// lib/fs-utils.ts
import fs from 'fs/promises';
import path from 'path';
import { RESOURCE_PATH } from './constants';

/**
 * Validate that a path doesn't escape the base directory (prevents path traversal)
 */
function validatePath(basePath: string, ...segments: string[]): string {
  const fullPath = path.resolve(basePath, ...segments);
  const normalizedBase = path.resolve(basePath);
  if (!fullPath.startsWith(normalizedBase)) {
    throw new Error('Invalid path: path traversal detected');
  }
  return fullPath;
}

/**
 * 获取所有项目目录
 */
export async function getProjects(): Promise<string[]> {
  const dirs = await fs.readdir(RESOURCE_PATH);
  const projectDirs = await Promise.all(
    dirs.map(async (dir) => {
      const dirPath = validatePath(RESOURCE_PATH, dir);
      try {
        const stats = await fs.stat(dirPath);
        return stats.isDirectory() ? dir : null;
      } catch {
        return null;
      }
    })
  );
  return projectDirs.filter((dir): dir is string => dir !== null);
}

/**
 * 获取指定项目的所有版本目录
 */
export async function getVersions(project: string): Promise<string[]> {
  const projectPath = validatePath(RESOURCE_PATH, project);
  const dirs = await fs.readdir(projectPath);
  const versionDirs = await Promise.all(
    dirs.map(async (dir) => {
      const dirPath = validatePath(projectPath, dir);
      try {
        const stats = await fs.stat(dirPath);
        return stats.isDirectory() ? dir : null;
      } catch {
        return null;
      }
    })
  );
  return versionDirs.filter((dir): dir is string => dir !== null).sort();
}

/**
 * 获取指定项目版本的 APK 文件列表
 */
export async function getApks(project: string, version: string, commitId?: string): Promise<{
  name: string;
  commit: string | null;
  size: number;
  modifiedAt: Date;
}[]> {
  const apksPath = validatePath(RESOURCE_PATH, project, version, 'apks');

  try {
    const files = await fs.readdir(apksPath);
    const apkFiles = files.filter(file => file.endsWith('.apk'));

    const apks = await Promise.all(
      apkFiles.map(async (file) => {
        const filePath = validatePath(apksPath, file);
        const stats = await fs.stat(filePath);

        // 提取 commit id (假设文件名格式为 xxx-{commit}-xxx.apk)
        const commitMatch = file.match(/([a-f0-9]{7,})/i);
        const commit = commitMatch ? commitMatch[1] : null;

        return {
          name: file,
          commit,
          size: stats.size,
          modifiedAt: stats.mtime,
        };
      })
    );

    // 如果指定了 commit id，进行过滤
    if (commitId) {
      return apks.filter(apk =>
        apk.commit && apk.commit.toLowerCase().includes(commitId.toLowerCase())
      );
    }

    return apks.sort((a, b) => b.modifiedAt.getTime() - a.modifiedAt.getTime());
  } catch (error) {
    // 如果 apks 目录不存在，返回空数组
    return [];
  }
}

/**
 * 格式化版本号显示 (0_42 -> 0.42)
 */
export function formatVersion(version: string): string {
  return version.replace('_', '.');
}

/**
 * 格式化文件大小
 */
export function formatFileSize(bytes: number): string {
  if (bytes < 1024) return bytes + ' B';
  if (bytes < 1024 * 1024) return (bytes / 1024).toFixed(2) + ' KB';
  if (bytes < 1024 * 1024 * 1024) return (bytes / (1024 * 1024)).toFixed(2) + ' MB';
  return (bytes / (1024 * 1024 * 1024)).toFixed(2) + ' GB';
}

/**
 * 格式化日期时间
 */
export function formatDateTime(date: Date): string {
  const year = date.getFullYear();
  const month = String(date.getMonth() + 1).padStart(2, '0');
  const day = String(date.getDate()).padStart(2, '0');
  const hours = String(date.getHours()).padStart(2, '0');
  const minutes = String(date.getMinutes()).padStart(2, '0');
  return `${year}-${month}-${day} ${hours}:${minutes}`;
}