//
// Copyright (c) 2008-2013 the Urho3D project.
//
// 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 "Context.h"
#include "Deserializer.h"
#include "FileSystem.h"
#include "Graphics.h"
#include "Log.h"
#include "Profiler.h"
#include "ResourceCache.h"
#include "Shader.h"
#include "ShaderVariation.h"
#include "XMLFile.h"

#include "DebugNew.h"

namespace Urho3D
{

Shader::Shader(Context* context) :
    Resource(context),
    vsSourceCodeLength_(0),
    psSourceCodeLength_(0)
{
}

Shader::~Shader()
{
    ResourceCache* cache = GetSubsystem<ResourceCache>();
    if (cache)
        cache->ResetDependencies(this);
}

void Shader::RegisterObject(Context* context)
{
    context->RegisterFactory<Shader>();
}

bool Shader::Load(Deserializer& source)
{
    PROFILE(LoadShader);
    
    Graphics* graphics = GetSubsystem<Graphics>();
    if (!graphics)
        return false;
    
    vsSourceCodeLength_ = 0;
    psSourceCodeLength_ = 0;
    
    SharedPtr<XMLFile> xml(new XMLFile(context_));
    if (!xml->Load(source))
        return false;

    XMLElement shaders = xml->GetRoot("shaders");
    if (!shaders)
    {
        LOGERROR("No shaders element in " + source.GetName());
        return false;
    }
    
    {
        PROFILE(ParseShaderDefinition);
        
        if (!vsParser_.Parse(VS, shaders))
        {
            LOGERROR("VS: " + vsParser_.GetErrorMessage());
            return false;
        }
        if (!psParser_.Parse(PS, shaders))
        {
            LOGERROR("PS: " + psParser_.GetErrorMessage());
            return false;
        }
    }
    
    String path, fileName, extension;
    SplitPath(GetName(), path, fileName, extension);
    
    {
        PROFILE(LoadShaderSource);
        
        if (!ProcessSource(vsSourceCode_, vsSourceCodeLength_, path + fileName + ".vert"))
            return false;
        if (!ProcessSource(psSourceCode_, psSourceCodeLength_, path + fileName + ".frag"))
            return false;
    }
    
    // If variations had already been created, release them and set new source code
    /// \todo Should also update defines
    for (HashMap<StringHash, SharedPtr<ShaderVariation> >::Iterator i = vsVariations_.Begin(); i != vsVariations_.End(); ++i)
    {
        i->second_->Release();
        i->second_->SetSourceCode(vsSourceCode_, vsSourceCodeLength_);
    }
    for (HashMap<StringHash, SharedPtr<ShaderVariation> >::Iterator i = psVariations_.Begin(); i != psVariations_.End(); ++i)
    {
        i->second_->Release();
        i->second_->SetSourceCode(psSourceCode_, psSourceCodeLength_);
    }
    
    SetMemoryUse(sizeof(Shader) + 2 * sizeof(ShaderParser) + (vsVariations_.Size() + psVariations_.Size()) *
        sizeof(ShaderVariation));
    
    return true;
}

ShaderVariation* Shader::GetVariation(ShaderType type, const String& name)
{
    StringHash nameHash(name);
    
    if (type == VS)
    {
        if (vsParser_.HasCombination(name))
        {
            HashMap<StringHash, SharedPtr<ShaderVariation> >::Iterator i = vsVariations_.Find(nameHash);
            // Create the shader variation now if not created yet
            if (i == vsVariations_.End())
            {
                ShaderCombination combination = vsParser_.GetCombination(name);
                
                i = vsVariations_.Insert(MakePair(nameHash, SharedPtr<ShaderVariation>(new ShaderVariation(this, VS))));
                
                String path, fileName, extension;
                SplitPath(GetName(), path, fileName, extension);
                String fullName = path + fileName + "_" + name;
                if (fullName.EndsWith("_"))
                    fullName.Resize(fullName.Length() - 1);
                
                i->second_->SetName(fullName);
                i->second_->SetSourceCode(vsSourceCode_, vsSourceCodeLength_);
                i->second_->SetDefines(combination.defines_, combination.defineValues_);
                
                SetMemoryUse(GetMemoryUse() + sizeof(ShaderVariation));
            }
            
            return i->second_;
        }
        else
            return 0;
    }
    else
    {
        if (psParser_.HasCombination(name))
        {
            HashMap<StringHash, SharedPtr<ShaderVariation> >::Iterator i = psVariations_.Find(nameHash);
            // Create the shader variation now if not created yet
            if (i == psVariations_.End())
            {
                ShaderCombination combination = psParser_.GetCombination(name);
                
                i = psVariations_.Insert(MakePair(nameHash, SharedPtr<ShaderVariation>(new ShaderVariation(this, PS))));
                
                String path, fileName, extension;
                SplitPath(GetName(), path, fileName, extension);
                String fullName = path + fileName + "_" + name;
                if (fullName.EndsWith("_"))
                    fullName.Resize(fullName.Length() - 1);
                
                i->second_->SetName(fullName);
                i->second_->SetSourceCode(psSourceCode_, psSourceCodeLength_);
                i->second_->SetDefines(combination.defines_, combination.defineValues_);
                
                SetMemoryUse(GetMemoryUse() + sizeof(ShaderVariation));
            }
            
            return i->second_;
        }
        else
            return 0;
    }
}

bool Shader::ProcessSource(SharedArrayPtr<char>& dest, unsigned& length, const String& fileName)
{
    ResourceCache* cache = GetSubsystem<ResourceCache>();
    if (!cache)
        return false;
    
    // Allow to define only a vertex shader or only a pixel shader
    if (!cache->Exists(fileName))
        return true;
    
    cache->StoreResourceDependency(this, fileName);
    
    Vector<String> glslCode;
    
    // Load the shader source code
    SharedPtr<File> glslFile = cache->GetFile(fileName);
    if (!glslFile)
        return false;
    
    while (!glslFile->IsEof())
        glslCode.Push(glslFile->ReadLine());
    
    // Process the code for includes
    for (unsigned i = 0; i < glslCode.Size(); ++i)
    {
        if (glslCode[i].StartsWith("#include"))
        {
            String includeFileName = GetPath(fileName) + glslCode[i].Substring(9).Replaced("\"", "").Trimmed();
            
            SharedPtr<File> glslIncludeFile = cache->GetFile(includeFileName);
            if (!glslIncludeFile)
                return false;
            
            // Remove the #include line, then include the code
            glslCode.Erase(i);
            unsigned pos = i;
            while (!glslIncludeFile->IsEof())
            {
                glslCode.Insert(pos, glslIncludeFile->ReadLine());
                ++pos;
            }
            // Finally insert an empty line to mark the space between files
            glslCode.Insert(pos, "");
        }
    }
    
    // Copy the final code into one memory block
    length = 0;
    for (unsigned i = 0; i < glslCode.Size(); ++i)
        length += glslCode[i].Length() + 1;
    
    dest = new char[length];
    char* destPtr = dest.Get();
    for (unsigned i = 0; i < glslCode.Size(); ++i)
    {
        memcpy(destPtr, glslCode[i].CString(), glslCode[i].Length());
        destPtr += glslCode[i].Length();
        *destPtr++ = '\n';
    }
    
    return true;
}

}