#include "glad/gl.h"
#include "GLFW/glfw3.h"

#include "spdlog/spdlog.h"

#include "glm/glm.hpp"
#include "glm/ext/matrix_clip_space.hpp"

#define STB_IMAGE_IMPLEMENTATION
#include "AssetRegistry.h"
#include "stb_image.h"

#include "Camera.h"
#include "Components.h"
#include "EditorContext.h"
#include "FreeCameraController.h"
#include "InputManager.h"
#include "ModelManager.h"
#include "ProjectManifest.h"
#include "ProjectManifestFile.h"
#include "Scene.h"
#include "ShaderManager.h"
#include "ShaderProgram.h"
#include "TextureManager.h"

#include "UIManager.h"
#include "ui/UIEntityInspector.h"
#include "ui/UIMenuBar.h"
#include "ui/UISceneGraph.h"
#include "ui/UISceneViewer.h"

#include <filesystem>

const char* B_ENGINE_VERSION = "v0.0.3";

GLFWwindow* gWindow = nullptr;
int gWindowWidth = 1920;
int gWindowHeight = 1080;

int glVersionMajor = 0;
int glVersionMinor = 0;

float gAspectRatio = 0.f;

float gMouseSensitivity = 0.1f;

std::unique_ptr<ProjectManifest> gCurrentProject {nullptr};

Scene gScene{};
EditorContext gEditorCtx{};

Camera gCamera {};
FreeCameraController gEditorCameraController{};

void glfw_error_callback(int error, const char* description);
void glfw_key_callback(GLFWwindow* window, int key, int scancode, int action, int mods);
void glfw_framebuffer_size_callback(GLFWwindow* window, int width, int height);

void init_glfw();
void create_main_window();
void load_gl();
void load_inputs();
void init_editor_camera();
void loop();

void create_entity(entt::entity parent);
void open_project(std::string_view _path);

auto xAxis = glm::vec3{1.f, 0.f, 0.f};
auto yAxis = glm::vec3{0.f, 1.f, 0.f};
auto zAxis = glm::vec3{0.f, 0.f, 1.f};

int main() {
    spdlog::info("b_engine {} start", B_ENGINE_VERSION);

    init_glfw();

    create_main_window();

    load_gl();

    stbi_set_flip_vertically_on_load(true);

    load_inputs();

    UIManager::init(gWindow);
    auto* menuBar = UIManager::add_ui_panel<UIMenuBar>("menu_bar");
    menuBar->create_entity = create_entity;
    menuBar->open_project = open_project;
    UIManager::add_ui_panel<UISceneViewer>("scene_viewer");
    UIManager::add_ui_panel<UISceneGraph>("scene_graph");
    UIManager::add_ui_panel<UIEntityInspector>("entity_inspector");

    gEditorCameraController.set_camera(gCamera);
    gEditorCameraController.look_sensitivity = 0.2;
    gEditorCameraController.movement_speed = 0.2;
    InputManager::add_mouse_listener([](float xoff, float yoff) {
        gEditorCameraController.on_mouse_delta(xoff, yoff);
    });

    gEditorCtx.scene = &gScene;
    gEditorCtx.window = gWindow;
    gEditorCtx.selectedEntity = entt::null;

    loop();

    ShaderManager::shaders.clear();
    TextureManager::textures.clear();
    ModelManager::models.clear();

    glfwDestroyWindow(gWindow);
    glfwTerminate();

    return 0;
}

void glfw_error_callback(int error, const char* description) {
    spdlog::error("glfw error: {}", description);
}

void glfw_framebuffer_size_callback(GLFWwindow *window, int width, int height) {
    glViewport(0, 0, width, height);
    gAspectRatio = (float)width / (float)height;
    gCamera.update_aspect_ratio(gAspectRatio);
}

void init_glfw() {
    if (!glfwInit()) {
        spdlog::error("could not initialize glfw");
        std::exit(1);
    }

    glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 4);
    glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 0);
    glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
    glfwWindowHint(GLFW_SAMPLES, 4);

    glfwSetErrorCallback(glfw_error_callback);
}

void create_main_window()
{
    std::string title = fmt::format("b_engine {}", B_ENGINE_VERSION);
    gWindow = glfwCreateWindow(gWindowWidth, gWindowHeight, title.c_str(), nullptr, nullptr);
    if (!gWindow) {
        spdlog::error("failed to create glfw window");
        std::exit(1);
    }

    glfwMakeContextCurrent(gWindow);

    glfwSetKeyCallback(gWindow, InputManager::key_callback);
    glfwSetCursorPosCallback(gWindow, InputManager::mouse_pos_callback);

    glfwSetFramebufferSizeCallback(gWindow, glfw_framebuffer_size_callback);
}

void load_gl()
{
    int version = gladLoadGL(glfwGetProcAddress);
    glVersionMajor = GLAD_VERSION_MAJOR(version);
    glVersionMinor = GLAD_VERSION_MINOR(version);
    spdlog::info("gl version {}.{}", glVersionMajor, glVersionMinor);

    if (gWindow)
    {
        int fbWidth, fbHeight;
        glfwGetFramebufferSize(gWindow, &fbWidth, &fbHeight);
        gAspectRatio = (float)fbWidth / (float)fbHeight;
    }

    glEnable(GL_DEPTH_TEST);
    glEnable(GL_MULTISAMPLE);
}

void init_editor_camera() {
    gCamera = {{10.f, 10.f, 10.f}, 0, 0, gAspectRatio};
    gCamera.rotate_yaw(-135.f);
    gCamera.rotate_pitch(-35.f);
}

void load_inputs() {
    InputManager::generate_input_action("move_forward", {{GLFW_KEY_W, KEY_DOWN}});
    InputManager::generate_input_action("move_backward", {{GLFW_KEY_S, KEY_DOWN}});
    InputManager::generate_input_action("move_right", {{GLFW_KEY_D, KEY_DOWN}});
    InputManager::generate_input_action("move_left", {{GLFW_KEY_A, KEY_DOWN}});
    InputManager::generate_input_action("move_up", {{GLFW_KEY_SPACE, KEY_DOWN}});
    InputManager::generate_input_action("move_down", {{GLFW_KEY_LEFT_SHIFT, KEY_DOWN}});
}

void loop() {
    while (!glfwWindowShouldClose(gWindow)) {
        // input
        glfwPollEvents();

        // update
        UIManager::update(gEditorCtx);
        gEditorCameraController.update(gEditorCtx);

        if (gCamera.aspect_ratio() != gEditorCtx.viewportAspectRatio) {
            gCamera.update_aspect_ratio(gEditorCtx.viewportAspectRatio);
        }

        gScene.update_transforms();

        const auto* uiScenePanel = dynamic_cast<UISceneViewer*>(UIManager::get_ui_panel("scene_viewer").get());
        if (uiScenePanel) {
            uiScenePanel->bind_fbo();
        }

        // draw
        glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
        glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

        // const auto shader = ShaderManager::shaders["phong_shader"];
        // gScene.draw_scene(shader.get());

        glBindVertexArray(0);
        ShaderProgram::unbind();
        glBindFramebuffer(GL_FRAMEBUFFER, 0);

        UIManager::draw();

        // end frame
        glfwSwapBuffers(gWindow);
    }
}

void create_entity(entt::entity parent) {
    gScene.create_game_object(parent);
}

void open_project(std::string_view _path) {
    const std::filesystem::path projectFilePath {_path};
    gCurrentProject = ProjectManifestFile::load(_path);
    gCurrentProject->projectDirectory = projectFilePath.parent_path();

    std::filesystem::path assetPath = gCurrentProject->projectDirectory.append(gCurrentProject->assetFolder);
    AssetRegistry::read_directory(assetPath);

    const std::string title = fmt::format("project \"{}\" | b_engine {}", gCurrentProject->name, B_ENGINE_VERSION);
    glfwSetWindowTitle(gWindow, title.c_str());
}