import * as fs from 'fs/promises';
import * as path from 'path';
import type { ToolResult } from '../../types/index.js';
import type { ToolWithMetadata } from '../types.js';
import { loadDescription } from '../load_description.js';
import { getPermissionManager } from '../../permission/index.js';

function formatSize(bytes: number): string {
  const units = ['B', 'KB', 'MB', 'GB', 'TB'];
  let unitIndex = 0;
  let size = bytes;

  while (size >= 1024 && unitIndex < units.length - 1) {
    size /= 1024;
    unitIndex++;
  }

  return `${size.toFixed(2)} ${units[unitIndex]}`;
}

function formatPermissions(mode: number): string {
  const types: Record<number, string> = {
    0o140000: 'socket',
    0o120000: 'symbolic link',
    0o100000: 'regular file',
    0o060000: 'block device',
    0o040000: 'directory',
    0o020000: 'character device',
    0o010000: 'FIFO',
  };

  const fileType = Object.entries(types).find(([mask]) => (mode & 0o170000) === Number(mask));

  const perms = [
    (mode & 0o400) ? 'r' : '-',
    (mode & 0o200) ? 'w' : '-',
    (mode & 0o100) ? 'x' : '-',
    (mode & 0o040) ? 'r' : '-',
    (mode & 0o020) ? 'w' : '-',
    (mode & 0o010) ? 'x' : '-',
    (mode & 0o004) ? 'r' : '-',
    (mode & 0o002) ? 'w' : '-',
    (mode & 0o001) ? 'x' : '-',
  ].join('');

  return `${fileType?.[1] || 'unknown'} (${perms})`;
}

export const getFileInfoTool: ToolWithMetadata = {
  name: 'get_file_info',
  description: loadDescription('get_file_info'),
  metadata: {
    name: 'get_file_info',
    category: 'filesystem',
    description: '获取文件元信息',
    keywords: ['file', 'info', 'stat', 'size', 'permission', 'metadata', '文件', '信息', '大小', '权限', '属性'],
    deferLoading: true,
  },
  parameters: {
    path: {
      type: 'string',
      description: '文件或目录的路径',
      required: true,
    },
  },
  execute: async (params: Record<string, unknown>): Promise<ToolResult> => {
    const filePath = params.path as string;
    const cwd = process.cwd();
    const absolutePath = path.isAbsolute(filePath)
      ? filePath
      : path.join(cwd, filePath);

    // 权限检查
    const permissionManager = getPermissionManager();
    const permResult = await permissionManager.checkFilePermission({
      operation: 'info',
      path: absolutePath,
      workdir: cwd,
    });

    if (!permResult.allowed) {
      if (permResult.needsConfirmation) {
        return {
          success: false,
          output: '',
          error: `需要用户确认: 获取文件信息 ${absolutePath}\n原因: ${permResult.reason || '需要权限确认'}`,
        };
      }
      return {
        success: false,
        output: '',
        error: `权限被拒绝: ${permResult.reason || '不允许获取此文件信息'}`,
      };
    }

    try {
      const stats = await fs.stat(absolutePath);
      const info = [
        `路径: ${absolutePath}`,
        `类型: ${stats.isDirectory() ? '目录' : stats.isFile() ? '文件' : stats.isSymbolicLink() ? '符号链接' : '其他'}`,
        `大小: ${formatSize(stats.size)}`,
        `权限: ${formatPermissions(stats.mode)}`,
        `创建时间: ${stats.birthtime.toLocaleString()}`,
        `修改时间: ${stats.mtime.toLocaleString()}`,
        `访问时间: ${stats.atime.toLocaleString()}`,
        `inode: ${stats.ino}`,
        `硬链接数: ${stats.nlink}`,
      ];

      // 如果是符号链接，显示目标
      if (stats.isSymbolicLink()) {
        try {
          const target = await fs.readlink(absolutePath);
          info.push(`链接目标: ${target}`);
        } catch {
          // 忽略
        }
      }

      // 如果是目录，统计子项数量
      if (stats.isDirectory()) {
        try {
          const entries = await fs.readdir(absolutePath);
          info.push(`子项数量: ${entries.length}`);
        } catch {
          // 忽略
        }
      }

      return {
        success: true,
        output: info.join('\n'),
      };
    } catch (error) {
      return {
        success: false,
        output: '',
        error: error instanceof Error ? error.message : String(error),
      };
    }
  },
};
