// 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.

#include "dawn_native/Surface.h"

#include "common/Platform.h"
#include "dawn_native/ChainUtils_autogen.h"
#include "dawn_native/Instance.h"
#include "dawn_native/SwapChain.h"

#if defined(DAWN_PLATFORM_WINDOWS)
#    include "common/windows_with_undefs.h"
#endif  // DAWN_PLATFORM_WINDOWS

#if defined(DAWN_USE_X11)
#    include "common/xlib_with_undefs.h"
#endif  // defined(DAWN_USE_X11)

namespace dawn_native {

#if defined(DAWN_ENABLE_BACKEND_METAL)
    bool InheritsFromCAMetalLayer(void* obj);
#endif  // defined(DAWN_ENABLE_BACKEND_METAL)

    MaybeError ValidateSurfaceDescriptor(const InstanceBase* instance,
                                         const SurfaceDescriptor* descriptor) {
        if (descriptor->nextInChain == nullptr) {
            return DAWN_VALIDATION_ERROR("Surface cannot be created with just the base descriptor");
        }

        DAWN_TRY(ValidateSingleSType(descriptor->nextInChain,
            wgpu::SType::SurfaceDescriptorFromMetalLayer,
            wgpu::SType::SurfaceDescriptorFromWindowsHWND,
            wgpu::SType::SurfaceDescriptorFromXlib));

#if defined(DAWN_ENABLE_BACKEND_METAL)
        const SurfaceDescriptorFromMetalLayer* metalDesc = nullptr;
        FindInChain(descriptor->nextInChain, &metalDesc);
        if (!metalDesc) {
            return DAWN_VALIDATION_ERROR("Unsupported sType");
        }
        // Check that the layer is a CAMetalLayer (or a derived class).
        if (!InheritsFromCAMetalLayer(metalDesc->layer)) {
            return DAWN_VALIDATION_ERROR("layer must be a CAMetalLayer");
        }
#endif  // defined(DAWN_ENABLE_BACKEND_METAL)

#if defined(DAWN_PLATFORM_WIN32)
        const SurfaceDescriptorFromWindowsHWND* hwndDesc = nullptr;
        FindInChain(descriptor->nextInChain, &hwndDesc);
        if (!hwndDesc) {
            return DAWN_VALIDATION_ERROR("Unsupported sType");
        }
        // Validate the hwnd using the windows.h IsWindow function.
        if (IsWindow(static_cast<HWND>(hwndDesc->hwnd)) == 0) {
            return DAWN_VALIDATION_ERROR("Invalid HWND");
        }
#endif  // defined(DAWN_PLATFORM_WIN32)

#if defined(DAWN_USE_X11)
        const SurfaceDescriptorFromXlib* xDesc = nullptr;
        FindInChain(descriptor->nextInChain, &xDesc);
        if (!xDesc) {
            return DAWN_VALIDATION_ERROR("Unsupported sType");
        }
        // Check the validity of the window by calling a getter function on the window that
        // returns a status code. If the window is bad the call return a status of zero. We
        // need to set a temporary X11 error handler while doing this because the default
        // X11 error handler exits the program on any error.
        XErrorHandler oldErrorHandler =
            XSetErrorHandler([](Display*, XErrorEvent*) { return 0; });
        XWindowAttributes attributes;
        int status = XGetWindowAttributes(reinterpret_cast<Display*>(xDesc->display),
                                          xDesc->window, &attributes);
        XSetErrorHandler(oldErrorHandler);

        if (status == 0) {
            return DAWN_VALIDATION_ERROR("Invalid X Window");
        }
#endif  // defined(DAWN_USE_X11)

        return {};
    }

    Surface::Surface(InstanceBase* instance, const SurfaceDescriptor* descriptor)
        : mInstance(instance) {
        ASSERT(descriptor->nextInChain != nullptr);
        const SurfaceDescriptorFromMetalLayer* metalDesc = nullptr;
        const SurfaceDescriptorFromWindowsHWND* hwndDesc = nullptr;
        const SurfaceDescriptorFromXlib* xDesc = nullptr;
        FindInChain(descriptor->nextInChain, &metalDesc);
        FindInChain(descriptor->nextInChain, &hwndDesc);
        FindInChain(descriptor->nextInChain, &xDesc);
        ASSERT(metalDesc || hwndDesc || xDesc);
        if (metalDesc) {
            mType = Type::MetalLayer;
            mMetalLayer = metalDesc->layer;
        } else if (hwndDesc) {
            mType = Type::WindowsHWND;
            mHInstance = hwndDesc->hinstance;
            mHWND = hwndDesc->hwnd;
        } else if (xDesc) {
            mType = Type::Xlib;
            mXDisplay = xDesc->display;
            mXWindow = xDesc->window;
        }
    }

    Surface::~Surface() {
        if (mSwapChain != nullptr) {
            mSwapChain->DetachFromSurface();
            mSwapChain = nullptr;
        }
    }

    NewSwapChainBase* Surface::GetAttachedSwapChain() {
        return mSwapChain.Get();
    }

    void Surface::SetAttachedSwapChain(NewSwapChainBase* swapChain) {
        mSwapChain = swapChain;
    }

    InstanceBase* Surface::GetInstance() {
        return mInstance.Get();
    }

    Surface::Type Surface::GetType() const {
        return mType;
    }

    void* Surface::GetMetalLayer() const {
        ASSERT(mType == Type::MetalLayer);
        return mMetalLayer;
    }

    void* Surface::GetHInstance() const {
        ASSERT(mType == Type::WindowsHWND);
        return mHInstance;
    }
    void* Surface::GetHWND() const {
        ASSERT(mType == Type::WindowsHWND);
        return mHWND;
    }

    void* Surface::GetXDisplay() const {
        ASSERT(mType == Type::Xlib);
        return mXDisplay;
    }
    uint32_t Surface::GetXWindow() const {
        ASSERT(mType == Type::Xlib);
        return mXWindow;
    }

}  // namespace dawn_native