#include <engine/Backend/Shader.h>
#include <engine/Backend/Camera.h>
#include <engine/Backend/Model.h>

#include <glad/glad.h>
#include <glfw/include/GLFW/glfw3.h>
#include <optional>
#include <iostream>

#include <glm/gtc/matrix_transform.hpp>

#include "engine/Backend/Backend.h"

namespace game
{
    const int SCREEN_WIDTH = 1366;
    const int SCREEN_HEIGHT = 768;

    std::optional<Shader> shader;
    std::optional<Model> model;
    std::optional<Camera> camera;

    float lastX = SCREEN_WIDTH / 2.0f;
    float lastY = SCREEN_HEIGHT / 2.0f;
    bool firstMouse = true;

    bool Init()
    {
        shader.emplace("assets/shaders/basicVertex.vert", "assets/shaders/basicFragment.frag");
        shader->Use();

        shader->setInt("ourTexture", 0);
        shader->setInt("material.diffuse", 0);
        shader->setInt("material.specular", 1);

        shader->setInt("numberOfPointLights", 1);
        shader->setInt("numberOfSpotLights", 1);

        camera.emplace(glm::vec3(0.0f, 0.0f, 0.0f));
        model.emplace("assets/models/sponza/Sponza.gltf");

        glfwSetInputMode(engine::Backend::getWindow(), GLFW_CURSOR, GLFW_CURSOR_DISABLED);
        glfwSetInputMode(engine::Backend::getWindow(), GLFW_RAW_MOUSE_MOTION, GLFW_TRUE);

        return true;
    }

    void PreFrame()
    {
        glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
        glClear(GL_COLOR_BUFFER_BIT);

        shader->Use();

        camera->Update(shader.value(), SCREEN_WIDTH, SCREEN_HEIGHT);

        shader->setFloat("material.shininess", 32.0f);

        shader->setVec3("dirLight.direction", -0.2f, -1.0f, -0.3f);
        shader->setVec3("dirLight.ambient", 0.05f, 0.05f, 0.05f);
        shader->setVec3("dirLight.diffuse", 0.8f, 0.8f, 0.8f);
        shader->setVec3("dirLight.specular", 0.8f, 0.8f, 0.8f);

        shader->setVec3("pointLights[0].position", -1.88f, 8.45f, -0.98f);
        shader->setVec3("pointLights[0].ambient", 0.05f, 0.05f, 0.05f);
        shader->setVec3("pointLights[0].diffuse", 1.0f, 0.7f, 0.4f);
        shader->setVec3("pointLights[0].specular", 1.0f, 1.0f, 1.0f);
        shader->setFloat("pointLights[0].constant", 1.0f);
        shader->setFloat("pointLights[0].linear", 0.09f);
        shader->setFloat("pointLights[0].quadratic", 0.032f);

        shader->setVec3("spotLights[0].position", camera->position);
        shader->setVec3("spotLights[0].direction", camera->front);
        shader->setVec3("spotLights[0].ambient", 0.0f, 0.0f, 0.0f);
        shader->setVec3("spotLights[0].diffuse", 1.0f, 1.0f, 1.0f);
        shader->setVec3("spotLights[0].specular", 1.0f, 1.0f, 1.0f);
        shader->setFloat("spotLights[0].constant", 1.0f);
        shader->setFloat("spotLights[0].linear", 0.09f);
        shader->setFloat("spotLights[0].quadratic", 0.032f);
        shader->setFloat("spotLights[0].cutOff", glm::cos(glm::radians(12.5f)));
        shader->setFloat("spotLights[0].outerCutOff", glm::cos(glm::radians(15.0f)));
    }

    void Render()
    {
        glm::mat4 modelTransform = glm::mat4(1.0f);
        modelTransform = glm::translate(modelTransform, glm::vec3(0.0f, 0.0f, 0.0f));
        modelTransform = glm::scale(modelTransform, glm::vec3(0.02f, 0.02f, 0.02f));
        shader->setMat4("model", modelTransform);
        model->Draw(shader.value());
    }

    void Update()
    {

    }

    void PostFrame()
    {

    }

    void Cleanup()
    {

    }
}