// SPDX-License-Identifier: Unlicense OR MIT

package headless

import (
	"errors"

	"gioui.org/gpu"
	_ "gioui.org/internal/cocoainit"
)

/*
#cgo CFLAGS: -Werror -Wno-deprecated-declarations -fobjc-arc -x objective-c
#cgo LDFLAGS: -framework CoreGraphics -framework Metal -framework Foundation

#import <Metal/Metal.h>

static CFTypeRef createDevice(void) {
	@autoreleasepool {
		id dev = MTLCreateSystemDefaultDevice();
		return CFBridgingRetain(dev);
	}
}

static CFTypeRef newCommandQueue(CFTypeRef devRef) {
	@autoreleasepool {
		id<MTLDevice> dev = (__bridge id<MTLDevice>)devRef;
		return CFBridgingRetain([dev newCommandQueue]);
	}
}
*/
import "C"

type mtlContext struct {
	dev   C.CFTypeRef
	queue C.CFTypeRef
}

func init() {
	newContextPrimary = func() (context, error) {
		dev := C.createDevice()
		if dev == 0 {
			return nil, errors.New("headless: failed to create Metal device")
		}
		queue := C.newCommandQueue(dev)
		if queue == 0 {
			C.CFRelease(dev)
			return nil, errors.New("headless: failed to create MTLQueue")
		}
		return &mtlContext{dev: dev, queue: queue}, nil
	}
}

func (c *mtlContext) API() gpu.API {
	return gpu.Metal{
		Device:      uintptr(c.dev),
		Queue:       uintptr(c.queue),
		PixelFormat: int(C.MTLPixelFormatRGBA8Unorm_sRGB),
	}
}

func (c *mtlContext) MakeCurrent() error {
	return nil
}

func (c *mtlContext) ReleaseCurrent() {}

func (d *mtlContext) Release() {
	C.CFRelease(d.dev)
	C.CFRelease(d.queue)
	*d = mtlContext{}
}