#define FSM_DEBUG 1
#include "gui/guecstra.hpp"
#include "gui/dnd_loot.hpp"
#include "gui/uisystems.hpp"

namespace gui {

  DNDLoot::DNDLoot(StatusUI& status_ui, LootUI& loot_ui, sf::RenderWindow &window, routing::Router& router) :
    $status_ui(status_ui),
    $loot_ui(loot_ui),
    $window(window),
    $router(router)
  {
    event(Event::STARTED);
  }

  bool DNDLoot::event(Event ev, std::any data) {
    switch($state) {
      FSM_STATE(DNDState, START, ev);
      FSM_STATE(DNDState, LOOTING, ev, data);
      FSM_STATE(DNDState, LOOT_GRAB, ev, data);
      FSM_STATE(DNDState, INV_GRAB, ev, data);
      FSM_STATE(DNDState, ITEM_PICKUP, ev, data);
      FSM_STATE(DNDState, END, ev);
    default:
      dbc::log(fmt::format("event received with data but state={} is not handled", int($state)));
    }

    return !in_state(DNDState::END);
  }

  void DNDLoot::START(Event ev) {
    dbc::check(ev == Event::STARTED, "START not given a STARTED event.");
    state(DNDState::END);
  }

  void DNDLoot::LOOTING(Event ev, std::any data) {
    using enum Event;

    switch(ev) {
      case LOOT_OPEN:
        $loot_ui.active = false;
        state(DNDState::END);
        break;
      case LOOT_SELECT:
        $grab_source = UISystem::loot_grab($loot_ui.$gui, data);
        if($grab_source) state(DNDState::LOOT_GRAB);
        break;
      case INV_SELECT:
        $grab_source = UISystem::loot_grab($status_ui.$gui, data);
        if($grab_source) state(DNDState::INV_GRAB);
        break;
      case MOUSE_DRAG_START:
      case MOUSE_CLICK:
        mouse_action(false);
        break;
      default:
        state(DNDState::LOOTING);
    }
  }

  void DNDLoot::LOOT_GRAB(Event ev, std::any data) {
    using enum Event;

    switch(ev) {
      case LOOT_OPEN:
        $loot_ui.active = false;
        state(DNDState::END);
        break;
      case LOOT_SELECT:
        $grab_source = UISystem::loot_grab($loot_ui.$gui, data);
        if($grab_source) state(DNDState::LOOTING);
        break;
      case INV_SELECT:
        if(UISystem::loot_drop($loot_ui.$gui,
              $status_ui.$gui, $grab_source, data))
        {
          state(DNDState::LOOTING);
        }
        break;
      default:
         handle_mouse(ev, $loot_ui.$gui);
    }
  }

  void DNDLoot::INV_GRAB(Event ev, std::any data) {
    using enum Event;

    switch(ev) {
      case LOOT_OPEN:
        $loot_ui.active = false;
        state(DNDState::END);
        break;
      case LOOT_SELECT:
        if(UISystem::loot_drop($status_ui.$gui,
              $loot_ui.$gui, $grab_source, data))
        {
          state(DNDState::LOOTING);
        }
        break;
      case INV_SELECT:
        $grab_source = UISystem::loot_grab($status_ui.$gui, data);
        state(DNDState::LOOTING);
        break;
      default:
         handle_mouse(ev, $status_ui.$gui);
    }
  }

  void DNDLoot::ITEM_PICKUP(Event ev, std::any data) {
    using enum Event;

    switch(ev) {
      case INV_SELECT:
        if(UISystem::loot_drop($loot_ui.$gui,
              $status_ui.$gui, $grab_source, data))
        {
          $grab_source = std::nullopt;
          $grab_sprite = nullptr;
          state(DNDState::END);
        }
        break;
      case LOOT_ITEM:
        dbc::log("PUT IT BACK!");
        break;
      default:
         handle_mouse(ev, $loot_ui.$gui);
    }
  }

  void DNDLoot::END(Event ev) {
    using enum Event;

    switch(ev) {
      case LOOT_ITEM: {
          // NOTE: if > 1 items, go to LOOT_OPEN instead
          auto gui_id = $loot_ui.$gui.entity("item_0");
          $grab_source = UISystem::loot_grab($loot_ui.$gui, gui_id);

          if($grab_source) {
            auto& source = $loot_ui.$gui.get<guecs::GrabSource>(*$grab_source);
            $grab_sprite = source.sprite;
            // call this once to properly position the sprite
            handle_mouse(Event::MOUSE_MOVE, $loot_ui.$gui);
            state(DNDState::ITEM_PICKUP);
          }
        } break;
      case LOOT_OPEN:
        $loot_ui.active = true;
        $grab_source = std::nullopt;
        $grab_sprite = nullptr;
        state(DNDState::LOOTING);
        break;
      default:
        dbc::sentinel(fmt::format("invalid event: {}", int(ev)));
    }
  }

  sf::Vector2f DNDLoot::mouse_position() {
    return $window.mapPixelToCoords($router.position);
  }

  void DNDLoot::mouse_action(bool hover) {
    sf::Vector2f pos = mouse_position();
    $status_ui.mouse(pos.x, pos.y, hover);
    if($loot_ui.active) $loot_ui.mouse(pos.x, pos.y, hover);
  }

  void DNDLoot::handle_mouse(Event ev, guecs::UI& gui) {
    using enum Event;

    switch(ev) {
      case MOUSE_CLICK:
        mouse_action(false);
        break;
      case MOUSE_DRAG:
      case MOUSE_MOVE: {
           if($grab_source) {
             fmt::println("MOVING that thing");
             auto& source = gui.get<guecs::GrabSource>(*$grab_source);
             source.move($window.mapPixelToCoords($router.position));
           }
           mouse_action(true);
         } break;
      case MOUSE_DRAG_START:
           mouse_action(false);
         break;
      case MOUSE_DROP:
         mouse_action(false);
         break;
      default:
         break; // ignored
    }
  }

  void DNDLoot::render() {
    if($grab_source && $grab_sprite) {
      $window.draw(*$grab_sprite);
    }
  }
}