/*

     File: NetworkManager.m

 Abstract: Shared state and utilities for networking.

  Version: 1.4

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 */

#import "NetworkManager.h"

@interface NetworkManager ()

// read/write redeclaration of public read-only property

@property (nonatomic, assign, readwrite) NSUInteger     networkOperationCount;

@end

@implementation NetworkManager

+ (NetworkManager *)sharedInstance

{

    static dispatch_once_t  onceToken;

    static NetworkManager * sSharedInstance;

    dispatch_once(&onceToken, ^{

        sSharedInstance = [[NetworkManager alloc] init];

    });

    return sSharedInstance;

}

- (NSURL *)smartURLForString:(NSString *)str

{

    NSURL *     result;

    NSString *  trimmedStr;

    NSRange     schemeMarkerRange;

    NSString *  scheme;

    assert(str != nil);

    result = nil;

    trimmedStr = [str stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceCharacterSet]];

    if ( (trimmedStr != nil) && ([trimmedStr length] != 0) ) {

        schemeMarkerRange = [trimmedStr rangeOfString:@"://"];

        if (schemeMarkerRange.location == NSNotFound) {

            result = [NSURL URLWithString:[NSString stringWithFormat:@"ftp://%@", trimmedStr]];

        } else {

            scheme = [trimmedStr substringWithRange:NSMakeRange(0, schemeMarkerRange.location)];

            assert(scheme != nil);

            if ( ([scheme compare:@"ftp"  options:NSCaseInsensitiveSearch] == NSOrderedSame) ) {

                result = [NSURL URLWithString:trimmedStr];

            } else {

                // It looks like this is some unsupported URL scheme.

            }

        }

    }

    return result;

}

- (BOOL)isImageURL:(NSURL *)url

{

    BOOL        result;

    NSString *  extension;

    assert(url != nil);

    extension = [url pathExtension];

    result = NO;

    if (extension != nil) {

        result = ([extension caseInsensitiveCompare:@"gif"] == NSOrderedSame)

              || ([extension caseInsensitiveCompare:@"png"] == NSOrderedSame)

              || ([extension caseInsensitiveCompare:@"jpg"] == NSOrderedSame);

    }

    return result;

}

- (NSString *)pathForTestImage:(NSUInteger)imageNumber

    // In order to fully test the send and receive code paths, we need some really big 

    // files.  Rather than carry theshe files around in our binary, we synthesise them. 

    // Specifically, for each test image, we expand the image by an order of magnitude, 

    // based on its image number.  That is, image 1 is not expanded, image 2 

    // gets expanded 10 times, and so on.  We expand the image by simply copying it 

    // to the temporary directory, writing the same data to the file over and over 

    // again.

{

    NSUInteger          power;

    NSUInteger          expansionFactor;

    NSString *          originalFilePath;

    NSString *          bigFilePath;

    NSFileManager *     fileManager;

    NSDictionary *      attrs;

    unsigned long long  originalFileSize;

    unsigned long long  bigFileSize;

    assert( (imageNumber >= 1) && (imageNumber <= 4) );

    // Argh, C has no built-in power operator, so I have to do 10 ** (imageNumber - 1)

    // in floating point and then cast back to integer.  Fortunately the range 

    // of values is small enough (1..1000) that floating point isn't going 

    // to cause me any problems.

    // On the simulator we expand by an extra order of magnitude; Macs are fast!

    power = imageNumber - 1;

    #if TARGET_IPHONE_SIMULATOR

        power += 1;

    #endif

    expansionFactor = (NSUInteger) pow(10, power);

    fileManager = [NSFileManager defaultManager];

    assert(fileManager != nil);

    // Calculate paths to both the original file and the expanded file.

    originalFilePath = [[NSBundle mainBundle] pathForResource:[NSString stringWithFormat:@"TestImage%zu", (size_t) imageNumber] ofType:@"png"];

    assert(originalFilePath != nil);

    bigFilePath = [NSTemporaryDirectory() stringByAppendingPathComponent:[NSString stringWithFormat:@"TestImage%zu.png", (size_t) imageNumber]];

    assert(bigFilePath != nil);

    // Get the sizes of each.

    attrs = [fileManager attributesOfItemAtPath:originalFilePath error:NULL];

    assert(attrs != nil);

    originalFileSize = [[attrs objectForKey:NSFileSize] unsignedLongLongValue];

    attrs = [fileManager attributesOfItemAtPath:bigFilePath error:NULL];

    if (attrs == NULL) {

        bigFileSize = 0;

    } else {

        bigFileSize = [[attrs objectForKey:NSFileSize] unsignedLongLongValue];

    }

    // If the expanded file is missing, or the wrong size, create it from scratch.

    if (bigFileSize != (originalFileSize * expansionFactor)) {

        NSOutputStream *    bigFileStream;

        NSData *            data;

        const uint8_t *     dataBuffer;

        NSUInteger          dataLength;

        NSUInteger          dataOffset;

        NSUInteger          counter;

        NSLog(@"%5zu - %@", (size_t) expansionFactor, bigFilePath);

        data = [NSData dataWithContentsOfMappedFile:originalFilePath];

        assert(data != nil);

        dataBuffer = [data bytes];

        dataLength = [data length];

        bigFileStream = [NSOutputStream outputStreamToFileAtPath:bigFilePath append:NO];

        assert(bigFileStream != NULL);

        [bigFileStream open];

        for (counter = 0; counter < expansionFactor; counter++) {

            dataOffset = 0;

            while (dataOffset != dataLength) {

                NSInteger       bytesWritten;

                bytesWritten = [bigFileStream write:&dataBuffer[dataOffset] maxLength:dataLength - dataOffset];

                assert(bytesWritten > 0);

                dataOffset += (NSUInteger) bytesWritten;

            }

        }

        [bigFileStream close];

    }

    return bigFilePath;

}

- (NSString *)pathForTemporaryFileWithPrefix:(NSString *)prefix

{

    NSString *  result;

    CFUUIDRef   uuid;

    CFStringRef uuidStr;

    uuid = CFUUIDCreate(NULL);

    assert(uuid != NULL);

    uuidStr = CFUUIDCreateString(NULL, uuid);

    assert(uuidStr != NULL);

    result = [NSTemporaryDirectory() stringByAppendingPathComponent:[NSString stringWithFormat:@"%@-%@", prefix, uuidStr]];

    assert(result != nil);

    CFRelease(uuidStr);

    CFRelease(uuid);

    return result;

}

- (void)didStartNetworkOperation

{

    // If you start a network operation off the main thread, you'll have to update this code 

    // to ensure that any observers of this property are thread safe.

    assert([NSThread isMainThread]);

    self.networkOperationCount += 1;

}

- (void)didStopNetworkOperation

{

    // If you stop a network operation off the main thread, you'll have to update this code 

    // to ensure that any observers of this property are thread safe.

    assert([NSThread isMainThread]);

    assert(self.networkOperationCount > 0);

    self.networkOperationCount -= 1;

}

@end