// Copyright 2020 The Dawn Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#if !defined(DAWN_ENABLE_BACKEND_METAL)
#error "GLFWUtils_metal.mm requires the Metal backend to be enabled."
#endif  // !defined(DAWN_ENABLE_BACKEND_METAL)

#include "dawn/utils/GLFWUtils.h"

#import <QuartzCore/CAMetalLayer.h>
#include "GLFW/glfw3.h"

#include <cstdlib>

#define GLFW_EXPOSE_NATIVE_COCOA
#include "GLFW/glfw3native.h"

namespace utils {

std::unique_ptr<wgpu::ChainedStruct> SetupWindowAndGetSurfaceDescriptor(GLFWwindow* window) {
    if (@available(macOS 10.11, *)) {
        NSWindow* nsWindow = glfwGetCocoaWindow(window);
        NSView* view = [nsWindow contentView];

        // Create a CAMetalLayer that covers the whole window that will be passed to
        // CreateSurface.
        [view setWantsLayer:YES];
        [view setLayer:[CAMetalLayer layer]];

        // Use retina if the window was created with retina support.
        [[view layer] setContentsScale:[nsWindow backingScaleFactor]];

        std::unique_ptr<wgpu::SurfaceDescriptorFromMetalLayer> desc =
            std::make_unique<wgpu::SurfaceDescriptorFromMetalLayer>();
        desc->layer = [view layer];
        return std::move(desc);
    }

    return nullptr;
}

}  // namespace utils