#!/usr/bin/env node
/**
 * 路由反馈权重学习 (v4.2)
 *
 * 记录路由纠正 → 分析模式 → 生成权重调整。
 * 配合 route-analyzer.js 实现闭环学习。
 *
 * 用法:
 *   node route-feedback.js --correct "<query>" <actualSkill>    记录纠正
 *   node route-feedback.js --learn                              生成权重调整
 *   node route-feedback.js --report                             反馈统计
 *   node route-feedback.js --json                               JSON 输出
 *
 * 文件:
 *   debug/route-feedback.jsonl   纠正记录
 *   debug/route-weights.json     学习后的权重增量
 */

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

const detectClaudeRoot = () => require('./paths.config.js').PATHS.root;

const ROOT = detectClaudeRoot();
const INDEX_FILE = path.join(ROOT, 'skills-index.json');
const DEBUG_DIR = path.join(ROOT, 'debug');
const FEEDBACK_FILE = path.join(DEBUG_DIR, 'route-feedback.jsonl');
const WEIGHTS_FILE = path.join(DEBUG_DIR, 'route-weights.json');
const WEIGHTS_HISTORY_DIR = path.join(DEBUG_DIR, 'weights-history');
const HOLDOUT_FILE = path.join(DEBUG_DIR, 'holdout-set.json');
const MAX_WEIGHT_SNAPSHOTS = 20;
const HOLDOUT_RATIO = 0.3; // 30% holdout

// === 参数解析 ===
const args = process.argv.slice(2);
const correctMode = args.includes('--correct');
const learnMode = args.includes('--learn');
const reportMode = args.includes('--report');
const jsonMode = args.includes('--json');
const validateMode = args.includes('--validate');
const splitMode = args.includes('--split');

// === 工具函数 ===

function ensureDebugDir() {
  if (!fs.existsSync(DEBUG_DIR)) fs.mkdirSync(DEBUG_DIR, { recursive: true });
}

/** 从 skills-index.json 加载有效技能名白名单 */
function loadSkillWhitelist() {
  const index = loadIndex();
  if (!index || !index.skills) return null;
  return new Set(index.skills.map(s => s.name));
}

function loadIndex() {
  if (!fs.existsSync(INDEX_FILE)) return null;
  return JSON.parse(fs.readFileSync(INDEX_FILE, 'utf8'));
}

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

function loadRouteLog(dateStr) {
  const logFile = path.join(DEBUG_DIR, `route-${dateStr}.jsonl`);
  if (!fs.existsSync(logFile)) return [];
  return fs.readFileSync(logFile, 'utf8')
    .split('\n')
    .filter(Boolean)
    .map(line => { try { return JSON.parse(line); } catch { return null; } })
    .filter(Boolean);
}

/** P0-3: 确定性哈希 — 基于 query 字符串生成稳定 hash */
function simpleHash(str) {
  let hash = 0;
  for (let i = 0; i < str.length; i++) {
    hash = ((hash << 5) - hash + str.charCodeAt(i)) | 0;
  }
  return Math.abs(hash);
}

/** P0-3: 拆分训练集/holdout 集，生成 holdout-set.json */
function splitHoldout() {
  const feedback = loadFeedback();
  const corrections = feedback.filter(f => f.routedTo !== f.correctedTo && f.routedTo !== 'unknown');

  if (corrections.length < 5) {
    console.error(`纠正数据不足 (${corrections.length} 条)，至少需要 5 条才能拆分`);
    process.exit(1);
  }

  const holdoutQueries = [];
  const trainQueries = [];

  for (const fb of corrections) {
    const bucket = simpleHash(fb.query) % 100;
    if (bucket < HOLDOUT_RATIO * 100) {
      holdoutQueries.push(fb.query);
    } else {
      trainQueries.push(fb.query);
    }
  }

  const holdoutData = {
    generated: new Date().toISOString(),
    ratio: HOLDOUT_RATIO,
    totalCorrections: corrections.length,
    holdoutCount: holdoutQueries.length,
    trainCount: trainQueries.length,
    holdoutQueries,
  };

  ensureDebugDir();
  fs.writeFileSync(HOLDOUT_FILE, JSON.stringify(holdoutData, null, 2) + '\n');

  console.log(`Holdout 拆分完成:`);
  console.log(`  纠正总数: ${corrections.length}`);
  console.log(`  训练集:   ${trainQueries.length} (${Math.round(trainQueries.length / corrections.length * 100)}%)`);
  console.log(`  Holdout:  ${holdoutQueries.length} (${Math.round(holdoutQueries.length / corrections.length * 100)}%)`);
  console.log(`  输出: ${HOLDOUT_FILE}`);
  return holdoutData;
}

/** P0-3: 加载 holdout 集查询列表 */
function loadHoldoutSet() {
  if (!fs.existsSync(HOLDOUT_FILE)) return null;
  try { return JSON.parse(fs.readFileSync(HOLDOUT_FILE, 'utf8')); } catch { return null; }
}

/** P0-3: 过滤掉 holdout 条目，仅返回训练集 */
function filterTrainSet(feedback) {
  const holdout = loadHoldoutSet();
  if (!holdout) return feedback; // 无 holdout 文件则不过滤
  const holdoutSet = new Set(holdout.holdoutQueries);
  return feedback.filter(fb => !holdoutSet.has(fb.query));
}

/** P0-3: 在 holdout 集上验证当前路由准确率 */
function validateHoldout() {
  const holdout = loadHoldoutSet();
  if (!holdout || holdout.holdoutQueries.length === 0) {
    console.log('无 holdout 集。运行 --split 先生成。');
    return null;
  }

  const feedback = loadFeedback();
  const holdoutSet = new Set(holdout.holdoutQueries);
  const holdoutEntries = feedback.filter(fb =>
    holdoutSet.has(fb.query) && fb.routedTo !== 'unknown' && fb.routedTo !== fb.correctedTo
  );

  // 使用 ab-backtest 的方式评估当前引擎
  let fixed = 0, missed = 0;
  let analyzer;
  try { analyzer = require('./route-analyzer.js'); } catch { console.error('route-analyzer.js 不可用'); return null; }

  const index = loadIndex();
  if (!index) { console.error('skills-index.json 不可用'); return null; }

  const bm25Params = analyzer.buildBM25Params ? analyzer.buildBM25Params(index) : null;

  for (const fb of holdoutEntries) {
    const queryTokens = analyzer.tokenize(fb.query);
    const results = index.skills.map(skill => {
      const { totalScore } = analyzer.scoreSkill(skill, queryTokens, bm25Params);
      return { name: skill.name, score: Math.round(totalScore * 100) / 100 };
    }).sort((a, b) => b.score - a.score);

    // v5.9: applyDisambiguation 返回 { results, firedRules } 对象
    let disambiguated = results;
    if (analyzer.applyDisambiguation) {
      const dr = analyzer.applyDisambiguation(results, fb.query, index);
      disambiguated = Array.isArray(dr) ? dr : (dr?.results || results);
    }
    if (!disambiguated || disambiguated.length === 0) { missed++; continue; }
    const normalized = analyzer.normalizeScores ? analyzer.normalizeScores(disambiguated) : disambiguated;
    const top = normalized[0];

    if (top && top.name === fb.correctedTo) {
      fixed++;
    } else {
      missed++;
    }
  }

  const result = {
    holdoutSize: holdoutEntries.length,
    fixed,
    missed,
    accuracy: holdoutEntries.length > 0 ? Math.round(fixed / holdoutEntries.length * 100 * 10) / 10 : 0,
  };

  if (jsonMode) {
    console.log(JSON.stringify(result, null, 2));
  } else {
    console.log(`Holdout 验证结果:`);
    console.log(`  Holdout 纠正数: ${holdoutEntries.length}`);
    console.log(`  修复: ${fixed}, 未修复: ${missed}`);
    console.log(`  准确率: ${result.accuracy}%`);
  }
  return result;
}

/** P0-2: 权重快照 — 备份当前权重文件，保留最新 N 个 */
function snapshotWeights() {
  if (!fs.existsSync(WEIGHTS_FILE)) return null;
  if (!fs.existsSync(WEIGHTS_HISTORY_DIR)) fs.mkdirSync(WEIGHTS_HISTORY_DIR, { recursive: true });

  const ts = new Date().toISOString().replace(/[:.]/g, '-');
  const dest = path.join(WEIGHTS_HISTORY_DIR, `route-weights-${ts}.json`);
  fs.copyFileSync(WEIGHTS_FILE, dest);

  // 清理旧快照，保留最新 MAX_WEIGHT_SNAPSHOTS 个
  const files = fs.readdirSync(WEIGHTS_HISTORY_DIR)
    .filter(f => f.startsWith('route-weights-') && f.endsWith('.json'))
    .sort();
  while (files.length > MAX_WEIGHT_SNAPSHOTS) {
    fs.unlinkSync(path.join(WEIGHTS_HISTORY_DIR, files.shift()));
  }
  return dest;
}

/** 简易文本 tokenize (与 route-analyzer.js 保持一致) */
function tokenize(text) {
  const tokens = new Set();
  const cnChars = text.match(/[\u4e00-\u9fff]+/g) || [];
  for (const chunk of cnChars) {
    for (let len = 2; len <= Math.min(6, chunk.length); len++) {
      for (let i = 0; i <= chunk.length - len; i++) {
        tokens.add(chunk.slice(i, i + len).toLowerCase());
      }
    }
  }
  const enWords = text.match(/[A-Za-z][\w.-]*(?:\s+[A-Za-z][\w.-]*){0,2}/g) || [];
  for (const w of enWords) {
    tokens.add(w.toLowerCase().trim());
    for (const single of w.split(/[\s.-]+/)) {
      if (single.length >= 2) tokens.add(single.toLowerCase());
    }
  }

  // v4.9: 同义词展开
  try {
    const { expandSynonyms } = require('./synonym-expander.js');
    return expandSynonyms(tokens);
  } catch {
    return tokens;
  }
}

// === 模式 1: 记录纠正 ===

function recordCorrection() {
  // 从路由日志找最近一条匹配 query 的记录
  const flagIdx = args.indexOf('--correct');
  const remaining = args.filter((a, i) => i > flagIdx && !a.startsWith('--'));
  if (remaining.length < 2) {
    console.error('Usage: --correct "<query>" <correctSkill>');
    process.exit(1);
  }

  const correctSkill = remaining.pop();
  const query = remaining.join(' ');

  // P0-1: 技能名白名单校验
  const whitelist = loadSkillWhitelist();
  if (whitelist && !whitelist.has(correctSkill)) {
    console.error(`Invalid skill name: "${correctSkill}"`);
    console.error(`Valid skills: ${Array.from(whitelist).sort().join(', ')}`);
    process.exit(1);
  }

  // 搜索最近路由日志找到这个 query 的路由结果
  let routedTo = 'unknown';
  let topConfidence = 0;
  const today = new Date().toISOString().slice(0, 10);
  for (let d = 0; d < 7; d++) {
    const date = new Date(Date.now() - d * 86400000).toISOString().slice(0, 10);
    const logs = loadRouteLog(date);
    const match = logs.reverse().find(l =>
      l.query && l.query.toLowerCase().includes(query.toLowerCase().slice(0, 50))
    );
    if (match) {
      routedTo = match.topResult;
      topConfidence = match.topConfidence;
      break;
    }
  }

  const entry = {
    ts: new Date().toISOString(),
    query: query.slice(0, 200),
    routedTo,
    correctedTo: correctSkill,
    topConfidence,
    queryTokens: Array.from(tokenize(query)),
  };

  ensureDebugDir();
  fs.appendFileSync(FEEDBACK_FILE, JSON.stringify(entry) + '\n');

  if (jsonMode) {
    console.log(JSON.stringify(entry, null, 2));
  } else {
    console.log(`Correction recorded:`);
    console.log(`  Query:     "${query}"`);
    console.log(`  Routed:    ${routedTo} (${(topConfidence * 100).toFixed(0)}%)`);
    console.log(`  Correct:   ${correctSkill}`);
  }
}

// === 模式 2: 学习权重调整 ===

function learnWeights() {
  const rawFeedback = loadFeedback();
  // P0-3: 仅在训练集上学习，排除 holdout 条目
  const feedback = filterTrainSet(rawFeedback);
  if (feedback.length === 0) {
    console.log('No feedback data. Use --correct to record corrections first.');
    return;
  }

  const index = loadIndex();
  if (!index) {
    console.error('skills-index.json not found');
    process.exit(1);
  }

  // 构建 skill → keywords 映射
  const skillKeywords = {};
  for (const skill of index.skills) {
    skillKeywords[skill.name] = new Set(
      skill.keywords.map(k => k.keyword.toLowerCase())
    );
  }

  // 权重增量: { skillName: { keyword: delta } }
  const deltas = {};

  // 指数衰减: 越新的反馈权重越大
  const now = Date.now();
  const DECAY_HALF_LIFE = 5 * 86400000; // 5 天半衰期

  for (const fb of feedback) {
    if (fb.routedTo === fb.correctedTo) continue; // 非纠正
    if (fb.routedTo === 'unknown') continue; // 无原始路由

    const age = now - new Date(fb.ts).getTime();
    const decay = Math.pow(0.5, age / DECAY_HALF_LIFE);

    // v5.9: 反馈权重分层 — 直接观测 > 手动纠正 > 隐式推断 > 超时确认
    const typeFactor = fb.type === 'observed' ? 0.8 : (fb.type === 'implicit' ? 0.5 : 1.0);
    const timeoutFactor = fb.implicit === 'timeout-confirm' ? (fb.weight || 0.1) : 1.0;
    const delta = 0.1 * decay * typeFactor * timeoutFactor;

    // Fix: implicit feedback 不含 queryTokens，需从 query 现场 tokenize
    let queryTokens;
    if (fb.queryTokens && fb.queryTokens.length > 0) {
      queryTokens = new Set(fb.queryTokens);
    } else if (fb.query) {
      queryTokens = tokenize(fb.query);
    } else {
      queryTokens = new Set();
    }

    // 降低被错误路由到的技能中匹配的关键词权重
    const wrongKw = skillKeywords[fb.routedTo];
    if (wrongKw) {
      for (const token of queryTokens) {
        if (wrongKw.has(token)) {
          if (!deltas[fb.routedTo]) deltas[fb.routedTo] = {};
          deltas[fb.routedTo][token] = (deltas[fb.routedTo][token] || 0) - delta;
        }
      }
    }

    // 提升正确技能中匹配的关键词权重
    const rightKw = skillKeywords[fb.correctedTo];
    if (rightKw) {
      for (const token of queryTokens) {
        if (rightKw.has(token)) {
          if (!deltas[fb.correctedTo]) deltas[fb.correctedTo] = {};
          deltas[fb.correctedTo][token] = (deltas[fb.correctedTo][token] || 0) + delta;
        }
      }
    }
  }

  // 裁剪极小增量 (|delta| < 0.01)
  for (const skill of Object.keys(deltas)) {
    for (const kw of Object.keys(deltas[skill])) {
      if (Math.abs(deltas[skill][kw]) < 0.01) {
        delete deltas[skill][kw];
      } else {
        // 限幅: [-0.5, +0.5]
        deltas[skill][kw] = Math.max(-0.5, Math.min(0.5, Math.round(deltas[skill][kw] * 100) / 100));
      }
    }
    if (Object.keys(deltas[skill]).length === 0) delete deltas[skill];
  }

  // P0-2: 写入前快照当前权重
  const snapshotPath = snapshotWeights();

  // 写入权重文件
  const output = {
    generated: new Date().toISOString(),
    feedbackCount: feedback.length,
    correctionCount: feedback.filter(f => f.routedTo !== f.correctedTo && f.routedTo !== 'unknown').length,
    implicitCount: feedback.filter(f => f.type === 'implicit').length,
    deltas,
  };

  ensureDebugDir();
  // MEDIUM-1: 使用 weight-store 的并发安全写入替代自实现 tmp+rename
  try {
    const weightStore = require('./weight-store.js');
    // writeWeights 是 async 的，但 learnWeights 是同步上下文
    // 使用 safeWriteJson 可写入任意路径，此处目标是 route-weights.json
    weightStore.writeWeights(output).catch(() => {
      // 异步写入失败时回退到直接写入
      fs.writeFileSync(WEIGHTS_FILE, JSON.stringify(output, null, 2) + '\n');
    });
  } catch {
    // weight-store 不可用时回退到直接写入
    fs.writeFileSync(WEIGHTS_FILE, JSON.stringify(output, null, 2) + '\n');
  }

  if (jsonMode) {
    console.log(JSON.stringify(output, null, 2));
  } else {
    const skillCount = Object.keys(deltas).length;
    const totalAdj = Object.values(deltas).reduce((n, obj) => n + Object.keys(obj).length, 0);
    console.log(`Weight learning complete:`);
    console.log(`  Feedback entries:  ${feedback.length} (${output.implicitCount} implicit)`);
    console.log(`  Corrections:       ${output.correctionCount}`);
    console.log(`  Skills adjusted:   ${skillCount}`);
    console.log(`  Total adjustments: ${totalAdj}`);
    console.log(`  Output: ${WEIGHTS_FILE}`);
    if (snapshotPath) console.log(`  Snapshot: ${snapshotPath}`);
  }
}

// === v4.9: 自动学习触发 ===

/**
 * 反馈 ≥10 条时自动触发 learnWeights()
 * @returns {boolean} 是否执行了学习
 */
function autoLearn() {
  const feedback = loadFeedback();
  if (feedback.length >= 10) {
    learnWeights();
    return true;
  }
  return false;
}

// === 模式 3: 反馈统计报告 ===

function showReport() {
  const feedback = loadFeedback();

  if (feedback.length === 0) {
    console.log('No feedback data yet.');
    return;
  }

  // 统计
  const corrections = feedback.filter(f => f.routedTo !== f.correctedTo && f.routedTo !== 'unknown');
  const routedToCount = {};
  const correctedToCount = {};
  const pairCount = {}; // "wrong → right" 频率

  for (const fb of corrections) {
    routedToCount[fb.routedTo] = (routedToCount[fb.routedTo] || 0) + 1;
    correctedToCount[fb.correctedTo] = (correctedToCount[fb.correctedTo] || 0) + 1;
    const pair = `${fb.routedTo} → ${fb.correctedTo}`;
    pairCount[pair] = (pairCount[pair] || 0) + 1;
  }

  // 准确率 (非纠正/总路由)
  const totalWithRoute = feedback.filter(f => f.routedTo !== 'unknown').length;
  const accuracy = totalWithRoute > 0
    ? ((totalWithRoute - corrections.length) / totalWithRoute * 100).toFixed(1)
    : 'N/A';

  // 加载学习状态
  let weights = null;
  if (fs.existsSync(WEIGHTS_FILE)) {
    try { weights = JSON.parse(fs.readFileSync(WEIGHTS_FILE, 'utf8')); } catch {}
  }

  if (jsonMode) {
    console.log(JSON.stringify({
      total: feedback.length,
      corrections: corrections.length,
      accuracy: accuracy + '%',
      topMisroutes: Object.entries(routedToCount).sort((a, b) => b[1] - a[1]).slice(0, 5),
      topCorrections: Object.entries(correctedToCount).sort((a, b) => b[1] - a[1]).slice(0, 5),
      topPairs: Object.entries(pairCount).sort((a, b) => b[1] - a[1]).slice(0, 10),
      weightsApplied: !!weights,
    }, null, 2));
    return;
  }

  console.log('# 路由反馈统计报告\n');
  console.log(`总反馈:     ${feedback.length}`);
  console.log(`纠正次数:   ${corrections.length}`);
  console.log(`准确率:     ${accuracy}%`);

  if (corrections.length > 0) {
    console.log('\n## 误路由频率 TOP 5 (被纠正的目标)');
    Object.entries(routedToCount)
      .sort((a, b) => b[1] - a[1])
      .slice(0, 5)
      .forEach(([name, cnt]) => console.log(`  ${name.padEnd(30)} ${cnt}`));

    console.log('\n## 纠正到 TOP 5 (正确目标)');
    Object.entries(correctedToCount)
      .sort((a, b) => b[1] - a[1])
      .slice(0, 5)
      .forEach(([name, cnt]) => console.log(`  ${name.padEnd(30)} ${cnt}`));

    console.log('\n## 常见纠正路径');
    Object.entries(pairCount)
      .sort((a, b) => b[1] - a[1])
      .slice(0, 10)
      .forEach(([pair, cnt]) => console.log(`  ${pair.padEnd(50)} ${cnt}`));
  }

  console.log(`\n权重文件:   ${weights ? `已生成 (${weights.generated})` : '未生成 (运行 --learn)'}`);
}

// === 模块导出 (供测试使用) ===
if (typeof module !== 'undefined') {
  module.exports = {
    tokenize,
    loadFeedback,
    loadRouteLog,
    loadIndex,
    loadSkillWhitelist,
    snapshotWeights,
    simpleHash,
    splitHoldout,
    loadHoldoutSet,
    filterTrainSet,
    validateHoldout,
    recordCorrection,
    learnWeights,
    autoLearn,
    showReport,
  };
}

// === 主入口 ===
if (require.main === module) {
  if (correctMode) {
    recordCorrection();
  } else if (splitMode) {
    splitHoldout();
  } else if (validateMode) {
    validateHoldout();
  } else if (learnMode) {
    learnWeights();
  } else if (reportMode) {
    showReport();
  } else {
    console.log('Usage:');
    console.log('  --correct "<query>" <skill>  记录路由纠正');
    console.log('  --split                       拆分训练集/holdout 集 (7:3)');
    console.log('  --validate                    在 holdout 集上验证准确率');
    console.log('  --learn                       生成权重调整 (仅训练集)');
    console.log('  --report                      查看反馈统计');
    console.log('  --json                        JSON 输出');
    process.exit(0);
  }
}