// Copyright (c) 2023 Dominic Masters
// 
// This software is released under the MIT License.
// https://opensource.org/licenses/MIT

#include "display/shader/SimpleTexturedShader.hpp"

using namespace Dawn;

void SimpleTexturedShader::getStages(
  const enum ShaderOpenGLVariant variant,
  const struct SimpleTexturedShaderData *rel,
  std::vector<std::shared_ptr<ShaderStage>> &stages,
  std::vector<struct ShaderParameter> &parameters,
  std::vector<struct IShaderStructure> &structures
) {
  // Stages
  std::shared_ptr<ShaderStage> vertex;
  std::shared_ptr<ShaderStage> fragment;

  switch(variant) {
    case ShaderOpenGLVariant::GLSL_330_CORE:
      vertex = std::make_shared<ShaderStage>(
        ShaderStageType::VERTEX,R"(
          #version 330 core
          layout (location = 0) in vec3 aPos;
          layout (location = 1) in vec2 aTexCoord;
          uniform mat4 u_Projection;
          uniform mat4 u_View;
          uniform mat4 u_Model;
          out vec2 o_TextCoord;
          void main() {
            gl_Position = u_Projection * u_View * u_Model * vec4(aPos, 1.0);
            o_TextCoord = vec2(aTexCoord.x, aTexCoord.y);
          }
        )"
      );
      
      fragment = std::make_shared<ShaderStage>(
        ShaderStageType::FRAGMENT,R"(
          #version 330 core
          in vec2 o_TextCoord;
          out vec4 o_Color;
          uniform vec4 u_Color;
          uniform bool u_HasTexture;
          uniform sampler2D u_Texture;
          void main() {
            if(u_HasTexture) {
              o_Color = texture(u_Texture, o_TextCoord);
            } else {
              o_Color = u_Color;
            }

            if(o_Color.a == 0) discard;
          }
        )"
      );
      break;

    default:
      assertUnreachable("Unsupported ShaderOpenGLVariant");
  }

  // Add stages
  stages.push_back(vertex);
  stages.push_back(fragment);

  // Parameters
  parameters.push_back(ShaderParameter(
    "u_Projection",
    &rel->projection,
    ShaderParameterType::MAT4
  ));

  parameters.push_back(ShaderParameter(
    "u_View",
    &rel->view,
    ShaderParameterType::MAT4
  ));

  parameters.push_back(ShaderParameter(
    "u_Model",
    &rel->model,
    ShaderParameterType::MAT4
  ));

  parameters.push_back(ShaderParameter(
    "u_Color",
    &rel->color,
    ShaderParameterType::COLOR
  ));

  parameters.push_back(ShaderParameter(
    "u_HasTexture",
    &rel->hasTexture,
    ShaderParameterType::BOOLEAN
  ));

  parameters.push_back(ShaderParameter(
    "u_Texture",
    &rel->texture,
    ShaderParameterType::TEXTURE
  ));
}