#include <GLFW/glfw3.h>
#include <llmr/llmr.hpp>
#include <llmr/map/settings.hpp>

class MapView {
public:
    MapView(llmr::Settings& settings, bool fullscreen = false) :
        fullscreen(fullscreen),
        settings(settings),
        map(settings) {
    }

    void init() {
        if (!glfwInit()) {
            fprintf(stderr, "Failed to initialize glfw\n");
            exit(1);
        }

        GLFWmonitor *monitor = nullptr;
        if (fullscreen) {
            monitor = glfwGetPrimaryMonitor();
        }

#ifdef GL_ES_VERSION_2_0
        glfwWindowHint(GLFW_CLIENT_API, GLFW_OPENGL_ES_API);
        glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 2);
        glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 0);
#endif

        glfwWindowHint(GLFW_RED_BITS, 8);
        glfwWindowHint(GLFW_GREEN_BITS, 8);
        glfwWindowHint(GLFW_BLUE_BITS, 8);
        glfwWindowHint(GLFW_ALPHA_BITS, 8);
        glfwWindowHint(GLFW_STENCIL_BITS, 8);
        glfwWindowHint(GLFW_DEPTH_BITS, 16);

        window = glfwCreateWindow(1024, 768, "llmr", monitor, NULL);
        if (!window) {
            glfwTerminate();
            fprintf(stderr, "Failed to initialize window\n");
            exit(1);
        }

        glfwSetWindowUserPointer(window, this);
        glfwMakeContextCurrent(window);


        int width, height;
        glfwGetWindowSize(window, &width, &height);
        int fb_width, fb_height;
        glfwGetFramebufferSize(window, &fb_width, &fb_height);

        settings.load();
        map.setup((double)fb_width / width);

        resize(window, 0, 0);

        glfwSwapInterval(1);

        map.loadSettings();

        glfwSetCursorPosCallback(window, mousemove);
        glfwSetMouseButtonCallback(window, mouseclick);
        glfwSetWindowSizeCallback(window, resize);
        glfwSetFramebufferSizeCallback(window, resize);
        glfwSetScrollCallback(window, scroll);
        glfwSetCharCallback(window, character);
        glfwSetKeyCallback(window, key);
    }

    static void character(GLFWwindow *window, unsigned int codepoint) {

    }

    static void key(GLFWwindow *window, int key, int scancode, int action, int mods) {
        MapView *mapView = (MapView *)glfwGetWindowUserPointer(window);

        if (action == GLFW_RELEASE) {
            switch (key) {
                case GLFW_KEY_ESCAPE:
                    glfwSetWindowShouldClose(window, true);
                    break;
                case GLFW_KEY_TAB:
                    mapView->map.toggleDebug();
                    break;
                case GLFW_KEY_R:
                    if (!mods) mapView->map.resetPosition();
                    break;
                case GLFW_KEY_N:
                    if (!mods) mapView->map.resetNorth();
                    break;
            }
        }
    }

    static void scroll(GLFWwindow *window, double xoffset, double yoffset) {
        MapView *mapView = (MapView *)glfwGetWindowUserPointer(window);
        double delta = yoffset * 40;

        bool is_wheel = delta != 0 && fmod(delta, 4.000244140625) == 0;

        double absdelta = delta < 0 ? -delta : delta;
        double scale = 2.0 / (1.0 + exp(-absdelta / 100.0));

        // Make the scroll wheel a bit slower.
        if (!is_wheel) {
            scale = (scale - 1.0) / 2.0 + 1.0;
        }

        // Zooming out.
        if (delta < 0 && scale != 0) {
            scale = 1.0 / scale;
        }

        mapView->map.startScaling();
        mapView->map.scaleBy(scale, mapView->last_x, mapView->last_y);
    }

    static void resize(GLFWwindow *window, int, int) {
        MapView *mapView = (MapView *)glfwGetWindowUserPointer(window);

        int width, height;
        glfwGetWindowSize(window, &width, &height);
        int fb_width, fb_height;
        glfwGetFramebufferSize(window, &fb_width, &fb_height);

        mapView->map.resize(width, height, fb_width, fb_height);
    }

    static void mouseclick(GLFWwindow *window, int button, int action, int modifiers) {
        MapView *mapView = (MapView *)glfwGetWindowUserPointer(window);

        if (button == GLFW_MOUSE_BUTTON_RIGHT || (button == GLFW_MOUSE_BUTTON_LEFT && modifiers & GLFW_MOD_CONTROL)) {
            mapView->rotating = action == GLFW_PRESS;
            if (mapView->rotating) {
                mapView->start_x = mapView->last_x;
                mapView->start_y = mapView->last_y;
            } else {
                mapView->map.stopRotating();
            }
        } else if (button == GLFW_MOUSE_BUTTON_LEFT) {
            mapView->tracking = action == GLFW_PRESS;

            if (action == GLFW_RELEASE) {
                mapView->map.stopPanning();
                double now = glfwGetTime();
                if (now - mapView->last_click < 0.4) {
                    mapView->map.scaleBy(2.0, mapView->last_x, mapView->last_y);
                }
                mapView->last_click = now;
            }
        }
    }

    static void mousemove(GLFWwindow *window, double x, double y) {
        MapView *mapView = (MapView *)glfwGetWindowUserPointer(window);
        if (mapView->tracking) {
            double dx = x - mapView->last_x;
            double dy = y - mapView->last_y;
            if (dx || dy) {
                mapView->map.startPanning();
                mapView->map.moveBy(dx, dy);
            }
        } else if (mapView->rotating) {
            mapView->map.startRotating();
            mapView->map.rotateBy(mapView->start_x, mapView->start_y, mapView->last_x, mapView->last_y, x, y);
        }
        mapView->last_x = x;
        mapView->last_y = y;
    }

    int run() {
        while (!glfwWindowShouldClose(window)) {
            llmr::platform::cleanup();

            if (dirty) {
                try {
                    dirty = render();
                } catch (std::exception& ex) {
                    fprintf(stderr, "exception: %s\n", ex.what());
                }
                glfwSwapBuffers(window);
                fps();
            }

            if (dirty) {
                glfwPollEvents();
            } else {
                glfwWaitEvents();
            }
        }

        return 0;
    }

    bool render() {
        return map.render();
    }

    void fps() {
        static int frames = 0;
        static double time_elapsed = 0;

        frames++;
        double current_time = glfwGetTime();

        if (current_time - time_elapsed >= 1) {
            fprintf(stderr, "FPS: %4.2f\n", frames / (current_time - time_elapsed));
            time_elapsed = current_time;
            frames = 0;
        }
    }

    ~MapView() {
        glfwTerminate();
    }

public:
    bool fullscreen = false;

    bool dirty = true;
    double last_x = 0, last_y = 0;
    bool tracking = false;

    double start_x = 0, start_y = 0;
    bool rotating = false;

    double last_click = -1;

    GLFWwindow *window = nullptr;
    llmr::Settings& settings;
    llmr::Map map;
};

namespace llmr {
namespace platform {

double time() {
    return glfwGetTime();
}


void show_debug_image(std::string name, const char *data, size_t width, size_t height) {
    static GLFWwindow *debug_window = nullptr;
    if (!debug_window) {
        debug_window = glfwCreateWindow(width, height, name.c_str(), nullptr, nullptr);
        if (!debug_window) {
            glfwTerminate();
            fprintf(stderr, "Failed to initialize window\n");
            exit(1);
        }
    }

    GLFWwindow *current_window = glfwGetCurrentContext();

    glfwSetWindowSize(debug_window, width, height);
    glfwMakeContextCurrent(debug_window);

    int fb_width, fb_height;
    glfwGetFramebufferSize(debug_window, &fb_width, &fb_height);
    float scale = (float)fb_width / (float)width;

    glPixelZoom(scale, -scale);
    glRasterPos2f(-1.0f, 1.0f);
    glDrawPixels(width, height, GL_LUMINANCE, GL_UNSIGNED_BYTE, data);
    glfwSwapBuffers(debug_window);

    glfwMakeContextCurrent(current_window);
}

}
}