//
//  RQDownloadManager.m
//  TEST
//
//  Created by 张嵘 on 2018/10/22.
//  Copyright © 2018 张嵘. All rights reserved.
//

#import "RQDownloadManager.h"
#import "AppDelegate.h"

@interface RQDownloadManager ()<NSURLSessionDataDelegate>{
	NSMutableArray *_downloadModels;
	NSMutableArray *_completeModels;
	NSMutableArray *_downloadingModels;
	NSMutableArray *_pauseModels;
	BOOL            _enableProgressLog;
}


@property (nonatomic, strong) NSOperationQueue *queue;

@property (nonatomic, strong) NSURLSession *backgroundSession;

@end

static UIBackgroundTaskIdentifier bgTask;


@implementation RQDownloadManager


#pragma mark - 单例相关
static id instace = nil;
+ (id)allocWithZone:(struct _NSZone *)zone {
	if (instace == nil) {
		static dispatch_once_t onceToken;
		dispatch_once(&onceToken, ^{
			instace = [super allocWithZone:zone];
			// 添加未捕获异常的监听
			[instace handleUncaughtExreption];
			// 添加监听
			[instace addObservers];
			// 创建缓存目录
			[instace createCacheDirectory];
		});
	}
	return instace;
}

- (instancetype)init {
	return instace;
}

+ (instancetype)sharedManager {
	return [[self alloc] init];
}

- (id)copyWithZone:(struct _NSZone *)zone {
	return instace;
}

- (id)mutableCopyWithZone:(struct _NSZone *)zone {
	return instace;
}


#pragma mark - 单例初始化调用
/**
 *  添加监听
 */
- (void)addObservers {
	[[NSNotificationCenter defaultCenter] addObserver:instace selector:@selector(recoverDownloadModels) name:UIApplicationDidFinishLaunchingNotification object:nil];
	
	[[NSNotificationCenter defaultCenter] addObserver:instace selector:@selector(applicationWillTerminate) name:UIApplicationWillTerminateNotification object:nil];
	
	[[NSNotificationCenter defaultCenter] addObserver:instace selector:@selector(endBackgroundTask) name:UIApplicationWillEnterForegroundNotification object:nil];
	
	[[NSNotificationCenter defaultCenter] addObserver:instace selector:@selector(getBackgroundTask) name:UIApplicationDidEnterBackgroundNotification object:nil];
	
	[[NSNotificationCenter defaultCenter] addObserver:instace selector:@selector(applicationWillTerminate) name:kNotificationUncaughtException object:nil];
}

/**
 *  创建缓存目录
 */
- (void)createCacheDirectory {
	NSFileManager *fileManager = [NSFileManager defaultManager];
	if (![fileManager fileExistsAtPath:RQCachesDirectory]) {
		[fileManager createDirectoryAtPath:RQCachesDirectory withIntermediateDirectories:YES attributes:nil error:NULL];
	}
	NSLog(@"创建缓存目录:%@",RQCachesDirectory);
}

/**
 *  添加未捕获异常的监听
 */
- (void)handleUncaughtExreption {
	[RQUncaughtExceptionHandler setDefaultHandler];
}

/**
 *  禁止打印进度日志
 */
- (void)enableProgressLog:(BOOL)enable {
	_enableProgressLog = enable;
}

#pragma mark - 模型相关
- (void)addDownloadModel:(RQDownloadModel *)model {
	if (![self checkExistWithDownloadModel:model]) {
		[self.downloadModels addObject:model];
		NSLog(@"下载模型添加成功");
	}
}

- (void)addDownloadModels:(NSArray<RQDownloadModel *> *)models {
	if ([models isKindOfClass:[NSArray class]]) {
		[models enumerateObjectsUsingBlock:^(RQDownloadModel * _Nonnull obj, NSUInteger idx, BOOL * _Nonnull stop) {
			[self addDownloadModel:obj];
		}];
	}
}

-(BOOL)checkExistWithDownloadModel:(RQDownloadModel *)model {
	
	for (RQDownloadModel *tmpModel in self.downloadModels) {
		if ([tmpModel.urlString isEqualToString:model.urlString]) {
			NSLog(@"Tip:下载数据模型已存在");
			return YES;
		}
	}
	return NO;
}


- (RQDownloadModel *)downloadModelWithUrl:(NSString *)url {
	for (RQDownloadModel *tmpModel in self.downloadModels) {
		if ([url isEqualToString:tmpModel.urlString]) {
			return tmpModel;
		}
	}
	return nil;
}
#pragma mark - 单任务下载控制
- (void)startWithDownloadModel:(RQDownloadModel *)model {
	if (model.status == RQDownloadStatus_Completed) {
		return;
	}
	
	[self addDownloadModel:model];
	
	//检查队列是否挂起
	if(self.queue.suspended){
		self.queue.suspended = NO;
	}
	
	model.operation = [[RQDownloadOperation alloc] initWithDownloadModel:model andSession:self.backgroundSession];
	[self.queue addOperation:model.operation];
}

//暂停后操作将销毁 若想继续执行 则需重新创建operation并添加
- (void)suspendWithDownloadModel:(RQDownloadModel *)model {
	[self suspendWithDownloadModel:model forAll:NO];
}


- (void)suspendWithDownloadModel:(RQDownloadModel *)model forAll:(BOOL)forAll {
	if (forAll) {//暂停全部
		if (model.status == RQDownloadStatus_Running) {//下载中 则暂停
			[model.operation suspend];
		}else if (model.status == RQDownloadStatus_Waiting){//等待中 则取消
			[model.operation cancel];
		}
	}else{
		if (model.status == RQDownloadStatus_Running) {
			[model.operation suspend];
		}
	}
	
	model.operation = nil;
}


- (void)resumeWithDownloadModel:(RQDownloadModel *)model {
	if (model.status == RQDownloadStatus_Completed ||
		model.status == RQDownloadStatus_Running) {
		return;
	}
	//等待中 且操作已在队列中 则无需恢复
	if (model.status == RQDownloadStatus_Waiting && model.operation) {
		return;
	}
	model.operation = nil;
	
	//检查队列是否挂起
	if(self.queue.suspended){
		self.queue.suspended = NO;
	}
	
	model.operation = [[RQDownloadOperation alloc] initWithDownloadModel:model andSession:self.backgroundSession];
	[self.queue addOperation:model.operation];
	
}



- (void)stopWithDownloadModel:(RQDownloadModel *)model {
	[self stopWithDownloadModel:model forAll:NO];
}



- (void)stopWithDownloadModel:(RQDownloadModel *)model forAll:(BOOL)forAll {
	if (model.status != RQDownloadStatus_Completed) {
		[model.operation cancel];
	}
	
	//移除对应的下载文件
	if([RQFileManager fileExistsAtPath:model.destinationPath]){
		NSError *error = nil;
		[RQFileManager removeItemAtPath:model.destinationPath error:&error];
		if (error) {
			NSLog(@"Tip:下载文件移除失败，%@",error);
		}else{
			NSLog(@"Tip:下载文件移除成功");
		}
	}
	
	//释放operation
	model.operation = nil;
	
	//单个删除 则直接从数组中移除下载模型 否则等清空文件后统一移除
	if(!forAll){
		[self.downloadModels removeObject:model];
	}
}


#pragma mark - 批量下载相关
/**
 *  批量下载操作
 */
- (void)startWithDownloadModels:(NSArray<RQDownloadModel *> *)downloadModels {
	NSLog(@">>>%@前 operationCount = %zd", NSStringFromSelector(_cmd),self.queue.operationCount);
	[self.queue setSuspended:NO];
	[self addDownloadModels:downloadModels];
	[self operateTasksWithOperationType:RQOperationType_startAll];
	NSLog(@"<<<%@后 operationCount = %zd",NSStringFromSelector(_cmd),self.queue.operationCount);
}

/**
 *  暂停所有下载任务
 */
- (void)suspendAll {
	[self.queue setSuspended:YES];
	[self operateTasksWithOperationType:RQOperationType_suspendAll];
}

/**
 *  恢复下载任务（进行中、已完成、等待中除外）
 */
- (void)resumeAll {
	[self.queue setSuspended:NO];
	[self operateTasksWithOperationType:RQOperationType_resumeAll];
}

/**
 *  停止并删除下载任务
 */
- (void)stopAll {
	//销毁前暂停队列 防止等待中的任务执行
	[self.queue setSuspended:YES];
	[self.queue cancelAllOperations];
	[self operateTasksWithOperationType:RQOperationType_stopAll];
	[self.queue setSuspended:NO];
	[self.downloadModels removeAllObjects];
	[self removeAllFiles];
}


- (void)operateTasksWithOperationType:(RQOperationType)operationType {
	[self.downloadModels enumerateObjectsUsingBlock:^(id  _Nonnull obj, NSUInteger idx, BOOL * _Nonnull stop) {
		RQDownloadModel *downloadModel = obj;
		switch (operationType) {
				case RQOperationType_startAll:
				[self startWithDownloadModel:downloadModel];
				break;
				case RQOperationType_suspendAll:
				[self suspendWithDownloadModel:downloadModel forAll:YES];
				break;
				case RQOperationType_resumeAll:
				[self resumeWithDownloadModel:downloadModel];
				break;
				case RQOperationType_stopAll:
				[self stopWithDownloadModel:downloadModel forAll:YES];
				break;
			default:
				break;
		}
	}];
}


/**
 *  从备份恢复下载数据
 */
- (void)recoverDownloadModels {
	if ([RQFileManager fileExistsAtPath:RQSavedDownloadModelsBackup]) {
		NSError * error = nil;
		[RQFileManager removeItemAtPath:RQSavedDownloadModelsFilePath error:nil];
		BOOL recoverSuccess = [RQFileManager copyItemAtPath:RQSavedDownloadModelsBackup toPath:RQSavedDownloadModelsFilePath error:&error];
		if (recoverSuccess) {
			NSLog(@"Tip:数据恢复成功");
			
			[self.downloadModels enumerateObjectsUsingBlock:^(id  _Nonnull obj, NSUInteger idx, BOOL * _Nonnull stop) {
				RQDownloadModel *model = (RQDownloadModel *)obj;
				if (model.status == RQDownloadStatus_Running ||
					model.status == RQDownloadStatus_Waiting){
					[self startWithDownloadModel:model];
				}
			}];
		}else{
			NSLog(@"Tip:数据恢复失败，%@",error);
		}
	}
}

#pragma mark - 文件相关
/**
 *  保存下载模型
 */
- (void)saveData {
	[RQFileManager removeItemAtPath:RQSavedDownloadModelsFilePath error:nil];
	BOOL flag = [NSKeyedArchiver archiveRootObject:self.downloadModels toFile:RQSavedDownloadModelsFilePath];
	NSLog(@"Tip:下载数据保存路径%@",RQSavedDownloadModelsFilePath);
	NSLog(@"Tip:下载数据保存-%@",flag?@"成功!":@"失败");
	
	if (flag) {
		[self backupFile];
	}
}
/**
 *  备份下载模型
 */
- (void)backupFile {
	dispatch_async(dispatch_get_global_queue(0, 0), ^{
		NSError *error = nil;
		[self removeBackupFile];
		BOOL exist = [RQFileManager fileExistsAtPath:RQSavedDownloadModelsFilePath];
		if (exist) {
			BOOL backupSuccess = [RQFileManager copyItemAtPath:RQSavedDownloadModelsFilePath toPath:RQSavedDownloadModelsBackup error:&error];
			if (backupSuccess) {
				NSLog(@"Tip:数据备份成功");
			}else{
				NSLog(@"Tip:数据备份失败，%@",error);
				[self backupFile];
			}
		}
	});
}
/**
 *  移除备份
 */
- (void)removeBackupFile {
	if ([RQFileManager fileExistsAtPath:RQSavedDownloadModelsBackup]) {
		NSError * error = nil;
		BOOL success = [RQFileManager removeItemAtPath:RQSavedDownloadModelsBackup error:&error];
		if (success) {
			NSLog(@"Tip:备份移除成功");
		}else{
			NSLog(@"Tip:备份移除失败，%@",error);
		}
	}
}

/**
 *  移除目录中所有文件
 */
- (void)removeAllFiles {
	//返回路径中的文件数组
	NSArray * files = [[NSFileManager defaultManager] subpathsAtPath:RQCachesDirectory];
	
	for(NSString *p in files){
		NSError*error;
		
		NSString*path = [RQCachesDirectory stringByAppendingString:[NSString stringWithFormat:@"/%@",p]];
		
		if([[NSFileManager defaultManager] fileExistsAtPath:path]){
			BOOL isRemove = [[NSFileManager defaultManager]removeItemAtPath:path error:&error];
			if(isRemove) {
				NSLog(@"文件：%@-->清除成功",p);
			}else{
				NSLog(@"文件：%@-->清除失败",p);
			}
		}
	}
}

#pragma mark - Private Method

#pragma mark - Getters/Setters
- (NSMutableArray *)downloadModels {
	if (!_downloadModels) {
		//查看本地是否有数据
		NSFileManager *fileManager = [NSFileManager defaultManager];
		BOOL exist = [fileManager fileExistsAtPath:RQSavedDownloadModelsFilePath isDirectory:nil];
		
		if (exist) {//有 则读取本地数据
			_downloadModels = [NSKeyedUnarchiver  unarchiveObjectWithFile:RQSavedDownloadModelsFilePath];
		}else{
			_downloadModels = [NSMutableArray array];
		}
	}
	return _downloadModels;
}

- (NSMutableArray *)completeModels {
	__block  NSMutableArray *tmpArr = [NSMutableArray array];
	if (self.downloadModels) {
		[self.downloadModels enumerateObjectsUsingBlock:^(id  _Nonnull obj, NSUInteger idx, BOOL * _Nonnull stop) {
			RQDownloadModel *model = obj;
			if (model.status == RQDownloadStatus_Completed) {
				[tmpArr addObject:model];
			}
		}];
	}
	
	_completeModels = tmpArr;
	return _completeModels;
}


- (NSMutableArray *)downloadingModels {
	__block  NSMutableArray *tmpArr = [NSMutableArray array];
	if (self.downloadModels) {
		[self.downloadModels enumerateObjectsUsingBlock:^(id  _Nonnull obj, NSUInteger idx, BOOL * _Nonnull stop) {
			RQDownloadModel *model = obj;
			if (model.status == RQDownloadStatus_Running) {
				[tmpArr addObject:model];
			}
		}];
	}
	
	_downloadingModels = tmpArr;
	return _downloadingModels;
}




- (NSMutableArray *)waitModels {
	__block  NSMutableArray *tmpArr = [NSMutableArray array];
	if (self.downloadModels) {
		[self.downloadModels enumerateObjectsUsingBlock:^(id  _Nonnull obj, NSUInteger idx, BOOL * _Nonnull stop) {
			RQDownloadModel *model = obj;
			if (model.status == RQDownloadStatus_Waiting) {
				[tmpArr addObject:model];
			}
		}];
	}
	return tmpArr;
}



- (NSMutableArray *)pauseModels {
	__block  NSMutableArray *tmpArr = [NSMutableArray array];
	if (self.downloadModels) {
		[self.downloadModels enumerateObjectsUsingBlock:^(id  _Nonnull obj, NSUInteger idx, BOOL * _Nonnull stop) {
			RQDownloadModel *model = obj;
			if (model.status == RQDownloadStatus_Suspended) {
				[tmpArr addObject:model];
			}
		}];
	}
	_pauseModels = tmpArr;
	return _pauseModels;
}



- (NSOperationQueue *)queue {
	if (!_queue) {
		_queue = [[NSOperationQueue alloc] init];
		[_queue setMaxConcurrentOperationCount:RQDownloadMaxConcurrentOperationCount];
	}
	return _queue;
}


- (void)setMaxConcurrentOperationCount:(NSInteger)maxConcurrentOperationCount {
	_maxConcurrentOperationCount = maxConcurrentOperationCount;
	self.queue.maxConcurrentOperationCount = _maxConcurrentOperationCount;
}


- (NSURLSession *)backgroundSession {
	if (!_backgroundSession) {
		NSURLSessionConfiguration *config = [NSURLSessionConfiguration backgroundSessionConfigurationWithIdentifier:[[NSBundle mainBundle] bundleIdentifier]];
		//不能传self.queue
		_backgroundSession = [NSURLSession sessionWithConfiguration:config delegate:self delegateQueue:nil];
	}
	
	return _backgroundSession;
}


- (BOOL)enableProgressLog {
	return _enableProgressLog;
}

#pragma mark - 后台任务相关
/**
 *  获取后台任务
 */
- (void)getBackgroundTask {
	NSLog(@"getBackgroundTask");
	UIBackgroundTaskIdentifier tempTask = [[UIApplication sharedApplication] beginBackgroundTaskWithExpirationHandler:^{
		
	}];
	
	if (bgTask != UIBackgroundTaskInvalid) {
		
		[self endBackgroundTask];
	}
	
	bgTask = tempTask;
	
	[self performSelector:@selector(getBackgroundTask) withObject:nil afterDelay:120];
}


/**
 *  结束后台任务
 */
- (void)endBackgroundTask {
	[[UIApplication sharedApplication] endBackgroundTask:bgTask];
	bgTask = UIBackgroundTaskInvalid;
}



#pragma mark - Event Response
/**
 *  应用强关或闪退时 保存下载数据
 */
- (void)applicationWillTerminate {
	[self saveData];
}


#pragma mark - NSURLSessionDataDelegate
/**
 * 接收到响应
 */
- (void)URLSession:(NSURLSession *)session dataTask:(NSURLSessionDataTask *)dataTask didReceiveResponse:(NSHTTPURLResponse *)response completionHandler:(void (^)(NSURLSessionResponseDisposition))completionHandler {
	
	RQDownloadModel *downloadModel = dataTask.downloadModel;
	
	// 打开流
	[downloadModel.stream open];
	
	// 获得服务器这次请求 返回数据的总长度
	NSInteger totalLength = [response.allHeaderFields[@"Content-Length"] integerValue] + downloadModel.fileDownloadSize;
	downloadModel.fileTotalSize = totalLength;
	
	// 接收这个请求，允许接收服务器的数据
	completionHandler(NSURLSessionResponseAllow);
}

/**
 * 接收到服务器返回的数据
 */
- (void)URLSession:(NSURLSession *)session dataTask:(NSURLSessionDataTask *)dataTask didReceiveData:(NSData *)data {
	
	NSLog(@"还在执行！");
	if (!dataTask.downloadModel) {
		return;
	}
	
	RQDownloadModel *downloadModel = dataTask.downloadModel;
	
	// 写入数据
	[downloadModel.stream write:data.bytes maxLength:data.length];
	
	// 下载进度
	NSInteger totalBytesWritten = downloadModel.fileDownloadSize;
	NSInteger totalBytesExpectedToWrite = downloadModel.fileTotalSize;
	
	double byts = totalBytesWritten * 1.0 / 1024 /1024;
	double total = totalBytesExpectedToWrite * 1.0 / 1024 /1024;
	NSString *text = [NSString stringWithFormat:@"%.1lfMB/%.1lfMB",byts,total];
	
	CGFloat progress = 1.0 * byts / total;
	
	downloadModel.statusText = text;
	downloadModel.progress = progress;
}

/**
 * 请求完毕 下载成功 | 失败
 */
- (void)URLSession:(NSURLSession *)session task:(NSURLSessionTask *)task didCompleteWithError:(NSError *)error {
	RQDownloadModel *downloadModel = task.downloadModel;
	[downloadModel.stream close];
	downloadModel.stream = nil;
	task = nil;
	if (downloadModel.status == RQDownloadStatus_Completed) {
		[self saveData];
	}
}
@end