/*

     File: APLCustomAVARLDelegate.m

 Abstract: Custom delegate class implementation. 

  Version: 1.0

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 */

#import "APLCustomAVARLDelegate.h"

static NSString *redirectScheme = @"rdtp";

static NSString *customPlaylistScheme = @"cplp";

static NSString *customKeyScheme = @"ckey";

static NSString *httpScheme = @"http";

static NSString *customPlayListFormatPrefix = @"#EXTM3U\n"

"#EXT-X-PLAYLIST-TYPE:EVENT\n"

"#EXT-X-TARGETDURATION:10\n"

"#EXT-X-VERSION:3\n"

"#EXT-X-MEDIA-SEQUENCE:0\n";

static NSString *customPlayListFormatElementInfo = @"#EXTINF:10, no desc\n";

static NSString *customPlaylistFormatElementSegment = @"%@/fileSequence%d.ts\n";

static NSString *customEncryptionKeyInfo = @"#EXT-X-KEY:METHOD=AES-128,URI=\"%@/crypt0.key\", IV=0x3ff5be47e1cdbaec0a81051bcc894d63\n";

static NSString *customPlayListFormatEnd = @"#EXT-X-ENDLIST";

static int redirectErrorCode = 302;

static int badRequestErrorCode = 400;

@interface APLCustomAVARLDelegate ()

- (BOOL) schemeSupported:(NSString*) scheme;

- (void) reportError:(AVAssetResourceLoadingRequest *) loadingRequest withErrorCode:(int) error;

@end

@interface APLCustomAVARLDelegate (Redirect)

- (BOOL) isRedirectSchemeValid:(NSString*) scheme;

- (BOOL) handleRedirectRequest:(AVAssetResourceLoadingRequest*) loadingRequest;

- (NSURLRequest* ) generateRedirectURL:(NSURLRequest *)sourceURL;

@end

@interface APLCustomAVARLDelegate (CustomPlaylist)

- (BOOL) isCustomPlaylistSchemeValid:(NSString*) scheme;

- (NSString*) getCustomPlaylist:(NSString *) urlPrefix andKeyPrefix:(NSString*) keyPrefix totalElements:(NSInteger) elements;

- (BOOL) handleCustomPlaylistRequest:(AVAssetResourceLoadingRequest*) loadingRequest;

@end

@interface APLCustomAVARLDelegate (CustomKey)

- (BOOL) isCustomKeySchemeValid:(NSString*) scheme;

- (NSData*) getKey:(NSURL*) url;

- (BOOL) handleCustomKeyRequest:(AVAssetResourceLoadingRequest*) loadingRequest;

@end

#pragma mark - APLCustomAVARLDelegate

@implementation APLCustomAVARLDelegate

/*!

 *  is scheme supported

 */

- (BOOL) schemeSupported:(NSString *)scheme

{

    if ( [self isRedirectSchemeValid:scheme] ||

        [self isCustomKeySchemeValid:scheme] ||

        [self isCustomPlaylistSchemeValid:scheme])

        return YES;

    return NO;

}

-(APLCustomAVARLDelegate *) init

{

    self = [super init];

    return self;

}

- (void) reportError:(AVAssetResourceLoadingRequest *) loadingRequest withErrorCode:(int) error

{

    [loadingRequest finishLoadingWithError:[NSError errorWithDomain: NSURLErrorDomain code:error userInfo: nil]];

}

/*!

 *  AVARLDelegateDemo's implementation of the protocol.

 *  Check the given request for valid schemes:

 * 

 * 1) Redirect 2) Custom Play list 3) Custom key

 */

- (BOOL) resourceLoader:(AVAssetResourceLoader *)resourceLoader shouldWaitForLoadingOfRequestedResource:(AVAssetResourceLoadingRequest *)loadingRequest

{

    NSString* scheme = [[[loadingRequest request] URL] scheme];

    if ([self isRedirectSchemeValid:scheme])

        return [self handleRedirectRequest:loadingRequest];

    if ([self isCustomPlaylistSchemeValid:scheme]) {

        dispatch_async (dispatch_get_main_queue(),  ^ {

            [self handleCustomPlaylistRequest:loadingRequest];

        });

        return YES;

    }

    if ([self isCustomKeySchemeValid:scheme]) {

        dispatch_async(dispatch_get_main_queue(), ^{

            [self handleCustomKeyRequest:loadingRequest];

        });

        return YES;

    }

    return NO;

}

@end

#pragma mark - APLCustomACARLDelegate Redirect

@implementation APLCustomAVARLDelegate (Redirect)

/*!

 * Validates the given redirect schme.

 */

- (BOOL) isRedirectSchemeValid:(NSString *)scheme

{

    return ([redirectScheme isEqualToString:scheme]);

}

-(NSURLRequest* ) generateRedirectURL:(NSURLRequest *)sourceURL

{

    NSURLRequest *redirect = [NSURLRequest requestWithURL:[NSURL URLWithString:[[[sourceURL URL] absoluteString] stringByReplacingOccurrencesOfString:redirectScheme withString:httpScheme]]];

    return redirect;

}

/*!

 *  The delegate handler, handles the received request:

 *

 *  1) Verifies its a redirect request, otherwise report an error.

 *  2) Generates the new URL 

 *  3) Create a reponse with the new URL and report success.

 */

- (BOOL) handleRedirectRequest:(AVAssetResourceLoadingRequest *)loadingRequest

{

    NSURLRequest *redirect = nil;

    redirect = [self generateRedirectURL:(NSURLRequest *)[loadingRequest request]];

    if (redirect)

    {

        [loadingRequest setRedirect:redirect];

        NSHTTPURLResponse *response = [[NSHTTPURLResponse alloc] initWithURL:[redirect URL] statusCode:redirectErrorCode HTTPVersion:nil headerFields:nil];

        [loadingRequest setResponse:response];

        [loadingRequest finishLoading];

    } else

    {

        [self reportError:loadingRequest withErrorCode:badRequestErrorCode];

    }

    return YES;

}

@end

#pragma mark - APLCustomAVARLDelegate CustomPlaylist

@implementation APLCustomAVARLDelegate (CustomPlaylist)

- (BOOL) isCustomPlaylistSchemeValid:(NSString *)scheme

{

    return ([customPlaylistScheme isEqualToString:scheme]);

}

/*!

 * create a play list based on the given prefix and total elements

 */

- (NSString*) getCustomPlaylist:(NSString *) urlPrefix andKeyPrefix:(NSString *) keyPrefix totalElements:(NSInteger) elements

{

    static NSMutableString  *customPlaylist = nil;

    if (customPlaylist)

        return customPlaylist;

    customPlaylist = [[NSMutableString alloc] init];

    [customPlaylist appendString:customPlayListFormatPrefix];

    for (int i = 0; i < elements; ++i)

    {

        [customPlaylist appendString:customPlayListFormatElementInfo];

        //We are using single key for all the segments but different IV, every 50 segments

        if (0 == i)

            [customPlaylist appendFormat:customEncryptionKeyInfo, keyPrefix];

        [customPlaylist appendFormat:customPlaylistFormatElementSegment, urlPrefix, i];

    }

    [customPlaylist appendString:customPlayListFormatEnd];

    return customPlaylist;

}

/*!

 *  Handles the custom play list scheme:

 *

 *  1) Verifies its a custom playlist request, otherwise report an error.

 *  2) Generates the play list.

 *  3) Create a reponse with the new URL and report success.

 */

- (BOOL) handleCustomPlaylistRequest:(AVAssetResourceLoadingRequest *)loadingRequest

{

    //Prepare the playlist with redirect scheme.

    NSString *prefix = [[[[loadingRequest request] URL] absoluteString] stringByReplacingOccurrencesOfString:customPlaylistScheme withString:redirectScheme];// stringByDeletingLastPathComponent];

    NSRange range = [prefix rangeOfString:@"/" options:NSBackwardsSearch];

    prefix = [prefix substringToIndex:range.location];

    NSString *keyPrefix = [prefix stringByReplacingOccurrencesOfString:redirectScheme withString:customKeyScheme];

    NSData *data = [[self getCustomPlaylist:prefix andKeyPrefix:keyPrefix totalElements:150] dataUsingEncoding:NSUTF8StringEncoding];

    if (data)

    {

        [loadingRequest.dataRequest respondWithData:data];

        [loadingRequest finishLoading];

    } else

    {

        [self reportError:loadingRequest withErrorCode:badRequestErrorCode];

    }

    return YES;

}

@end

#pragma mark - APLCustomAVARLDelegate CustomKey

@implementation APLCustomAVARLDelegate (CustomKey)

- (BOOL) isCustomKeySchemeValid:(NSString*) scheme

{

    return ([customKeyScheme isEqualToString:scheme]);

}

- (NSData*) getKey:(NSURL*) url

{

    NSURL *newURL = [NSURL URLWithString:[[url absoluteString] stringByReplacingOccurrencesOfString:customKeyScheme withString:httpScheme]];

    return [[NSData alloc] initWithContentsOfURL:newURL];

}

/*!

 *  Handles the custom key scheme:

 *

 *  1) Verifies its a custom key request, otherwise report an error.

 *  2) Creates the URL for the key

 *  3) Create a response with the new URL and report success.

 */

- (BOOL) handleCustomKeyRequest:(AVAssetResourceLoadingRequest*) loadingRequest

{

    NSData* data = [self getKey:[[loadingRequest request] URL]];

    if (data)

    {

        [loadingRequest.dataRequest respondWithData:data];

        [loadingRequest finishLoading];

    } else

    {

        [self reportError:loadingRequest withErrorCode:badRequestErrorCode];

    }

    return YES;

}

@end