// Builds the 1024x1024 iOS app icon from the project logo (assets/logo.png, transparent).
// The emblem is drawn with high-quality interpolation onto an opaque, full-bleed dark background:
// iOS app icons must be opaque and square (the system applies the rounded mask).
// Usage: make_icon SOURCE_PNG OUTPUT_PNG
#import <Foundation/Foundation.h>
#import <CoreGraphics/CoreGraphics.h>
#import <ImageIO/ImageIO.h>

int main(int argc, char **argv) {
    @autoreleasepool {
        if (argc != 3) { fprintf(stderr, "usage: make_icon SOURCE_PNG OUTPUT_PNG\n"); return 2; }
        CGImageSourceRef src = CGImageSourceCreateWithURL((__bridge CFURLRef)[NSURL fileURLWithPath:@(argv[1])], NULL);
        CGImageRef gear = src ? CGImageSourceCreateImageAtIndex(src, 0, NULL) : NULL;
        if (!gear) { fprintf(stderr, "cannot read %s\n", argv[1]); return 1; }
        const size_t size = 1024;
        CGColorSpaceRef rgb = CGColorSpaceCreateWithName(kCGColorSpaceSRGB);
        CGContextRef ctx = CGBitmapContextCreate(NULL, size, size, 8, 0, rgb, (CGBitmapInfo)kCGImageAlphaNoneSkipLast);
        // Dark warm gradient, close to Factorio's menu backdrop.
        CGFloat stops[] = {0.20, 0.17, 0.14, 1, 0.07, 0.06, 0.05, 1};
        CGGradientRef gradient = CGGradientCreateWithColorComponents(rgb, stops, NULL, 2);
        CGContextDrawRadialGradient(ctx, gradient, CGPointMake(size / 2.0, size * 0.55), 0,
                                    CGPointMake(size / 2.0, size / 2.0), size * 0.75, kCGGradientDrawsAfterEndLocation);
        CGContextSetInterpolationQuality(ctx, kCGInterpolationHigh);
        CGFloat inset = size * 0.14;  // keep the emblem clear of the mask's corners
        CGContextDrawImage(ctx, CGRectMake(inset, inset, size - 2 * inset, size - 2 * inset), gear);
        CGImageRef icon = CGBitmapContextCreateImage(ctx);
        CGImageDestinationRef dst = CGImageDestinationCreateWithURL((__bridge CFURLRef)[NSURL fileURLWithPath:@(argv[2])],
                                                                    CFSTR("public.png"), 1, NULL);
        CGImageDestinationAddImage(dst, icon, NULL);
        BOOL ok = CGImageDestinationFinalize(dst);
        CFRelease(dst); CGImageRelease(icon); CGGradientRelease(gradient); CGContextRelease(ctx);
        CGColorSpaceRelease(rgb); CGImageRelease(gear); CFRelease(src);
        return ok ? 0 : 1;
    }
}