
    appendManifest({ ts: new Date().toISOString(), event: 'snapshot-write-fail', originalPath: filePath, error: e.code || e.message });
    process.exit(0);
  }
  appendManifest({
    ts: new Date().toISOString(), event: 'staged', sessionId, hash, tool,
    originalPath: filePath, stagingPath, status: 'pending', size: content.length,
    elapsedMs: Date.now() - t0,
  });
  if (flag.mode === 'warn' || flag.mode === 'enforce') {
    if (fs.existsSync(VALIDATOR)) {
      try {
        const child = spawn(process.execPath, [VALIDATOR, stagingPath, filePath, hash, flag.mode], {
          detached: true, stdio: 'ignore', windowsHide: true,
        });
        child.unref();
      } catch (_) {}
    }
  }
  process.exit(0);
}
try { main(); } catch (_) { process.exit(0); }