/*

     File: FilterDetailCategory.m

 Abstract: Extensions to MainViewController that handle configuring a CIFilter's parameters with

 random values.

  Version: 1.0

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 */

#import "MainViewController.h"

@implementation MainViewController (FilterDetailCategory)

//

// Helper method.

// Returns an NSDictionary containg only the parameters we want our configure method

// to operate on.

+ (NSDictionary*)deriveEditableAttributesForFilter:(CIFilter*)filter

{

    NSMutableDictionary *editableAttributes = [NSMutableDictionary dictionary];

    NSDictionary *filterAttributes = [filter attributes];

    for (NSString *key in filterAttributes) {

        if ([key isEqualToString:@"CIAttributeFilterCategories"]) continue;

        else if ([key isEqualToString:@"CIAttributeFilterDisplayName"]) continue;

        else if ([key isEqualToString:@"inputImage"]) continue;

        else if ([key isEqualToString:@"outputImage"]) continue;

        else if (![[[filter attributes] objectForKey:key] isKindOfClass:[NSDictionary class]]) continue;

        [editableAttributes setObject:[[filter attributes] objectForKey:key] forKey:key];

    }

    return editableAttributes;

}

//

// Helper function that returns a random float value within the specified range.

float randFloat(float a, float b);

float randFloat(float a, float b)

{

    srand(time(NULL)); 

    return ((b-a)*((float)arc4random()/RAND_MAX))+a;

}

//

// Given a filter, examine all its parameters and configure them with randomly generated values.

+ (void)configureFilter:(CIFilter*)filter

{

    // Get the filter's parameters we're interested in configuring here.

    NSDictionary *editableAttributes = [MainViewController deriveEditableAttributesForFilter:filter];

    for (NSString *key in editableAttributes) {

        NSDictionary *attributeDictionary = [editableAttributes objectForKey:key];

        // Our method here only supports generating random values for parameters that expect numbers.

        // Some paramters take an image, color, or vector.  

        if ([[attributeDictionary objectForKey:kCIAttributeClass] isEqualToString:@"NSNumber"]) {

            // The number types are further broken down into sub types.  For our purposes, we

            // can group them into types that require either a boolean, float, or integer.

            if ([attributeDictionary objectForKey:kCIAttributeType] == kCIAttributeTypeBoolean)

            {

                NSInteger randomValue = (rand() % 2); 

                NSLog(@"Setting %i for key %@ of type BOOL", randomValue, key);

                [filter setValue:[NSNumber numberWithInteger:randomValue] forKey:key];

            }

            else if([attributeDictionary objectForKey:kCIAttributeType] == kCIAttributeTypeScalar ||

                    [attributeDictionary objectForKey:kCIAttributeType] == kCIAttributeTypeDistance ||

                    [attributeDictionary objectForKey:kCIAttributeType] == kCIAttributeTypeAngle)

            {

                // Get the min and max values

                float maximumValue = [[attributeDictionary valueForKey:kCIAttributeSliderMax] floatValue];

                float minimumValue = [[attributeDictionary valueForKey:kCIAttributeSliderMin] floatValue];

                float randomValue = randFloat(minimumValue, maximumValue);

                NSLog(@"Setting %f for key %@ of type Decimal", randomValue, key);

                [filter setValue:[NSNumber numberWithFloat:randomValue] forKey:key];

            }

            else

            {

                // Get the min and max values

                NSInteger maximumValue = [[attributeDictionary valueForKey:kCIAttributeMax] integerValue];

                NSInteger minimumValue = [[attributeDictionary valueForKey:kCIAttributeMin] integerValue];

                NSInteger randomValue = (rand() % (maximumValue - minimumValue)) + minimumValue;

                NSLog(@"Setting %i for key %@ of type Integer", randomValue, key);

                [filter setValue:[NSNumber numberWithInteger:randomValue] forKey:key];

            }

        }

    }

}

@end