//
//  AppCacheManager.swift
//  QuickLocation
//
//  Created by 八条 on 2026/6/11.
//

import Foundation

final class AppCacheManager {
    
    // MARK: - 计算单个文件夹大小(字节)
    static func folderSize(at path: String) -> Int64 {
        guard FileManager.default.fileExists(atPath: path) else { return 0 }
        var totalSize: Int64 = 0
        let manager = FileManager.default
        
        guard let filePaths = try? manager.subpaths(atPath: path) else {
            return totalSize
        }
        
        for subPath in filePaths {
            let fullPath = path + "/" + subPath
            var isDir: ObjCBool = false
            if manager.fileExists(atPath: fullPath, isDirectory: &isDir) {
                if isDir.boolValue {
                    totalSize += folderSize(at: fullPath)
                } else {
                    // 读取文件属性，失败则跳过
                    if let attrs = try? manager.attributesOfItem(atPath: fullPath) {
                        totalSize += attrs[.size] as? Int64 ?? 0
                    }
                }
            }
        }
        return totalSize
    }
    
    // MARK: - 获取 App 总缓存大小（Caches + tmp）
    static func totalCacheSize() -> Int64 {
        let cachesPath = NSSearchPathForDirectoriesInDomains(.cachesDirectory, .userDomainMask, true).first ?? ""
        let tmpPath = NSTemporaryDirectory()
        
        let cachesSize = folderSize(at: cachesPath)
        let tmpSize = folderSize(at: tmpPath)
        return cachesSize + tmpSize
    }
    
    // MARK: - 字节 转 可读字符串（B/KB/MB/GB）
    static func formatByte(_ byte: Int64) -> String {
        guard byte > 0 else { return "0 B" }
        let units: [String] = ["B", "KB", "M", "G"]
        var size = Double(byte)
        var unitIndex = 0
        while size >= 1024, unitIndex < units.count - 1 {
            size /= 1024
            unitIndex += 1
        }
        return String(format: "%.2f %@", size, units[unitIndex])
    }
    
    // MARK: - 清理缓存（Caches + tmp）
    static func clearCache(completion: @escaping () -> Void) {
        DispatchQueue.global(qos: .background).async {
            let manager = FileManager.default
            // 清理 Caches
            let cachesPath = NSSearchPathForDirectoriesInDomains(.cachesDirectory, .userDomainMask, true).first ?? ""
            try? manager.removeItem(atPath: cachesPath)
            try? manager.createDirectory(atPath: cachesPath, withIntermediateDirectories: true)
            
            // 清理 tmp
            let tmpPath = NSTemporaryDirectory()
            let tmpFiles = (try? manager.contentsOfDirectory(atPath: tmpPath)) ?? []
            tmpFiles.forEach { file in
                try? manager.removeItem(atPath: tmpPath + file)
            }
            
            DispatchQueue.main.async {
                completion()
            }
        }
    }
}