//
//  MP_DownloadManager.swift
//  MusicPlayer
//
//  Created by 忆海16 on 2024/5/14.
//

import Foundation
import Foundation
import Tiercel
class MP_DownloadManager: NSObject {
    static let shared = MP_DownloadManager()

    var session: SessionManager!
    var progressHandlers: [String: (CGFloat) -> Void] = [:]
    var completionHandlers: [URL: (Result<MPPositive_SongItemModel, Error>) -> Void] = [:]
    var downloadTasks: [URL: URLSessionDownloadTask] = [:]
    var progressStorage: [String: CGFloat] = [:] // 新增进度存储
    var songHandlers:[URL: MPPositive_SongItemModel] = [:]
    private override init() {
        super.init()
        var configuration = SessionConfiguration()
        configuration.timeoutIntervalForRequest = 60
        configuration.maxConcurrentTasksLimit = 6
        configuration.allowsCellularAccess = true
        session = SessionManager("com.yourApp.backgroundDownload", configuration: configuration)
    }
    func downloadVideo(from url: URL, song:MPPositive_SongItemModel, progressHandler: @escaping (CGFloat) -> Void, completion: @escaping (Result<MPPositive_SongItemModel, Error>) -> Void) {
        progressHandlers[song.videoId] = progressHandler
        completionHandlers[url] = completion
        songHandlers[url] = song
        let downloadTask = session.download(url, headers: ["Accept-Encoding": "gzip, deflate"])
        //配置进度条
        downloadTask?.progress(handler: { [weak self] (task) in
            guard let self = self else {return}
            progressHandlers[song.videoId]?(task.progress.fractionCompleted)
            progressStorage[song.videoId] = task.progress.fractionCompleted
        })
        //配置任务完成事件
        downloadTask?.success(handler: { [weak self] (task) in
            guard let self = self else {return}
            //任务下载成功,进行文件转移
            let originalURL = task.url
            //任务下载地址
            let filePathUrl:URL = URL(fileURLWithPath: task.filePath)
            print("任务下载地址:\(filePathUrl)")
            let downloadsURL = DocumentsURL.appendingPathComponent("Downloads")
            if !FileManager.default.fileExists(atPath: downloadsURL.path) {
                do {
                    try FileManager.default.createDirectory(at: downloadsURL, withIntermediateDirectories: true, attributes: nil)
                } catch {
                    completionHandlers[originalURL]?(.failure(error))
                    return
                }
            }

            let fileURL = downloadsURL.appendingPathComponent("\(song.videoId ?? "").mp4")
            do {
                try FileManager.default.moveItem(at: filePathUrl, to: fileURL)
                //回调VideoID
                completionHandlers[originalURL]?(.success(songHandlers[originalURL]!))
                progressStorage[song.videoId] = nil // 清除已完成任务的进度记录
            } catch {
                completionHandlers[originalURL]?(.failure(error))
            }
            //移除任务
            if task.status == .succeeded {
                session.remove(task, completely: true) {_ in
                    print("\(song.title ?? "")下载任务完成，移除任务")
                }
            }
        }).failure(handler: {  [weak self] (task) in
            guard let self = self else {return}
            //任务下载失败
            let originalURL = task.url
            if let error = task.error {
                completionHandlers[originalURL]?(.failure(error))
            }
            if task.status == .failed {
                session.cancel(task) { _ in
                    print("\(song.title ?? "")下载任务失败，取消任务")
                }
            }
        })
    }
    func getProgress(for videoId: String) -> CGFloat? {
        return progressStorage[videoId]
    }
    func cancelAllTasksIfNeeded() {
        // 根据需求，取消所有任务，或者根据任务状态进行过滤
        for key in progressStorage.keys {
            session.cancel(key)
        }
    }
    //删除下载文件
    func deleteFileDocuments(_ videoId:String, completion:@escaping((String) -> Void)) {
        let downloadsURL = DocumentsURL.appendingPathComponent("Downloads")
        let fileURL = downloadsURL.appendingPathComponent("\(videoId).mp4")
        if FileManager.default.fileExists(atPath: fileURL.path) {
            do{
                try FileManager.default.removeItem(at: fileURL)
                //文件删除成功
                completion(videoId)
                print("成功删除了\(videoId)文件")
            }catch{
                print("删除文件时发生错误：\(error)")
            }
        }else {
            print("文件不存在")
        }
    }
}