/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#ifndef WEBGLTEXTURE_H_
#define WEBGLTEXTURE_H_

#include "WebGLObjectModel.h"
#include "WebGLFramebufferAttachable.h"

#include "nsWrapperCache.h"

#include "mozilla/CheckedInt.h"
#include "mozilla/LinkedList.h"
#include <algorithm>

namespace mozilla {

// Zero is not an integer power of two.
inline bool is_pot_assuming_nonnegative(GLsizei x)
{
    return x && (x & (x-1)) == 0;
}

// NOTE: When this class is switched to new DOM bindings, update the (then-slow)
// WrapObject calls in GetParameter and GetFramebufferAttachmentParameter.
class WebGLTexture MOZ_FINAL
    : public nsWrapperCache
    , public WebGLRefCountedObject<WebGLTexture>
    , public LinkedListElement<WebGLTexture>
    , public WebGLContextBoundObject
    , public WebGLFramebufferAttachable
{
public:
    WebGLTexture(WebGLContext *context);

    ~WebGLTexture() {
        DeleteOnce();
    }

    void Delete();

    bool HasEverBeenBound() const { return mHasEverBeenBound; }
    void SetHasEverBeenBound(bool x) { mHasEverBeenBound = x; }
    GLuint GLName() const { return mGLName; }
    GLenum Target() const { return mTarget; }

    WebGLContext *GetParentObject() const {
        return Context();
    }

    virtual JSObject* WrapObject(JSContext *cx) MOZ_OVERRIDE;

    NS_INLINE_DECL_CYCLE_COLLECTING_NATIVE_REFCOUNTING(WebGLTexture)
    NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_NATIVE_CLASS(WebGLTexture)

protected:

    friend class WebGLContext;
    friend class WebGLFramebuffer;

    bool mHasEverBeenBound;
    GLuint mGLName;

    // we store information about the various images that are part of
    // this texture (cubemap faces, mipmap levels)

public:

    class ImageInfo
        : public WebGLRectangleObject
    {
    public:
        ImageInfo()
            : mWebGLFormat(LOCAL_GL_NONE)
            , mWebGLType(LOCAL_GL_NONE)
            , mImageDataStatus(WebGLImageDataStatus::NoImageData)
        {}

        ImageInfo(GLsizei width,
                  GLsizei height,
                  GLenum webGLFormat,
                  GLenum webGLType,
                  WebGLImageDataStatus status)
            : WebGLRectangleObject(width, height)
            , mWebGLFormat(webGLFormat)
            , mWebGLType(webGLType)
            , mImageDataStatus(status)
        {
            // shouldn't use this constructor to construct a null ImageInfo
            MOZ_ASSERT(status != WebGLImageDataStatus::NoImageData);
        }

        bool operator==(const ImageInfo& a) const {
            return mImageDataStatus == a.mImageDataStatus &&
                   mWidth == a.mWidth &&
                   mHeight == a.mHeight &&
                   mWebGLFormat == a.mWebGLFormat &&
                   mWebGLType == a.mWebGLType;
        }
        bool operator!=(const ImageInfo& a) const {
            return !(*this == a);
        }
        bool IsSquare() const {
            return mWidth == mHeight;
        }
        bool IsPositive() const {
            return mWidth > 0 && mHeight > 0;
        }
        bool IsPowerOfTwo() const {
            return is_pot_assuming_nonnegative(mWidth) &&
                   is_pot_assuming_nonnegative(mHeight); // negative sizes should never happen (caught in texImage2D...)
        }
        bool HasUninitializedImageData() const {
            return mImageDataStatus == WebGLImageDataStatus::UninitializedImageData;
        }
        int64_t MemoryUsage() const;
        /*! This is the format passed from JS to WebGL.
         * It can be converted to a value to be passed to driver with
         * DriverFormatsFromFormatAndType().
         */
        GLenum WebGLFormat() const { return mWebGLFormat; }
        /*! This is the type passed from JS to WebGL.
         * It can be converted to a value to be passed to driver with
         * DriverTypeFromType().
         */
        GLenum WebGLType() const { return mWebGLType; }

    protected:
        GLenum mWebGLFormat; //!< This is the WebGL/GLES format
        GLenum mWebGLType;   //!< This is the WebGL/GLES type
        WebGLImageDataStatus mImageDataStatus;

        friend class WebGLTexture;
    };

private:
    static size_t FaceForTarget(GLenum target) {
        // Call this out explicitly:
        MOZ_ASSERT(target != LOCAL_GL_TEXTURE_CUBE_MAP);
        MOZ_ASSERT(target == LOCAL_GL_TEXTURE_2D ||
                   (target >= LOCAL_GL_TEXTURE_CUBE_MAP_POSITIVE_X &&
                    target <= LOCAL_GL_TEXTURE_CUBE_MAP_NEGATIVE_Z));
        return target == LOCAL_GL_TEXTURE_2D ? 0 : target - LOCAL_GL_TEXTURE_CUBE_MAP_POSITIVE_X;
    }

    ImageInfo& ImageInfoAtFace(size_t face, GLint level) {
        MOZ_ASSERT(face < mFacesCount, "wrong face index, must be 0 for TEXTURE_2D and at most 5 for cube maps");

        // no need to check level as a wrong value would be caught by ElementAt().
        return mImageInfos.ElementAt(level * mFacesCount + face);
    }

    const ImageInfo& ImageInfoAtFace(size_t face, GLint level) const {
        return const_cast<const ImageInfo&>(
            const_cast<WebGLTexture*>(this)->ImageInfoAtFace(face, level)
        );
    }

public:
    ImageInfo& ImageInfoAt(GLenum imageTarget, GLint level) {
        MOZ_ASSERT(imageTarget);

        size_t face = FaceForTarget(imageTarget);
        return ImageInfoAtFace(face, level);
    }

    const ImageInfo& ImageInfoAt(GLenum imageTarget, GLint level) const {
        return const_cast<WebGLTexture*>(this)->ImageInfoAt(imageTarget, level);
    }

    bool HasImageInfoAt(GLenum imageTarget, GLint level) const {
        MOZ_ASSERT(imageTarget);

        size_t face = FaceForTarget(imageTarget);
        CheckedUint32 checked_index = CheckedUint32(level) * mFacesCount + face;
        return checked_index.isValid() &&
               checked_index.value() < mImageInfos.Length() &&
               ImageInfoAt(imageTarget, level).mImageDataStatus != WebGLImageDataStatus::NoImageData;
    }

    ImageInfo& ImageInfoBase() {
        return ImageInfoAtFace(0, 0);
    }

    const ImageInfo& ImageInfoBase() const {
        return ImageInfoAtFace(0, 0);
    }

    int64_t MemoryUsage() const;

    void SetImageDataStatus(GLenum imageTarget, GLint level, WebGLImageDataStatus newStatus) {
        MOZ_ASSERT(HasImageInfoAt(imageTarget, level));
        ImageInfo& imageInfo = ImageInfoAt(imageTarget, level);
        // there is no way to go from having image data to not having any
        MOZ_ASSERT(newStatus != WebGLImageDataStatus::NoImageData ||
                   imageInfo.mImageDataStatus == WebGLImageDataStatus::NoImageData);
        if (imageInfo.mImageDataStatus != newStatus) {
            SetFakeBlackStatus(WebGLTextureFakeBlackStatus::Unknown);
        }
        imageInfo.mImageDataStatus = newStatus;
    }

    void DoDeferredImageInitialization(GLenum imageTarget, GLint level);

protected:

    GLenum mTarget;
    GLenum mMinFilter, mMagFilter, mWrapS, mWrapT;

    size_t mFacesCount, mMaxLevelWithCustomImages;
    nsTArray<ImageInfo> mImageInfos;

    bool mHaveGeneratedMipmap;
    WebGLTextureFakeBlackStatus mFakeBlackStatus;

    void EnsureMaxLevelWithCustomImagesAtLeast(size_t aMaxLevelWithCustomImages) {
        mMaxLevelWithCustomImages = std::max(mMaxLevelWithCustomImages, aMaxLevelWithCustomImages);
        mImageInfos.EnsureLengthAtLeast((mMaxLevelWithCustomImages + 1) * mFacesCount);
    }

    bool CheckFloatTextureFilterParams() const {
        // Without OES_texture_float_linear, only NEAREST and NEAREST_MIMPAMP_NEAREST are supported
        return (mMagFilter == LOCAL_GL_NEAREST) &&
            (mMinFilter == LOCAL_GL_NEAREST || mMinFilter == LOCAL_GL_NEAREST_MIPMAP_NEAREST);
    }

    bool AreBothWrapModesClampToEdge() const {
        return mWrapS == LOCAL_GL_CLAMP_TO_EDGE && mWrapT == LOCAL_GL_CLAMP_TO_EDGE;
    }

    bool DoesTexture2DMipmapHaveAllLevelsConsistentlyDefined(GLenum texImageTarget) const;

public:

    void Bind(GLenum aTarget);

    void SetImageInfo(GLenum aTarget, GLint aLevel,
                      GLsizei aWidth, GLsizei aHeight,
                      GLenum aFormat, GLenum aType, WebGLImageDataStatus aStatus);

    void SetMinFilter(GLenum aMinFilter) {
        mMinFilter = aMinFilter;
        SetFakeBlackStatus(WebGLTextureFakeBlackStatus::Unknown);
    }
    void SetMagFilter(GLenum aMagFilter) {
        mMagFilter = aMagFilter;
        SetFakeBlackStatus(WebGLTextureFakeBlackStatus::Unknown);
    }
    void SetWrapS(GLenum aWrapS) {
        mWrapS = aWrapS;
        SetFakeBlackStatus(WebGLTextureFakeBlackStatus::Unknown);
    }
    void SetWrapT(GLenum aWrapT) {
        mWrapT = aWrapT;
        SetFakeBlackStatus(WebGLTextureFakeBlackStatus::Unknown);
    }
    GLenum MinFilter() const { return mMinFilter; }

    bool DoesMinFilterRequireMipmap() const {
        return !(mMinFilter == LOCAL_GL_NEAREST || mMinFilter == LOCAL_GL_LINEAR);
    }

    void SetGeneratedMipmap();

    void SetCustomMipmap();

    bool IsFirstImagePowerOfTwo() const {
        return ImageInfoBase().IsPowerOfTwo();
    }

    bool AreAllLevel0ImageInfosEqual() const;

    bool IsMipmapTexture2DComplete() const;

    bool IsCubeComplete() const;

    bool IsMipmapCubeComplete() const;

    void SetFakeBlackStatus(WebGLTextureFakeBlackStatus x);
    
    // Returns the current fake-black-status, except if it was Unknown,
    // in which case this function resolves it first, so it never returns Unknown.
    WebGLTextureFakeBlackStatus ResolvedFakeBlackStatus();
};

} // namespace mozilla

#endif
