//
// Urho3D Engine
// Copyright (c) 2008-2011 Lasse Öörni
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
//

#include "Precompiled.h"
#include "Graphics.h"
#include "ShaderProgram.h"
#include "Texture.h"
#include "UIElement.h"

#include "DebugNew.h"

void UIBatch::Begin(PODVector<UIQuad>* quads)
{
    if (quads)
    {
        quads_ = quads;
        quadStart_ = quads_->Size();
        quadCount_ = 0;
    }
}

void UIBatch::AddQuad(UIElement& element, int x, int y, int width, int height, int texOffsetX, int texOffsetY)
{
    if (!quads_)
        return;
    
    UIQuad quad;
    const IntVector2& screenPos = element.GetScreenPosition();
    
    quad.left_ = x + screenPos.x_;
    quad.top_ = y + screenPos.y_;
    quad.right_ = quad.left_ + width;
    quad.bottom_ = quad.top_ + height;
    quad.leftUV_ = texOffsetX;
    quad.topUV_ = texOffsetY;
    quad.rightUV_ = texOffsetX + width;
    quad.bottomUV_ = texOffsetY + height;
    
    if (element.HasColorGradient())
    {
        quad.topLeftColor_ = GetInterpolatedColor(element, x, y);
        quad.topRightColor_ = GetInterpolatedColor(element, x + width, y);
        quad.bottomLeftColor_ = GetInterpolatedColor(element, x, y + height);
        quad.bottomRightColor_ = GetInterpolatedColor(element, x + width, y + height);
    }
    else
    {
        unsigned uintColor = element.GetUIntColor();
        // If alpha is 0, nothing will be rendered, so do not add the quad
        if (!(uintColor & 0xff000000))
            return;
        quad.topLeftColor_ = uintColor;
        quad.topRightColor_ = uintColor;
        quad.bottomLeftColor_ = uintColor;
        quad.bottomRightColor_ = uintColor;
    }
    
    quads_->Push(quad);
    quadCount_++;
}

void UIBatch::AddQuad(UIElement& element, int x, int y, int width, int height, int texOffsetX, int texOffsetY, int texWidth,
    int texHeight)
{
    if (!quads_)
        return;
    
    UIQuad quad;
    const IntVector2& screenPos = element.GetScreenPosition();
    
    quad.left_ = x + screenPos.x_;
    quad.top_ = y + screenPos.y_;
    quad.right_ = quad.left_ + width;
    quad.bottom_ = quad.top_ + height;
    quad.leftUV_ = texOffsetX;
    quad.topUV_ = texOffsetY;
    quad.rightUV_ = texOffsetX + texWidth;
    quad.bottomUV_ = texOffsetY + texHeight;
    
    if (element.HasColorGradient())
    {
        quad.topLeftColor_ = GetInterpolatedColor(element, x, y);
        quad.topRightColor_ = GetInterpolatedColor(element, x + width, y);
        quad.bottomLeftColor_ = GetInterpolatedColor(element, x, y + height);
        quad.bottomRightColor_ = GetInterpolatedColor(element, x + width, y + height);
    }
    else
    {
        unsigned uintColor = element.GetUIntColor();
        // If alpha is 0, nothing will be rendered, so do not add the quad
        if (!(uintColor & 0xff000000))
            return;
        quad.topLeftColor_ = uintColor;
        quad.topRightColor_ = uintColor;
        quad.bottomLeftColor_ = uintColor;
        quad.bottomRightColor_ = uintColor;
    }
    
    quads_->Push(quad);
    quadCount_++;
}

void UIBatch::AddQuad(UIElement& element, int x, int y, int width, int height, int texOffsetX, int texOffsetY, int texWidth,
    int texHeight, const Color& color)
{
    if (!quads_)
        return;
    
    UIQuad quad;
    const IntVector2& screenPos = element.GetScreenPosition();
    
    quad.left_ = x + screenPos.x_;
    quad.top_ = y + screenPos.y_;
    quad.right_ = quad.left_ + width;
    quad.bottom_ = quad.top_ + height;
    quad.leftUV_ = texOffsetX;
    quad.topUV_ = texOffsetY;
    quad.rightUV_ = texOffsetX + texWidth;
    quad.bottomUV_ = texOffsetY + texHeight;
    
    Color derivedColor(color.r_, color.g_, color.b_, color.a_ * element.GetDerivedOpacity());
    // If alpha is 0, nothing will be rendered, so exit without adding the quad
    if (derivedColor.a_ <= 0.0f)
        return;
    unsigned uintColor = derivedColor.ToUInt();
    quad.topLeftColor_ = uintColor;
    quad.topRightColor_ = uintColor;
    quad.bottomLeftColor_ = uintColor;
    quad.bottomRightColor_ = uintColor;
    
    quads_->Push(quad);
    quadCount_++;
}

bool UIBatch::Merge(const UIBatch& batch)
{
    if ((batch.blendMode_ != blendMode_) ||
        (batch.scissor_ != scissor_) ||
        (batch.texture_ != texture_) ||
        (batch.quads_ != quads_) ||
        (batch.quadStart_ != quadStart_ + quadCount_))
        return false;
    
    quadCount_ += batch.quadCount_;
    return true;
}

void UIBatch::Draw(Graphics* graphics, ShaderProgram* vs, ShaderProgram* ps) const
{
    if ((!quads_) || (!quadCount_))
        return;
    
    // Use alpha test if not alpha blending
    if ((blendMode_ != BLEND_ALPHA) && (blendMode_ != BLEND_ADDALPHA) && (blendMode_ != BLEND_PREMULALPHA))
        graphics->SetAlphaTest(true, CMP_GREATEREQUAL, 0.5f);
    else
        graphics->SetAlphaTest(false);
    
    graphics->SetBlendMode(blendMode_);
    graphics->SetScissorTest(true, scissor_);
    graphics->SetTexture(0, texture_);
    graphics->SetShaders(vs, ps);
    
    Vector2 posAdjust(0.5f, 0.5f);
    Vector2 invScreenSize(1.0f / (float)graphics->GetWidth(), 1.0f / (float)graphics->GetHeight());
    
    const PODVector<UIQuad>& quads = *quads_;
    
    if (texture_)
    {
        Vector2 invTextureSize(1.0f / (float)texture_->GetWidth(), 1.0f / (float)texture_->GetHeight());
        
        graphics->BeginImmediate(TRIANGLE_LIST, quadCount_ * 6, MASK_POSITION | MASK_COLOR | MASK_TEXCOORD1);
        float* dest = (float*)graphics->GetImmediateDataPtr();
        
        for (unsigned i = quadStart_; i < quadStart_ + quadCount_; ++i)
        {
            const UIQuad& quad = quads[i];
            Vector2 topLeft, bottoright_, topLeftUV, bottorightUV_;
            
            topLeft = (Vector2((float)quad.left_, (float)quad.top_) - posAdjust) * invScreenSize;
            bottoright_ = (Vector2((float)quad.right_, (float)quad.bottom_) - posAdjust) * invScreenSize;
            topLeftUV = Vector2((float)quad.leftUV_, (float)quad.topUV_) * invTextureSize;
            bottorightUV_ = Vector2((float)quad.rightUV_, (float)quad.bottomUV_) * invTextureSize;
            
            *dest++ = topLeft.x_; *dest++ = topLeft.y_; *dest++ = 0.0f;
            *((unsigned*)dest) = quads[i].topLeftColor_; dest++;
            *dest++ = topLeftUV.x_; *dest++ = topLeftUV.y_;
            
            *dest++ = bottoright_.x_; *dest++ = topLeft.y_; *dest++ = 0.0f;
            *((unsigned*)dest) = quads[i].topRightColor_; dest++;
            *dest++ = bottorightUV_.x_; *dest++ = topLeftUV.y_;
            
            *dest++ = topLeft.x_; *dest++ = bottoright_.y_; *dest++ = 0.0f;
            *((unsigned*)dest) = quads[i].bottomLeftColor_; dest++;
            *dest++ = topLeftUV.x_; *dest++ = bottorightUV_.y_;
            
            *dest++ = bottoright_.x_; *dest++ = topLeft.y_; *dest++ = 0.0f;
            *((unsigned*)dest) = quads[i].topRightColor_; dest++;
            *dest++ = bottorightUV_.x_; *dest++ = topLeftUV.y_;
            
            *dest++ = bottoright_.x_; *dest++ = bottoright_.y_; *dest++ = 0.0f;
            *((unsigned*)dest) = quads[i].bottomRightColor_; dest++;
            *dest++ = bottorightUV_.x_; *dest++ = bottorightUV_.y_;
            
            *dest++ = topLeft.x_; *dest++ = bottoright_.y_; *dest++ = 0.0f;
            *((unsigned*)dest) = quads[i].bottomLeftColor_; dest++;
            *dest++ = topLeftUV.x_; *dest++ = bottorightUV_.y_;
        }
        
        graphics->EndImmediate();
    }
    else
    {
        graphics->BeginImmediate(TRIANGLE_LIST, quadCount_ * 6, MASK_POSITION | MASK_COLOR);
        float* dest = (float*)graphics->GetImmediateDataPtr();
        
        for (unsigned i = quadStart_; i < quadStart_ + quadCount_; ++i)
        {
            const UIQuad& quad = quads[i];
            Vector2 topLeft, bottoright_, topLeftUV, bottorightUV_;
            
            topLeft = (Vector2((float)quad.left_, (float)quad.top_) - posAdjust) * invScreenSize;
            bottoright_ = (Vector2((float)quad.right_, (float)quad.bottom_) - posAdjust) * invScreenSize;
            
            *dest++ = topLeft.x_; *dest++ = topLeft.y_; *dest++ = 0.0f;
            *((unsigned*)dest) = quads[i].topLeftColor_; dest++;
            
            *dest++ = bottoright_.x_; *dest++ = topLeft.y_; *dest++ = 0.0f;
            *((unsigned*)dest) = quads[i].topRightColor_; dest++;
            
            *dest++ = topLeft.x_; *dest++ = bottoright_.y_; *dest++ = 0.0f;
            *((unsigned*)dest) = quads[i].bottomLeftColor_; dest++;
            
            *dest++ = bottoright_.x_; *dest++ = topLeft.y_; *dest++ = 0.0f;
            *((unsigned*)dest) = quads[i].topRightColor_; dest++;
            
            *dest++ = bottoright_.x_; *dest++ = bottoright_.y_; *dest++ = 0.0f;
            *((unsigned*)dest) = quads[i].bottomRightColor_; dest++;
            
            *dest++ = topLeft.x_; *dest++ = bottoright_.y_; *dest++ = 0.0f;
            *((unsigned*)dest) = quads[i].bottomLeftColor_; dest++;
        }
        
        graphics->EndImmediate();
    }
}

void UIBatch::AddOrMerge(const UIBatch& batch, PODVector<UIBatch>& batches)
{
    if (!batch.quadCount_)
        return;
    
    if (!batches.Size())
        batches.Push(batch);
    else
    {
        if (batches.Back().Merge(batch))
            return;
        else
            batches.Push(batch);
    }
}

unsigned UIBatch::GetInterpolatedColor(UIElement& element, int x, int y)
{
    const IntVector2& size = element.GetSize();
    
    if ((size.x_) && (size.y_))
    {
        float cLerpX = Clamp((float)x / (float)size.x_, 0.0f, 1.0f);
        float cLerpY = Clamp((float)y / (float)size.y_, 0.0f, 1.0f);
        
        Color topColor = element.GetColor(C_TOPLEFT).Lerp(element.GetColor(C_TOPRIGHT), cLerpX);
        Color bottocolor_ = element.GetColor(C_BOTTOMLEFT).Lerp(element.GetColor(C_BOTTOMRIGHT), cLerpX);
        Color color = topColor.Lerp(bottocolor_, cLerpY);
        color.a_ *= element.GetDerivedOpacity();
        return color.ToUInt();
    }
    else
    {
        Color color = element.GetColor(C_TOPLEFT);
        color.a_ *= element.GetDerivedOpacity();
        return color.ToUInt();
    }
}