/*

    File: Controller.m

Abstract: Handles all UI interaction and code for saving the image.

 Version: 1.1

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*/

#import "Controller.h"

#import "DataProvider.h"

@interface Controller()

-(bool)userCanceled;

-(void)progress:(float)percent;

-(void)updateProgress;

-(void)startSaveUI;

-(void)endSaveUI;

@end

@implementation Controller

static NSString *kWidthKey = @"width";

static NSString *kHeightKey = @"height";

static NSString *kLocationKey = @"location";

// Callback for our custom data provider in order to provide progress for UI.

static void MyProgressCallback(void *context, float percentProgress)

{

    [(Controller*)context progress:percentProgress];

}

// Callback for our custom data provider to determine if we should stop providing data in order to implement cancel

static bool MyCancelCallback(void *context)

{

    return [(Controller*)context userCanceled];

}

-(void)saveTo:(NSDictionary*)info;

{

    // Since we are being spun off into a thread, we need our own auto-release pool

    NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];

    // Signal that we are ready to start so that our progress sheet is displayed

    [self performSelectorOnMainThread:@selector(startSaveUI) withObject:nil waitUntilDone:YES]; 

    // Collect the size and save location for the image in question

    size_t w = [[info objectForKey:kWidthKey] intValue];

    size_t h = [[info objectForKey:kHeightKey] intValue];

    NSURL *location = [info objectForKey:kLocationKey];

    // Create a generic rgb color space

    CGColorSpaceRef colorSpace = CGColorSpaceCreateWithName(kCGColorSpaceGenericRGB);

    // Setup our data provider

    CGDataProviderRef provider = CreateDataProvider(w, h, self, MyProgressCallback, MyCancelCallback);

    // Create the image with our data provider and color space - it will retain both so we will release them both after

    CGImageRef image = CGImageCreate(

        w, h, // width & height

        kBitsPerComponent, kBitsPerPixel, // bits per component, bits per pixel

        w * kBytesPerPixel, // bytes per row

        colorSpace, // color space

        kImageFlags, // format (XRGB) (see DataProvider.h)

        provider, // data provider

        NULL, // color decode array

        true, // allow interpolation

        kCGRenderingIntentDefault); // default rendering intent

    CFRelease(colorSpace);

    CFRelease(provider);

    // Create a URL to our file destination and a CGImageDestination to save to.

    CGImageDestinationRef imageDestination = CGImageDestinationCreateWithURL((CFURLRef)location, kUTTypeJPEG, 1, NULL);

    // Add the image created above

    CGImageDestinationAddImage(imageDestination, image, NULL);

    // Finalize the image destination, which will write the image data to disk.

    success = CGImageDestinationFinalize(imageDestination);

    CFRelease(imageDestination);

    CFRelease(image);

    // Finally, signal that we are done so that the UI becomes active again.

    [self performSelectorOnMainThread:@selector(endSaveUI) withObject:nil waitUntilDone:YES];   

    // Clean out our auto release pool.

    [pool drain];

}

-(IBAction)save:(id)sender

{

    #pragma unused(sender)

    // Clear the message just to avoid confusion.

    [messageText setStringValue:@""];

    // Verify the image width & height. Appkit's NSNumberFormatter

    // will complain about out of range, but won't actually clip the range

    // We just clip the range here and push it back out to the UI.

    // Since JPEG doesn't seem to support images larger than 65500 per side, that is our new limit.

    int w = [width intValue], h = [height intValue];

    if((w < 1) || (w > 65500) || (h < 1) || (h > 65500))

    {

        [messageText setStringValue:[NSString stringWithFormat:@"%i x %i is too big", w, h]];

    }

    else

    {

        // Configure and start a save panel to save the image

        // If the panel is successful then saveImageDidEnd:returnCode:contextInfo

        // will complete the transaction.

        NSSavePanel * panel = [NSSavePanel savePanel];

        [panel setCanSelectHiddenExtension:YES];

        [panel setRequiredFileType:@"jpg"];

        [panel setAllowsOtherFileTypes:NO];

        [panel

            beginSheetForDirectory:nil

            file:@"Test Image"

            modalForWindow:[self window]

            modalDelegate:self

            didEndSelector:@selector(saveImageDidEnd:returnCode:contextInfo:)

            contextInfo:nil];

    }

}

-(void)saveImageDidEnd:(NSSavePanel*)panel returnCode:(int)returnCode contextInfo:(void*)contextInfo

{

    #pragma unused(contextInfo)

    // If the user elected to save, then do so.

    if(returnCode == NSOKButton)

    {

        // Fill out the information needed to save

        NSDictionary * info = [NSDictionary dictionaryWithObjectsAndKeys:[width objectValue], kWidthKey, [height objectValue], kHeightKey, [panel URL], kLocationKey, nil];

        // And dispatch the operation to a background thread to avoid locking up the UI.

        // detachNewThreadSelector:toTarget:withObject: will retain it's parameters so we don't have to.

        // Equivalent to [self saveTo:info]

        [NSThread detachNewThreadSelector:@selector(saveTo:) toTarget:self withObject:info];

    }

}

-(IBAction)cancel:(id)sender

{

    #pragma unused(sender)

    // Set the cancel flag - this will be picked up later in the Data Provider.

    cancel = true;

}

-(bool)userCanceled

{

    // Return the cancel flag's current state.

    return cancel;

}

-(void)progress:(float)percent

{

    // Only update the progress bar if the new value is significantly different

    // from the old value. Here we define significant as 1%

    if(percent > lastProgressUpdate + 1.0f)

    {

        // Remeber the new significant percentage...

        lastProgressUpdate = percent;

        // And call back to the main thread to update the progress bar

        // (this is called within our provider on the background thread)

        [self performSelectorOnMainThread:@selector(updateProgress) withObject:nil waitUntilDone:NO];

    }

}

-(void)updateProgress

{

    [progress setDoubleValue:lastProgressUpdate];

}

-(void)startSaveUI

{

    // Reset UI variables for this run

    lastProgressUpdate = 0.0;

    cancel = false;

    [progress setDoubleValue:0.0];

    // Begin our progress sheet.

    [NSApp beginSheet:sheetWindow modalForWindow:[self window] modalDelegate:nil didEndSelector:nil contextInfo:nil];

}

-(void)endSaveUI

{

    // End the progress sheet.

    [NSApp endSheet:sheetWindow];

    // Send it on it's merry way.

    [sheetWindow orderOut:self];

    // Provide some feedback to the user about what just happened.

    if(success)

    {

        [messageText setStringValue:@"Save succeeded."];

    }

    else if(cancel)

    {

        [messageText setStringValue:@"Save canceled by user."];

    }

    else

    {

        [messageText setStringValue:@"Save failed."];

    }

}

@end