#!/usr/bin/env node
/**
 * PreToolUse Hook: Skill 合规校验门控 (v5.2 Neural Gateway)
 * Matcher: Skill
 *
 * 校验 Skill 调用是否在路由推荐集合内。
 * 不匹配 → exit(2) 拦截 + 注入纠正提示。
 *
 * stdin: { tool_name: "Skill", tool_input: { skill, args } }
 * 退出码: 0=放行, 2=拦截(deny)
 *
 * Fail-close: 解析异常 → exit(2) ask (安全组件不可因故障静默放行)
 */

const fs = require('fs');
const path = require('path');
const { safeAppendJsonl } = require('./lib/safe-append.js');

const readStdin = require('./lib/read-stdin.js');


const CLAUDE_ROOT = require('./lib/root.js');
const DEBUG_DIR = path.join(CLAUDE_ROOT, 'debug');
const STATE_FILE = path.join(DEBUG_DIR, 'route-state-current.json');


const os = require('os');
const DISK_CACHE_FILE = require('path').join((function(){ try { return require('../scripts/paths.config.js').PATHS.root; } catch { return require('path').join(process.env.USERPROFILE || process.env.HOME, '.claude'); } })(), 'debug', '.disk-cache.json');
const DISK_CACHE_TTL = 5 * 60 * 1000; // 5 分钟缓存 TTL

/**
 * 磁盘空间断路器: 可用空间 < 100MB 时返回 true
 * 防止磁盘满导致状态文件写入失败 → 安全门控级联失效
 * v5.9: 优先 PowerShell Get-CimInstance，fallback wmic (兼容旧系统)
 */
function isDiskCritical() {
  // 先检查磁盘检测缓存（5 分钟有效）
  try {
    if (require('fs').existsSync(DISK_CACHE_FILE)) {
      const cache = JSON.parse(require('fs').readFileSync(DISK_CACHE_FILE, 'utf8'));
      if (Date.now() - cache.ts < DISK_CACHE_TTL) return cache.critical;
    }
  } catch {}

  const THRESHOLD = 100 * 1024 * 1024; // 100MB
  let result = false;
  try {
    const { spawnSync } = require('child_process');
    const drive = CLAUDE_ROOT.charAt(0) + ':';

    // XC2 修复: driveLetter 输入校验，防止命令注入
    const driveLetter = drive.charAt(0);
    if (!/^[A-Za-z]$/.test(driveLetter)) {
      return false; // 非法驱动器字母，默认不阻断
    }

    // 优先 PowerShell Get-PSDrive (Windows 10/11 通用，无弃用风险)
    let psSuccess = false;
    try {
      const psResult = spawnSync('powershell', ['-NoProfile', '-Command', `(Get-PSDrive ${driveLetter}).Free`], { encoding: 'utf8', timeout: 3000 });
      const psOut = (psResult.stdout || '').trim();
      const freeSpace = parseInt(psOut, 10);
      if (!isNaN(freeSpace)) {
        result = freeSpace < THRESHOLD;
        psSuccess = true;
        // XC2 修复: PowerShell 成功后立即写缓存并返回，不再执行 wmic
        try {
          require('fs').writeFileSync(DISK_CACHE_FILE, JSON.stringify({ ts: Date.now(), critical: result }));
        } catch {}
        return result;
      }
    } catch {}

    // XC2 修复: Fallback wmic 仅在 PowerShell 失败时执行
    if (!psSuccess) {
      const wmicResult = spawnSync('wmic', ['logicaldisk', 'where', `DeviceID='${driveLetter}:'`, 'get', 'FreeSpace', '/value'], { encoding: 'utf8', timeout: 2000 });
      const wmicOut = wmicResult.stdout || '';
      const match = wmicOut.match(/FreeSpace=(\d+)/);
      if (match) { result = parseInt(match[1], 10) < THRESHOLD; }
    }
  } catch {}
  // 写入缓存（无论检测成功还是失败默认 false 都缓存）
  try {
    require('fs').writeFileSync(DISK_CACHE_FILE, JSON.stringify({ ts: Date.now(), critical: result }));
  } catch {}
  return result; // 检测失败时 result=false，不触发断路器
}

/**
 * 加载路由状态
 * @returns {Object|null}
 */
function loadRouteState(currentSessionId) {
  try {
    if (!fs.existsSync(STATE_FILE)) return null;
    return JSON.parse(fs.readFileSync(STATE_FILE, 'utf8'));
  } catch {
    return null;
  }
}

/**
 * 构建允许的技能集合
 * @param {Object} state - route-state-current.json
 * @param {string} prompt - 原始用户 prompt (用于检测显式调用)
 * @returns {Set<string>}
 */
function buildAllowedSet(state, prompt) {
  const allowed = new Set();

  // 主路由
  if (state.routing?.primary) {
    allowed.add(state.routing.primary);
  }

  // 候选 (置信度 ≥ 0.3)
  for (const c of (state.routing?.candidates || [])) {
    if (c.confidence >= 0.3) {
      allowed.add(c.name);
    }
  }

  // 技能链中所有技能
  for (const s of (state.routing?.chain || [])) {
    allowed.add(s);
  }

  // 始终允许 developer-expert (通用回退)
  allowed.add('developer-expert');

  // 用户 prompt 中显式调用 /skill-name → 放行
  if (prompt) {
    const explicitMatch = prompt.match(/^\/([\w-]+)/);
    if (explicitMatch) {
      allowed.add(explicitMatch[1]);
    }
  }

  return allowed;
}

/**
 * 记录 compliance 事件
 * @param {Object} entry
 */
function logCompliance(entry) {
  try {
    const dateStr = new Date().toISOString().slice(0, 10);
    const logFile = path.join(DEBUG_DIR, `compliance-${dateStr}.jsonl`);
    safeAppendJsonl(logFile, entry);
  } catch (e) {
    // v5.9: 记录日志写入失败到 stderr (可通过 hook-errors.log 追踪)
    try { process.stderr.write(`[compliance-gate] log write failed: ${e.message}\n`); } catch {}
  }
}

// === 主流程 ===
function main() {
  readStdin({ maxSize: 128 * 1024 }).then(input => {
    const skillName = input.tool_input?.skill;

    if (!skillName) {
      process.exit(0);
      return;
    }

    // === Phase 0: 逃生舱覆盖检查 ===
    try {
      const userOverrides = require('../scripts/user-overrides.js');

      // /force 检查: 放行 + 记录 + 清除 force
      const forceState = userOverrides.isForceActive();
      if (forceState.active) {
        logCompliance({
          ts: new Date().toISOString(),
          traceId: 'override',
          event: 'gate-force-bypass',
          skill: skillName,
          override: 'force',
          forceSkill: forceState.skill || null,
        });
        userOverrides.clearForce(); // 单次生效
        process.exit(0);
        return;
      }

      // /checks off 检查: 直接放行
      if (userOverrides.isChecksDisabled()) {
        logCompliance({
          ts: new Date().toISOString(),
          traceId: 'override',
          event: 'gate-checks-bypass',
          skill: skillName,
          override: 'checksOff',
        });
        process.exit(0);
        return;
      }
    } catch (e) {
      // v5.9: 记录 user-overrides 加载失败 (模块不存在是预期情况，其他错误需排查)
      if (e && e.code !== 'MODULE_NOT_FOUND') {
        try { process.stderr.write(`[compliance-gate] user-overrides error: ${e.message}\n`); } catch {}
      }
    }

    // v5.9: 磁盘空间断路器 — 防止状态文件不可写导致安全门控级联失效
    if (isDiskCritical()) {
      logCompliance({
        ts: new Date().toISOString(),
        traceId: 'circuit-breaker',
        event: 'gate-disk-critical',
        skill: skillName,
      });
      process.stderr.write(JSON.stringify({
        hookSpecificOutput: { permissionDecision: 'ask' },
        systemMessage: '[合规门控] 磁盘空间不足(<100MB)，安全门控无法正常工作，请用户确认操作。',
      }));
      process.exit(2);
      return;
    }

    // 加载路由状态
    const state = loadRouteState();

    // 无 route-state → 放行 (可能是非用户消息触发的 Skill 调用)
    if (!state) {
      process.exit(0);
      return;
    }

    // simple 复杂度 → 放行 (不需要路由)
    if (state.intent?.complexity === 'simple') {
      process.exit(0);
      return;
    }

    // 构建允许集合 (传递 promptRaw 用于检测显式 /skill-name 调用)
    const allowed = buildAllowedSet(state, state.promptRaw || '');

    // 校验
    if (allowed.has(skillName)) {
      // 合规: 放行并记录
      logCompliance({
        ts: new Date().toISOString(),
        traceId: state.traceId,
        event: 'gate-pass',
        skill: skillName,
        primary: state.routing?.primary,
        compliant: true,
      });


      // v5.9: 去耦合 — 不再回写 route-state-current.json (消除共享可变状态)
      // actualSkill 记录到独立的 compliance 日志中，供 route-auditor 通过 traceId 关联
      try {
        // H1 修复: append-only jsonl 防 TOCTOU 污染 (原 actual-skill.json 单文件 lastWriter-wins)
        const actualJsonl = path.join(DEBUG_DIR, 'actual-skills.jsonl');
        const line = JSON.stringify({
          traceId: state.traceId,
          actualSkill: skillName,
          ts: new Date().toISOString(),
        }) + '\n';
        fs.appendFileSync(actualJsonl, line);
        // W2 (2026-04-16): 旧 actual-skill.json 默认不写，由 feature flag 恢复
        // 回滚: set BOOKWORM_LEGACY_ACTUAL_SKILL=1
        if (process.env.BOOKWORM_LEGACY_ACTUAL_SKILL === '1') {
          const actualFile = path.join(DEBUG_DIR, 'actual-skill.json');
          fs.writeFileSync(actualFile, line);
        }
      } catch {}

      process.exit(0);
      return;
    }

    // 不合规: 拦截
    const primary = state.routing?.primary || 'developer-expert';

    logCompliance({
      ts: new Date().toISOString(),
      traceId: state.traceId,
      event: 'gate-block',
      skill: skillName,
      primary,
      allowed: Array.from(allowed),
      compliant: false,
    });

    // 输出 deny 决策
    const output = {
      hookSpecificOutput: {
        permissionDecision: 'deny',
      },
      systemMessage: `[BWR 合规校验] ${skillName} 不在路由推荐集合中。推荐: ${primary}。请使用 /${primary} 或候选技能处理此请求。`,
    };

    process.stderr.write(JSON.stringify(output));
    process.exit(2);
  }).catch((e) => {
    // Fail-close: 安全组件解析异常 → 请求用户确认而非静默放行
    try {
      logCompliance({
        ts: new Date().toISOString(),
        traceId: 'error',
        event: 'gate-parse-error',
        error: (e && e.message) || 'unknown',
      });
    } catch {}
    process.stderr.write(JSON.stringify({
      hookSpecificOutput: { permissionDecision: 'ask' },
      systemMessage: `[合规门控] 校验遇到异常(${(e && e.message) || 'unknown'})，请用户确认是否继续。`,
    }));
    process.exit(2);
  });
}

// 模块导出 (供测试)
if (typeof module !== 'undefined') {
  module.exports = { detectClaudeRoot: require('./lib/root.js'), loadRouteState, buildAllowedSet, logCompliance };
}

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