#!/usr/bin/env node
/**
 * IR 评估模块 (P1-FIX)
 *
 * 计算路由系统的标准 IR 指标:
 * - MRR (Mean Reciprocal Rank): 正确技能在排名中的平均倒数位置
 * - P@1 (Precision at 1): 首位命中率
 *
 * 数据源: route-feedback.jsonl 中的纠正记录
 *
 * 用法:
 *   node scripts/ir-eval.js                  # 评估当前系统
 *   node scripts/ir-eval.js --json           # JSON 输出
 *   node scripts/ir-eval.js --reject 0.5     # MRR 低于 0.5 时返回非零退出码
 */

const fs = require('fs');
const path = require('path');
const CLAUDE_ROOT = require('./paths.config.js').PATHS.root;
const FEEDBACK_FILE = path.join(CLAUDE_ROOT, 'debug', 'route-feedback.jsonl');

function loadCorrections() {
  if (!fs.existsSync(FEEDBACK_FILE)) return [];
  return fs.readFileSync(FEEDBACK_FILE, 'utf8').trim().split('\n')
    .map(line => { try { return JSON.parse(line); } catch { return null; } })
    .filter(e => e && e.correctedTo && e.routedTo !== e.correctedTo);
}


function loadGoldenSet() {
  const gsFile = path.join(CLAUDE_ROOT, 'scripts', 'golden-set.json');
  if (!fs.existsSync(gsFile)) return [];
  try {
    const gs = JSON.parse(fs.readFileSync(gsFile, 'utf8'));
    return (gs.entries || []).map(e => ({
      query: e.query,
      correctedTo: e.expectedSkill,
      source: e.source || 'golden',
    }));
  } catch { return []; }
}

function evaluate() {
  const corrections = loadCorrections();
  const goldenEntries = loadGoldenSet();
  // 合并: golden set + corrections (golden set 优先作为评估数据源)
  const allEntries = goldenEntries.length > 0 ? goldenEntries : corrections;
  // 如果有 golden set，忽略 vacuous check
  if (allEntries.length === 0) return { mrr: 1.0, p1: 1.0, samples: 0, note: 'No data' };

  // 加载路由引擎进行离线评估
  let routeAnalyzer;
  try { routeAnalyzer = require('./route-analyzer.js'); } catch { return { error: 'Cannot load route-analyzer' }; }

  let rrSum = 0; // 倒数排名之和
  let p1Hits = 0; // P@1 命中数
  let evaluated = 0;

  for (const c of allEntries) {
    if (!c.query && !c.prompt) continue;
    const query = c.query || c.prompt || '';
    const correctSkill = c.correctedTo;

    try {
      // 加载索引
      const idxFile = path.join(CLAUDE_ROOT, 'skills-index-lite.json');
      if (!fs.existsSync(idxFile)) continue;
      const index = JSON.parse(fs.readFileSync(idxFile, 'utf8'));

      const tokens = routeAnalyzer.tokenize ? routeAnalyzer.tokenize(query) : new Set(query.toLowerCase().split(/\s+/));
      const bm25Params = routeAnalyzer.buildBM25Params ? routeAnalyzer.buildBM25Params(index) : null;

      const scores = [];
      for (const skill of (index.skills || [])) {
        const result = routeAnalyzer.scoreSkill
          ? routeAnalyzer.scoreSkill(skill, tokens, bm25Params)
          : { totalScore: 0 };
        scores.push({ name: skill.name, score: result.totalScore });
      }
      scores.sort((a, b) => b.score - a.score);

      // 找正确技能的排名
      const rank = scores.findIndex(s => s.name === correctSkill) + 1;
      if (rank > 0) {
        rrSum += 1.0 / rank;
        if (rank === 1) p1Hits++;
      }
      evaluated++;
    } catch {}
  }

  if (evaluated === 0) return { mrr: 1.0, p1: 1.0, samples: 0, note: 'No evaluable corrections' };

  return {
    mrr: Math.round((rrSum / evaluated) * 1000) / 1000,
    p1: Math.round((p1Hits / evaluated) * 1000) / 1000,
    samples: evaluated,
    totalCorrections: allEntries.length,
    goldenSetSize: goldenEntries.length,
  };
}

// CLI 入口
if (require.main === module) {
  const result = evaluate();
  const isJson = process.argv.includes('--json');
  const rejectIdx = process.argv.indexOf('--reject');
  const rejectThreshold = rejectIdx >= 0 ? parseFloat(process.argv[rejectIdx + 1]) : null;

  if (isJson) {
    console.log(JSON.stringify(result, null, 2));
  } else {
    console.log('=== IR Evaluation ===');
    console.log('MRR:     ' + (result.mrr || 'N/A'));
    console.log('P@1:     ' + (result.p1 || 'N/A'));
    console.log('Samples: ' + (result.samples || 0));
    if (result.note) console.log('Note:    ' + result.note);
  }

  if (rejectThreshold !== null && result.mrr < rejectThreshold) {
    console.error('MRR ' + result.mrr + ' below threshold ' + rejectThreshold);
    process.exit(1);
  }
}

module.exports = { evaluate, loadCorrections };