#import "THDownloadWebService.h"

#import "THWebDefine.h"

@implementation THDownloadWebService

@synthesize overwrite;

@synthesize fileName=_fileName;

@synthesize filePath=_filePath;

@synthesize fileSize;

@synthesize peakSpeed;

@synthesize averageSpeed;

@synthesize downloadBlock;

+ (void)serviceWithUrl:(NSURL *)url handler:(THDownloadWebServiceBlock)block

{

THDownloadWebService *service = [[[self class] alloc] init];

service.url = url;

[service startWithHandler:block];

}

- (void)setDelegate:(id)anObject

{

_delegate = anObject;

}

- (id)delegate

{

return _delegate;

}

- (void)stop

{

[super stop];

[_fileHandle closeFile];

_fileHandle = nil;

[_timer invalidate];

_timer = nil;

_startDate = nil;

totalDownSize = 0;

onceDownSize = 0;

peakSpeed =0;

averageSpeed = 0;

fileSize = 0;

}

- (NSURLRequest *)setUpRequest:(NSError **)error

{

//当url为空的时间，返回失败

if (!_url)

{

if (error) *error = THErrorURLFail;

return nil;

}

//未指定文件名

if (!_fileName)

{

NSURLResponse *response = [[NSURLResponse alloc] initWithURL:_url MIMEType:NULL expectedContentLength:0 textEncodingName:NULL];

_fileName = [response suggestedFilename];

/*

}

//未指定路径

if (!_filePath)

{

NSArray *documentPaths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);

NSString *documentsDir = [documentPaths objectAtIndex:0];

_filePath = documentsDir;

}

//目标地址与缓存地址

_destinationPath=[_filePath stringByAppendingPathComponent:_fileName];

_temporaryPath=[_destinationPath stringByAppendingFormat:kTHDownLoadTask_TempSuffix];

//处理如果文件已经存在的情况

if ([[NSFileManager defaultManager] fileExistsAtPath:_destinationPath])

{

if (overwrite)

{

[[NSFileManager defaultManager] removeItemAtPath:_destinationPath error:nil];

}else

{

if (error) *error = THErrorFileExist;

return nil;

}

}

//缓存文件不存在，则创建缓存文件

if (![[NSFileManager defaultManager] fileExistsAtPath:_temporaryPath])

{

BOOL createSucces = [[NSFileManager defaultManager] createFileAtPath:_temporaryPath contents:nil attributes:nil];

if (!createSucces)

{

if (error) *error = THErrorCreateFail;

return nil;

}

}

//设置fileHandle

_fileHandle = [NSFileHandle fileHandleForWritingAtPath:_temporaryPath];

offset = [_fileHandle seekToEndOfFile];

NSString *range = [NSString stringWithFormat:@"bytes=%llu-",offset];

//设置下载的一些属性

NSMutableURLRequest *request = [[NSMutableURLRequest alloc] initWithURL:_url];

[request addValue:range forHTTPHeaderField:@"Range"];

if (error) *error = NULL;

return request;

}

- (void)startWithHandler:(THDownloadWebServiceBlock)block;

{

self.downloadBlock = block;

[self startAsynchronous];

}

- (BOOL)startAsynchronous

{

BOOL sucess = [super startAsynchronous];

if (sucess)

{

_timer = [[NSTimer alloc] initWithFireDate:[NSDate date] interval:kTHDownLoadTimerInterval target:self selector:@selector(lisenProgressAndSpeed) userInfo:nil repeats:YES];

[[NSRunLoop currentRunLoop] addTimer:_timer forMode:NSRunLoopCommonModes];

_startDate = [[NSDate alloc] init];

}

return sucess;

}

- (void)lisenProgressAndSpeed

{

offset = [_fileHandle offsetInFile];

double totalTimeGap = fabs([_startDate timeIntervalSinceNow]);

double onceTimeGap = [_timer timeInterval];

averageSpeed = totalDownSize/totalTimeGap;

peakSpeed = onceDownSize/onceTimeGap;

onceDownSize = 0;

double progress = 0;

if (fileSize > 0)

{

progress = offset*1.0/fileSize;

}

if ([_delegate respondsToSelector:@selector(downloadProgressChange:progress:)])

{

[[self delegate] downloadProgressChange:self progress:progress];

}

if (self.downloadBlock)

{

self.downloadBlock(NULL,NULL,progress,NO);

}

}

#pragma mark -

#pragma mark NSURLConnectionDelegate

- (void)didReceiveResponse:(NSURLResponse *)response

{

if ([response expectedContentLength] != NSURLResponseUnknownLength)

{

fileSize = [response expectedContentLength] + offset;

}

[super didReceiveResponse:response];

if (self.downloadBlock)

{

self.downloadBlock(response,NULL,0,NO);

}

}

- (void)didReceiveData:(NSData *)aData

{

totalDownSize += aData.length;

onceDownSize += aData.length;

[_fileHandle writeData:aData];

}

- (void)didFailWithError:(NSError *)error

{

[super didFailWithError:error];

if (self.downloadBlock)

{

self.downloadBlock(NULL,error,0,NO);

}

}

- (void)didFinishLoading

{

[[NSFileManager defaultManager] moveItemAtPath:_temporaryPath toPath:_destinationPath error:nil];

[super didFinishLoading];

if (self.downloadBlock)

{

self.downloadBlock(NULL,NULL,0,YES);

}

}