/*

    File:       LinkedImageFetcher.h

    Contains:   Downloads an HTML page and then downloads all of the referenced images.

    Written by: DTS

    Copyright:  Copyright (c) 2011-2013 Apple Inc. All Rights Reserved.

    Disclaimer: IMPORTANT: This Apple software is supplied to you by Apple Inc.

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                The Apple Software is provided by Apple on an "AS IS" basis. 

                APPLE MAKES NO WARRANTIES, EXPRESS OR IMPLIED, INCLUDING

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*/

#import <Foundation/Foundation.h>

#import "QWatchedOperationQueue.h"

@protocol LinkedImageFetcherDelegate;

@interface LinkedImageFetcher : NSObject

{

    NSURL *                         _URL;

    NSUInteger                      _maximumDepth;

    NSString *                      _imagesDirPath;

    id<LinkedImageFetcherDelegate>  _delegate;

    QWatchedOperationQueue *        _queue;

    BOOL                            _done;

    NSError *                       _error;

    NSMutableSet *                  _foundPageURLs;

    NSMutableDictionary *           _foundImageURLToPathMap;

    NSUInteger                      _runningOperationCount;

}

+ (BOOL)isSupportedURL:(NSURL *)url;

- (id)initWithURL:(NSURL *)url;

    // Initialises the object to start by downloading the HTML at the 

    // specified URL.

// Things that are configured by the init method and can't be changed.

@property (nonatomic, copy,   readonly ) NSURL *        URL;

// Things you can change before calling -start.

@property (nonatomic, assign, readwrite) NSUInteger     maximumDepth;       // defaults to 0

@property (nonatomic, copy,   readwrite) NSString *     imagesDirPath;      // defaults to the "images" directory within the temporary directory

                                                                            // don't change this after calling -startWithURLString:

@property (nonatomic, assign, readwrite) id<LinkedImageFetcherDelegate> delegate;

// Things that are meaningful after you've called -start.

@property (nonatomic, assign, readwrite) BOOL           done;               // observable

@property (nonatomic, copy,   readonly ) NSError *      error;              // nil if no error

@property (nonatomic, copy,   readonly ) NSDictionary * imageURLToPathMap;  // NSURL -> NSNull (in progress), NSError (failed), NSString (downloaded)

// Methods to start and stop the fetch.  Note that this is a one-shot thing; 

// you can't call -stop and then call -start again.

- (BOOL)start;

- (void)stop;

+ (id)fetcherWithURLString:(const char *)urlCStr maximumDepth:(int)maximumDepth;

    // Convenience method for the command line test program.

    // Handles urlStr being nil.  Handles the URL scheme being unsupported.  

    // Handles maximum depth being negative.

@end

@protocol LinkedImageFetcherDelegate <NSObject>

@optional

- (void)linkedImageFetcher:(LinkedImageFetcher *)fetcher logText:(NSString *)text URL:(NSURL *)url depth:(NSUInteger)depth error:(NSError *)error;

    // You can implement this delegate method to do your own logging.

    // You're called with some text, the URL that the text relates to, 

    // the depth of that URL (0 if the it relates to the main page, 1 

    // if it relates to resource directly linked to from the main page, 

    // and so on) and an optional error.

@end