#include "common.hpp"
#include "ui.hpp"

#include <imgui.h>
#include <imgui_impl_glfw.h>
#include <imgui_impl_opengl3.h>
#include <imgui_impl_opengl3_loader.h>
#include <cstdio>
#include <stdexcept>

// Different packaging defines this inconsistently, e.g. Xrepo but not most Linux distros
// We need it, so define just in case
#define GLFW_INCLUDE_NONE
#include <GLFW/glfw3.h>
#include <GLFW/glfw3native.h>

static void glfw_error_handler(int err, const char* desc) {
    fprintf(stderr, MSG_ERROR "GLFW error %d: %s", err, desc);
}

static const char* imgui_glsl_version = nullptr;

struct GlfwInit {
    GlfwInit() {
        if (!glfwInit()) {
            throw std::runtime_error("failed to init GLFW");
        }
        glfwSetErrorCallback(&glfw_error_handler);

// Decide GL+GLSL versions
#if defined(IMGUI_IMPL_OPENGL_ES2)
        // GL ES 2.0 + GLSL 100
        imgui_glsl_version = "#version 100";
        glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 2);
        glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 0);
        glfwWindowHint(GLFW_CLIENT_API, GLFW_OPENGL_ES_API);
#elif defined(__APPLE__)
        // GL 3.2 + GLSL 150
        imgui_glsl_version = "#version 150";
        glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
        glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 2);
        glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE); // 3.2+ only
        glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE); // Required on Mac
#else
        // GL 3.0 + GLSL 130
        imgui_glsl_version = "#version 130";
        glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
        glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 0);
#endif
    }

    ~GlfwInit() {
        glfwTerminate();
    }
};

struct GlfwWindow {
    GLFWwindow* _h;

    GlfwWindow(int width, int height, const char* title) {
        _h = glfwCreateWindow(width, height, title, nullptr, nullptr);
        if (_h == nullptr)
            throw std::runtime_error("failed to create GLFW window");
    }

    ~GlfwWindow() {
        glfwDestroyWindow(_h);
    }
};

struct ImGuiInit {
    ImGuiInit(GLFWwindow* window) {
        IMGUI_CHECKVERSION();
        ImGui::CreateContext();

        ImGui_ImplGlfw_InitForOpenGL(window, true);
        ImGui_ImplOpenGL3_Init("#version 130");
    }

    ~ImGuiInit() {
        ImGui_ImplOpenGL3_Shutdown();
        ImGui_ImplGlfw_Shutdown();

        ImGui::DestroyContext();
    }
};

int main() {
    GlfwInit i_glfw;

    GlfwWindow i_window(1280, 730, "Sand Physics");
    GLFWwindow* window = i_window._h;

    glfwMakeContextCurrent(window);
    // V-sync to make timing easier, we don't really care about latency
    glfwSwapInterval(1);

    ImGuiInit i_imgui(window);

    ImVec4 bg_col(1.0f, 1.0f, 1.0f, 1.0f);
    bg_col.x *= bg_col.w;
    bg_col.y *= bg_col.w;
    bg_col.z *= bg_col.w;

    while (!glfwWindowShouldClose(window)) {
        glfwPollEvents();

        ImGui_ImplOpenGL3_NewFrame();
        ImGui_ImplGlfw_NewFrame();
        ImGui::NewFrame();

        ShowEverything();

        ImGui::Render();
        int display_w, display_h;
        glfwGetFramebufferSize(window, &display_w, &display_h);
        glViewport(0, 0, display_w, display_h);
        glClearColor(bg_col.x * bg_col.w, bg_col.y * bg_col.w, bg_col.z * bg_col.w, bg_col.w);
        glClear(GL_COLOR_BUFFER_BIT);
        ImGui_ImplOpenGL3_RenderDrawData(ImGui::GetDrawData());

        glfwSwapBuffers(window);
    }
}