/*
 * Copyright 2013 The Android Open Source Project
 *
 * 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.
 */

#ifndef SF_RENDERENGINE_H_
#define SF_RENDERENGINE_H_

#include <stdint.h>
#include <sys/types.h>
#include <memory>

#include <android-base/unique_fd.h>
#include <math/mat4.h>
#include <renderengine/DisplaySettings.h>
#include <renderengine/Framebuffer.h>
#include <renderengine/Image.h>
#include <renderengine/LayerSettings.h>
#include <ui/GraphicTypes.h>
#include <ui/Transform.h>

/**
 * Allows to set RenderEngine backend to GLES (default) or Vulkan (NOT yet supported).
 */
#define PROPERTY_DEBUG_RENDERENGINE_BACKEND "debug.renderengine.backend"

struct ANativeWindowBuffer;

namespace android {

class Rect;
class Region;

namespace renderengine {

class BindNativeBufferAsFramebuffer;
class Image;
class Mesh;
class Texture;
struct RenderEngineCreationArgs;

namespace impl {
class RenderEngine;
}

enum class Protection {
    UNPROTECTED = 1,
    PROTECTED = 2,
};

class RenderEngine {
public:
    enum class ContextPriority {
        LOW = 1,
        MEDIUM = 2,
        HIGH = 3,
    };

    static std::unique_ptr<impl::RenderEngine> create(const RenderEngineCreationArgs& args);

    virtual ~RenderEngine() = 0;

    // ----- BEGIN DEPRECATED INTERFACE -----
    // This interface, while still in use until a suitable replacement is built,
    // should be considered deprecated, minus some methods which still may be
    // used to support legacy behavior.
    virtual void primeCache() const = 0;

    // dump the extension strings. always call the base class.
    virtual void dump(std::string& result) = 0;

    virtual bool useNativeFenceSync() const = 0;
    virtual bool useWaitSync() const = 0;
    virtual void genTextures(size_t count, uint32_t* names) = 0;
    virtual void deleteTextures(size_t count, uint32_t const* names) = 0;
    virtual void bindExternalTextureImage(uint32_t texName, const Image& image) = 0;
    // Legacy public method used by devices that don't support native fence
    // synchronization in their GPU driver, as this method provides implicit
    // synchronization for latching buffers.
    virtual status_t bindExternalTextureBuffer(uint32_t texName, const sp<GraphicBuffer>& buffer,
                                               const sp<Fence>& fence) = 0;
    // Caches Image resources for this buffer, but does not bind the buffer to
    // a particular texture.
    // Note that work is deferred to an additional thread, i.e. this call
    // is made asynchronously, but the caller can expect that cache/unbind calls
    // are performed in a manner that's conflict serializable, i.e. unbinding
    // a buffer should never occur before binding the buffer if the caller
    // called {bind, cache}ExternalTextureBuffer before calling unbind.
    virtual void cacheExternalTextureBuffer(const sp<GraphicBuffer>& buffer) = 0;
    // Removes internal resources referenced by the bufferId. This method should be
    // invoked when the caller will no longer hold a reference to a GraphicBuffer
    // and needs to clean up its resources.
    // Note that work is deferred to an additional thread, i.e. this call
    // is made asynchronously, but the caller can expect that cache/unbind calls
    // are performed in a manner that's conflict serializable, i.e. unbinding
    // a buffer should never occur before binding the buffer if the caller
    // called {bind, cache}ExternalTextureBuffer before calling unbind.
    virtual void unbindExternalTextureBuffer(uint64_t bufferId) = 0;
    // When binding a native buffer, it must be done before setViewportAndProjection
    // Returns NO_ERROR when binds successfully, NO_MEMORY when there's no memory for allocation.
    virtual status_t bindFrameBuffer(Framebuffer* framebuffer) = 0;
    virtual void unbindFrameBuffer(Framebuffer* framebuffer) = 0;
    // Clean-up method that should be called on the main thread after the
    // drawFence returned by drawLayers fires. This method will free up
    // resources used by the most recently drawn frame. If the frame is still
    // being drawn, then this call is silently ignored.
    //
    // Returns true if resources were cleaned up, and false if we didn't need to
    // do any work.
    virtual bool cleanupPostRender() = 0;

    // queries
    virtual size_t getMaxTextureSize() const = 0;
    virtual size_t getMaxViewportDims() const = 0;

    // ----- END DEPRECATED INTERFACE -----

    // ----- BEGIN NEW INTERFACE -----

    virtual bool isProtected() const = 0;
    virtual bool supportsProtectedContent() const = 0;
    virtual bool useProtectedContext(bool useProtectedContext) = 0;

    // Renders layers for a particular display via GPU composition. This method
    // should be called for every display that needs to be rendered via the GPU.
    // @param display The display-wide settings that should be applied prior to
    // drawing any layers.
    //
    // Assumptions when calling this method:
    // 1. There is exactly one caller - i.e. multi-threading is not supported.
    // 2. Additional threads may be calling the {bind,cache}ExternalTexture
    // methods above. But the main thread is responsible for holding resources
    // such that Image destruction does not occur while this method is called.
    //
    // TODO(b/136806342): This should behavior should ideally be fixed since
    // the above two assumptions are brittle, as conditional thread safetyness
    // may be insufficient when maximizing rendering performance in the future.
    //
    // @param layers The layers to draw onto the display, in Z-order.
    // @param buffer The buffer which will be drawn to. This buffer will be
    // ready once drawFence fires.
    // @param useFramebufferCache True if the framebuffer cache should be used.
    // If an implementation does not cache output framebuffers, then this
    // parameter does nothing.
    // @param bufferFence Fence signalling that the buffer is ready to be drawn
    // to.
    // @param drawFence A pointer to a fence, which will fire when the buffer
    // has been drawn to and is ready to be examined. The fence will be
    // initialized by this method. The caller will be responsible for owning the
    // fence.
    // @return An error code indicating whether drawing was successful. For
    // now, this always returns NO_ERROR.
    virtual status_t drawLayers(const DisplaySettings& display,
                                const std::vector<const LayerSettings*>& layers,
                                ANativeWindowBuffer* buffer, const bool useFramebufferCache,
                                base::unique_fd&& bufferFence, base::unique_fd* drawFence) = 0;

protected:
    // Gets a framebuffer to render to. This framebuffer may or may not be
    // cached depending on the implementation.
    //
    // Note that this method does not transfer ownership, so the caller most not
    // live longer than RenderEngine.
    virtual Framebuffer* getFramebufferForDrawing() = 0;
    friend class BindNativeBufferAsFramebuffer;
};

struct RenderEngineCreationArgs {
    int pixelFormat;
    uint32_t imageCacheSize;
    bool useColorManagement;
    bool enableProtectedContext;
    bool precacheToneMapperShaderOnly;
    bool supportsBackgroundBlur;
    RenderEngine::ContextPriority contextPriority;

    struct Builder;

private:
    // must be created by Builder via constructor with full argument list
    RenderEngineCreationArgs(
            int _pixelFormat,
            uint32_t _imageCacheSize,
            bool _useColorManagement,
            bool _enableProtectedContext,
            bool _precacheToneMapperShaderOnly,
            bool _supportsBackgroundBlur,
            RenderEngine::ContextPriority _contextPriority)
        : pixelFormat(_pixelFormat)
        , imageCacheSize(_imageCacheSize)
        , useColorManagement(_useColorManagement)
        , enableProtectedContext(_enableProtectedContext)
        , precacheToneMapperShaderOnly(_precacheToneMapperShaderOnly)
        , supportsBackgroundBlur(_supportsBackgroundBlur)
        , contextPriority(_contextPriority) {}
    RenderEngineCreationArgs() = delete;
};

struct RenderEngineCreationArgs::Builder {
    Builder() {}

    Builder& setPixelFormat(int pixelFormat) {
        this->pixelFormat = pixelFormat;
        return *this;
    }
    Builder& setImageCacheSize(uint32_t imageCacheSize) {
        this->imageCacheSize = imageCacheSize;
        return *this;
    }
    Builder& setUseColorManagerment(bool useColorManagement) {
        this->useColorManagement = useColorManagement;
        return *this;
    }
    Builder& setEnableProtectedContext(bool enableProtectedContext) {
        this->enableProtectedContext = enableProtectedContext;
        return *this;
    }
    Builder& setPrecacheToneMapperShaderOnly(bool precacheToneMapperShaderOnly) {
        this->precacheToneMapperShaderOnly = precacheToneMapperShaderOnly;
        return *this;
    }
    Builder& setSupportsBackgroundBlur(bool supportsBackgroundBlur) {
        this->supportsBackgroundBlur = supportsBackgroundBlur;
        return *this;
    }
    Builder& setContextPriority(RenderEngine::ContextPriority contextPriority) {
        this->contextPriority = contextPriority;
        return *this;
    }
    RenderEngineCreationArgs build() const {
        return RenderEngineCreationArgs(pixelFormat, imageCacheSize, useColorManagement,
                                        enableProtectedContext, precacheToneMapperShaderOnly,
                                        supportsBackgroundBlur, contextPriority);
    }

private:
    // 1 means RGBA_8888
    int pixelFormat = 1;
    uint32_t imageCacheSize = 0;
    bool useColorManagement = true;
    bool enableProtectedContext = false;
    bool precacheToneMapperShaderOnly = false;
    bool supportsBackgroundBlur = false;
    RenderEngine::ContextPriority contextPriority = RenderEngine::ContextPriority::MEDIUM;
};

class BindNativeBufferAsFramebuffer {
public:
    BindNativeBufferAsFramebuffer(RenderEngine& engine, ANativeWindowBuffer* buffer,
                                  const bool useFramebufferCache)
          : mEngine(engine), mFramebuffer(mEngine.getFramebufferForDrawing()), mStatus(NO_ERROR) {
        mStatus = mFramebuffer->setNativeWindowBuffer(buffer, mEngine.isProtected(),
                                                      useFramebufferCache)
                ? mEngine.bindFrameBuffer(mFramebuffer)
                : NO_MEMORY;
    }
    ~BindNativeBufferAsFramebuffer() {
        mFramebuffer->setNativeWindowBuffer(nullptr, false, /*arbitrary*/ true);
        mEngine.unbindFrameBuffer(mFramebuffer);
    }
    status_t getStatus() const { return mStatus; }

private:
    RenderEngine& mEngine;
    Framebuffer* mFramebuffer;
    status_t mStatus;
};

namespace impl {

// impl::RenderEngine contains common implementation that is graphics back-end agnostic.
class RenderEngine : public renderengine::RenderEngine {
public:
    virtual ~RenderEngine() = 0;

    bool useNativeFenceSync() const override;
    bool useWaitSync() const override;

protected:
    RenderEngine(const RenderEngineCreationArgs& args);
    const RenderEngineCreationArgs mArgs;
};

} // namespace impl
} // namespace renderengine
} // namespace android

#endif /* SF_RENDERENGINE_H_ */