// Copyright (C) 2022 RozK
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

#include "../events.hpp"
#include "events_x11.hpp"
#include "../display/display_x11.hpp"
#include <cstdio>

static void rk_x11_printf(
    char const * messsage) {
    printf("[X11] %s\n", messsage);
}

static void rk_backup(rk_events_x11 & events) {
    XKeyboardState backup;
    XGetKeyboardControl(events.display, &backup);
    events.backup_autorepeat = (AutoRepeatModeOn == backup.global_auto_repeat);
    XGetPointerControl(
        events.display, &events.backup_numerator, &events.backup_denominator, &events.backup_threshold);
}

static void rk_restore(rk_events_x11 & events) {
    if (events.backup_autorepeat) {
        XAutoRepeatOn(events.display);
    } else {
        XAutoRepeatOff(events.display);
    }
    XChangePointerControl(
        events.display, True, True, events.backup_numerator, events.backup_denominator, events.backup_threshold);
}

static void rk_apply(rk_events_x11 & events) {
    if (events.key_autorepeat) {
        XAutoRepeatOn(events.display);
    } else {
        XAutoRepeatOff(events.display);
    }
    XChangePointerControl(
        events.display, True, True, events.motion_numerator, events.motion_denominator, events.motion_threshold);
}

static void rk_focus_in(rk_events_x11 & events) {
    if (!events.focused) {
        rk_backup(events);
        rk_apply(events);
        XGrabPointer(events.display, events.window, True,
            ButtonPressMask | ButtonReleaseMask | PointerMotionMask,
            GrabModeAsync, GrabModeAsync, events.window, None, CurrentTime);
        events.focused = true;
    }
}

static void rk_focus_out(rk_events_x11 & events) {
    if (events.focused) {
        XUngrabPointer(events.display, CurrentTime);
        rk_restore(events);
        events.focused = false;
    }
}

rk_events_t rk_create_events(
    rk_display_t _display) {
    rk_display_x11 const * const display = reinterpret_cast<rk_display_x11 const *>(_display);
    if (!display || !display->display || !display->window) {
        return nullptr;
    }
    rk_events_x11 * const events = new rk_events_x11;
    events->display = display->display;
    events->window = display->window;
    events->input_manager = XOpenIM(display->display, nullptr, nullptr, nullptr);
    if (!events->input_manager) {
        rk_x11_printf("Failed to open input manager.");
        delete events;
        return nullptr;
    }
    events->input_context = XCreateIC(events->input_manager,
        XNInputStyle, XIMPreeditNone | XIMStatusNone,
        XNClientWindow, display->window,
        NULL);
    if (!events->input_context) {
        rk_x11_printf("Failed to create input context.");
        XCloseIM(events->input_manager);
        delete events;
        return nullptr;
    }
    events->focused = false;
    rk_backup(*events);
    events->key_autorepeat = events->backup_autorepeat;
    events->motion_numerator = events->backup_numerator;
    events->motion_denominator = events->backup_denominator;
    events->motion_threshold = events->backup_threshold;
    XSetICFocus(events->input_context);
    return reinterpret_cast<rk_events_t>(events);
}

void rk_destroy_events(
    rk_display_t _display,
    rk_events_t _events) {
    rk_display_x11 const * const display = reinterpret_cast<rk_display_x11 const *>(_display);
    rk_events_x11 * const events = reinterpret_cast<rk_events_x11 *>(_events);
    if (display && events && display->display && display->display == events->display) {
        rk_restore(*events);
        if (events->input_context) {
            XUnsetICFocus(events->input_context);
            XDestroyIC(events->input_context);
        }
        if (events->input_manager) {
            XCloseIM(events->input_manager);
        }
    }
    if (events) {
        delete events;
    }
}

void rk_set_key_autorepeat(
    rk_events_t _events,
    rk_bool autorepeat) {
    rk_events_x11 * const events = reinterpret_cast<rk_events_x11 *>(_events);
    if (events) {
        events->key_autorepeat = autorepeat;
        if (events->focused) {
            rk_apply(*events);
        }
    }
}

void rk_set_motion_acceleration(
    rk_events_t _events,
    rk_uint numerator,
    rk_uint denominator,
    rk_uint threshold) {
    rk_events_x11 * const events = reinterpret_cast<rk_events_x11 *>(_events);
    if (events) {
        events->motion_numerator = numerator;
        events->motion_denominator = denominator;
        events->motion_threshold = threshold;
        if (events->focused) {
            rk_apply(*events);
        }
    }
}

rk_uint rk_consume_events(
    rk_events_t _events,
    rk_event * buffer,
    rk_uint max_events) {
    static wchar_t string[256];
    rk_events_x11 * const events = reinterpret_cast<rk_events_x11 *>(_events);
    if (!events || !buffer || !max_events) {
        return 0;
    }
    XEvent x11_event;
    KeySym keysym;
    Status status;
    unsigned nevents = 0;
    while (nevents < max_events && XCheckWindowEvent(events->display, events->window, RK_EVENTS_MASK, &x11_event)) {
        if (XFilterEvent(&x11_event, 0)) {
            continue;
        }
        rk_event & event = buffer[nevents];
        switch (x11_event.type) {

            case FocusIn:
                if (NotifyNormal == x11_event.xfocus.mode) {
                    rk_focus_in(*events);
                    event.type = RK_EVENT_FOCUS_IN;
                    ++nevents;
                }
                break;

            case FocusOut:
                if (NotifyNormal == x11_event.xfocus.mode) {
                    rk_focus_out(*events);
                    event.type = RK_EVENT_FOCUS_OUT;
                    ++nevents;
                }
                break;

            case KeyPress:
                event.type = RK_EVENT_KEY_PRESS;
                event.key.code = x11_event.xkey.keycode;
                XwcLookupString(events->input_context, &x11_event.xkey, string, 256, &keysym, &status);
                switch (status) {
                    case XLookupChars:
                        event.key.symbol = XLookupKeysym(&x11_event.xkey, 0);
                        event.key.character = string[0];
                        break;
                    case XLookupKeySym:
                        event.key.symbol = keysym;
                        event.key.character = 0;
                        break;
                    case XLookupBoth:
                        event.key.symbol = keysym;
                        event.key.character = string[0];
                        break;
                    default:
                        event.key.symbol = 0;
                        event.key.character = 0;
                        break;
                }
                ++nevents;
                break;

            case KeyRelease:
                event.type = RK_EVENT_KEY_RELEASE;
                event.key.code = x11_event.xkey.keycode;
                event.key.symbol = XLookupKeysym(&x11_event.xkey, 0);
                event.key.character = 0;
                ++nevents;
                break;

            case ButtonPress:
                event.type = RK_EVENT_BUTTON_PRESS;
                event.button.index = x11_event.xbutton.button;
                ++nevents;
                break;

            case ButtonRelease:
                event.type = RK_EVENT_BUTTON_RELEASE;
                event.button.index = x11_event.xbutton.button;
                ++nevents;
                break;

            case MotionNotify:
                event.type = RK_EVENT_MOTION;
                event.motion.x = x11_event.xbutton.x;
                event.motion.y = x11_event.xbutton.y;
                ++nevents;
                break;
        }
    }
    return nevents;
}