#!/usr/bin/env node
/**
 * Patch L1c: rerankTopK 仲裁感知化 (2026-04-25)
 *
 * 上下文 (承接 L1/L1b):
 *   L1b 完成后, disambiguation 层成功把 self-auditor (winner, ~0.881)
 *   置于 project-audit-expert (loser, ~0.837) 之上. 但 rerankTopK
 *   随后给 loser 打 _rerankBoost=1.2076 + _rerankProtected=true,
 *   把 loser.score 拉回 ~2.43 反超 winner. 端到端 self-auditor 失败.
 *
 * 根因:
 *   route-analyzer.js Line 597-616 中:
 *   1. r.disambiguated 是"曾被 boost 过"的单纯标记 (Line 860 设置),
 *      不区分 winner / loser. L1b loser 仍带 disambiguated=true.
 *   2. Line 599: `r.score *= max(rerankMultiplier, 1.0)` —— 对 loser
 *      也按 1.2076× 放大, 抹掉 L1b 的 cap (winner.score * 0.95).
 *   3. Line 600: `_rerankProtected=true` 给 loser 加锁.
 *   4. Line 608 cap: `topK.find(r => r.disambiguated)` 取第一个匹配,
 *      在 winner/loser 都 disambiguated 时可能错把 loser 当 cap 基线.
 *
 * 修复 (方案 A+B+C 组合, 选用最稳):
 *   A. 让 loser (有 _arbitratedBy 标记) 不进入 rerank 保护分支
 *   B. cap 基线改为"真 winner": disambiguated && !_arbitratedBy
 *   C. loser 的 rerankMultiplier 硬 cap 到 1.0 (禁止再放大), 防越界
 *
 * 安全性:
 *   - 业务路由 (project-audit-expert 在"帮我审一下项目"场景独占 boost,
 *     无 _arbitratedBy 标记) 不受影响, 仍走 winner 保护分支.
 *   - 单 boost 路径 (无跨域竞争) 行为完全不变 (无 _arbitratedBy).
 *   - cold-start skill 发现 (_rerankBoost 主流程) 保留.
 *
 * Fail-close:
 *   异常退化到旧行为 + stderr 警告. sentinel 防重复 patch.
 *
 * 用法:
 *   node patches/patch-l1c-rerank-arbitration-aware.js          # dry-run
 *   node patches/patch-l1c-rerank-arbitration-aware.js --apply  # 实际写入
 */

'use strict';

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

const TARGET = path.join(__dirname, '..', 'route-analyzer.js');
const SENTINEL = '/* L1c-RERANK-ARBITRATION-AWARE-2026-04-25 */';
const APPLY = process.argv.includes('--apply');

function fail(msg, code = 2) {
  process.stderr.write('[L1c] ' + msg + '\n');
  process.exit(code);
}

if (!fs.existsSync(TARGET)) fail('target missing: ' + TARGET);

const original = fs.readFileSync(TARGET, 'utf8');
// 检测行尾, patch 字符串用 LF, 必要时转 CRLF 匹配源文件
const EOL = original.includes('\r\n') ? '\r\n' : '\n';
const toEOL = (s) => EOL === '\r\n' ? s.replace(/\r?\n/g, '\r\n') : s;

if (original.includes(SENTINEL)) {
  process.stdout.write('[L1c] sentinel present, already patched. no-op.\n');
  process.exit(0);
}

// 精准锚点: 旧 rerank 保护代码块 (Line 595-605 区域)
const OLD_BLOCK =
`    // rerank score = 原始 BM25 × (1 + jaccard×0.3 + tierRatio×0.2)
    // 消歧 boosted 技能受保护: rerank 不降低其排名
    const rerankMultiplier = 1 + jaccard * 0.3 + tierRatio * 0.2;
    if (r.disambiguated) {
      // 消歧已确认此技能优先: 只允许 rerank 增强，不允许被其他技能超越
      r.score = r.score * Math.max(rerankMultiplier, 1.0);
      r._rerankProtected = true;
    } else {
      r.score = r.score * rerankMultiplier;
    }
    r._rerankBoost = rerankMultiplier;`;

const NEW_BLOCK =
`    // rerank score = 原始 BM25 × (1 + jaccard×0.3 + tierRatio×0.2)
    // 消歧 boosted 技能受保护: rerank 不降低其排名
    ${SENTINEL}
    const rerankMultiplier = 1 + jaccard * 0.3 + tierRatio * 0.2;
    // L1c: L1b 仲裁 loser (_arbitratedBy 标记) 不享受保护, 且 multiplier 硬 cap 到 1.0
    // 防止被 rerank boost 反超已被 cap 到 winner*0.95 的位置
    const _isArbLoser = !!r._arbitratedBy;
    if (r.disambiguated && !_isArbLoser) {
      // 消歧 winner: 只允许 rerank 增强，不允许被其他技能超越
      r.score = r.score * Math.max(rerankMultiplier, 1.0);
      r._rerankProtected = true;
    } else if (_isArbLoser) {
      // 仲裁 loser: 严格不放大, 仅允许收紧 (jaccard/tier 真低分自然降级 OK)
      const _capped = Math.min(rerankMultiplier, 1.0);
      r.score = r.score * _capped;
      r._rerankBoost = _capped;
      continue;
    } else {
      r.score = r.score * rerankMultiplier;
    }
    r._rerankBoost = rerankMultiplier;`;

const OLD_CAP =
`  // 消歧保护 cap: 非消歧技能不得超越消歧 top
  const disambTop = topK.find(r => r.disambiguated);
  if (disambTop) {
    for (const r of topK) {
      if (!r.disambiguated && r.score > disambTop.score) {
        r.score = disambTop.score * 0.98;
        r._rerankCapped = true;
      }
    }
  }`;

const NEW_CAP =
`  // 消歧保护 cap: 非消歧技能不得超越消歧 winner
  // L1c: cap 基线必须是真 winner (disambiguated && !_arbitratedBy);
  // 跨域仲裁 loser 虽然 disambiguated=true, 但被 L1b cap 到 winner*0.95,
  // 不可作为 cap 基线 (否则真 winner 会被反向 cap)
  const disambTop = topK.find(r => r.disambiguated && !r._arbitratedBy);
  if (disambTop) {
    for (const r of topK) {
      if (r === disambTop) continue;
      // 仲裁 loser 也参与 cap: 它的 disambiguated 是历史标记, 不豁免
      if (r.score > disambTop.score) {
        r.score = disambTop.score * 0.98;
        r._rerankCapped = true;
      }
    }
  }`;

const OLD_BLOCK_E = toEOL(OLD_BLOCK);
const NEW_BLOCK_E = toEOL(NEW_BLOCK);
const OLD_CAP_E   = toEOL(OLD_CAP);
const NEW_CAP_E   = toEOL(NEW_CAP);

if (!original.includes(OLD_BLOCK_E)) fail('anchor missing: rerank protected block');
if (!original.includes(OLD_CAP_E))   fail('anchor missing: disambig cap block');

const patched = original.replace(OLD_BLOCK_E, NEW_BLOCK_E).replace(OLD_CAP_E, NEW_CAP_E);

if (patched === original) fail('no-op replacement, abort to avoid silent failure');
if (!patched.includes(SENTINEL)) fail('sentinel missing post-patch');

// 语法预校验
try {
  new (require('vm').Script)(patched, { filename: TARGET });
} catch (e) {
  fail('syntax check failed: ' + e.message);
}

const oldHash = crypto.createHash('sha256').update(original).digest('hex').slice(0, 16);
const newHash = crypto.createHash('sha256').update(patched).digest('hex').slice(0, 16);

process.stdout.write('[L1c] target  : ' + TARGET + '\n');
process.stdout.write('[L1c] old sha : ' + oldHash + '\n');
process.stdout.write('[L1c] new sha : ' + newHash + '\n');
process.stdout.write('[L1c] +' + (patched.split('\n').length - original.split('\n').length) + ' lines\n');

if (!APPLY) {
  process.stdout.write('[L1c] dry-run OK. re-run with --apply to write.\n');
  process.exit(0);
}

// 备份 + 原子写
const bakDir = path.join(__dirname, 'bak');
if (!fs.existsSync(bakDir)) fs.mkdirSync(bakDir, { recursive: true });
const ts = new Date().toISOString().replace(/[:.]/g, '-');
const bakPath = path.join(bakDir, 'route-analyzer.js.' + ts + '.l1c.bak');
fs.writeFileSync(bakPath, original);

const tmp = TARGET + '.l1c.tmp';
fs.writeFileSync(tmp, patched);
fs.renameSync(tmp, TARGET);

process.stdout.write('[L1c] backup  : ' + bakPath + '\n');
process.stdout.write('[L1c] applied OK.\n');