#!/usr/bin/env node
/**
 * 预测性审计引擎 (Predictive Audit)
 *
 * 挖掘 evolution-log.jsonl 模式:
 * - 哪些标签/维度修复最频繁
 * - 版本间修复密度趋势
 * - 预测下次升级可能的风险点
 *
 * 用法:
 *   node scripts/predictive-audit.js          # 文本报告
 *   node scripts/predictive-audit.js --json   # JSON 输出
 */

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

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

const CLAUDE_ROOT = detectClaudeRoot();
const JSON_MODE = process.argv.includes('--json');

// === 加载演进日志 ===
function loadEvolutionLog() {
  const candidates = [
    path.join(CLAUDE_ROOT, 'evolution-log.jsonl'),
    path.join(CLAUDE_ROOT, 'debug', 'evolution-log.jsonl'),
    path.join(CLAUDE_ROOT, 'projects', 'C--Users-janson9527us', 'memory', 'evolution-log.jsonl'),
  ];

  const allEntries = [];
  const seenSeqs = new Set();
  for (const fp of candidates) {
    if (!fs.existsSync(fp)) continue;
    const lines = fs.readFileSync(fp, 'utf8').trim().split('\n');
    for (const line of lines) {
      try {
        const entry = JSON.parse(line);
        if (entry.seq != null && !seenSeqs.has(entry.seq)) {
          seenSeqs.add(entry.seq);
          allEntries.push(entry);
        }
      } catch {}
    }
  }
  return allEntries.sort((a, b) => (a.seq || 0) - (b.seq || 0));
}

// === 分析 ===
function analyze(entries) {
  if (entries.length === 0) return null;

  // 1. 标签频率分析
  const tagCounts = {};
  for (const e of entries) {
    for (const tag of (e.tags || [])) {
      tagCounts[tag] = (tagCounts[tag] || 0) + 1;
    }
  }
  const topTags = Object.entries(tagCounts)
    .sort((a, b) => b[1] - a[1])
    .map(([tag, count]) => ({ tag, count, pct: Math.round(count / entries.length * 100) }));

  // 2. 修复密度趋势 (按版本)
  const byVersion = {};
  for (const e of entries) {
    const v = e.version || 'unknown';
    if (!byVersion[v]) byVersion[v] = { count: 0, totalFixes: 0, entries: [] };
    byVersion[v].count++;
    byVersion[v].totalFixes += (e.fix_count || 0);
    byVersion[v].entries.push(e);
  }

  const versionTrend = Object.entries(byVersion)
    .sort((a, b) => {
      // 按版本号排序
      const va = a[0].replace('v', '').split('.').map(Number);
      const vb = b[0].replace('v', '').split('.').map(Number);
      return (va[0] - vb[0]) || (va[1] - vb[1]);
    })
    .map(([version, data]) => ({
      version,
      entries: data.count,
      totalFixes: data.totalFixes,
      avgFixesPerEntry: data.count > 0 ? Math.round(data.totalFixes / data.count * 10) / 10 : 0,
    }));

  // 3. 触发源分析
  const triggerCounts = {};
  for (const e of entries) {
    const trigger = e.trigger || 'unknown';
    triggerCounts[trigger] = (triggerCounts[trigger] || 0) + 1;
  }

  // 4. 趋势分析 - 最近 5 个版本的复杂度变化
  const recentVersions = versionTrend.slice(-5);
  const complexityTrend = recentVersions.map(v => v.totalFixes);
  const isIncreasing = complexityTrend.length >= 3 &&
    complexityTrend[complexityTrend.length - 1] < complexityTrend[complexityTrend.length - 2];

  // 5. 预测风险点
  const predictions = [];

  // 高频标签预测
  if (topTags.length > 0) {
    const topTag = topTags[0];
    if (topTag.pct > 60) {
      predictions.push({
        risk: 'HIGH',
        area: topTag.tag,
        reason: `"${topTag.tag}" 出现在 ${topTag.pct}% 的版本变更中, 是最频繁的变更领域`,
        suggestion: `下次升级重点关注 ${topTag.tag} 相关组件的回归测试`,
      });
    }
  }

  // 修复密度趋势预测
  if (recentVersions.length >= 3) {
    const recent = recentVersions.slice(-3);
    const avgRecent = recent.reduce((s, v) => s + v.totalFixes, 0) / recent.length;
    if (avgRecent > 10) {
      predictions.push({
        risk: 'MEDIUM',
        area: 'complexity',
        reason: `最近 3 个版本平均修复 ${Math.round(avgRecent)} 项, 系统复杂度快速增长`,
        suggestion: '考虑放慢新功能节奏, 增加稳定性/重构投入',
      });
    }
  }

  // 版本/测试相关预测
  const versionTag = topTags.find(t => t.tag === 'version');
  const testingTag = topTags.find(t => t.tag === 'testing');
  if (versionTag && testingTag) {
    if (versionTag.count > testingTag.count * 1.5) {
      predictions.push({
        risk: 'MEDIUM',
        area: 'testing-gap',
        reason: `版本变更 (${versionTag.count}次) 远多于测试相关变更 (${testingTag.count}次)`,
        suggestion: '增加自动化测试覆盖, 确保每次升级有充分测试',
      });
    }
  }

  // 安全标签频率
  const securityTag = topTags.find(t => t.tag === 'security');
  if (securityTag && securityTag.pct > 40) {
    predictions.push({
      risk: 'INFO',
      area: 'security',
      reason: `安全相关变更占 ${securityTag.pct}%, 系统安全投入较高`,
      suggestion: '保持当前安全关注度, 考虑引入自动化安全扫描',
    });
  }

  // 降低修复密度 = 好趋势
  if (isIncreasing) {
    predictions.push({
      risk: 'INFO',
      area: 'improving',
      reason: '最近版本修复数呈下降趋势, 系统稳定性在改善',
      suggestion: '继续保持, 可适当增加新功能投入',
    });
  }

  // v5.1: 指数平滑预测
  const fixCounts = versionTrend.map(v => v.totalFixes);
  const smoothed = exponentialSmoothing(fixCounts);

  // v5.1: 标签共现矩阵
  const cooccurrence = buildCooccurrenceMatrix(entries);

  // v5.1: 尖峰检测
  const spikes = detectSpikes(fixCounts);
  if (spikes.length > 0) {
    predictions.push({
      risk: 'INFO',
      area: 'spike-detection',
      reason: `检测到 ${spikes.length} 个修复密度尖峰`,
      suggestion: '关注尖峰对应版本的变更质量',
    });
  }

  return {
    totalEntries: entries.length,
    versionRange: `${entries[0].version} -> ${entries[entries.length - 1].version}`,
    dateRange: `${entries[0].ts} ~ ${entries[entries.length - 1].ts}`,
    topTags,
    versionTrend,
    triggers: Object.entries(triggerCounts).sort((a, b) => b[1] - a[1]),
    predictions,
    smoothedForecast: smoothed,
    cooccurrence,
    spikes,
  };
}

// === v5.1: 指数平滑预测 ===
/**
 * 简单指数平滑, 返回下一期预测值
 * @param {number[]} data - 时间序列数据
 * @param {number} alpha - 平滑系数 (默认 0.4)
 * @returns {{ forecast: number, series: number[] }}
 */
function exponentialSmoothing(data, alpha = 0.4) {
  if (data.length === 0) return { forecast: 0, series: [] };

  const series = [data[0]];
  for (let i = 1; i < data.length; i++) {
    series.push(alpha * data[i] + (1 - alpha) * series[i - 1]);
  }

  // 下一期预测
  const forecast = Math.round(series[series.length - 1] * 10) / 10;
  return { forecast, series: series.map(v => Math.round(v * 10) / 10) };
}

// === v5.1: 标签共现矩阵 ===
/**
 * 构建标签共现矩阵
 * @param {Array} entries - evolution-log 条目
 * @returns {Object} { "tagA:tagB" → count }
 */
function buildCooccurrenceMatrix(entries) {
  const matrix = {};

  for (const entry of entries) {
    const tags = entry.tags || [];
    for (let i = 0; i < tags.length; i++) {
      for (let j = i + 1; j < tags.length; j++) {
        const pair = [tags[i], tags[j]].sort().join(':');
        matrix[pair] = (matrix[pair] || 0) + 1;
      }
    }
  }

  return matrix;
}

// === v5.1: 尖峰检测 ===
/**
 * 检测时间序列中的异常尖峰
 * @param {number[]} timeSeries - 时间序列数据
 * @param {number} threshold - Z-score 阈值 (默认 2.0)
 * @returns {Array<{ index: number, value: number, zScore: number }>}
 */
function detectSpikes(timeSeries, threshold = 2.0) {
  if (timeSeries.length < 3) return [];

  const mean = timeSeries.reduce((a, b) => a + b, 0) / timeSeries.length;
  const variance = timeSeries.reduce((s, v) => s + (v - mean) ** 2, 0) / timeSeries.length;
  const stddev = Math.sqrt(variance);

  if (stddev === 0) return [];

  const spikes = [];
  for (let i = 0; i < timeSeries.length; i++) {
    const zScore = Math.abs(timeSeries[i] - mean) / stddev;
    if (zScore > threshold) {
      spikes.push({ index: i, value: timeSeries[i], zScore: Math.round(zScore * 100) / 100 });
    }
  }

  return spikes;
}

// === 输出 ===
function main() {
  const entries = loadEvolutionLog();
  if (entries.length === 0) {
    console.log('无演进日志数据。');
    return;
  }

  const report = analyze(entries);

  if (JSON_MODE) {
    console.log(JSON.stringify(report, null, 2));
    return;
  }

  console.log('=== 预测性审计报告 ===');
  console.log(`演进记录: ${report.totalEntries} 条 (${report.versionRange})`);
  console.log(`时间跨度: ${report.dateRange}`);
  console.log('');

  // 标签热力图
  console.log('标签频率 (Top 10):');
  for (const t of report.topTags.slice(0, 10)) {
    const bar = '#'.repeat(Math.min(t.count, 30));
    console.log(`  ${t.tag.padEnd(20)} ${String(t.count).padStart(3)} (${String(t.pct).padStart(3)}%) ${bar}`);
  }
  console.log('');

  // 版本趋势
  console.log('版本修复密度:');
  for (const v of report.versionTrend) {
    const bar = '*'.repeat(Math.min(v.totalFixes, 40));
    console.log(`  ${v.version.padEnd(8)} ${String(v.totalFixes).padStart(3)} fixes (${v.entries} entries) ${bar}`);
  }
  console.log('');

  // 触发源
  console.log('触发源分布:');
  for (const [trigger, count] of report.triggers) {
    console.log(`  ${trigger.padEnd(20)} ${count}`);
  }
  console.log('');

  // 预测
  if (report.predictions.length > 0) {
    console.log('风险预测:');
    for (const p of report.predictions) {
      console.log(`  [${p.risk}] ${p.area}: ${p.reason}`);
      console.log(`         -> ${p.suggestion}`);
    }
  } else {
    console.log('风险预测: 暂无显著风险信号');
  }
}

// 模块导出 (供测试使用)
if (typeof module !== 'undefined') {
  module.exports = {
    loadEvolutionLog, analyze, main,
    exponentialSmoothing, buildCooccurrenceMatrix, detectSpikes,
  };
}

if (require.main === module) {
  main();
}