#!/usr/bin/env node
// patch-x01-pre-agent-gate-regex.js — P0: restore from backup + fix \\b → \b
const fs = require('fs');
const path = require('path');

const target = path.join(__dirname, '..', '..', 'hooks', 'pre-agent-gate.js');
const bakOrig = target + '.bak.2026-04-26';

// Step 1: Restore from original backup if it exists (undo broken fix)
if (fs.existsSync(bakOrig)) {
  const origBuf = fs.readFileSync(bakOrig);
  // Verify backup has the double-backslash pattern (5c 5c 62)
  let hasDoubleBS = false;
  for (let i = 0; i < origBuf.length - 2; i++) {
    if (origBuf[i] === 0x5c && origBuf[i+1] === 0x5c && origBuf[i+2] === 0x62) {
      hasDoubleBS = true; break;
    }
  }
  if (hasDoubleBS) {
    fs.writeFileSync(target, origBuf);
    process.stdout.write('[RESTORE] Restored from backup (has \\\\b pattern)\n');
  }
}

// Step 2: Read target, do byte-level \\b → \b replacement on lines 15-16
const content = fs.readFileSync(target, 'utf8');
const lines = content.split('\n');

let fixCount = 0;
for (let i = 14; i <= 15; i++) {
  if (!lines[i]) continue;
  const lineBuf = Buffer.from(lines[i], 'utf8');
  const result = [];
  for (let j = 0; j < lineBuf.length; j++) {
    if (j + 2 < lineBuf.length &&
        lineBuf[j] === 0x5c && lineBuf[j+1] === 0x5c &&
        (lineBuf[j+2] === 0x62 || lineBuf[j+2] === 0x73)) {
      // \\b (5c 5c 62) → \b (5c 62)  or  \\s (5c 5c 73) → \s (5c 73)
      result.push(0x5c);
      result.push(lineBuf[j+2]);
      j += 2;
      fixCount++;
    } else {
      result.push(lineBuf[j]);
    }
  }
  lines[i] = Buffer.from(result).toString('utf8');
}

if (fixCount === 0) {
  process.stdout.write('[SKIP] No \\\\b patterns found on lines 15-16\n');
  process.exit(0);
}

fs.writeFileSync(target, lines.join('\n'), 'utf8');

// Step 3: Verify
const vBuf = Buffer.from(fs.readFileSync(target, 'utf8').split('\n')[14], 'utf8');
const hex = [];
for (let i = 2; i < 14 && i < vBuf.length; i++) hex.push(vBuf[i].toString(16).padStart(2, '0'));
process.stdout.write('[DONE] ' + fixCount + ' replacements. Line 15 hex: ' + hex.join(' ') + '\n');
// Expected: 5c 62 66 69 6e 64 5c 62 2f 69 2c 20  →  \bfind\b/i,