/*
 * Copyright 2026 Joel Klinghed
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to
 * deal in the Software without restriction, including without limitation the
 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
 * sell copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 * IN THE SOFTWARE.
 */

#include "xcb_xkb.hh"

#include <cstdint>
#include <memory>
#include <string>
#include <xcb/xcb.h>
#include <xcb/xcb_event.h>
#define explicit dont_use_cxx_explicit
#include <xcb/xkb.h>
#undef explicit
#include <utility>
#include <xcb/xproto.h>
#include <xkbcommon/xkbcommon-x11.h>
#include <xkbcommon/xkbcommon.h>

namespace xcb {

namespace {

struct KeymapDeleter {
  void operator()(xkb_keymap* keymap) const {
    if (keymap)
      xkb_keymap_unref(keymap);
  }
};

struct StateDeleter {
  void operator()(xkb_state* state) const {
    if (state)
      xkb_state_unref(state);
  }
};

struct ContextDeleter {
  void operator()(xkb_context* context) const {
    if (context)
      xkb_context_unref(context);
  }
};

class KeyboardImpl : public Keyboard {
 public:
  KeyboardImpl() = default;

  bool init(xcb_connection_t* conn) {
    if (!xkb_x11_setup_xkb_extension(
            conn, XKB_X11_MIN_MAJOR_XKB_VERSION, XKB_X11_MIN_MINOR_XKB_VERSION,
            XKB_X11_SETUP_XKB_EXTENSION_NO_FLAGS, nullptr, nullptr,
            &first_xkb_event_, nullptr))
      return false;

    ctx_.reset(xkb_context_new(XKB_CONTEXT_NO_FLAGS));
    if (!ctx_)
      return false;
    device_id_ = xkb_x11_get_core_keyboard_device_id(conn);
    if (device_id_ == -1)
      return false;
    if (!update_keymap(conn))
      return false;
    select_events(conn);
    return true;
  }

  bool handle_event(xcb_connection_t* conn,
                    xcb_generic_event_t* event) override {
    if (XCB_EVENT_RESPONSE_TYPE(event) == first_xkb_event_) {
      auto* xkb_event = reinterpret_cast<xkb_generic_event_t*>(event);
      if (std::cmp_equal(xkb_event->deviceID, device_id_)) {
        switch (xkb_event->xkbType) {
          case XCB_XKB_NEW_KEYBOARD_NOTIFY: {
            auto* e =
                reinterpret_cast<xcb_xkb_new_keyboard_notify_event_t*>(event);
            if (e->changed & XCB_XKB_NKN_DETAIL_KEYCODES)
              update_keymap(conn);
            break;
          }
          case XCB_XKB_MAP_NOTIFY:
            update_keymap(conn);
            break;
          case XCB_XKB_STATE_NOTIFY: {
            auto* e = reinterpret_cast<xcb_xkb_state_notify_event_t*>(event);
            xkb_state_update_mask(state_.get(), e->baseMods, e->latchedMods,
                                  e->lockedMods, e->baseGroup, e->latchedGroup,
                                  e->lockedGroup);
            break;
          }
          default:
            break;
        }
      }
      return true;
    }
    return false;
  }

  std::string get_utf8(xcb_key_press_event_t* event) override {
    char tmp[16];
    xkb_state_key_get_utf8(state_.get(), event->detail, tmp, sizeof(tmp));
    return {tmp};
  }

 private:
  struct xkb_generic_event_t {
    uint8_t response_type;
    uint8_t xkbType;
    uint16_t sequence;
    xcb_timestamp_t time;
    uint8_t deviceID;
  };

  bool update_keymap(xcb_connection_t* conn) {
    auto* keymap = xkb_x11_keymap_new_from_device(ctx_.get(), conn, device_id_,
                                                  XKB_KEYMAP_COMPILE_NO_FLAGS);
    if (!keymap)
      return false;
    auto* state = xkb_x11_state_new_from_device(keymap, conn, device_id_);
    if (!state) {
      xkb_keymap_unref(keymap);
      return false;
    }
    keymap_.reset(keymap);
    state_.reset(state);
    return true;
  }

  void select_events(xcb_connection_t* conn) const {
    static const uint16_t new_keyboard_details = XCB_XKB_NKN_DETAIL_KEYCODES;
    static const uint16_t map_parts =
        XCB_XKB_MAP_PART_KEY_TYPES | XCB_XKB_MAP_PART_KEY_SYMS |
        XCB_XKB_MAP_PART_MODIFIER_MAP | XCB_XKB_MAP_PART_EXPLICIT_COMPONENTS |
        XCB_XKB_MAP_PART_KEY_ACTIONS | XCB_XKB_MAP_PART_VIRTUAL_MODS |
        XCB_XKB_MAP_PART_VIRTUAL_MOD_MAP;
    static const uint16_t state_details =
        XCB_XKB_STATE_PART_MODIFIER_BASE | XCB_XKB_STATE_PART_MODIFIER_LATCH |
        XCB_XKB_STATE_PART_MODIFIER_LOCK | XCB_XKB_STATE_PART_GROUP_BASE |
        XCB_XKB_STATE_PART_GROUP_LATCH | XCB_XKB_STATE_PART_GROUP_LOCK;

    xcb_xkb_select_events_details_t details = {};
    details.affectNewKeyboard = new_keyboard_details;
    details.newKeyboardDetails = new_keyboard_details;
    details.affectState = state_details;
    details.stateDetails = state_details;

    xcb_xkb_select_events_aux(conn, device_id_,
                              XCB_XKB_EVENT_TYPE_NEW_KEYBOARD_NOTIFY |
                                  XCB_XKB_EVENT_TYPE_MAP_NOTIFY |
                                  XCB_XKB_EVENT_TYPE_STATE_NOTIFY,
                              0, 0, map_parts, map_parts, &details);
  }

  std::unique_ptr<xkb_context, ContextDeleter> ctx_;
  std::unique_ptr<xkb_keymap, KeymapDeleter> keymap_;
  std::unique_ptr<xkb_state, StateDeleter> state_;
  uint8_t first_xkb_event_;
  int32_t device_id_;
};

}  // namespace

std::unique_ptr<Keyboard> Keyboard::create(xcb_connection_t* conn) {
  auto ret = std::make_unique<KeyboardImpl>();
  if (ret->init(conn))
    return ret;
  return nullptr;
}

}  // namespace xcb