/*
 * Copyright (c) 2020 Samsung Electronics Co., Ltd.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 */

#include <dali-toolkit/dali-toolkit.h>
#include <dali-toolkit/devel-api/controls/tool-bar/tool-bar.h>
#include <dali/devel-api/adaptor-framework/file-stream.h>
#include <dali/integration-api/debug.h>
#include <stdio.h>
#include "shared/utility.h"
#include "shared/view.h"

using namespace Dali;
using Dali::Toolkit::Control;
using Dali::Toolkit::TextLabel;
using Dali::Toolkit::ToolBar;

const char* BACKGROUND_IMAGE("");
const char* TOOLBAR_IMAGE(DEMO_IMAGE_DIR "top-bar.png");
const char* APPLICATION_TITLE("Ray Marching");
const char* SHADER_NAME("raymarch_sphere_shaded");

/**
 * @brief LoadShaderCode
 * @param filename
 * @param output
 * @return
 */
bool LoadShaderCode(const char* path, const char* filename, std::vector<char>& output)
{
  std::string fullpath(path);
  fullpath += filename;

  Dali::FileStream fileStream(fullpath, Dali::FileStream::READ | Dali::FileStream::BINARY);
  FILE*            file = fileStream.GetFile();
  if(!file)
  {
    return false;
  }

  bool retValue = false;
  if(!fseek(file, 0, SEEK_END))
  {
    long int size = ftell(file);

    if((size != -1L) &&
       (!fseek(file, 0, SEEK_SET)))
    {
      output.resize(size + 1);
      std::fill(output.begin(), output.end(), 0);
      ssize_t result = fread(output.data(), size, 1, file);

      retValue = (result >= 0);
    }
  }

  return retValue;
}

/**
 * @brief LoadShaders
 * @param shaderName
 * @return
 */
Shader LoadShaders(const std::string& shaderName)
{
  std::vector<char> bufV, bufF;
  std::string       shaderVSH(shaderName);
  std::string       shaderFSH(shaderName);
  shaderVSH += ".vsh";
  shaderFSH += ".fsh";

  Shader shader;
  if(LoadShaderCode(DEMO_SHADER_DIR, shaderVSH.c_str(), bufV) &&
     LoadShaderCode(DEMO_SHADER_DIR, shaderFSH.c_str(), bufF))
  {
    shader = Shader::New(bufV.data(), bufF.data());
  }
  return shader;
}

// This example shows how to create a Ray Marching using a shader
//
class RayMarchingExample : public ConnectionTracker
{
public:
  RayMarchingExample(Application& application)
  : mApplication(application)
  {
    // Connect to the Application's Init signal
    mApplication.InitSignal().Connect(this, &RayMarchingExample::Create);
  }

  ~RayMarchingExample()
  {
    // Nothing to do here;
  }

  // The Init signal is received once (only) during the Application lifetime
  void Create(Application& application)
  {
    // Get a handle to the window
    Window window = application.GetWindow();

    window.GetRootLayer().TouchedSignal().Connect(this, &RayMarchingExample::OnTouch);

    window.KeyEventSignal().Connect(this, &RayMarchingExample::OnKeyEvent);

    window.SetBackgroundColor(Color::YELLOW);

    // Creates a default view with a default tool bar.
    // The view is added to the window.
    mContentLayer = DemoHelper::CreateView(application,
                                           mView,
                                           mToolBar,
                                           BACKGROUND_IMAGE,
                                           TOOLBAR_IMAGE,
                                           APPLICATION_TITLE);

    // Add an extra space on the right to center the title text.
    mToolBar.AddControl(Actor::New(), DemoHelper::DEFAULT_VIEW_STYLE.mToolBarButtonPercentage, Toolkit::Alignment::HORIZONTAL_RIGHT);

    AddContentLayer();
  }
  bool OnTouch(Actor actor, const TouchEvent& touch)
  {
    // quit the application
    mApplication.Quit();
    return true;
  }

  /**
   * Main key event handler
   */
  void OnKeyEvent(const KeyEvent& event)
  {
    if(event.GetState() == KeyEvent::DOWN)
    {
      if(IsKey(event, Dali::DALI_KEY_ESCAPE) || IsKey(event, Dali::DALI_KEY_BACK))
      {
        mApplication.Quit();
      }
    }
  }

  /**
   * Creates quad renderer
   */
  Renderer CreateQuadRenderer()
  {
    // Create shader & geometry needed by Renderer
    Shader shader = LoadShaders(SHADER_NAME);

    Property::Map vertexFormat;
    vertexFormat["aPosition"] = Property::VECTOR2;
    VertexBuffer vertexBuffer = VertexBuffer::New(vertexFormat);

    const float   P(0.5f);
    const Vector2 vertices[] = {
      Vector2(-P, -P),
      Vector2(+P, -P),
      Vector2(-P, +P),
      Vector2(+P, +P)};

    vertexBuffer.SetData(vertices, 4);

    // Instantiate quad geometry
    Geometry geometry = Geometry::New();
    geometry.AddVertexBuffer(vertexBuffer);
    geometry.SetType(Geometry::TRIANGLE_STRIP);

    // Create renderer
    Renderer renderer = Renderer::New(geometry, shader);

    renderer.RegisterProperty("uRadius", 0.0f);
    renderer.RegisterProperty("uAdjuster", -4.0f);

    //  Animate the sphere radius uniform and a generic uAdjust uniform currently used to move the light around
    Animation animation = Animation::New(8.0f);
    animation.AnimateTo(Property(renderer, "uRadius"), 1.2f, AlphaFunction::BOUNCE);
    animation.AnimateTo(Property(renderer, "uAdjuster"), 4.0f, AlphaFunction::BOUNCE);
    animation.SetLooping(true);
    animation.Play();

    return renderer;
  }

  void AddContentLayer()
  {
    Window window = mApplication.GetWindow();

    //Create all the renderers
    Renderer renderer = CreateQuadRenderer();

    Actor actor = Actor::New();
    actor.AddRenderer(renderer);

    actor.SetProperty(Actor::Property::ANCHOR_POINT, Dali::AnchorPoint::CENTER);
    actor.SetProperty(Actor::Property::PARENT_ORIGIN, Dali::ParentOrigin::CENTER);
    actor.SetResizePolicy(Dali::ResizePolicy::FILL_TO_PARENT, Dali::Dimension::ALL_DIMENSIONS);

    mContentLayer.Add(actor);
  }

private:
  Application& mApplication;
  Control      mView;
  Layer        mContentLayer;
  ToolBar      mToolBar;
};

int DALI_EXPORT_API main(int argc, char** argv)
{
  Application        application = Application::New(&argc, &argv);
  RayMarchingExample test(application);
  application.MainLoop();
  return 0;
}