#include <mglpp/mglpp.hpp>
#include <mglpp/window/Window.hpp>
#include <mglpp/window/Event.hpp>
#include <mglpp/system/Clock.hpp>
#include <mglpp/graphics/Rectangle.hpp>
#include <mglpp/system/MemoryMappedFile.hpp>
#include <mglpp/graphics/Font.hpp>
#include <mglpp/graphics/Text.hpp>
#include <mglpp/graphics/Texture.hpp>
#include <mglpp/graphics/Sprite.hpp>

#include <stdio.h>
#include <string.h>
#include <array>
#include <map>
#include <assert.h>

#include <X11/Xlib.h>
#include <X11/extensions/Xfixes.h>
#include <X11/extensions/shape.h>

extern "C" {
#include <mgl/mgl.h>
}

enum class State {
    SLIDE_IN_WINDOW,
    SLIDE_IN_CONTENT,
    FADE_IN_CONTENT,
    FADE_OUT_CONTENT,
    SLIDE_OUT_CONTENT,
    SLIDE_OUT_WINDOW,
    PAUSE
};

struct StateWithPayload {
    State state;
    double time_in_state_sec;
};

// Linear interpolation
static double interpolate(double a, double b, double interpolation) {
    return a + (b - a) * interpolation;
}

static double min_double(double a, double b) {
    return a < b ? a : b;
}

#define _NET_WM_STATE_REMOVE  0
#define _NET_WM_STATE_ADD     1
#define _NET_WM_STATE_TOGGLE  2

static Bool set_window_wm_state(Display *display, Window window, Atom atom) {
    Atom net_wm_state_atom = XInternAtom(display, "_NET_WM_STATE", False);
    if(!net_wm_state_atom) {
        fprintf(stderr, "Error: failed to find atom _NET_WM_STATE\n");
        return False;
    }

    XClientMessageEvent xclient;
    memset(&xclient, 0, sizeof(xclient));

    xclient.type = ClientMessage;
    xclient.window = window;
    xclient.message_type = net_wm_state_atom;
    xclient.format = 32;
    xclient.data.l[0] = _NET_WM_STATE_ADD;
    xclient.data.l[1] = atom;
    xclient.data.l[2] = 0;
    xclient.data.l[3] = 0;
    xclient.data.l[4] = 0;

    XSendEvent(display, DefaultRootWindow(display), False, SubstructureRedirectMask | SubstructureNotifyMask, (XEvent*)&xclient);
    XFlush(display);
    return True;
}

static Bool make_window_sticky(Display* display, Window window) {
    Atom net_wm_state_sticky_atom = XInternAtom(display, "_NET_WM_STATE_STICKY", False);
    if(!net_wm_state_sticky_atom) {
        fprintf(stderr, "Error: failed to find atom _NET_WM_STATE_STICKY\n");
        return False;
    }
    
    return set_window_wm_state(display, window, net_wm_state_sticky_atom);
}

static void make_window_click_through(Display *display, Window window) {
    XRectangle rect;
    memset(&rect, 0, sizeof(rect));
    XserverRegion region = XFixesCreateRegion(display, &rect, 1);
    XFixesSetWindowShapeRegion(display, window, ShapeInput, 0, 0, region);
    XFixesDestroyRegion(display, region);
}

static void usage() {
    fprintf(stderr, "usage: gpu-screen-recorder-notification <--text text> <--timeout timeout> [--icon filepath] [--icon-color color] [--bg-color color]\n");
    fprintf(stderr, "options:\n");
    fprintf(stderr, "  --text        The text to display in the notification. Required.\n");
    fprintf(stderr, "  --timeout     The time to display the notification in seconds (excluding animation time), expected to be a floating point number. Required.\n");
    fprintf(stderr, "  --icon        A path to an image file to display on the left side of the text. Optional.\n");
    fprintf(stderr, "  --icon-color  The color to display the icon as in hex format, for example FF0000. Optional, set to FFFFFF by default.\n");
    fprintf(stderr, "  --bg-color    The notification background (and side bar) color in hex format, for example FF0000. Optional, set to 76b900 by default.\n");
    fprintf(stderr, "examples:\n");
    fprintf(stderr, "  gpu-screen-recorder-notification --text 'Recording has started' --timeout 3.0\n");
    fprintf(stderr, "  gpu-screen-recorder-notification --text 'Recording has started' --timeout 3.0 --icon '/usr/share/gpu-screen-recorder/images/record.png'\n");
    fprintf(stderr, "  gpu-screen-recorder-notification --text 'Recording has started' --timeout 3.0 --icon '/usr/share/gpu-screen-recorder/images/record.png' --icon-color FF0000\n");
    exit(1);
}

static int hex_character_to_number(char c) {
    if(c >= '0' && c <= '9')
        return c - '0';
    else if(c >= 'a' && c <= 'f')
        return 10 + c - 'a';
    else if(c >= 'A' && c <= 'F')
        return 10 + c - 'A';
    else
        return -1;
}

static mgl::Color parse_hex_color(const char *str) {
    const int len = strlen(str);
    if(len != 6) {
        fprintf(stderr, "error: expected icon-color to be 6 characters long, was: %d\n", len);
        usage();
    }

    mgl::Color color;
    uint8_t *comp = &color.r;
    for(int i = 0; i < len; i += 2) {
        const int val1 = hex_character_to_number(str[i + 0]);
        const int val2 = hex_character_to_number(str[i + 1]);
        if(val1 == -1 || val2 == -1) {
            fprintf(stderr, "error: icon-color is an invalid hex color: '%s'\n", str);
            usage();
        }
        comp[i / 2] = (val1 << 4) | val2;
    }
    return color;
}

// Returns the first monitor if not found. Assumes there is at least one monitor connected.
static const mgl_monitor* find_monitor_by_cursor_position(mgl::Window &window) {
    const mgl_window *win = window.internal_window();
    assert(win->num_monitors > 0);
    for(int i = 0; i < win->num_monitors; ++i) {
        const mgl_monitor *mon = &win->monitors[i];
        if(mgl::IntRect({ mon->pos.x, mon->pos.y }, { mon->size.x, mon->size.y }).contains({ win->cursor_position.x, win->cursor_position.y }))
            return mon;
    }
    return &win->monitors[0];
}

int main(int argc, char **argv) {
    if(argc == 1)
        usage();

    if(argc == 2 && (strcmp(argv[1], "-h") == 0 || strcmp(argv[1], "--help") == 0))
        usage();

    std::map<std::string, const char*> args = {
        {"--text", nullptr},
        {"--timeout", nullptr},
        {"--icon", nullptr},
        {"--icon-color", nullptr},
        {"--bg-color", nullptr},
    };

    for(int i = 1; i < argc; i += 2) {
        auto it = args.find(argv[i]);
        if(it == args.end()) {
            fprintf(stderr, "error: invalid option '%s'\n", argv[i]);
            usage();
        }

        if(i + 1 >= argc) {
            fprintf(stderr, "error: missing value after option '%s'\n", argv[i]);
            usage();
        }

        it->second = argv[i + 1];
    }

    const char *notification_text = args["--text"];
    const char *timeout_str = args["--timeout"];
    const char *icon_filepath = args["--icon"];
    const char *icon_color_str = args["--icon-color"];
    const char *bg_color_str = args["--bg-color"];

    if(!notification_text) {
        fprintf(stderr, "error: missing required option '--text'\n");
        usage();
    }

    if(!timeout_str) {
        fprintf(stderr, "error: missing required option '--timeout'\n");
        usage();
    }

    float notification_timeout_sec = 0.0;
    if(sscanf(timeout_str, "%f", &notification_timeout_sec) != 1) {
        fprintf(stderr, "error: expected timeout to be a floating point number, was: '%s'\n", timeout_str);
        usage();
    }

    const mgl::Color icon_color = parse_hex_color(icon_color_str ? icon_color_str : "FFFFFF");
    const mgl::Color bg_color = parse_hex_color(bg_color_str ? bg_color_str : "76b900");

    mgl::Init init;

    mgl::Window::CreateParams window_create_params;
    window_create_params.size = { 1280, 720 };
    window_create_params.min_size = window_create_params.size;
    window_create_params.max_size = window_create_params.max_size;
    window_create_params.hidden = true;
    window_create_params.override_redirect = true;
    window_create_params.background_color = bg_color;
    window_create_params.hide_decorations = true;
    window_create_params.window_type = MGL_WINDOW_TYPE_NOTIFICATION;

    mgl::Window window;
    if(!window.create("GPU Screen Recorder Notification", window_create_params))
        return 1;

    mgl_window *win = window.internal_window();
    if(win->num_monitors == 0) {
        fprintf(stderr, "Error: no monitors found\n");
        exit(1);
    }

    const mgl_monitor *focused_monitor = find_monitor_by_cursor_position(window);

    mgl::MemoryMappedFile font_file;
    if(!font_file.load("/usr/share/fonts/noto/NotoSans-Bold.ttf", mgl::MemoryMappedFile::LoadOptions{true, false}))
        return 1;

    mgl::Font font;
    if(!font.load_from_file(font_file, focused_monitor->size.y / 60))
        return 1;

    mgl::Texture logo_texture;
    if(icon_filepath) {
        if(!logo_texture.load_from_file(icon_filepath, {false, false, true})) {
            fprintf(stderr, "Warning: failed to load icon\n");
        }
    }

    const int window_height = focused_monitor->size.y / 13;
    float content_padding_left = (int)(window_height * 0.05f);
    if(content_padding_left < 2.0f)
        content_padding_left = 2.0f;

    mgl::Text text(notification_text, font);
    text.set_color(mgl::Color(255, 255, 255, 0));

    mgl::Sprite logo_sprite;
    float logo_sprite_padding_x = 20.0f;
    float padding_between_icon_and_text_x = 0.0f;
    if(logo_texture.is_valid()) {
        logo_sprite.set_texture(&logo_texture);
        logo_sprite.set_color(mgl::Color(icon_color.r, icon_color.g, icon_color.b, 0));
        logo_sprite.set_height((int)(window_height * 0.4f));
        logo_sprite_padding_x = (int)((window_height - logo_sprite.get_size().y) * 0.4f);
        padding_between_icon_and_text_x = (int)(logo_sprite_padding_x * 0.7f);
    }

    Display *display = (Display*)mgl_get_context()->connection;

    // TODO: Use the monitor that the cursor is on or the focused window is on.
    // TODO: Update position when workspace changes (in dwm, sticky property handles it in real workspaces).
    // TODO: Make sure the notification always stays on top. Test with starting the notification and then opening youtube in fullscreen.
    const int window_width = content_padding_left + logo_sprite_padding_x + logo_sprite.get_size().x + padding_between_icon_and_text_x + text.get_bounds().size.x + logo_sprite_padding_x + padding_between_icon_and_text_x;
    const mgl::vec2i window_size{window_width, window_height};
    const mgl::vec2i window_start_position{focused_monitor->pos.x + focused_monitor->size.x, focused_monitor->pos.y + window_size.y};
    window.set_size_limits(window_size, window_size);
    window.set_size(window_size);
    window.set_position(window_start_position);
    make_window_click_through(display, window.get_system_handle());
    window.set_visible(true);
    make_window_sticky(display, window.get_system_handle());

    const int slide_window_start_x = focused_monitor->pos.x + focused_monitor->size.x;
    const int slide_window_end_x = focused_monitor->pos.x + focused_monitor->size.x - window_size.x;

    const std::array<StateWithPayload, 9> states_to_execute_in_order = {
        StateWithPayload{State::SLIDE_IN_WINDOW,   0.15},
        StateWithPayload{State::PAUSE,             0.03},
        StateWithPayload{State::SLIDE_IN_CONTENT,  0.10},
        StateWithPayload{State::FADE_IN_CONTENT,   0.20},
        StateWithPayload{State::PAUSE,             notification_timeout_sec},
        StateWithPayload{State::FADE_OUT_CONTENT,  0.001},
        StateWithPayload{State::SLIDE_OUT_CONTENT, 0.10},
        StateWithPayload{State::PAUSE,             0.10},
        StateWithPayload{State::SLIDE_OUT_WINDOW,  0.10},
    };
    int current_state_index = 0;

    mgl::Clock state_timer;

    mgl::Rectangle content_bg(window_size.to_vec2f() - mgl::vec2f(content_padding_left, 0.0f));
    content_bg.set_color(mgl::Color(0, 0, 0));

    const int slide_content_start_x = window_size.x + content_padding_left;
    const int slide_content_end_x = content_padding_left;

    const mgl::vec2f content_bg_start_position{(float)slide_content_start_x, 0.0f};
    content_bg.set_position(content_bg_start_position);

    const float content_start_alpha = 0.0f;
    const float content_end_alpha = 1.0f;

    const auto slide_content_handler = [&](double interpolate_start, double interpolate_end, double interpolation) {
        double new_slide_x = interpolate(interpolate_start, interpolate_end, interpolation);
        content_bg.set_position(mgl::vec2f(new_slide_x, content_bg_start_position.y).floor());
        logo_sprite.set_position((content_bg.get_position() + mgl::vec2f(logo_sprite_padding_x, content_bg.get_size().y * 0.5f - logo_sprite.get_size().y * 0.5f)).floor());
        const float content_space_left_pos_x = logo_sprite.get_position().x + logo_sprite.get_size().x + padding_between_icon_and_text_x;
        //const float content_space_left_x = content_bg.get_size().x - content_space_left_pos_x;
        text.set_position((mgl::vec2f(content_space_left_pos_x, content_bg.get_position().y) + mgl::vec2f(0.0f, content_bg.get_size().y) * 0.5f - mgl::vec2f(0.0f, text.get_bounds().size.y) * 0.5f).floor());
    };

    mgl::Event event;
    while(window.is_open()) {
        while(window.poll_event(event)) {}

        const StateWithPayload current_state = states_to_execute_in_order[current_state_index];
        const double state_elapsed_time_sec = state_timer.get_elapsed_time_seconds();
        const double state_interpolation = min_double(1.0, state_elapsed_time_sec / current_state.time_in_state_sec);

        switch(current_state.state) {
            case State::SLIDE_IN_WINDOW: {
                double new_slide_x = interpolate(slide_window_start_x, slide_window_end_x, state_interpolation);
                window.set_position(mgl::vec2i(new_slide_x, window_start_position.y));
                break;
            }
            case State::SLIDE_IN_CONTENT: {
                slide_content_handler(slide_content_start_x, slide_content_end_x, state_interpolation);
                break;
            }
            case State::FADE_IN_CONTENT: {
                double new_alpha = interpolate(content_start_alpha, content_end_alpha, state_interpolation);
                text.set_color(mgl::Color(255, 255, 255, new_alpha * 255.0f));
                logo_sprite.set_color(mgl::Color(icon_color.r, icon_color.g, icon_color.b, new_alpha * 255.0f));
                break;
            }
            case State::FADE_OUT_CONTENT: {
                double new_alpha = interpolate(content_end_alpha, content_start_alpha, state_interpolation);
                text.set_color(mgl::Color(255, 255, 255, new_alpha * 255.0f));
                logo_sprite.set_color(mgl::Color(icon_color.r, icon_color.g, icon_color.b, new_alpha * 255.0f));
                break;
            }
            case State::SLIDE_OUT_CONTENT: {
                slide_content_handler(slide_content_end_x, slide_content_start_x, state_interpolation);
                break;
            }
            case State::SLIDE_OUT_WINDOW: {
                double new_slide_x = interpolate(slide_window_end_x, slide_window_start_x, state_interpolation);
                window.set_position(mgl::vec2i(new_slide_x, window_start_position.y));
                break;
            }
            case State::PAUSE: {
                break;
            }
        }

        window.clear(bg_color);
        window.draw(content_bg);
        window.draw(logo_sprite);
        window.draw(text);
        window.display();

        if(state_interpolation >= 1.0) {
            state_timer.restart();
            ++current_state_index;
            if(current_state_index >= (int)states_to_execute_in_order.size())
                window.close();
        }
    }
}