// macOS-only MTLDevice properties, added to the device's concrete class before the game starts.
// Values describe a built-in Apple GPU. Other selectors iOS lacks are logged and answer zero.
#import <Metal/Metal.h>
#import <objc/runtime.h>
#import "fx.h"

static id fx_zero(id self, SEL _cmd, ...) { return nil; }
static BOOL fx_no(id self, SEL _cmd) { return NO; }
static BOOL fx_yes(id self, SEL _cmd) { return YES; }
static NSUInteger fx_uint_zero(id self, SEL _cmd) { return 0; }
static NSUInteger fx_uint_one(id self, SEL _cmd) { return 1; }

static void fx_add(Class cls, const char *name, IMP imp, const char *types) {
    SEL sel = sel_registerName(name);
    if (!class_getInstanceMethod(cls, sel)) {
        class_addMethod(cls, sel, imp, types);
        fx_log("[fx] Metal compat: -[%s %s]", class_getName(cls), name);
    }
}

static BOOL (*fx_original_resolve)(id, SEL, SEL);
static BOOL fx_device_resolve(id cls, SEL _cmd, SEL sel) {
    if (fx_original_resolve && fx_original_resolve(cls, _cmd, sel)) return YES;
    const char *name = sel_getName(sel);
    if (name[0] == '_' || name[0] == '.') return NO;
    fx_log("[fx] Metal compat: unknown -[%s %s] -> 0", class_getName(cls), name);
    class_addMethod(cls, sel, (IMP)fx_zero, "@@:");
    return YES;
}

FX_EXPORT void fx_patch_metal(void) {
    id<MTLDevice> device = MTLCreateSystemDefaultDevice();
    if (!device) { fx_log("[fx] no Metal device"); return; }
    Class cls = object_getClass(device);
    fx_log("[fx] Metal device %s (%s), unified memory %d", device.name.UTF8String, class_getName(cls), device.hasUnifiedMemory);
    fx_add(cls, "isDepth24Stencil8PixelFormatSupported", (IMP)fx_no, "B@:");
    fx_add(cls, "isLowPower", (IMP)fx_no, "B@:");
    fx_add(cls, "isHeadless", (IMP)fx_no, "B@:");
    fx_add(cls, "isRemovable", (IMP)fx_no, "B@:");
    fx_add(cls, "location", (IMP)fx_uint_zero, "Q@:");          // MTLDeviceLocationBuiltIn
    fx_add(cls, "locationNumber", (IMP)fx_uint_zero, "Q@:");
    fx_add(cls, "maxTransferRate", (IMP)fx_uint_zero, "Q@:");
    fx_add(cls, "peerGroupID", (IMP)fx_uint_zero, "Q@:");
    fx_add(cls, "peerIndex", (IMP)fx_uint_zero, "I@:");
    fx_add(cls, "peerCount", (IMP)fx_uint_one, "I@:");
    fx_add(cls, "supportsBCTextureCompression", (IMP)fx_no, "B@:");
    fx_add(cls, "areProgrammableSamplePositionsSupported", (IMP)fx_yes, "B@:");
    Method resolve = class_getClassMethod(cls, @selector(resolveInstanceMethod:));
    fx_original_resolve = (BOOL (*)(id, SEL, SEL))method_getImplementation(resolve);
    // Overrides only this concrete class; inherited NSObject behavior is kept via fx_original_resolve.
    if (!class_addMethod(object_getClass(cls), @selector(resolveInstanceMethod:), (IMP)fx_device_resolve, "B@::"))
        method_setImplementation(resolve, (IMP)fx_device_resolve);
}