#include <math.h>
#include <stdio.h>
#include <string.h>

#include "imgui.h"
#include "imgui_impl_glfw.h"
#include "imgui_impl_opengl3.h"

#include <glad/glad.h>
#include <GLFW/glfw3.h>

static void error_callback(int error, const char* description)
{
   fprintf(stderr, "Error %d: %s\n", error, description);
}

int main(int argc, char** argv)
{
    GLFWwindow* window;

    /* Initialize the library */
    glfwSetErrorCallback(error_callback);
    if (!glfwInit()) {
       fprintf(stdout, "[GFLW] Error: failed to init!\n");
       return -1;
    }

    /* Create a windowed mode window and its OpenGL context */
    glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
    glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 0);
    window = glfwCreateWindow(1024, 768, "Client", NULL, NULL);
    glfwSetWindowAttrib(window, GLFW_DECORATED, GLFW_TRUE);
    if (!window) {
        glfwTerminate();
        return -1;
    }
    glfwMakeContextCurrent(window);
    glfwSwapInterval(1); // Vsync

    if (!gladLoadGL()) {
       fprintf(stderr, "[GLAD] Error loading\n");
       return 1;
    }

    // Setup Dear ImGui context
    IMGUI_CHECKVERSION();
    ImGui::CreateContext();
    ImGuiIO& io = ImGui::GetIO(); (void)io;
    //io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;     // Enable Keyboard Controls
    //io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad;      // Enable Gamepad Controls

    // Setup Dear ImGui style
    ImGui::StyleColorsDark();
    //ImGui::StyleColorsClassic();

    // Setup Platform/Renderer bindings
    ImGui_ImplGlfw_InitForOpenGL(window, true);
    ImGui_ImplOpenGL3_Init("#version 130");

    int height = 0, width = 0;
    ImVec4 clear_color = ImVec4(0.45f, 0.55f, 0.60f, 1.00f);
    while(!glfwWindowShouldClose(window)) {
       glfwPollEvents();
       // Process input.

       // Start the Dear ImGui frame
       ImGui_ImplOpenGL3_NewFrame();
       ImGui_ImplGlfw_NewFrame();
       ImGui::NewFrame();

       {
          static float f = 0.0f;
          static int counter = 0;

          ImGui::Begin("Hello, world!");                          // Create a window called "Hello, world!" and append into it.

          ImGui::Text("This is some useful text.");               // Display some text (you can use a format strings too)

          ImGui::SliderFloat("float", &f, 0.0f, 1.0f);            // Edit 1 float using a slider from 0.0f to 1.0f
          ImGui::ColorEdit3("clear color", (float*)&clear_color); // Edit 3 floats representing a color

          if (ImGui::Button("Button")) {                            // Buttons return true when clicked (most widgets return true when edited/activated)
             counter++;
          }
          ImGui::SameLine();
          ImGui::Text("counter = %d", counter);

          ImGui::Text("Application average %.3f ms/frame (%.1f FPS)", 1000.0f / ImGui::GetIO().Framerate, ImGui::GetIO().Framerate);
          ImGui::End();
       }
       // @TODO Game tick

       // Rendering
       ImGui::Render();
       int display_w, display_h;
       glfwGetFramebufferSize(window, &display_w, &display_h);
       glViewport(0, 0, display_w, display_h);
       glClearColor(clear_color.x, clear_color.y, clear_color.z, clear_color.w);
       glClear(GL_COLOR_BUFFER_BIT);
       ImGui_ImplOpenGL3_RenderDrawData(ImGui::GetDrawData());
       glfwSwapBuffers(window);
    }

    // Cleanup
    ImGui_ImplOpenGL3_Shutdown();
    ImGui_ImplGlfw_Shutdown();
    ImGui::DestroyContext();

    glfwTerminate();
    return 0;
}