/* -*- 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/. */

#include "WebGLContext.h"

#include "GLContext.h"
#include "WebGLBuffer.h"
#include "WebGLTransformFeedback.h"
#include "WebGLVertexArray.h"

#include "mozilla/CheckedInt.h"

namespace mozilla {

WebGLRefPtr<WebGLBuffer>*
WebGLContext::ValidateBufferSlot(const char* funcName, GLenum target)
{
    WebGLRefPtr<WebGLBuffer>* slot = nullptr;

    switch (target) {
    case LOCAL_GL_ARRAY_BUFFER:
        slot = &mBoundArrayBuffer;
        break;

    case LOCAL_GL_ELEMENT_ARRAY_BUFFER:
        slot = &(mBoundVertexArray->mElementArrayBuffer);
        break;
    }

    if (IsWebGL2()) {
        switch (target) {
        case LOCAL_GL_COPY_READ_BUFFER:
            slot = &mBoundCopyReadBuffer;
            break;

        case LOCAL_GL_COPY_WRITE_BUFFER:
            slot = &mBoundCopyWriteBuffer;
            break;

        case LOCAL_GL_PIXEL_PACK_BUFFER:
            slot = &mBoundPixelPackBuffer;
            break;

        case LOCAL_GL_PIXEL_UNPACK_BUFFER:
            slot = &mBoundPixelUnpackBuffer;
            break;

        case LOCAL_GL_TRANSFORM_FEEDBACK_BUFFER:
            slot = &(mBoundTransformFeedback->mGenericBufferBinding);
            break;

        case LOCAL_GL_UNIFORM_BUFFER:
            slot = &mBoundUniformBuffer;
            break;
        }
    }

    if (!slot) {
        ErrorInvalidEnum("%s: Bad `target`: 0x%04x", funcName, target);
        return nullptr;
    }

    return slot;
}

WebGLBuffer*
WebGLContext::ValidateBufferSelection(const char* funcName, GLenum target)
{
    const auto& slot = ValidateBufferSlot(funcName, target);
    if (!slot)
        return nullptr;
    const auto& buffer = *slot;

    if (!buffer) {
        ErrorInvalidOperation("%s: Buffer for `target` is null.", funcName);
        return nullptr;
    }

    if (target == LOCAL_GL_TRANSFORM_FEEDBACK_BUFFER) {
        if (mBoundTransformFeedback->IsActiveAndNotPaused()) {
            ErrorInvalidOperation("%s: Cannot select TRANSFORM_FEEDBACK_BUFFER when"
                                  " transform feedback is active and unpaused.",
                                  funcName);
            return nullptr;
        }
        if (buffer->IsBoundForNonTF()) {
            ErrorInvalidOperation("%s: Specified WebGLBuffer is currently bound for"
                                  " non-transform-feedback.",
                                  funcName);
            return nullptr;
        }
    } else {
        if (buffer->IsBoundForTF()) {
            ErrorInvalidOperation("%s: Specified WebGLBuffer is currently bound for"
                                  " transform feedback.",
                                  funcName);
            return nullptr;
        }
    }

    return buffer.get();
}

IndexedBufferBinding*
WebGLContext::ValidateIndexedBufferSlot(const char* funcName, GLenum target, GLuint index)
{
    decltype(mIndexedUniformBufferBindings)* bindings;
    const char* maxIndexEnum;
    switch (target) {
    case LOCAL_GL_TRANSFORM_FEEDBACK_BUFFER:
        bindings = &(mBoundTransformFeedback->mIndexedBindings);
        maxIndexEnum = "MAX_TRANSFORM_FEEDBACK_SEPARATE_ATTRIBS";
        break;

    case LOCAL_GL_UNIFORM_BUFFER:
        bindings = &mIndexedUniformBufferBindings;
        maxIndexEnum = "MAX_UNIFORM_BUFFER_BINDINGS";
        break;

    default:
        ErrorInvalidEnum("%s: Bad `target`: 0x%04x", funcName, target);
        return nullptr;
    }

    if (index >= bindings->size()) {
        ErrorInvalidValue("%s: `index` >= %s.", funcName, maxIndexEnum);
        return nullptr;
    }

    return &(*bindings)[index];
}

////////////////////////////////////////

void
WebGLContext::BindBuffer(GLenum target, WebGLBuffer* buffer)
{
    const char funcName[] = "bindBuffer";
    if (IsContextLost())
        return;

    if (buffer && !ValidateObject(funcName, *buffer))
        return;

    const auto& slot = ValidateBufferSlot(funcName, target);
    if (!slot)
        return;

    if (buffer && !buffer->ValidateCanBindToTarget(funcName, target))
        return;

    gl->MakeCurrent();
    gl->fBindBuffer(target, buffer ? buffer->mGLName : 0);

    WebGLBuffer::SetSlot(target, buffer, slot);
    if (buffer) {
        buffer->SetContentAfterBind(target);
    }

    switch (target) {
    case LOCAL_GL_PIXEL_PACK_BUFFER:
    case LOCAL_GL_PIXEL_UNPACK_BUFFER:
        gl->fBindBuffer(target, 0);
        break;
    }
}

////////////////////////////////////////

bool
WebGLContext::ValidateIndexedBufferBinding(const char* funcName, GLenum target,
                                           GLuint index,
                                           WebGLRefPtr<WebGLBuffer>** const out_genericBinding,
                                           IndexedBufferBinding** const out_indexedBinding)
{
    *out_genericBinding = ValidateBufferSlot(funcName, target);
    if (!*out_genericBinding)
        return false;

    *out_indexedBinding = ValidateIndexedBufferSlot(funcName, target, index);
    if (!*out_indexedBinding)
        return false;

    if (target == LOCAL_GL_TRANSFORM_FEEDBACK_BUFFER &&
        mBoundTransformFeedback->mIsActive)
    {
        ErrorInvalidOperation("%s: Cannot update indexed buffer bindings on active"
                              " transform feedback objects.",
                              funcName);
        return false;
    }

    return true;
}

void
WebGLContext::BindBufferBase(GLenum target, GLuint index, WebGLBuffer* buffer)
{
    const char funcName[] = "bindBufferBase";
    if (IsContextLost())
        return;

    if (buffer && !ValidateObject(funcName, *buffer))
        return;

    WebGLRefPtr<WebGLBuffer>* genericBinding;
    IndexedBufferBinding* indexedBinding;
    if (!ValidateIndexedBufferBinding(funcName, target, index, &genericBinding,
                                      &indexedBinding))
    {
        return;
    }

    if (buffer && !buffer->ValidateCanBindToTarget(funcName, target))
        return;

    ////

    gl->MakeCurrent();
    gl->fBindBufferBase(target, index, buffer ? buffer->mGLName : 0);

    ////

    WebGLBuffer::SetSlot(target, buffer, genericBinding);
    WebGLBuffer::SetSlot(target, buffer, &indexedBinding->mBufferBinding);
    indexedBinding->mRangeStart = 0;
    indexedBinding->mRangeSize = 0;

    if (buffer) {
        buffer->SetContentAfterBind(target);
    }
}

void
WebGLContext::BindBufferRange(GLenum target, GLuint index, WebGLBuffer* buffer,
                              WebGLintptr offset, WebGLsizeiptr size)
{
    const char funcName[] = "bindBufferRange";
    if (IsContextLost())
        return;

    if (buffer && !ValidateObject(funcName, *buffer))
        return;

    if (!ValidateNonNegative(funcName, "offset", offset) ||
        !ValidateNonNegative(funcName, "size", size))
    {
        return;
    }

    WebGLRefPtr<WebGLBuffer>* genericBinding;
    IndexedBufferBinding* indexedBinding;
    if (!ValidateIndexedBufferBinding(funcName, target, index, &genericBinding,
                                      &indexedBinding))
    {
        return;
    }

    if (buffer && !buffer->ValidateCanBindToTarget(funcName, target))
        return;

    if (buffer && !size) {
        ErrorInvalidValue("%s: size must be non-zero for non-null buffer.", funcName);
        return;
    }

    ////

    gl->MakeCurrent();

    switch (target) {
    case LOCAL_GL_TRANSFORM_FEEDBACK_BUFFER:
        if (offset % 4 != 0 || size % 4 != 0) {
            ErrorInvalidValue("%s: For %s, `offset` and `size` must be multiples of 4.",
                              funcName, "TRANSFORM_FEEDBACK_BUFFER");
            return;
        }
        break;

    case LOCAL_GL_UNIFORM_BUFFER:
        {
            GLuint offsetAlignment = 0;
            gl->GetUIntegerv(LOCAL_GL_UNIFORM_BUFFER_OFFSET_ALIGNMENT, &offsetAlignment);
            if (offset % offsetAlignment != 0) {
                ErrorInvalidValue("%s: For %s, `offset` must be a multiple of %s.",
                                  funcName, "UNIFORM_BUFFER",
                                  "UNIFORM_BUFFER_OFFSET_ALIGNMENT");
                return;
            }
        }
        break;
    }

    ////

    gl->fBindBufferRange(target, index, buffer ? buffer->mGLName : 0, offset, size);

    ////

    WebGLBuffer::SetSlot(target, buffer, genericBinding);
    WebGLBuffer::SetSlot(target, buffer, &indexedBinding->mBufferBinding);
    indexedBinding->mRangeStart = offset;
    indexedBinding->mRangeSize = size;

    if (buffer) {
        buffer->SetContentAfterBind(target);
    }
}

////////////////////////////////////////

void
WebGLContext::BufferDataImpl(GLenum target, size_t dataLen, const uint8_t* data,
                             GLenum usage)
{
    const char funcName[] = "bufferData";

    const auto& buffer = ValidateBufferSelection(funcName, target);
    if (!buffer)
        return;

    buffer->BufferData(target, dataLen, data, usage);
}

////

void
WebGLContext::BufferData(GLenum target, WebGLsizeiptr size, GLenum usage)
{
    const char funcName[] = "bufferData";
    if (IsContextLost())
        return;

    if (!ValidateNonNegative(funcName, "size", size))
        return;

    ////

    const auto checkedSize = CheckedInt<size_t>(size);
    if (!checkedSize.isValid())
      return ErrorOutOfMemory("%s: Size too large for platform.", funcName);
     
    const UniqueBuffer zeroBuffer(calloc(size, 1));
    if (!zeroBuffer)
        return ErrorOutOfMemory("%s: Failed to allocate zeros.", funcName);

    BufferDataImpl(target, size_t(size), (const uint8_t*)zeroBuffer.get(), usage);
}

void
WebGLContext::BufferData(GLenum target, const dom::Nullable<dom::ArrayBuffer>& maybeSrc,
                         GLenum usage)
{
    if (IsContextLost())
        return;

    if (!ValidateNonNull("bufferData", maybeSrc))
        return;
    const auto& src = maybeSrc.Value();

    src.ComputeLengthAndData();
    BufferDataImpl(target, src.LengthAllowShared(), src.DataAllowShared(), usage);
}

void
WebGLContext::BufferData(GLenum target, const dom::ArrayBufferView& src, GLenum usage,
                         GLuint srcElemOffset, GLuint srcElemCountOverride)
{
    const char funcName[] = "bufferData";
    if (IsContextLost())
        return;

    uint8_t* bytes;
    size_t byteLen;
    if (!ValidateArrayBufferView(funcName, src, srcElemOffset, srcElemCountOverride,
                                 &bytes, &byteLen))
    {
        return;
    }

    BufferDataImpl(target, byteLen, bytes, usage);
}

////////////////////////////////////////

void
WebGLContext::BufferSubDataImpl(GLenum target, WebGLsizeiptr dstByteOffset,
                                size_t dataLen, const uint8_t* data)
{
    const char funcName[] = "bufferSubData";

    if (!ValidateNonNegative(funcName, "byteOffset", dstByteOffset))
        return;

    const auto& buffer = ValidateBufferSelection(funcName, target);
    if (!buffer)
        return;

    if (!buffer->ValidateRange(funcName, dstByteOffset, dataLen))
        return;

    if (!CheckedInt<GLintptr>(dataLen).isValid()) {
        ErrorOutOfMemory("%s: Size too large.", funcName);
        return;
    }
    const GLintptr glDataLen(dataLen);

    ////

    MakeContextCurrent();
    const ScopedLazyBind lazyBind(gl, target, buffer);

    // Warning: Possibly shared memory.  See bug 1225033.
    gl->fBufferSubData(target, dstByteOffset, glDataLen, data);

    // Warning: Possibly shared memory.  See bug 1225033.
    buffer->ElementArrayCacheBufferSubData(dstByteOffset, data, size_t(glDataLen));
}

void
WebGLContext::BufferSubData(GLenum target, WebGLsizeiptr dstByteOffset,
                            const dom::ArrayBuffer& src)
{
    if (IsContextLost())
        return;

    src.ComputeLengthAndData();
    BufferSubDataImpl(target, dstByteOffset, src.LengthAllowShared(),
                      src.DataAllowShared());
}

void
WebGLContext::BufferSubData(GLenum target, WebGLsizeiptr dstByteOffset,
                            const dom::ArrayBufferView& src, GLuint srcElemOffset,
                            GLuint srcElemCountOverride)
{
    const char funcName[] = "bufferSubData";
    if (IsContextLost())
        return;

    uint8_t* bytes;
    size_t byteLen;
    if (!ValidateArrayBufferView(funcName, src, srcElemOffset, srcElemCountOverride,
                                 &bytes, &byteLen))
    {
        return;
    }

    BufferSubDataImpl(target, dstByteOffset, byteLen, bytes);
}

////////////////////////////////////////

already_AddRefed<WebGLBuffer>
WebGLContext::CreateBuffer()
{
    if (IsContextLost())
        return nullptr;

    GLuint buf = 0;
    MakeContextCurrent();
    gl->fGenBuffers(1, &buf);

    RefPtr<WebGLBuffer> globj = new WebGLBuffer(this, buf);
    return globj.forget();
}

void
WebGLContext::DeleteBuffer(WebGLBuffer* buffer)
{
    if (!ValidateDeleteObject("deleteBuffer", buffer))
        return;

    ////

    const auto fnClearIfBuffer = [&](GLenum target, WebGLRefPtr<WebGLBuffer>& bindPoint) {
        if (bindPoint == buffer) {
            WebGLBuffer::SetSlot(target, nullptr, &bindPoint);
        }
    };

    fnClearIfBuffer(0, mBoundArrayBuffer);
    fnClearIfBuffer(0, mBoundVertexArray->mElementArrayBuffer);

    for (auto& cur : mBoundVertexArray->mAttribs) {
        fnClearIfBuffer(0, cur.mBuf);
    }

    // WebGL binding points
    if (IsWebGL2()) {
        fnClearIfBuffer(0, mBoundCopyReadBuffer);
        fnClearIfBuffer(0, mBoundCopyWriteBuffer);
        fnClearIfBuffer(0, mBoundPixelPackBuffer);
        fnClearIfBuffer(0, mBoundPixelUnpackBuffer);
        fnClearIfBuffer(0, mBoundUniformBuffer);
        fnClearIfBuffer(LOCAL_GL_TRANSFORM_FEEDBACK_BUFFER,
                        mBoundTransformFeedback->mGenericBufferBinding);

        if (!mBoundTransformFeedback->mIsActive) {
            for (auto& binding : mBoundTransformFeedback->mIndexedBindings) {
                fnClearIfBuffer(LOCAL_GL_TRANSFORM_FEEDBACK_BUFFER,
                                binding.mBufferBinding);
            }
        }

        for (auto& binding : mIndexedUniformBufferBindings) {
            fnClearIfBuffer(0, binding.mBufferBinding);
        }
    }

    ////

    buffer->RequestDelete();
}

bool
WebGLContext::IsBuffer(WebGLBuffer* buffer)
{
    if (!ValidateIsObject("isBuffer", buffer))
        return false;

    MakeContextCurrent();
    return gl->fIsBuffer(buffer->mGLName);
}

} // namespace mozilla