/*
 * This file is part of the SDWebImage package.
 * (c) Olivier Poitrey <rs@dailymotion.com>
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */ 

#import "SDWebImageManager.h"
#import "SDImageCache.h"
#import "SDWebImageDownloader.h"

static SDWebImageManager *instance;

@implementation SDWebImageManager

- (id)init
{
    if (self = [super init])
    {
        delegates = [[NSMutableArray alloc] init];
        downloaders = [[NSMutableArray alloc] init];
        downloaderForURL = [[NSMutableDictionary alloc] init];
        failedURLs = [[NSMutableArray alloc] init];
    }
    return self;
}

- (void) dealloc
{
    [delegates release];
    [downloaders release];
    [downloaderForURL release];
    [failedURLs release];
    [super dealloc];
}


+ (id)sharedManager
{
    if (instance == nil)
    {
        instance = [[SDWebImageManager alloc] init];
    }

    return instance;
}

- (UIImage *)imageWithURL:(NSURL *)url
{
    return [[SDImageCache sharedImageCache] imageFromKey:[url absoluteString]];
}

- (void)downloadWithURL:(NSURL *)url delegate:(id<SDWebImageManagerDelegate>)delegate
{
    if ([failedURLs containsObject:url])
    {
        return;
    }

    // Share the same downloader for identical URLs so we don't download the same URL several times
    SDWebImageDownloader *downloader = [downloaderForURL objectForKey:url];

    if (!downloader)
    {
        downloader = [SDWebImageDownloader downloaderWithURL:url delegate:self];
        [downloaderForURL setObject:downloader forKey:url];
    }

    @synchronized(self)
    {
        [delegates addObject:delegate];
        [downloaders addObject:downloader];
    }
}

- (void)cancelForDelegate:(id<SDWebImageManagerDelegate>)delegate
{
    @synchronized(self)
    {
        NSUInteger index = [delegates indexOfObjectIdenticalTo:delegate];

        if (index == NSNotFound)
        {
            return;
        }

        SDWebImageDownloader *downloader = [[downloaders objectAtIndex:index] retain];
    
        [delegates removeObjectAtIndex:index];
        [downloaders removeObjectAtIndex:index];

        if (![downloaders containsObject:downloader])
        {
            NSLog(@"cancel download");
            // No more delegate are waiting for this download, cancel it
            [downloader cancel];
            [downloaderForURL removeObjectForKey:downloader.url];
        }

        [downloader release];
    }
}

- (void)imageDownloader:(SDWebImageDownloader *)downloader didFinishWithImage:(UIImage *)image
{
    [downloader retain];

    @synchronized(self)
    {
        // Notify all the delegates with this downloader
        for (NSInteger index = [downloaders count] - 1; index >= 0; index--)
        {
            SDWebImageDownloader *aDownloader = [downloaders objectAtIndex:index];
            if (aDownloader == downloader)
            {
                id<SDWebImageManagerDelegate> delegate = [delegates objectAtIndex:index];

                if (image && [delegate respondsToSelector:@selector(imageHelper:didFinishWithImage:)])
                {
                    [delegate performSelector:@selector(imageHelper:didFinishWithImage:) withObject:self withObject:image];
                }

                [downloaders removeObjectAtIndex:index];
                [delegates removeObjectAtIndex:index];
            }
        }
    }

    if (image)
    {
        // Store the image in the cache
        [[SDImageCache sharedImageCache] storeImage:image forKey:[downloader.url absoluteString]];
    }
    else
    {
        // The image can't be downloaded from this URL, mark the URL as failed so we won't try and fail again and again
        [failedURLs addObject:downloader.url];
    }


    // Release the downloader
    [downloaderForURL removeObjectForKey:downloader.url];
    [downloader release];
}


@end