class Renderbuffer: public Resource
{
public:
    Texture::Format getFormat() const { return format; }

    unsigned int getWidth() const { return width; }
    unsigned int getHeight() const { return height; }
};

class Framebuffer: public Resource
{
public:
    virtual void download(void* data, unsigned int size) = 0;

    unsigned int getWidth() const { return width; }
    unsigned int getHeight() const { return height; }
};

class VertexLayout: public Resource
{
public:
    enum Semantic
    {
        Semantic_Position,
        Semantic_Normal,
        Semantic_Color,
        Semantic_Texture,

        Semantic_Count
    };

    enum Format
    {
        Format_Float1,
        Format_Float2,
        Format_Float3,
        Format_Float4,
        Format_Short2,
        Format_Short4,
        Format_UByte4,
        Format_Color,

        Format_Count
    };

    struct Element
    {
        unsigned int stream;
        unsigned int offset;

        Format format;

        Semantic semantic;
        unsigned int semanticIndex;

        Element(unsigned int stream, unsigned int offset, Format format, Semantic semantic, unsigned int semanticIndex = 0);
    };

    const std::vector<Element>& getElements() const { return elements; }
};

class GeometryBuffer: public Resource
{
public:
    enum Usage
    {
        Usage_Static,
        Usage_Dynamic,

        Usage_Count
    };

    enum LockMode
    {
        Lock_Normal,
        Lock_Discard,

        Lock_Count
    };

    virtual void* lock(LockMode mode = Lock_Normal) = 0;
    virtual void unlock() = 0;

    virtual void upload(unsigned int offset, const void* data, unsigned int size) = 0;

    size_t getElementSize() const { return elementSize; }
    size_t getElementCount() const { return elementCount; }
};

class VertexBuffer: public GeometryBuffer
{
};

class IndexBuffer: public GeometryBuffer
{
};

class Geometry: public Resource
{
public:
    enum Primitive
    {
        Primitive_Triangles,
        Primitive_Lines,
        Primitive_Points,
        Primitive_TriangleStrip,

        Primitive_Count
    };
};

class GeometryBatch
{
public:
    GeometryBatch(const shared_ptr<Geometry>& geometry, Geometry::Primitive primitive, unsigned int count, unsigned int indexRangeSize);
    GeometryBatch(const shared_ptr<Geometry>& geometry, Geometry::Primitive primitive, unsigned int offset, unsigned int count, unsigned int indexRangeBegin, unsigned int indexRangeEnd);

    Geometry* getGeometry() const { return geometry.get(); }

    Geometry::Primitive getPrimitive() const { return primitive; }
    unsigned int getOffset() const { return offset; }
    unsigned int getCount() const { return count; }

    unsigned int getIndexRangeBegin() const { return indexRangeBegin; }
    unsigned int getIndexRangeEnd() const { return indexRangeEnd; }
};

class VertexShader: public Resource
{
};

class FragmentShader: public Resource
{
};

class ShaderProgram: public Resource
{
public:
    ~ShaderProgram();

    virtual int getConstantHandle(const char* name) const = 0;

    virtual unsigned int getMaxWorldTransforms() const = 0;
    virtual unsigned int getSamplerMask() const = 0;
};

struct ShaderGlobalConstant
{
    const char* name;
    unsigned int offset;
    unsigned int size;

    ShaderGlobalConstant(const char* name, unsigned int offset, unsigned int size);
};

class RasterizerState
{
public:
    enum CullMode
    {
        Cull_None,
        Cull_Back,
        Cull_Front,

        Cull_Count
    };

    RasterizerState(CullMode cullMode, int depthBias = 0);

    CullMode getCullMode() const { return cullMode; }
    int getDepthBias() const { return depthBias; }

    bool operator==(const RasterizerState& other) const;
    bool operator!=(const RasterizerState& other) const;
};

class BlendState
{
public:
    enum Mode
    {
        Mode_None,
        Mode_Additive,
        Mode_Multiplicative,
        Mode_AlphaBlend,
        Mode_PremultipliedAlphaBlend,
        Mode_AlphaOne,

        Mode_Count
    };

    enum ColorMask
    {
        Color_None = 0,
        Color_R = 1 << 0,
        Color_G = 1 << 1,
        Color_B = 1 << 2,
        Color_A = 1 << 3,
        Color_All = Color_R | Color_G | Color_B | Color_A
    };

    BlendState(Mode mode, unsigned int colorMask = Color_All);

    Mode getMode() const { return mode; }
    unsigned int getColorMask() const { return colorMask; }

    bool operator==(const BlendState& other) const;
    bool operator!=(const BlendState& other) const;
};

class DepthState
{
public:
    enum Function
    {
        Function_Always,
        Function_Less,
        Function_LessEqual,

        Function_Count
    };

    enum StencilMode
    {
        Stencil_None,
        Stencil_IsNotZero,
        Stencil_UpdateZFail,

        Stencil_Count
    };

    DepthState(Function function, bool write, StencilMode stencilMode = Stencil_None);

    Function getFunction() const { return function; }
    bool getWrite() const { return write; }
    StencilMode getStencilMode() const { return stencilMode; }

    bool operator==(const DepthState& other) const;
    bool operator!=(const DepthState& other) const;
};

class SamplerState
{
public:
    enum Filter
    {
        Filter_Point,
        Filter_Linear,
        Filter_Anisotropic,

        Filter_Count
    };

    enum Address
    {
        Address_Wrap,
        Address_Clamp,

        Address_Count
    };

    SamplerState(Filter filter, Address address = Address_Wrap, unsigned int anisotropy = 0);

    Filter getFilter() const { return filter; }
    Address getAddress() const { return address; }
    unsigned int getAnisotropy() const { return anisotropy; }

    bool operator==(const SamplerState& other) const;
    bool operator!=(const SamplerState& other) const;
};

struct TextureRegion
{
    unsigned int x;
    unsigned int y;
    unsigned int z;

    unsigned int width;
    unsigned int height;
    unsigned int depth;

    TextureRegion(unsigned int x, unsigned int y, unsigned int z, unsigned int width, unsigned int height, unsigned int depth);
    TextureRegion(unsigned int x, unsigned int y, unsigned int width, unsigned int height);
};

class Texture: public Resource
{
public:
    enum Type
    {
        Type_2D,
        Type_3D,
        Type_Cube,

        Type_Count
    };

    enum Usage
    {
        Usage_Static,
        Usage_Dynamic,
        Usage_Renderbuffer,

        Usage_Count
    };

    enum Format
    {
        Format_L8,
        Format_LA8,
        Format_RGB5A1,
        Format_RGBA8,
        Format_RG16,
        Format_RGBA16F,
        Format_BC1,
        Format_BC2,
        Format_BC3,
        Format_PVRTC_RGB2,
        Format_PVRTC_RGBA2,
        Format_PVRTC_RGB4,
        Format_PVRTC_RGBA4,
        Format_D24S8,

        Format_Count
    };

    struct LockResult
    {
        void* data;
        unsigned int rowPitch;
        unsigned int slicePitch;
    };

    virtual void upload(unsigned int index, unsigned int mip, const TextureRegion& region, const void* data, unsigned int size) = 0;

    virtual bool supportsLocking() const = 0;
    virtual LockResult lock(unsigned int index, unsigned int mip, const TextureRegion& region) = 0;
    virtual void unlock(unsigned int index, unsigned int mip) = 0;

    virtual shared_ptr<Renderbuffer> getRenderbuffer(unsigned int index, unsigned int mip) = 0;

    Type getType() const { return type; }
    Format getFormat() const { return format; }

    unsigned int getWidth() const { return width; }
    unsigned int getHeight() const { return height; }
    unsigned int getDepth() const { return depth; }

    unsigned int getMipLevels() const { return mipLevels; }

    Usage getUsage() const { return usage; }
};

class DeviceContext
{
public:
    enum ClearMask
    {
        Clear_Color = 1 << 0,
        Clear_Depth = 1 << 1,
        Clear_Stencil = 1 << 2
    };

    virtual ~DeviceContext();

    virtual void setDefaultAnisotropy(unsigned int value) = 0;

    virtual void updateGlobalConstants(const void* data, size_t dataSize) = 0;

    virtual void bindFramebuffer(Framebuffer* buffer) = 0;
    virtual void clearFramebuffer(unsigned int mask, const float color[4], float depth, unsigned int stencil) = 0;

    virtual void copyFramebuffer(Framebuffer* buffer, Texture* texture) = 0;

    virtual void bindProgram(ShaderProgram* program) = 0;
    virtual void setWorldTransforms4x3(const float* data, size_t matrixCount) = 0;
    virtual void setConstant(int handle, const float* data, size_t vectorCount) = 0;

    virtual void bindTexture(unsigned int stage, Texture* texture, const SamplerState& state) = 0;

    virtual void setRasterizerState(const RasterizerState& state) = 0;
    virtual void setBlendState(const BlendState& state) = 0;
    virtual void setDepthState(const DepthState& state) = 0;

    virtual void draw(Geometry* geometry, Geometry::Primitive primitive, unsigned int offset, unsigned int count, unsigned int indexRangeBegin, unsigned int indexRangeEnd) = 0;
    virtual void draw(const GeometryBatch& geometryBatch) = 0;
};

struct DeviceCaps
{
    bool supportsFramebuffer;
    bool supportsShaders;
    bool supportsFFP;
    bool supportsStencil;
    bool supportsIndex32;

    bool supportsTextureDXT;
    bool supportsTexturePVR;
    bool supportsTextureHalfFloat;
    bool supportsTexture3D;
    bool supportsTextureNPOT;

    unsigned int maxDrawBuffers;
    unsigned int maxTextureSize;

    bool colorOrderBGR;
    bool needsHalfPixelOffset;
    bool requiresRenderTargetFlipping;

    void dumpToFLog(int channel) const;
};

struct DeviceStats
{
    float gpuFrameTime;
};

class Device
{
public:
    enum API
    {
        API_OpenGL,
        API_Direct3D9
    };

    static Device* create(API api, void* windowHandle);

    virtual ~Device();

    virtual DeviceContext* beginFrame() = 0;
    virtual void endFrame() = 0;

    virtual Framebuffer* getMainFramebuffer() = 0;

    virtual void defineGlobalConstants(size_t dataSize, const std::vector<ShaderGlobalConstant>& constants) = 0;

    virtual std::string getShadingLanguage() = 0;
    virtual std::string createShaderSource(const std::string& path, const std::string& defines, boost::function<std::string (const std::string&)> fileCallback) = 0;
    virtual std::vector<char> createShaderBytecode(const std::string& source, const std::string& target, const std::string& entrypoint) = 0;

    virtual shared_ptr<VertexShader> createVertexShader(const std::vector<char>& bytecode) = 0;
    virtual shared_ptr<FragmentShader> createFragmentShader(const std::vector<char>& bytecode) = 0;
    virtual shared_ptr<ShaderProgram> createShaderProgram(const shared_ptr<VertexShader>& vertexShader, const shared_ptr<FragmentShader>& fragmentShader) = 0;
    virtual shared_ptr<ShaderProgram> createShaderProgramFFP() = 0;

    virtual shared_ptr<VertexBuffer> createVertexBuffer(size_t elementSize, size_t elementCount, GeometryBuffer::Usage usage) = 0;
    virtual shared_ptr<IndexBuffer> createIndexBuffer(size_t elementSize, size_t elementCount, GeometryBuffer::Usage usage) = 0;
    virtual shared_ptr<VertexLayout> createVertexLayout(const std::vector<VertexLayout::Element>& elements) = 0;

    virtual shared_ptr<Geometry> createGeometry(const shared_ptr<VertexLayout>& layout, const shared_ptr<VertexBuffer>& vertexBuffer, const shared_ptr<IndexBuffer>& indexBuffer, unsigned int baseVertexIndex = 0) = 0;
    virtual shared_ptr<Geometry> createGeometry(const shared_ptr<VertexLayout>& layout, const std::vector<shared_ptr<VertexBuffer> >& vertexBuffers, const shared_ptr<IndexBuffer>& indexBuffer, unsigned int baseVertexIndex = 0) = 0;

    virtual shared_ptr<Texture> createTexture(Texture::Type type, Texture::Format format, unsigned int width, unsigned int height, unsigned int depth, unsigned int mipLevels, Texture::Usage usage) = 0;

    virtual shared_ptr<Renderbuffer> createRenderbuffer(Texture::Format format, unsigned int width, unsigned int height) = 0;

    virtual shared_ptr<Framebuffer> createFramebuffer(const shared_ptr<Renderbuffer>& color, const shared_ptr<Renderbuffer>& depth = shared_ptr<Renderbuffer>()) = 0;
    virtual shared_ptr<Framebuffer> createFramebuffer(const std::vector<shared_ptr<Renderbuffer> >& color, const shared_ptr<Renderbuffer>& depth = shared_ptr<Renderbuffer>()) = 0;

    virtual const DeviceCaps& getCaps() const = 0;

    virtual DeviceStats getStatistics() const = 0;

    virtual void setFrameDataCallback(const DeviceFrameDataCallback& callback) = 0;
};