//
//  Color+Interpolation.m
//
//  Created by Leo Natan on 01/10/2016.
//  Copyright © 2016 Leo Natan. All rights reserved.
//

#if __has_include(<UIKit/UIKit.h>) || __has_include(<AppKit/AppKit.h>)

#import "Color+Interpolation.h"

#if __has_include(<UIKit/UIKit.h>)
#define Color UIColor
#else
#define Color NSColor
#endif

#define SWAP(x, y) do { __typeof(x) __ZZZZ__SWAP = x; x = y; y = __ZZZZ__SWAP; } while(0)

//Same value as LNInterpolationBehaviorUseDefault
LNInterpolationBehavior const RNUIInterpolationBehaviorUseLABColorSpace = @"LNInterpolationBehaviorUseDefault";
LNInterpolationBehavior const RNUIInterpolationBehaviorUseRGBColorSpace = @"LNInterpolationBehaviorUseRGB";

extern double LNLinearInterpolate(double from, double to, double p);

static NSArray<NSNumber*>* LNRGBComponentsFromColor(Color* color)
{
    size_t numberOfComponents = CGColorGetNumberOfComponents(color.CGColor);
    const CGFloat* components = CGColorGetComponents(color.CGColor);
    
    return numberOfComponents == 2 ? @[@(components[0]), @(components[0]), @(components[0]), @(components[1])] : @[@(components[0]), @(components[1]), @(components[2]), @(components[3])];
}

static Color* LNColorFromRGBComponents(NSArray<NSNumber*>* components)
{
    return [Color colorWithRed:components[0].doubleValue green:components[1].doubleValue blue:components[2].doubleValue alpha:components[3].doubleValue];
}

static NSArray<NSNumber*>* LNLabComponentsFromColor(Color* color)
{
    NSArray<NSNumber*>* rgbComponents = LNRGBComponentsFromColor(color);
    CGFloat r = rgbComponents[0].doubleValue;
    CGFloat g = rgbComponents[1].doubleValue;
    CGFloat b = rgbComponents[2].doubleValue;
    
    //RGB -> XYZ
    //http://www.brucelindbloom.com/index.html?Eqn_RGB_to_XYZ.html

    r = (r > 0.04045) ? pow((r + 0.055) / 1.055, 2.4) : (r / 12.92);
    g = (g > 0.04045) ? pow((g + 0.055) / 1.055, 2.4) : (g / 12.92);
    b = (b > 0.04045) ? pow((b + 0.055) / 1.055, 2.4) : (b / 12.92);
    
    //http://www.brucelindbloom.com/index.html?Eqn_RGB_XYZ_Matrix.html (sRGB -> XYZ)
    CGFloat x = r * 41.24564 + g * 35.75761 + b * 18.04375;
    CGFloat y = r * 21.26729 + g * 71.51522 + b * 07.21750;
    CGFloat z = r * 01.93339 + g * 11.91920 + b * 95.03041;
    
    //XYZ -> Lab
    //http://www.brucelindbloom.com/index.html?Eqn_XYZ_to_Lab.html
    
    static const CGFloat eps = 216.0 / 24389.0;
    static const CGFloat k = 24389.0 / 27.0;
    
    x = x / 100.0;//95.047;
    y = y / 100.0;//100.000;
    z = z / 100.0;//108.883;
    
    x = x > eps ? pow(x, 1.0 / 3.0) : (k * x + 16.0) / 116.0;
    y = y > eps ? pow(y, 1.0 / 3.0) : (k * y + 16.0) / 116.0;
    z = z > eps ? pow(z, 1.0 / 3.0) : (k * z + 16.0) / 116.0;
    
    CGFloat l = 116 * y - 16;
    CGFloat a = 500 * (x - y);
            b = 200 * (y - z);
    
    return @[@(l), @(a), @(b), rgbComponents[3]];
}

static Color* LNColorFromLabComponents(NSArray<NSNumber*>* components)
{
    CGFloat l = components[0].doubleValue;
    CGFloat a = components[1].doubleValue;
    CGFloat b = components[2].doubleValue;
    
    //Lab -> XYZ
    //http://www.brucelindbloom.com/index.html?Eqn_Lab_to_XYZ.html
    
    static const CGFloat eps = 216.0 / 24389.0;
    static const CGFloat k = 24389.0 / 27.0;
    
    CGFloat y = (l + 16.0) / 116.0;
    CGFloat x = a / 500 + y;
    CGFloat z = y - b / 200;

    x = pow(x, 3.0) > eps ? pow(x, 3.0) : (116 * x - 16) / k;
    y = l > k * eps ? pow((l + 16) / 116, 3.0) : l / k;
    z = pow(z, 3.0) > eps ? pow(z, 3.0) : (116 * z - 16) / k;
    
    x = x * 1.0;//.95047;
    y = y * 1.0;//1.00000;
    z = z * 1.0;//1.08883;
    
    //XYZ -> RGB
    
    //http://www.brucelindbloom.com/index.html?Eqn_RGB_XYZ_Matrix.html (XYZ -> sRGB)
    CGFloat r = x *  3.2404542 + y * -1.5371385 + z * -0.4985314;
    CGFloat g = x * -0.9692660 + y *  1.8760108 + z *  0.0415560;
            b = x *  0.0556434 + y * -0.2040259 + z *  1.0572252;
    
    r = r <= 0.0031308 ? 12.92 * r : 1.055 * pow(r, 1.0 / 2.4) - 0.055;
    g = g <= 0.0031308 ? 12.92 * g : 1.055 * pow(g, 1.0 / 2.4) - 0.055;
    b = b <= 0.0031308 ? 12.92 * b : 1.055 * pow(b, 1.0 / 2.4) - 0.055;
    
    // return Color
    return LNColorFromRGBComponents(@[@(r), @(g), @(b), components[3]]);
}

static inline Color* LNInterpolateColor(Color* fromValue, Color* toValue, CGFloat p, NSArray* (*compConverter)(Color*), Color* (*colorConverter)(NSArray*))
{
    NSArray<NSNumber*>* arrayC1 = compConverter(fromValue);
    NSArray<NSNumber*>* arrayC2 = compConverter(toValue);
    
    NSMutableArray<NSNumber*>* arrayOutput = [NSMutableArray new];
    [arrayC1 enumerateObjectsUsingBlock:^(NSNumber * _Nonnull obj, NSUInteger idx, BOOL * _Nonnull stop) {
        arrayOutput[idx] = @(LNLinearInterpolate(obj.doubleValue, arrayC2[idx].doubleValue, p));
    }];
    
    return colorConverter(arrayOutput);
}

@implementation Color (Interpolation)

- (instancetype)interpolateToValue:(Color*)toValue progress:(double)p
{
    return [self interpolateToValue:toValue progress:p behavior:LNInterpolationBehaviorUseDefault];
}

- (instancetype)interpolateToValue:(id)toValue progress:(double)p behavior:(LNInterpolationBehavior)behavior
{
    if([toValue isKindOfClass:[Color class]] == NO)
    {
        return nil;
    }
    
    if(p <= 0)
    {
        return self;
    }
    
    if(p >= 1)
    {
        return toValue;
    }
    
    return LNInterpolateColor(self, toValue, p, behavior == RNUIInterpolationBehaviorUseRGBColorSpace ? LNRGBComponentsFromColor : LNLabComponentsFromColor, behavior == RNUIInterpolationBehaviorUseRGBColorSpace ? LNColorFromRGBComponents : LNColorFromLabComponents);
}

@end

#endif