#!/usr/bin/env node
/**
 * PreToolUse Hook: 阻止写入敏感文件
 * 匹配器: Write|Edit
 * 退出码: 0=放行, 2=阻断(stderr输出JSON)
 *
 * v3.8 升级:
 * - 规则外部化: 从 rules/*.json 热加载
 * - 安全事件日志: deny/ask 事件写入 debug/security-YYYY-MM-DD.jsonl
 * - 同时检查 Write 的 content 和 Edit 的 new_string 字段
 * - 路径规范化（resolve .., 大小写无关匹配）
 * - catch 块默认 ask（fail-closed）
 */

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

const { logSecurityEvent } = require('./lib/security-log.js');
const { loadRules, compilePatterns, RULES_DIR } = require('./lib/rule-loader.js');

const MAX_STDIN_SIZE = 1024 * 1024; // 1MB 防止内存溢出

// CRIT-4: 规则文件丢失时使用硬编码最小安全规则，而非空数组
const FALLBACK = {
  'sensitive-paths': [
    { regex: '\\.env(?:\\.|$)', reason: '环境变量文件', flags: 'i' },
    { regex: 'settings\\.json$', reason: '系统配置文件', flags: 'i' },
    { regex: 'id_rsa|id_ed25519', reason: 'SSH 密钥', flags: 'i' },
    { regex: 'credentials?\\.json$', reason: '凭证文件', flags: 'i' },
  ],
  'sensitive-content': [],
  'sensitive-content-deny': [],
};

const SENSITIVE_PATH_PATTERNS = loadRules('sensitive-paths.json', FALLBACK);
const SENSITIVE_CONTENT_PATTERNS = loadRules('sensitive-content.json', FALLBACK);
const SENSITIVE_CONTENT_DENY_PATTERNS = loadRules('sensitive-content-deny.json', FALLBACK);

// ─── 工具函数 ──────────────────────────────────────────
/**
 * 规范化路径: resolve 相对路径 + .. 遍历，统一为正斜杠
 */
function normalizePath(filePath) {
  if (!filePath) return '';
  let resolved = path.resolve(filePath.trim());
  // P0: 解析符号链接，防止 symlink 绕过 (与 block-sensitive-reads 对齐)
  try { resolved = fs.realpathSync(resolved); } catch {}
  return resolved.replace(/\\/g, '/')
    .replace(/\.+$/, '')          // P0: 剥离尾部点 (Windows 忽略尾部点)
    .replace(/::?\$DATA$/i, '');  // P0: 剥离 NTFS ADS 后缀
}

/**
 * 提取内容字段: Write 用 content，Edit 用 new_string
 */
function extractContent(toolInput) {
  if (!toolInput) return '';
  return (toolInput.content || '') + (toolInput.new_string || '');
}

// ─── 主流程 ────────────────────────────────────────────
function main() {
  let rawInput = '';
  process.stdin.setEncoding('utf8');
  process.stdin.on('data', (chunk) => {
    rawInput += chunk;
    if (rawInput.length > MAX_STDIN_SIZE) {
      process.stderr.write(JSON.stringify({
        hookSpecificOutput: { permissionDecision: 'ask' },
        systemMessage: '[安全防护] 输入数据过大(>1MB)，无法完成安全扫描，请用户确认操作。',
      }));
      process.exit(2);
    }
  });
  process.stdin.on('end', () => {
    try {
      const input = JSON.parse(rawInput);
      const ti = input.tool_input || {};
      const rawPath = ti.file_path || ti.filePath || ti.notebook_path || ti.path || '';
      const filePath = normalizePath(rawPath);
      const content = extractContent(input.tool_input);

      // ─── F1-6: self-healer 白名单 ──────────────────────
      // 允许 self-healer 修改 settings.json 中已知安全的配置键
      const SETTINGS_SAFE_KEYS = new Set([
        'skipDangerousModePermissionPrompt',
      ]);
      // XC11 修复: 除键名白名单外，还限制允许写入的值
      const SETTINGS_SAFE_VALUES = { ["skipDangerousModePermissionPrompt"]: [false] };
      function isSettingsSafeWrite(fp, c) {
        if (!/[\/].claude[\/]settings.json$/.test(fp)) return false;
        if (!c) return false;
        try {
          const parsed = JSON.parse(c);
          const keys = Object.keys(parsed);
          if (keys.length === 0) return false;
          if (!keys.every(k => SETTINGS_SAFE_KEYS.has(k))) return false;
          // XC11 修复: 校验每个键的值是否在允许列表中
          for (const [k, v] of Object.entries(parsed)) {
            const allowed = SETTINGS_SAFE_VALUES[k];
            if (allowed !== undefined && !allowed.includes(v)) return false;
          }
          return true;
        } catch { return false; }
      }
      // ──────────────────────────────────────────────────────

      // 检查文件路径
      for (const { pattern, reason } of SENSITIVE_PATH_PATTERNS) {
        if (pattern.test(filePath)) {
          // F1-6: self-healer 白名单豁免
          if (isSettingsSafeWrite(filePath, content)) break;
          logSecurityEvent('deny', 'block-sensitive-files', reason, rawPath);
          process.stderr.write(JSON.stringify({
            hookSpecificOutput: { permissionDecision: 'deny' },
            systemMessage: `[安全防护] 阻止写入敏感文件: ${rawPath}\n原因: ${reason}\n如确需写入，请用户手动操作。`
          }));
          process.exit(2);
          return;
        }
      }

      // F6: 内容级 deny — 危险安全配置回写拦截
      if (content) {
        for (const { pattern, reason } of SENSITIVE_CONTENT_DENY_PATTERNS) {
          if (pattern.test(content)) {
            logSecurityEvent('deny', 'block-sensitive-files', 'content-deny: ' + reason, rawPath);
            process.stderr.write(JSON.stringify({
              hookSpecificOutput: { permissionDecision: 'deny' },
              systemMessage: `[安全防护] 阻止危险配置回写: ${reason}\n此操作已被安全策略强制禁止。`
            }));
            process.exit(2);
            return;
          }
        }
      }

            // 检查文件内容（仅当有内容时）
      if (content) {
        for (const { pattern, reason } of SENSITIVE_CONTENT_PATTERNS) {
          if (pattern.test(content)) {
            logSecurityEvent('ask', 'block-sensitive-files', reason, rawPath);
            process.stderr.write(JSON.stringify({
              hookSpecificOutput: { permissionDecision: 'ask' },
              systemMessage: `[安全警告] 文件 ${rawPath} 内容中检测到疑似 ${reason}。请用户确认是否继续写入。`
            }));
            process.exit(2);
            return;
          }
        }
      }

      // 安全，放行
      process.exit(0);
    } catch (e) {
      // Fail-closed: 解析异常时请求用户确认而非静默放行
      process.stderr.write(JSON.stringify({
        hookSpecificOutput: { permissionDecision: 'ask' },
        systemMessage: `[安全防护] 文件写入检查遇到异常(${e.message})，请用户确认是否继续。`
      }));
      process.exit(2);
    }
  });
}

/**
 * 可导出的文件安全检查函数 (供 dispatcher 调用)
 * @param {object} input - 完整的 hook stdin JSON 输入
 * @returns {object|null} 检查结果，null 表示放行
 *   { decision: 'deny'|'ask', message: string }
 */
function checkFile(input) {
  try {
    const ti = input.tool_input || {};
    const rawPath = ti.file_path || ti.filePath || ti.notebook_path || ti.path || '';
    const filePath = normalizePath(rawPath);
    const content = extractContent(input.tool_input);

    // F1-6: self-healer 白名单
    const SETTINGS_SAFE_KEYS = new Set(['skipDangerousModePermissionPrompt']);
    const SETTINGS_SAFE_VALUES = { ["skipDangerousModePermissionPrompt"]: [false] };
    function isSettingsSafeWrite(fp, c) {
      if (!/[\/].claude[\/]settings.json$/.test(fp)) return false;
      if (!c) return false;
      try {
        const parsed = JSON.parse(c);
        const keys = Object.keys(parsed);
        if (keys.length === 0) return false;
        if (!keys.every(k => SETTINGS_SAFE_KEYS.has(k))) return false;
        for (const [k, v] of Object.entries(parsed)) {
          const allowed = SETTINGS_SAFE_VALUES[k];
          if (allowed !== undefined && !allowed.includes(v)) return false;
        }
        return true;
      } catch { return false; }
    }

    // 检查文件路径
    for (const { pattern, reason } of SENSITIVE_PATH_PATTERNS) {
      if (pattern.test(filePath)) {
        if (isSettingsSafeWrite(filePath, content)) break;
        logSecurityEvent('deny', 'block-sensitive-files', reason, rawPath);
        return {
          decision: 'deny',
          message: `[安全防护] 阻止写入敏感文件: ${rawPath}\n原因: ${reason}\n如确需写入，请用户手动操作。`,
        };
      }
    }

    // F6: 内容级 deny
    if (content) {
      for (const { pattern, reason } of SENSITIVE_CONTENT_DENY_PATTERNS) {
        if (pattern.test(content)) {
          logSecurityEvent('deny', 'block-sensitive-files', 'content-deny: ' + reason, rawPath);
          return {
            decision: 'deny',
            message: `[安全防护] 阻止危险配置回写: ${reason}\n此操作已被安全策略强制禁止。`,
          };
        }
      }
    }

    // 检查文件内容
    if (content) {
      for (const { pattern, reason } of SENSITIVE_CONTENT_PATTERNS) {
        if (pattern.test(content)) {
          logSecurityEvent('ask', 'block-sensitive-files', reason, rawPath);
          return {
            decision: 'ask',
            message: `[安全警告] 文件 ${rawPath} 内容中检测到疑似 ${reason}。请用户确认是否继续写入。`,
          };
        }
      }
    }

    return null; // 放行
  } catch (e) {
    // Fail-closed: 解析异常时请求用户确认
    return {
      decision: 'ask',
      message: `[安全防护] 文件写入检查遇到异常(${e.message})，请用户确认是否继续。`,
    };
  }
}

// 模块导出 (供测试和 dispatcher 使用)
if (typeof module !== 'undefined') {
  module.exports = { normalizePath, extractContent, checkFile };
}

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