/*
 * Copyright (c) 2015 NAVER Corp.
 * egjs projects are licensed under the MIT license
 */
import Component, { ComponentEvent } from "@egjs/component";

import FlickingError from "./core/FlickingError";
import Viewport from "./core/Viewport";
import AutoResizer from "./core/AutoResizer";
import { Panel } from "./core/panel";
import { VanillaElementProvider } from "./core/panel/provider";
import VirtualManager, { VirtualOptions } from "./core/VirtualManager";
import { Control, SnapControl, SnapControlOptions, FreeControl, StrictControl, FreeControlOptions, StrictControlOptions } from "./control";
import { Camera } from "./camera";
import { Renderer, VanillaRenderer, ExternalRenderer, RendererOptions, NormalRenderingStrategy, VirtualRenderingStrategy } from "./renderer";
import { EVENTS, ALIGN, MOVE_TYPE, DIRECTION, CIRCULAR_FALLBACK } from "./const/external";
import * as ERROR from "./const/error";
import { findIndex, getElement, includes, parseElement } from "./utils";
import { HoldStartEvent, HoldEndEvent, MoveStartEvent, SelectEvent, MoveEvent, MoveEndEvent, WillChangeEvent, WillRestoreEvent, NeedPanelEvent, VisibleChangeEvent, ReachEdgeEvent, ReadyEvent, AfterResizeEvent, BeforeResizeEvent, ChangedEvent, RestoredEvent, PanelChangeEvent } from "./type/event";
import { LiteralUnion, ValueOf } from "./type/internal";
import { ElementLike, Plugin, Status, MoveTypeOptions } from "./type/external";

/**
 * @interface
 */
export interface FlickingEvents {
  [EVENTS.READY]: ReadyEvent;
  [EVENTS.BEFORE_RESIZE]: BeforeResizeEvent;
  [EVENTS.AFTER_RESIZE]: AfterResizeEvent;
  [EVENTS.HOLD_START]: HoldStartEvent;
  [EVENTS.HOLD_END]: HoldEndEvent;
  [EVENTS.MOVE_START]: MoveStartEvent;
  [EVENTS.MOVE]: MoveEvent;
  [EVENTS.MOVE_END]: MoveEndEvent;
  [EVENTS.WILL_CHANGE]: WillChangeEvent;
  [EVENTS.CHANGED]: ChangedEvent;
  [EVENTS.WILL_RESTORE]: WillRestoreEvent;
  [EVENTS.RESTORED]: RestoredEvent;
  [EVENTS.SELECT]: SelectEvent;
  [EVENTS.NEED_PANEL]: NeedPanelEvent;
  [EVENTS.VISIBLE_CHANGE]: VisibleChangeEvent;
  [EVENTS.REACH_EDGE]: ReachEdgeEvent;
  [EVENTS.PANEL_CHANGE]: PanelChangeEvent;
}

/**
 * @interface
 */
export interface FlickingOptions {
  // UI / LAYOUT
  align: LiteralUnion<ValueOf<typeof ALIGN>> | number | { panel: number | string; camera: number | string };
  defaultIndex: number;
  horizontal: boolean;
  circular: boolean;
  circularFallback: LiteralUnion<ValueOf<typeof CIRCULAR_FALLBACK>>;
  bound: boolean;
  adaptive: boolean;
  panelsPerView: number;
  noPanelStyleOverride: boolean;
  resizeOnContentsReady: boolean;
  nested: boolean;

  // EVENT
  needPanelThreshold: number;
  preventEventsBeforeInit: boolean;

  // ANIMATION
  deceleration: number;
  duration: number;
  easing: (x: number) => number;

  // INPUT
  inputType: string[];
  moveType: ValueOf<typeof MOVE_TYPE> | MoveTypeOptions<ValueOf<typeof MOVE_TYPE>>;
  threshold: number;
  interruptable: boolean;
  bounce: number | string | [number | string, number | string];
  iOSEdgeSwipeThreshold: number;
  preventClickOnDrag: boolean;
  disableOnInit: boolean;
  changeOnHold: boolean;

  // PERFORMANCE
  renderOnlyVisible: boolean;
  virtual: VirtualOptions | null;

  // OTHERS
  autoInit: boolean;
  autoResize: boolean;
  useResizeObserver: boolean;
  resizeDebounce: number;
  maxResizeDebounce: number;
  useFractionalSize: boolean;
  externalRenderer: ExternalRenderer | null;

  // @deprecated
  renderExternal: {
    renderer: new (options: RendererOptions) => ExternalRenderer;
    rendererOptions: RendererOptions;
  } | null;
}

/**
 * @extends Component
 * @support {"ie": "9+(with polyfill)", "ch" : "latest", "ff" : "latest",  "sf" : "latest", "edge" : "latest", "ios" : "7+", "an" : "4.X+"}
 * @requires {@link https://github.com/naver/egjs-component|@egjs/component}
 * @requires {@link https://github.com/naver/egjs-axes|@egjs/axes}
 */
class Flicking extends Component<FlickingEvents> {
  /**
   * Version info string
   * @ko 버전정보 문자열
   * @type {string}
   * @readonly
   * @example
   * ```ts
   * Flicking.VERSION;  // ex) 4.0.0
   * ```
   */
  public static VERSION = "#__VERSION__#";

  // Core components
  private _viewport: Viewport;
  private _autoResizer: AutoResizer;
  private _camera: Camera;
  private _control: Control;
  private _renderer: Renderer;
  private _virtualManager: VirtualManager;

  // Options
  private _align: FlickingOptions["align"];
  private _defaultIndex: FlickingOptions["defaultIndex"];
  private _horizontal: FlickingOptions["horizontal"];
  private _circular: FlickingOptions["circular"];
  private _circularFallback: FlickingOptions["circularFallback"];
  private _bound: FlickingOptions["bound"];
  private _adaptive: FlickingOptions["adaptive"];
  private _panelsPerView: FlickingOptions["panelsPerView"];
  private _noPanelStyleOverride: FlickingOptions["noPanelStyleOverride"];
  private _resizeOnContentsReady: FlickingOptions["resizeOnContentsReady"];
  private _virtual: FlickingOptions["virtual"];
  private _nested: FlickingOptions["nested"];

  private _needPanelThreshold: FlickingOptions["needPanelThreshold"];
  private _preventEventsBeforeInit: FlickingOptions["preventEventsBeforeInit"];

  private _deceleration: FlickingOptions["deceleration"];
  private _duration: FlickingOptions["duration"];
  private _easing: FlickingOptions["easing"];

  private _inputType: FlickingOptions["inputType"];
  private _moveType: FlickingOptions["moveType"];
  private _threshold: FlickingOptions["threshold"];
  private _interruptable: FlickingOptions["interruptable"];
  private _bounce: FlickingOptions["bounce"];
  private _iOSEdgeSwipeThreshold: FlickingOptions["iOSEdgeSwipeThreshold"];
  private _preventClickOnDrag: FlickingOptions["preventClickOnDrag"];
  private _disableOnInit: FlickingOptions["disableOnInit"];
  private _changeOnHold: FlickingOptions["changeOnHold"];

  private _renderOnlyVisible: FlickingOptions["renderOnlyVisible"];

  private _autoInit: FlickingOptions["autoInit"];
  private _autoResize: FlickingOptions["autoResize"];
  private _useResizeObserver: FlickingOptions["useResizeObserver"];
  private _resizeDebounce: FlickingOptions["resizeDebounce"];
  private _maxResizeDebounce: FlickingOptions["maxResizeDebounce"];
  private _useFractionalSize: FlickingOptions["useFractionalSize"];
  private _externalRenderer: FlickingOptions["externalRenderer"];
  private _renderExternal: FlickingOptions["renderExternal"];

  // Internal State
  private _initialized: boolean;
  private _plugins: Plugin[];

  // Components
  /**
   * {@link Control} instance of the Flicking
   * @ko 현재 Flicking에 활성화된 {@link Control} 인스턴스
   * @type {Control}
   * @default SnapControl
   * @readonly
   * @see Control
   * @see SnapControl
   * @see FreeControl
   */
  public get control() { return this._control; }
  /**
   * {@link Camera} instance of the Flicking
   * @ko 현재 Flicking에 활성화된 {@link Camera} 인스턴스
   * @type {Camera}
   * @default LinearCamera
   * @readonly
   * @see Camera
   * @see LinearCamera
   * @see BoundCamera
   * @see CircularCamera
   */
  public get camera() { return this._camera; }
  /**
   * {@link Renderer} instance of the Flicking
   * @ko 현재 Flicking에 활성화된 {@link Renderer} 인스턴스
   * @type {Renderer}
   * @default VanillaRenderer
   * @readonly
   * @see Renderer
   * @see VanillaRenderer
   * @see ExternalRenderer
   */
  public get renderer() { return this._renderer; }
  /**
   * A component that manages viewport size
   * @ko 뷰포트 크기 정보를 담당하는 컴포넌트
   * @type {Viewport}
   * @readonly
   * @see Viewport
   */
  public get viewport() { return this._viewport; }
  // Internal States
  /**
   * Whether Flicking's {@link Flicking#init init()} is called.
   * This is `true` when {@link Flicking#init init()} is called, and is `false` after calling {@link Flicking#destroy destroy()}.
   * @ko Flicking의 {@link Flicking#init init()}이 호출되었는지를 나타내는 멤버 변수.
   * 이 값은 {@link Flicking#init init()}이 호출되었으면 `true`로 변하고, {@link Flicking#destroy destroy()}호출 이후에 다시 `false`로 변경됩니다.
   * @type {boolean}
   * @default false
   * @readonly
   */
  public get initialized() { return this._initialized; }
  /**
   * Whether the `circular` option is enabled.
   * The {@link Flicking#circular circular} option can't be enabled when sum of the panel sizes are too small.
   * @ko {@link Flicking#circular circular} 옵션이 활성화되었는지 여부를 나타내는 멤버 변수.
   * {@link Flicking#circular circular} 옵션은 패널의 크기의 합이 충분하지 않을 경우 비활성화됩니다.
   * @type {boolean}
   * @default false
   * @readonly
   */
  public get circularEnabled() { return this._camera.circularEnabled; }
  /**
   * Whether the `virtual` option is enabled.
   * The {@link Flicking#virtual virtual} option can't be enabled when  {@link Flicking#panelsPerView panelsPerView} is less or equal than zero.
   * @ko {@link Flicking#virtual virtual} 옵션이 활성화되었는지 여부를 나타내는 멤버 변수.
   * {@link Flicking#virtual virtual} 옵션은 {@link Flicking#panelsPerView panelsPerView} 옵션의 값이 0보다 같거나 작으면 비활성화됩니다.
   * @type {boolean}
   * @default false
   * @readonly
   */
  public get virtualEnabled() { return this._panelsPerView > 0 && this._virtual != null; }
  /**
   * Index number of the {@link Flicking#currentPanel currentPanel}
   * @ko {@link Flicking#currentPanel currentPanel}의 인덱스 번호
   * @type {number}
   * @default 0
   * @readonly
   */
  public get index() { return this._control.activeIndex; }
  /**
   * The root(`.flicking-viewport`) element
   * @ko root(`.flicking-viewport`) 엘리먼트
   * @type {HTMLElement}
   * @readonly
   */
  public get element() { return this._viewport.element; }
  /**
   * Currently active panel
   * @ko 현재 선택된 패널
   * @type {Panel}
   * @readonly
   * @see Panel
   */
  public get currentPanel() { return this._control.activePanel; }
  /**
   * Array of panels
   * @ko 전체 패널들의 배열
   * @type {Panel[]}
   * @readonly
   * @see Panel
   */
  public get panels() { return this._renderer.panels; }
  /**
   * Count of panels
   * @ko 전체 패널의 개수
   * @type {number}
   * @readonly
   */
  public get panelCount() { return this._renderer.panelCount; }
  /**
   * Array of panels that is visible at the current position
   * @ko 현재 보이는 패널의 배열
   * @type {Panel[]}
   * @readonly
   * @see Panel
   */
  public get visiblePanels() { return this._camera.visiblePanels; }
  /**
   * Whether Flicking's animating
   * @ko 현재 애니메이션 동작 여부
   * @type {boolean}
   * @readonly
   */
  public get animating() { return this._control.animating; }
  /**
   * Whether user is clicking or touching
   * @ko 현재 사용자가 클릭/터치중인지 여부
   * @type {boolean}
   * @readonly
   */
  public get holding() { return this._control.holding; }
  /**
   * A current list of activated plugins
   * @ko 현재 활성화된 플러그인 목록
   * @type {Plugin[]}
   * @readonly
   */
  public get activePlugins() { return this._plugins; }

  // Options Getter
  // UI / LAYOUT
  /**
   * Align position of the panels within viewport. You can set different values each for the panel and camera
   * @ko 뷰포트 내에서 패널 정렬방식을 설정하는 옵션. 카메라와 패널 개별로 옵션을 설정할 수도 있습니다
   * @type {ALIGN | string | number | { panel: string | number, camera: string | number }}
   * @property {ALIGN | string | number} panel The align value for each {@link Panel}s<ko>개개의 {@link Panel}에 적용할 값</ko>
   * @property {ALIGN | string | number} camera The align value for {@link Camera}<ko>{@link Camera}에 적용할 값</ko>
   * @default "center"
   * @example
   * ```ts
   * const possibleOptions = [
   *   // Literal strings
   *   "prev", "center", "next",
   *   // % values, applied to both panel & camera
   *   "0%", "25%", "42%",
   *   // px values, arithmetic calculation with (+/-) is also allowed.
   *   "0px", "100px", "50% - 25px",
   *   // numbers, same to number + px ("0px", "100px")
   *   0, 100, 1000,
   *   // Setting a different value for panel & camera
   *   { panel: "10%", camera: "25%" }
   * ];
   *
   * possibleOptions.forEach(align => {
   *   new Flicking("#el", { align });
   * });
   * ```
   */
  public get align() { return this._align; }
  /**
   * Index of the panel to move when Flicking's {@link Flicking#init init()} is called. A zero-based integer
   * @ko Flicking의 {@link Flicking#init init()}이 호출될 때 이동할 디폴트 패널의 인덱스로, 0부터 시작하는 정수입니다
   * @type {number}
   * @default 0
   */
  public get defaultIndex() { return this._defaultIndex; }
  /**
   * Direction of panel movement (true: horizontal, false: vertical)
   * @ko 패널 이동 방향 (true: 가로방향, false: 세로방향)
   * @type {boolean}
   * @default true
   */
  public get horizontal() { return this._horizontal; }
  /**
   * Enables circular(continuous loop) mode, which connects first/last panel for continuous scrolling.
   * @ko 순환 모드를 활성화합니다. 순환 모드에서는 양 끝의 패널이 서로 연결되어 끊김없는 스크롤이 가능합니다.
   * @type {boolean}
   * @default false
   */
  public get circular() { return this._circular; }
  /**
   * Set panel control mode for the case when circular cannot be enabled.
   * "linear" will set the view's range from the top of the first panel to the top of the last panel.
   * "bound" will prevent the view from going out of the first/last panel, so it won't show empty spaces before/after the first/last panel.
   * @ko 순환 모드 사용 불가능시 사용할 패널 조작 범위 설정 방식을 변경합니다.
   * "linear" 사용시 시점이 첫번째 엘리먼트 위에서부터 마지막 엘리먼트 위까지 움직일 수 있도록 설정합니다.
   * "bound" 사용시 시점이 첫번째 엘리먼트와 마지막 엘리먼트의 끝과 끝 사이에서 움직일 수 있도록 설정합니다.
   * @see CIRCULAR_FALLBACK
   * @type {string}
   * @default "linear"
   */
  public get circularFallback() { return this._circularFallback; }
  /**
   * Prevent the view(camera element) from going out of the first/last panel, so it won't show empty spaces before/after the first/last panel
   * Only can be enabled when `circular=false`
   * @ko 뷰(카메라 엘리먼트)가 첫번째와 마지막 패널 밖으로 넘어가지 못하게 하여, 첫번째/마지막 패널 전/후의 빈 공간을 보이지 않도록 하는 옵션입니다
   * `circular=false`인 경우에만 사용할 수 있습니다
   * @type {boolean}
   * @default false
   */
  public get bound() { return this._bound; }
  /**
   * Update height of the viewport element after movement same to the height of the panel below. This can be only enabled when `horizontal=true`
   * @ko 이동한 후 뷰포트 엘리먼트의 크기를 현재 패널의 높이와 동일하게 설정합니다. `horizontal=true`인 경우에만 사용할 수 있습니다.
   * @type {boolean}
   * @default false
   */
  public get adaptive() { return this._adaptive; }
  /**
   * A visible number of panels on viewport. Enabling this option will automatically resize panel size
   * @ko 한 화면에 보이는 패널의 개수. 이 옵션을 활성화할 경우 패널의 크기를 강제로 재조정합니다
   * @type {number}
   * @default -1
   */
  public get panelsPerView() { return this._panelsPerView; }
  /**
   * Enabling this option will not change `width/height` style of the panels if {@link Flicking#panelsPerView} is enabled.
   * This behavior can be useful in terms of performance when you're manually managing all panel sizes
   * @ko 이 옵션을 활성화할 경우, {@link Flicking#panelsPerView} 옵션이 활성화되었을 때 패널의 `width/height` 스타일을 변경하지 않도록 설정합니다.
   * 모든 패널들의 크기를 직접 관리하고 있을 경우, 이 옵션을 활성화하면 성능면에서 유리할 수 있습니다
   * @type {boolean}
   * @default false
   */
  public get noPanelStyleOverride() { return this._noPanelStyleOverride; }
  /**
   * Enabling this option will automatically call {@link Flicking#resize} when all image/video inside panels are loaded.
   * This can be useful when you have contents inside Flicking that changes its size when it's loaded
   * @ko 이 옵션을 활성화할 경우, Flicking 패널 내부의 이미지/비디오들이 로드되었을 때 자동으로 {@link Flicking#resize}를 호출합니다.
   * 이 동작은 Flicking 내부에 로드 전/후로 크기가 변하는 콘텐츠를 포함하고 있을 때 유용하게 사용하실 수 있습니다.
   * @type {boolean}
   * @default false
   */
  public get resizeOnContentsReady() { return this._resizeOnContentsReady; }
  /**
   * If you enable this option on child Flicking when the Flicking is placed inside the Flicking, the parent Flicking will move in the same direction after the child Flicking reaches the first/last panel.
   * If the parent Flicking and child Flicking have different horizontal option, you do not need to set this option.
   * @ko Flicking 내부에 Flicking이 배치될 때 하위 Flicking에서 이 옵션을 활성화하면 하위 Flicking이 첫/마지막 패널에 도달한 뒤부터 같은 방향으로 상위 Flicking이 움직입니다.
   * 만약 상위 Flicking과 하위 Flicking이 서로 다른 horizontal 옵션을 가지고 있다면 이 옵션을 설정할 필요가 없습니다.
   * @type {boolean}
   * @default false
   */
  public get nested() { return this._nested; }
  // EVENTS
  /**
   * A Threshold from viewport edge before triggering `needPanel` event
   * @ko `needPanel`이벤트가 발생하기 위한 뷰포트 끝으로부터의 최대 거리
   * @type {number}
   * @default 0
   */
  public get needPanelThreshold() { return this._needPanelThreshold; }
  /**
   * When enabled, events are not triggered before `ready` when initializing
   * @ko 활성화할 경우 초기화시 `ready` 이벤트 이전의 이벤트가 발생하지 않습니다.
   * @type {boolean}
   * @default true
   */
  public get preventEventsBeforeInit() { return this._preventEventsBeforeInit; }
  // ANIMATION
  /**
   * Deceleration value for panel movement animation which is triggered by user input. A higher value means a shorter animation time
   * @ko 사용자의 동작으로 가속도가 적용된 패널 이동 애니메이션의 감속도. 값이 높을수록 애니메이션 실행 시간이 짧아집니다
   * @type {number}
   * @default 0.0075
   */
  public get deceleration() { return this._deceleration; }
  /**
   * An easing function applied to the panel movement animation. Default value is `easeOutCubic`
   * @ko 패널 이동 애니메이션에 적용할 easing 함수. 기본값은 `easeOutCubic`이다
   * @type {function}
   * @default x => 1 - Math.pow(1 - x, 3)
   * @see Easing Functions Cheat Sheet {@link http://easings.net/} <ko>이징 함수 Cheat Sheet {@link http://easings.net/}</ko>
   */
  public get easing() { return this._easing; }
  /**
   * Default duration of the animation (ms)
   * @ko 디폴트 애니메이션 재생 시간 (ms)
   * @type {number}
   * @default 500
   */
  public get duration() { return this._duration; }
  // INPUT
  /**
   * Types of input devices to enable
   * @ko 활성화할 입력 장치 종류
   * @type {string[]}
   * @default ["touch", "mouse"]
   * @see {@link https://naver.github.io/egjs-axes/release/latest/doc/global.html#PanInputOption Possible values (PanInputOption#inputType)}
   * <ko>{@link https://naver.github.io/egjs-axes/release/latest/doc/global.html#PanInputOption 가능한 값들 (PanInputOption#inputType)}</ko>
   */
  public get inputType() { return this._inputType; }
  /**
   * Movement style by user input. This will change instance type of {@link Flicking#control}
   * You can use the values of the constant {@link MOVE_TYPE}
   * @ko 사용자 입력에 의한 이동 방식. 이 값에 따라 {@link Flicking#control}의 인스턴스 타입이 결정됩니다
   * 상수 {@link MOVE_TYPE}에 정의된 값들을 이용할 수 있습니다
   * @type {MOVE_TYPE | Pair<string, object>}
   * @default "snap"
   * @example
   * |moveType|control|options|
   * |:---:|:---:|:---:|
   * |"snap"|{@link SnapControl}||
   * |"freeScroll"|{@link FreeControl}|{@link FreeControlOptions}|
   *
   * ```ts
   * import Flicking, { MOVE_TYPE } from "@egjs/flicking";
   *
   * const flicking = new Flicking({
   *   moveType: MOVE_TYPE.SNAP
   * });
   * ```
   *
   * ```ts
   * const flicking = new Flicking({
   *   // If you want more specific settings for the moveType
   *   // [moveType, options for that moveType]
   *   // In this case, it's ["freeScroll", FreeControlOptions]
   *   moveType: [MOVE_TYPE.FREE_SCROLL, { stopAtEdge: true }]
   * });
   * ```
   */
  public get moveType() { return this._moveType; }
  /**
   * Movement threshold to change panel (unit: px). It should be dragged above the threshold to change the current panel.
   * @ko 패널 변경을 위한 이동 임계값 (단위: px). 주어진 값 이상으로 스크롤해야만 패널 변경이 가능하다.
   * @type {number}
   * @default 40
   */
  public get threshold() { return this._threshold; }
  /**
   * Set animation to be interruptable by click/touch.
   * @ko 사용자의 클릭/터치로 인해 애니메이션을 도중에 멈출 수 있도록 설정합니다.
   * @type {boolean}
   * @default true
   */
  public get interruptable() { return this._interruptable; }
  /**
   * The size value of the bounce area. Only can be enabled when `circular=false`.
   * You can set different bounce value for prev/next direction by using array.
   * `number` for px value, and `string` for px, and % value relative to viewport size.
   * You have to call {@link Control#updateInput} after changing this to take effect.
   * @ko Flicking이 최대 영역을 넘어서 갈 수 있는 최대 크기. `circular=false`인 경우에만 사용할 수 있습니다.
   * 배열을 통해 prev/next 방향에 대해 서로 다른 바운스 값을 지정할 수 있습니다.
   * `number`를 통해 px값을, `stirng`을 통해 px 혹은 뷰포트 크기 대비 %값을 사용할 수 있습니다.
   * 이 값을 변경시 {@link Control#updateInput}를 호출해야 합니다.
   * @type {string | number | Array<string | number>}
   * @default "20%"
   * @example
   * ```ts
   * const possibleOptions = [
   *   // % values, relative to viewport element(".flicking-viewport")'s size
   *   "0%", "25%", "42%",
   *   // px values, arithmetic calculation with (+/-) is also allowed.
   *   "0px", "100px", "50% - 25px",
   *   // numbers, same to number + px ("0px", "100px")
   *   0, 100, 1000
   * ];
   * ```
   *
   * @example
   * ```ts
   * const flicking = new Flicking("#el", { bounce: "20%" });
   *
   * flicking.bounce = "100%";
   * flicking.control.updateInput(); // Call this to update!
   * ```
   */
  public get bounce() { return this._bounce; }
  /**
   * Size of the area from the right edge in iOS safari (in px) which enables swipe-back or swipe-forward
   * @ko iOS Safari에서 swipe를 통한 뒤로가기/앞으로가기를 활성화하는 오른쪽 끝으로부터의 영역의 크기 (px)
   * @type {number}
   * @default 30
   */
  public get iOSEdgeSwipeThreshold() { return this._iOSEdgeSwipeThreshold; }
  /**
   * Automatically prevent `click` event if the user has dragged at least a single pixel on the viewport element
   * @ko 사용자가 뷰포트 영역을 1픽셀이라도 드래그했을 경우 자동으로 {@link https://developer.mozilla.org/ko/docs/Web/API/Element/click_event click} 이벤트를 취소합니다
   * @type {boolean}
   * @default true
   */
  public get preventClickOnDrag() { return this._preventClickOnDrag; }
  /**
   * Automatically call {@link Flicking#disableInput disableInput()} on initialization
   * @ko Flicking init시에 {@link Flicking#disableInput disableInput()}을 바로 호출합니다
   * @type {boolean}
   * @default false
   */
  public get disableOnInit() { return this._disableOnInit; }
  /**
   * Change active panel index on mouse/touch hold while animating.
   * `index` of the `willChange`/`willRestore` event will be used as new index.
   * @ko 애니메이션 도중 마우스/터치 입력시 현재 활성화된 패널의 인덱스를 변경합니다.
   * `willChange`/`willRestore` 이벤트의 `index`값이 새로운 인덱스로 사용될 것입니다.
   * @type {boolean}
   * @default false
   */
  public get changeOnHold() { return this._changeOnHold; }
  // PERFORMANCE
  /**
   * Whether to render visible panels only. This can dramatically increase performance when there're many panels
   * @ko 보이는 패널만 렌더링할지 여부를 설정합니다. 패널이 많을 경우에 퍼포먼스를 크게 향상시킬 수 있습니다
   * @type {boolean}
   * @default false
   */
  public get renderOnlyVisible() { return this._renderOnlyVisible; }
  /**
   * By enabling this option, it will reduce memory consumption by restricting the number of DOM elements to `panelsPerView + 1`
   * Must be used with `panelsPerview`.
   * After Flicking's initialized, this property can be used to add/remove the panel count.
   * @ko 이 옵션을 활성화할 경우 패널 엘리먼트의 개수를 `panelsPerView + 1` 개로 고정함으로써, 메모리 사용량을 줄일 수 있습니다.
   * `panelsPerView` 옵션과 함께 사용되어야만 합니다.
   * Flicking 초기화 이후에, 이 프로퍼티는 렌더링하는 패널의 개수를 추가/제거하기 위해 사용될 수 있습니다.
   * @type {VirtualManager}
   * @property {function} renderPanel A rendering function for the panel element's innerHTML<ko>패널 엘리먼트의 innerHTML을 렌더링하는 함수</ko>
   * @property {number} initialPanelCount Initial panel count to render<ko>최초로 렌더링할 패널의 개수</ko>
   * @property {boolean} [cache=false] Whether to cache rendered panel's innerHTML<ko>렌더링된 패널의 innerHTML 정보를 캐시할지 여부</ko>
   * @property {string} [panelClass="flicking-panel"] The class name that will be applied to rendered panel elements<ko>렌더링되는 패널 엘리먼트에 적용될 클래스 이름</ko>
   * @example
   * ```ts
   * import Flicking, { VirtualPanel } from "@egjs/flicking";
   *
   * const flicking = new Flicking("#some_el", {
   *   panelsPerView: 3,
   *   virtual: {
   *     renderPanel: (panel: VirtualPanel, index: number) => `Panel ${index}`,
   *     initialPanelCount: 100
   *   }
   * });
   *
   * // Add 100 virtual panels (at the end)
   * flicking.virtual.append(100);
   *
   * // Remove 100 virtual panels from 0 to 100
   * flicking.virtual.remove(0, 100);
   * ```
   */
  public get virtual() { return this._virtualManager; }

  // OTHERS
  /**
   * Call {@link Flicking#init init()} automatically when creating Flicking's instance
   * @ko Flicking 인스턴스를 생성할 때 자동으로 {@link Flicking#init init()}를 호출합니다
   * @type {boolean}
   * @default true
   * @readonly
   */
  public get autoInit() { return this._autoInit; }
  /**
   * Whether to automatically call {@link Flicking#resize resize()} when the viewport element(.flicking-viewport)'s size is changed
   * @ko 뷰포트 엘리먼트(.flicking-viewport)의 크기 변경시 {@link Flicking#resize resize()} 메소드를 자동으로 호출할지 여부를 설정합니다
   * @type {boolean}
   * @default true
   */
  public get autoResize() { return this._autoResize; }
  /**
   * Whether to listen {@link https://developer.mozilla.org/en-US/docs/Web/API/ResizeObserver ResizeObserver}'s event instead of Window's {@link https://developer.mozilla.org/ko/docs/Web/API/Window/resize_event resize} event when using the `autoResize` option
   * @ko autoResize 옵션 사용시 {@link https://developer.mozilla.org/en-US/docs/Web/API/ResizeObserver ResizeObserver}의 이벤트를 Window객체의 {@link https://developer.mozilla.org/ko/docs/Web/API/Window/resize_event resize} 이벤트 대신 수신할지 여부를 설정합니다
   * @type {boolean}
   * @default true
   */
  public get useResizeObserver() { return this._useResizeObserver; }
  /**
   * Delays size recalculation from `autoResize` by the given time in milisecond.
   * If the size is changed again while being delayed, it cancels the previous one and delays from the beginning again.
   * This can increase performance by preventing `resize` being called too often.
   * @ko `autoResize` 설정시에 호출되는 크기 재계산을 주어진 시간(단위: ms)만큼 지연시킵니다.
   * 지연시키는 도중 크기가 다시 변경되었을 경우, 이전 것을 취소하고 주어진 시간만큼 다시 지연시킵니다.
   * 이를 통해 `resize`가 너무 많이 호출되는 것을 방지하여 성능을 향상시킬 수 있습니다.
   * @type {number}
   * @default 0
   */
  public get resizeDebounce() { return this._resizeDebounce; }
  /**
   * The maximum time for size recalculation delay when using `resizeDebounce`, in milisecond.
   * This guarantees that size recalculation is performed at least once every (n)ms.
   * @ko `resizeDebounce` 사용시에 크기 재계산이 지연되는 최대 시간을 지정합니다. (단위: ms)
   * 이를 통해, 적어도 (n)ms에 한번은 크기 재계산을 수행하는 것을 보장할 수 있습니다.
   * @type {number}
   * @default 100
   */
  public get maxResizeDebounce() { return this._maxResizeDebounce; }
  /**
   * By enabling this, Flicking will calculate all internal size with CSS width computed with getComputedStyle.
   * This can prevent 1px offset issue in some cases where panel size has the fractional part.
   * All sizes will have the original size before CSS {@link https://developer.mozilla.org/en-US/docs/Web/CSS/transform transform} is applied on the element.
   * @ko 이 옵션을 활성화할 경우, Flicking은 내부의 모든 크기를 {@link https://developer.mozilla.org/en-US/docs/Web/API/Element/getBoundingClientRect getBoundingClientRect}를 이용하여 계산합니다.
   * 이를 통해, 패널 크기에 소수점을 포함할 경우에 발생할 수 있는 일부 1px 오프셋 이슈를 해결 가능합니다.
   * 모든 크기는 CSS {@link https://developer.mozilla.org/en-US/docs/Web/CSS/transform transform}이 엘리먼트에 적용되기 이전의 크기를 사용할 것입니다.
   * @type {boolean}
   * @default false
   */
  public get useFractionalSize() { return this._useFractionalSize; }
  /**
   * This is an option for the frameworks(React, Vue, Angular, ...). Don't set it as it's automatically managed by Flicking.
   * @ko 프레임워크(React, Vue, Angular, ...)에서만 사용하는 옵션으로, 자동으로 설정되므로 따로 사용하실 필요 없습니다!
   * @default null
   * @internal
   * @readonly
   */
  public get externalRenderer() { return this._externalRenderer; }
  /**
   * This is an option for the frameworks(React, Vue, Angular, ...). Don't set it as it's automatically managed by Flicking.
   * @ko 프레임워크(React, Vue, Angular, ...)에서만 사용하는 옵션으로, 자동으로 설정되므로 따로 사용하실 필요 없습니다!
   * @default null
   * @internal
   * @readonly
   * @deprecated
   */
  public get renderExternal() { return this._renderExternal; }

  // Options Setter
  // UI / LAYOUT
  public set align(val: FlickingOptions["align"]) {
    this._align = val;
    this._renderer.align = val;
    this._camera.align = val;
  }

  public set defaultIndex(val: FlickingOptions["defaultIndex"]) { this._defaultIndex = val; }
  public set horizontal(val: FlickingOptions["horizontal"]) { this._horizontal = val; }
  public set circular(val: FlickingOptions["circular"]) { this._circular = val; }
  public set bound(val: FlickingOptions["bound"]) { this._bound = val; }
  public set adaptive(val: FlickingOptions["adaptive"]) { this._adaptive = val; }
  public set panelsPerView(val: FlickingOptions["panelsPerView"]) { this._panelsPerView = val; }
  public set noPanelStyleOverride(val: FlickingOptions["noPanelStyleOverride"]) { this._noPanelStyleOverride = val; }
  public set resizeOnContentsReady(val: FlickingOptions["resizeOnContentsReady"]) { this._resizeOnContentsReady = val; }
  public set nested(val: FlickingOptions["nested"]) { this._nested = val; }
  // EVENTS
  public set needPanelThreshold(val: FlickingOptions["needPanelThreshold"]) { this._needPanelThreshold = val; }
  public set preventEventsBeforeInit(val: FlickingOptions["preventEventsBeforeInit"]) { this._preventEventsBeforeInit = val; }
  // ANIMATION
  public set deceleration(val: FlickingOptions["deceleration"]) { this._deceleration = val; }
  public set easing(val: FlickingOptions["easing"]) { this._easing = val; }
  public set duration(val: FlickingOptions["duration"]) { this._duration = val; }
  // INPUT
  public set inputType(val: FlickingOptions["inputType"]) { this._inputType = val; }
  public set moveType(val: FlickingOptions["moveType"]) { this._moveType = val; }
  public set threshold(val: FlickingOptions["threshold"]) { this._threshold = val; }
  public set interruptable(val: FlickingOptions["interruptable"]) { this._interruptable = val; }
  public set bounce(val: FlickingOptions["bounce"]) { this._bounce = val; }
  public set iOSEdgeSwipeThreshold(val: FlickingOptions["iOSEdgeSwipeThreshold"]) { this._iOSEdgeSwipeThreshold = val; }
  public set preventClickOnDrag(val: FlickingOptions["preventClickOnDrag"]) {
    const prevVal = this._preventClickOnDrag;

    if (val === prevVal) return;

    const controller = this._control.controller;

    if (val) {
      controller.addPreventClickHandler();
    } else {
      controller.removePreventClickHandler();
    }

    this._preventClickOnDrag = val;
  }

  public set disableOnInit(val: FlickingOptions["disableOnInit"]) { this._disableOnInit = val; }
  public set changeOnHold(val: FlickingOptions["changeOnHold"]) { this._changeOnHold = val; }
  // PERFORMANCE
  public set renderOnlyVisible(val: FlickingOptions["renderOnlyVisible"]) { this._renderOnlyVisible = val; }
  // OTHERS
  public set autoResize(val: FlickingOptions["autoResize"]) {
    this._autoResize = val;

    if (val) {
      this._autoResizer.enable();
    } else {
      this._autoResizer.disable();
    }
  }

  public set useResizeObserver(val: FlickingOptions["useResizeObserver"]) {
    this._useResizeObserver = val;

    if (this._autoResize) {
      this._autoResizer.enable();
    }
  }

  /**
   * @param root A root HTMLElement to initialize Flicking on it. When it's a typeof `string`, it should be a css selector string
   * <ko>Flicking을 초기화할 HTMLElement로, `string` 타입으로 지정시 css 선택자 문자열을 지정해야 합니다.</ko>
   * @param {object} [options={}] An options object for Flicking.<ko>Flicking에 적용할 옵션 오브젝트</ko>
   * @throws {FlickingError}
   * |code|condition|
   * |---|---|
   * |{@link ERROR_CODE WRONG_TYPE}|When the root is not either string or HTMLElement|
   * |{@link ERROR_CODE ELEMENT_NOT_FOUND}|When the element with given CSS selector does not exist|
   * <ko>
   *
   * |code|조건|
   * |---|---|
   * |{@link ERROR_CODE WRONG_TYPE}|루트 엘리먼트가 string이나 HTMLElement가 아닐 경우|
   * |{@link ERROR_CODE ELEMENT_NOT_FOUND}|주어진 CSS selector로 엘리먼트를 찾지 못했을 경우|
   *
   * </ko>
   * @example
   * ```ts
   * import Flicking from "@egjs/flicking";
   *
   * // Creating new instance of Flicking with HTMLElement
   * const flicking = new Flicking(document.querySelector(".flicking-viewport"), { circular: true });
   *
   * // Creating new instance of Flicking with CSS selector
   * const flicking2 = new Flicking(".flicking-viewport", { circular: true });
   * ```
   */
  public constructor(root: HTMLElement | string, {
    align = ALIGN.CENTER,
    defaultIndex = 0,
    horizontal = true,
    circular = false,
    circularFallback = CIRCULAR_FALLBACK.LINEAR,
    bound = false,
    adaptive = false,
    panelsPerView = -1,
    noPanelStyleOverride = false,
    resizeOnContentsReady = false,
    nested = false,
    needPanelThreshold = 0,
    preventEventsBeforeInit = true,
    deceleration = 0.0075,
    duration = 500,
    easing = x => 1 - Math.pow(1 - x, 3),
    inputType = ["mouse", "touch"],
    moveType = "snap",
    threshold = 40,
    interruptable = true,
    bounce = "20%",
    iOSEdgeSwipeThreshold = 30,
    preventClickOnDrag = true,
    disableOnInit = false,
    changeOnHold = false,
    renderOnlyVisible = false,
    virtual = null,
    autoInit = true,
    autoResize = true,
    useResizeObserver = true,
    resizeDebounce = 0,
    maxResizeDebounce = 100,
    useFractionalSize = false,
    externalRenderer = null,
    renderExternal = null
  }: Partial<FlickingOptions> = {}) {
    super();

    // Internal states
    this._initialized = false;
    this._plugins = [];

    // Bind options
    this._align = align;
    this._defaultIndex = defaultIndex;
    this._horizontal = horizontal;
    this._circular = circular;
    this._circularFallback = circularFallback;
    this._bound = bound;
    this._adaptive = adaptive;
    this._panelsPerView = panelsPerView;
    this._noPanelStyleOverride = noPanelStyleOverride;
    this._resizeOnContentsReady = resizeOnContentsReady;
    this._nested = nested;
    this._virtual = virtual;
    this._needPanelThreshold = needPanelThreshold;
    this._preventEventsBeforeInit = preventEventsBeforeInit;
    this._deceleration = deceleration;
    this._duration = duration;
    this._easing = easing;
    this._inputType = inputType;
    this._moveType = moveType;
    this._threshold = threshold;
    this._interruptable = interruptable;
    this._bounce = bounce;
    this._iOSEdgeSwipeThreshold = iOSEdgeSwipeThreshold;
    this._preventClickOnDrag = preventClickOnDrag;
    this._disableOnInit = disableOnInit;
    this._changeOnHold = changeOnHold;
    this._renderOnlyVisible = renderOnlyVisible;
    this._autoInit = autoInit;
    this._autoResize = autoResize;
    this._useResizeObserver = useResizeObserver;
    this._resizeDebounce = resizeDebounce;
    this._maxResizeDebounce = maxResizeDebounce;
    this._useFractionalSize = useFractionalSize;
    this._externalRenderer = externalRenderer;
    this._renderExternal = renderExternal;

    // Create core components
    this._viewport = new Viewport(this, getElement(root));
    this._autoResizer = new AutoResizer(this);
    this._renderer = this._createRenderer();
    this._camera = this._createCamera();
    this._control = this._createControl();
    this._virtualManager = new VirtualManager(this, virtual);

    if (this._autoInit) {
      void this.init();
    }
  }

  /**
   * Initialize Flicking and move to the default index
   * This is automatically called on Flicking's constructor when `autoInit` is true(default)
   * @ko Flicking을 초기화하고, 디폴트 인덱스로 이동합니다
   * 이 메소드는 `autoInit` 옵션이 true(default)일 경우 Flicking이 생성될 때 자동으로 호출됩니다
   * @fires Flicking#ready
   * @return {Promise<void>}
   */
  public init(): Promise<void> {
    if (this._initialized) return Promise.resolve();

    const camera = this._camera;
    const renderer = this._renderer;
    const control = this._control;
    const virtualManager = this._virtualManager;
    const originalTrigger = this.trigger;
    const preventEventsBeforeInit = this._preventEventsBeforeInit;

    camera.init();
    virtualManager.init();
    renderer.init(this);
    control.init(this);

    if (preventEventsBeforeInit) {
      this.trigger = () => this;
    }

    this._initialResize();

    // Look at initial panel
    this._moveToInitialPanel();

    if (this._autoResize) {
      this._autoResizer.enable();
    }
    if (this._preventClickOnDrag) {
      control.controller.addPreventClickHandler();
    }
    if (this._disableOnInit) {
      this.disableInput();
    }
    renderer.checkPanelContentsReady(renderer.panels);

    return renderer.render().then(() => {
      // Done initializing & emit ready event
      this._plugins.forEach(plugin => plugin.init(this));
      this._initialized = true;
      if (preventEventsBeforeInit) {
        this.trigger = originalTrigger;
      }
      this.trigger(new ComponentEvent(EVENTS.READY));
    });
  }

  /**
   * Destroy Flicking and remove all event handlers
   * @ko Flicking과 하위 컴포넌트들을 초기 상태로 되돌리고, 부착된 모든 이벤트 핸들러를 제거합니다
   * @return {void}
   */
  public destroy(): void {
    this.off();

    this._autoResizer.disable();
    this._control.destroy();
    this._camera.destroy();
    this._renderer.destroy();

    this._plugins.forEach(plugin => plugin.destroy());

    this._initialized = false;
  }

  /**
   * Move to the previous panel (current index - 1)
   * @ko 이전 패널로 이동합니다 (현재 인덱스 - 1)
   * @param {number} [duration={@link Flicking#duration options.duration}] Duration of the panel movement animation (unit: ms)<ko>패널 이동 애니메이션 진행 시간 (단위: ms)</ko>
   * @async
   * @fires Flicking#moveStart
   * @fires Flicking#move
   * @fires Flicking#moveEnd
   * @fires Flicking#willChange
   * @fires Flicking#changed
   * @fires Flicking#willRestore
   * @fires Flicking#restored
   * @fires Flicking#needPanel
   * @fires Flicking#visibleChange
   * @fires Flicking#reachEdge
   * @throws {FlickingError}
   * |code|condition|
   * |---|---|
   * |{@link ERROR_CODE INDEX_OUT_OF_RANGE}|When the previous panel does not exist|
   * |{@link ERROR_CODE ANIMATION_ALREADY_PLAYING}|When the animation is already playing|
   * |{@link ERROR_CODE ANIMATION_INTERRUPTED}|When the animation is interrupted by user input|
   * |{@link ERROR_CODE STOP_CALLED_BY_USER}|When the any of the event's `stop()` is called|
   * <ko>
   *
   * |code|condition|
   * |---|---|
   * |{@link ERROR_CODE INDEX_OUT_OF_RANGE}|이전 패널이 존재하지 않을 경우|
   * |{@link ERROR_CODE ANIMATION_ALREADY_PLAYING}|애니메이션이 이미 진행중인 경우|
   * |{@link ERROR_CODE ANIMATION_INTERRUPTED}|사용자 입력에 의해 애니메이션이 중단된 경우|
   * |{@link ERROR_CODE STOP_CALLED_BY_USER}|발생된 이벤트들 중 하나라도 `stop()`이 호출된 경우|
   * </ko>
   * @return {Promise<void>} A Promise which will be resolved after reaching the previous panel<ko>이전 패널 도달시에 resolve되는 Promise</ko>
   */
  public prev(duration: number = this._duration): Promise<void> {
    return this.moveTo(this._control.activePanel?.prev()?.index ?? -1, duration, DIRECTION.PREV);
  }

  /**
   * Move to the next panel (current index + 1)
   * @ko 다음 패널로 이동합니다 (현재 인덱스 + 1)
   * @param {number} [duration={@link Flicking#duration options.duration}] Duration of the panel movement animation (unit: ms).<ko>패널 이동 애니메이션 진행 시간 (단위: ms)</ko>
   * @async
   * @fires Flicking#moveStart
   * @fires Flicking#move
   * @fires Flicking#moveEnd
   * @fires Flicking#willChange
   * @fires Flicking#changed
   * @fires Flicking#willRestore
   * @fires Flicking#restored
   * @fires Flicking#needPanel
   * @fires Flicking#visibleChange
   * @fires Flicking#reachEdge
   * @throws {FlickingError}
   * |code|condition|
   * |---|---|
   * |{@link ERROR_CODE INDEX_OUT_OF_RANGE}|When the next panel does not exist|
   * |{@link ERROR_CODE ANIMATION_ALREADY_PLAYING}|When the animation is already playing|
   * |{@link ERROR_CODE ANIMATION_INTERRUPTED}|When the animation is interrupted by user input|
   * |{@link ERROR_CODE STOP_CALLED_BY_USER}|When the any of the event's `stop()` is called|
   * <ko>
   *
   * |code|condition|
   * |---|---|
   * |{@link ERROR_CODE INDEX_OUT_OF_RANGE}|다음 패널이 존재하지 않을 경우|
   * |{@link ERROR_CODE ANIMATION_ALREADY_PLAYING}|애니메이션이 이미 진행중인 경우|
   * |{@link ERROR_CODE ANIMATION_INTERRUPTED}|사용자 입력에 의해 애니메이션이 중단된 경우|
   * |{@link ERROR_CODE STOP_CALLED_BY_USER}|발생된 이벤트들 중 하나라도 `stop()`이 호출된 경우|
   *
   * </ko>
   * @return {Promise<void>} A Promise which will be resolved after reaching the next panel<ko>다음 패널 도달시에 resolve되는 Promise</ko>
   */
  public next(duration: number = this._duration) {
    return this.moveTo(this._control.activePanel?.next()?.index ?? this._renderer.panelCount, duration, DIRECTION.NEXT);
  }

  /**
   * Move to the panel with given index
   * @ko 주어진 인덱스에 해당하는 패널로 이동합니다
   * @param {number} index The index of the panel to move<ko>이동할 패널의 인덱스</ko>
   * @param {number} [duration={@link Flicking#duration options.duration}] Duration of the animation (unit: ms)<ko>애니메이션 진행 시간 (단위: ms)</ko>
   * @param {DIRECTION} [direction=DIRECTION.NONE] Direction to move, only available in the {@link Flicking#circular circular} mode<ko>이동할 방향. {@link Flicking#circular circular} 옵션 활성화시에만 사용 가능합니다</ko>
   * @async
   * @fires Flicking#moveStart
   * @fires Flicking#move
   * @fires Flicking#moveEnd
   * @fires Flicking#willChange
   * @fires Flicking#changed
   * @fires Flicking#willRestore
   * @fires Flicking#restored
   * @fires Flicking#needPanel
   * @fires Flicking#visibleChange
   * @fires Flicking#reachEdge
   * @throws {FlickingError}
   * |code|condition|
   * |---|---|
   * |{@link ERROR_CODE INDEX_OUT_OF_RANGE}|When the root is not either string or HTMLElement|
   * |{@link ERROR_CODE ANIMATION_ALREADY_PLAYING}|When the animation is already playing|
   * |{@link ERROR_CODE ANIMATION_INTERRUPTED}|When the animation is interrupted by user input|
   * |{@link ERROR_CODE STOP_CALLED_BY_USER}|When the any of the event's `stop()` is called|
   * <ko>
   *
   * |code|condition|
   * |---|---|
   * |{@link ERROR_CODE INDEX_OUT_OF_RANGE}|해당 인덱스를 가진 패널이 존재하지 않을 경우|
   * |{@link ERROR_CODE ANIMATION_ALREADY_PLAYING}|애니메이션이 이미 진행중인 경우|
   * |{@link ERROR_CODE ANIMATION_INTERRUPTED}|사용자 입력에 의해 애니메이션이 중단된 경우|
   * |{@link ERROR_CODE STOP_CALLED_BY_USER}|발생된 이벤트들 중 하나라도 `stop()`이 호출된 경우|
   *
   * </ko>
   * @return {Promise<void>} A Promise which will be resolved after reaching the target panel<ko>해당 패널 도달시에 resolve되는 Promise</ko>
   */
  public moveTo(index: number, duration: number = this._duration, direction: ValueOf<typeof DIRECTION> = DIRECTION.NONE) {
    const renderer = this._renderer;
    const panelCount = renderer.panelCount;

    const panel = renderer.getPanel(index);

    if (!panel) {
      return Promise.reject(new FlickingError(ERROR.MESSAGE.INDEX_OUT_OF_RANGE(index, 0, panelCount - 1), ERROR.CODE.INDEX_OUT_OF_RANGE));
    }

    if (this._control.animating) {
      return Promise.reject(new FlickingError(ERROR.MESSAGE.ANIMATION_ALREADY_PLAYING, ERROR.CODE.ANIMATION_ALREADY_PLAYING));
    }

    if (this._control.holding) {
      this._control.controller.release();
    }

    return this._control.moveToPanel(panel, {
      duration,
      direction
    });
  }

  /**
   * Return the {@link Panel} at the given index. `null` if it doesn't exists.
   * @ko 주어진 인덱스에 해당하는 {@link Panel}을 반환합니다. 주어진 인덱스에 해당하는 패널이 존재하지 않을 경우 `null`을 반환합니다.
   * @return {Panel | null} Panel at the given index<ko>주어진 인덱스에 해당하는 패널</ko>
   * @see Panel
   * @example
   * ```ts
   * const panel = flicking.getPanel(0);
   * // Which is a shorthand to...
   * const samePanel = flicking.panels[0];
   * ```
   */
  public getPanel(index: number): Panel | null {
    return this._renderer.getPanel(index);
  }

  /**
   * Enable input from the user (mouse/touch)
   * @ko 사용자의 입력(마우스/터치)를 활성화합니다
   * @return {this}
   */
  public enableInput(): this {
    this._control.enable();
    return this;
  }

  /**
   * Disable input from the user (mouse/touch)
   * @ko 사용자의 입력(마우스/터치)를 막습니다
   * @return {this}
   */
  public disableInput(): this {
    this._control.disable();
    return this;
  }

  /**
   * Get current flicking status. You can restore current state by giving returned value to {@link Flicking#setStatus setStatus()}
   * @ko 현재 상태를 반환합니다. 반환받은 값을 {@link Flicking#setStatus setStatus()} 메소드의 인자로 지정하면 현재 상태를 복원할 수 있습니다
   * @param {object} options Status retrieving options<ko>Status 반환 옵션</ko>
   * @param {boolean} [options.index=true] Include current panel index to the returning status. Camera will automatically move to the given index when the {@link Flicking#setStatus setStatus} is called<ko>현재 패널 인덱스를 반환값에 포함시킵니다. {@link Flicking#setStatus setStatus} 호출시 자동으로 해당 인덱스로 카메라를 움직입니다</ko>
   * @param {boolean} [options.position=true] Include camera position to the returning status. This works only when the {@link Flicking#moveType moveType} is `freeScroll`<ko>카메라의 현재 위치를 반환값에 포함시킵니다. 이 옵션은 {@link Flicking#moveType moveType}이 `freeScroll`일 경우에만 동작합니다</ko>
   * @param {boolean} [options.includePanelHTML=false] Include panel's `outerHTML` to the returning status<ko>패널의 `outerHTML`을 반환값에 포함시킵니다</ko>
   * @param {boolean} [options.visiblePanelsOnly=false] Include only {@link Flicking#visiblePanel visiblePanel}'s HTML. This option is available only when the `includePanelHTML` is true
   * <ko>현재 보이는 패널({@link Flicking#visiblePanel visiblePanel})의 HTML만 반환합니다. `includePanelHTML`이 `true`일 경우에만 동작합니다.</ko>
   * @return {Status} An object with current status value information<ko>현재 상태값 정보를 가진 객체.</ko>
   */
  public getStatus({
    index = true,
    position = true,
    includePanelHTML = false,
    visiblePanelsOnly = false
  }: Partial<{
    index: boolean;
    position: boolean;
    includePanelHTML: boolean;
    visiblePanelsOnly: boolean;
  }> = {}): Status {
    const camera = this._camera;
    const panels = visiblePanelsOnly ? this.visiblePanels : this.panels;

    const status: Status = {
      panels: panels.map(panel => {
        const panelInfo: Status["panels"][0] = { index: panel.index };

        if (includePanelHTML) {
          panelInfo.html = panel.element.outerHTML;
        }

        return panelInfo;
      })
    };

    if (index) {
      status.index = this.index;
    }
    if (position) {
      const nearestAnchor = camera.findNearestAnchor(camera.position);

      if (nearestAnchor) {
        status.position = {
          panel: nearestAnchor.panel.index,
          progressInPanel: camera.getProgressInPanel(nearestAnchor.panel)
        };
      }

    }

    if (visiblePanelsOnly) {
      const visiblePanels = this.visiblePanels;

      status.visibleOffset = visiblePanels[0]?.index ?? 0;
    }

    return status;
  }

  /**
   * Restore to the state of the given {@link Status}
   * @ko 주어진 {@link Status}의 상태로 복원합니다
   * @param {Partial<Status>} status Status value to be restored. You should use the return value of the {@link Flicking#getStatus getStatus()} method<ko>복원할 상태 값. {@link Flicking#getStatus getStatus()} 메서드의 반환값을 지정하면 됩니다</ko>
   * @return {void}
   */
  public setStatus(status: Status): void {
    if (!this._initialized) {
      throw new FlickingError(ERROR.MESSAGE.NOT_INITIALIZED, ERROR.CODE.NOT_INITIALIZED);
    }

    const {
      index,
      position,
      visibleOffset,
      panels
    } = status;

    const renderer = this._renderer;
    const control = this._control;

    // Can't add/remove panels on external rendering
    if (panels[0]?.html && !this._renderExternal) {
      renderer.batchRemove({ index: 0, deleteCount: this.panels.length, hasDOMInElements: true });
      renderer.batchInsert({ index: 0, elements: parseElement(panels.map(panel => panel.html!)), hasDOMInElements: true });
    }

    if (index) {
      const panelIndex = visibleOffset
        ? index - visibleOffset
        : index;

      void this.moveTo(panelIndex, 0).catch(() => void 0);
    }

    if (position && this._moveType === MOVE_TYPE.FREE_SCROLL) {
      const { panel, progressInPanel } = position;
      const panelIndex = visibleOffset
        ? panel - visibleOffset
        : panel;
      const panelRange = renderer.panels[panelIndex].range;
      const newCameraPos = panelRange.min + (panelRange.max - panelRange.min) * progressInPanel;

      void control.moveToPosition(newCameraPos, 0).catch(() => void 0);
    }
  }

  /**
   * Add plugins that can have different effects on Flicking
   * @ko 플리킹에 다양한 효과를 부여할 수 있는 플러그인을 추가합니다
   * @param {...Plugin} plugins The plugin(s) to add<ko>추가할 플러그인(들)</ko>
   * @return {this}
   * @see https://github.com/naver/egjs-flicking-plugins
   */
  public addPlugins(...plugins: Plugin[]) {
    if (this._initialized) {
      plugins.forEach(item => item.init(this));
    }

    this._plugins.push(...plugins);

    return this;
  }

  /**
   * Remove plugins from Flicking.
   * @ko 플리킹으로부터 플러그인들을 제거합니다.
   * @param {...Plugin} plugin The plugin(s) to remove.<ko>제거 플러그인(들).</ko>
   * @return {this}
   * @see https://github.com/naver/egjs-flicking-plugins
   */
  public removePlugins(...plugins: Plugin[]) {
    plugins.forEach(item => {
      const foundIndex = findIndex(this._plugins, val => val === item);

      if (foundIndex >= 0) {
        item.destroy();
        this._plugins.splice(foundIndex, 1);
      }
    });

    return this;
  }

  /**
   * Update viewport/panel sizes
   * @ko 패널 및 뷰포트의 크기를 갱신합니다
   * @method
   * @fires Flicking#beforeResize
   * @fires Flicking#afterResize
   * @return {this}
   */
  public async resize(): Promise<void> {
    const viewport = this._viewport;
    const renderer = this._renderer;
    const camera = this._camera;
    const control = this._control;

    const activePanel = control.activePanel;
    const prevWidth = viewport.width;
    const prevHeight = viewport.height;
    const prevProgressInPanel = activePanel
      ? camera.getProgressInPanel(activePanel)
      : 0;

    this.trigger(new ComponentEvent(EVENTS.BEFORE_RESIZE, {
      width: prevWidth,
      height: prevHeight,
      element: viewport.element
    }));

    viewport.resize();
    await renderer.forceRenderAllPanels(); // Render all panel elements, to update sizes
    renderer.updatePanelSize();
    camera.updateAlignPos();
    camera.updateRange();
    camera.updateAnchors();
    camera.updateAdaptiveHeight();
    camera.updateOffset();
    await renderer.render();

    if (control.animating) {
      // TODO:
    } else {
      control.updatePosition(prevProgressInPanel);
      control.updateInput();
    }

    const newWidth = viewport.width;
    const newHeight = viewport.height;
    const sizeChanged = newWidth !== prevWidth || newHeight !== prevHeight;

    this.trigger(new ComponentEvent(EVENTS.AFTER_RESIZE, {
      width: viewport.width,
      height: viewport.height,
      prev: {
        width: prevWidth,
        height: prevHeight
      },
      sizeChanged,
      element: viewport.element
    }));
  }

  /**
   * Add new panels after the last panel
   * @ko 패널 목록의 제일 끝에 새로운 패널들을 추가합니다
   * @param {ElementLike | ElementLike[]} element A new HTMLElement, a outerHTML of element, or an array of both
   * <ko>새로운 HTMLElement, 혹은 엘리먼트의 outerHTML, 혹은 그것들의 배열</ko>
   * @return {Panel[]} An array of appended panels<ko>추가된 패널들의 배열</ko>
   * @see Panel
   * @see ElementLike
   * @throws {FlickingError} {@link ERROR_CODE ERROR_CODE.NOT_ALLOWED_IN_FRAMEWORK} if called on frameworks (React, Angular, Vue...)
   * @example
   * ```ts
   * const flicking = new Flicking("#flick");
   * // These are possible parameters
   * flicking.append(document.createElement("div"));
   * flicking.append("\<div\>Panel\</div\>");
   * flicking.append(["\<div\>Panel\</div\>", document.createElement("div")]);
   * // Even this is possible
   * flicking.append("\<div\>Panel 1\</div\>\<div\>Panel 2\</div\>");
   * ```
   */
  public append(element: ElementLike | ElementLike[]): Panel[] {
    return this.insert(this._renderer.panelCount, element);
  }

  /**
   * Add new panels before the first panel
   * This will increase index of panels after by the number of panels added
   * @ko 패널 목록의 제일 앞(index 0)에 새로운 패널들을 추가합니다
   * 추가한 패널의 개수만큼 기존 패널들의 인덱스가 증가합니다.
   * @param {ElementLike | ElementLike[]} element A new HTMLElement, a outerHTML of element, or an array of both
   * <ko>새로운 HTMLElement, 혹은 엘리먼트의 outerHTML, 혹은 그것들의 배열</ko>
   * @return {Panel[]} An array of prepended panels<ko>추가된 패널들의 배열</ko>
   * @see Panel
   * @see ElementLike
   * @throws {FlickingError} {@link ERROR_CODE ERROR_CODE.NOT_ALLOWED_IN_FRAMEWORK} if called on frameworks (React, Angular, Vue...)
   * @example
   * ```ts
   * const flicking = new eg.Flicking("#flick");
   * flicking.prepend(document.createElement("div"));
   * flicking.prepend("\<div\>Panel\</div\>");
   * flicking.prepend(["\<div\>Panel\</div\>", document.createElement("div")]);
   * // Even this is possible
   * flicking.prepend("\<div\>Panel 1\</div\>\<div\>Panel 2\</div\>");
   * ```
   */
  public prepend(element: ElementLike | ElementLike[]): Panel[] {
    return this.insert(0, element);
  }

  /**
   * Insert new panels at given index
   * This will increase index of panels after by the number of panels added
   * @ko 주어진 인덱스에 새로운 패널들을 추가합니다
   * 해당 인덱스보다 같거나 큰 인덱스를 가진 기존 패널들은 추가한 패널의 개수만큼 인덱스가 증가합니다.
   * @param {number} index Index to insert new panels at<ko>새로 패널들을 추가할 인덱스</ko>
   * @param {ElementLike | ElementLike[]} element A new HTMLElement, a outerHTML of element, or an array of both
   * <ko>새로운 HTMLElement, 혹은 엘리먼트의 outerHTML, 혹은 그것들의 배열</ko>
   * @return {Panel[]} An array of prepended panels<ko>추가된 패널들의 배열</ko>
   * @throws {FlickingError} {@link ERROR_CODE ERROR_CODE.NOT_ALLOWED_IN_FRAMEWORK} if called on frameworks (React, Angular, Vue...)
   * @example
   * ```ts
   * const flicking = new eg.Flicking("#flick");
   * flicking.insert(0, document.createElement("div"));
   * flicking.insert(2, "\<div\>Panel\</div\>");
   * flicking.insert(1, ["\<div\>Panel\</div\>", document.createElement("div")]);
   * // Even this is possible
   * flicking.insert(3, "\<div\>Panel 1\</div\>\<div\>Panel 2\</div\>");
   * ```
   */
  public insert(index: number, element: ElementLike | ElementLike[]): Panel[] {
    if (this._renderExternal) {
      throw new FlickingError(ERROR.MESSAGE.NOT_ALLOWED_IN_FRAMEWORK, ERROR.CODE.NOT_ALLOWED_IN_FRAMEWORK);
    }

    return this._renderer.batchInsert({ index, elements: parseElement(element), hasDOMInElements: true });
  }

  /**
   * Remove the panel at the given index
   * This will decrease index of panels after by the number of panels removed
   * @ko 주어진 인덱스의 패널을 제거합니다
   * 해당 인덱스보다 큰 인덱스를 가진 기존 패널들은 제거한 패널의 개수만큼 인덱스가 감소합니다
   * @param {number} index Index of panel to remove<ko>제거할 패널의 인덱스</ko>
   * @param {number} [deleteCount=1] Number of panels to remove from index<ko>`index` 이후로 제거할 패널의 개수</ko>
   * @return {Panel[]} An array of removed panels<ko>제거된 패널들의 배열</ko>
   */
  public remove(index: number, deleteCount: number = 1): Panel[] {
    if (this._renderExternal) {
      throw new FlickingError(ERROR.MESSAGE.NOT_ALLOWED_IN_FRAMEWORK, ERROR.CODE.NOT_ALLOWED_IN_FRAMEWORK);
    }

    return this._renderer.batchRemove({ index, deleteCount, hasDOMInElements: true });
  }

  private _createControl(): Control {
    const moveType = this._moveType;
    const moveTypes = Object.keys(MOVE_TYPE).map(key => MOVE_TYPE[key] as ValueOf<typeof MOVE_TYPE>);

    const moveTypeStr = Array.isArray(moveType)
      ? moveType[0]
      : moveType;

    const moveTypeOptions = Array.isArray(moveType)
      ? moveType[1] ?? {}
      : {};

    if (!includes(moveTypes, moveTypeStr)) {
      throw new FlickingError(ERROR.MESSAGE.WRONG_OPTION("moveType", JSON.stringify(moveType)), ERROR.CODE.WRONG_OPTION);
    }

    switch (moveTypeStr) {
      case MOVE_TYPE.SNAP:
        return new SnapControl(moveTypeOptions as SnapControlOptions);
      case MOVE_TYPE.FREE_SCROLL:
        return new FreeControl(moveTypeOptions as FreeControlOptions);
      case MOVE_TYPE.STRICT:
        return new StrictControl(moveTypeOptions as StrictControlOptions);
    }
  }

  private _createCamera(): Camera {
    if (this._circular && this._bound) {
      // eslint-disable-next-line no-console
      console.warn("\"circular\" and \"bound\" option cannot be used together, ignoring bound.");
    }

    return new Camera(this, {
      align: this._align
    });
  }

  private _createRenderer(): Renderer {
    const externalRenderer = this._externalRenderer;
    if (this._virtual && this._panelsPerView <= 0) {
      // eslint-disable-next-line no-console
      console.warn("\"virtual\" and \"panelsPerView\" option should be used together, ignoring virtual.");
    }

    return externalRenderer
      ? externalRenderer
      : this._renderExternal
        ? this._createExternalRenderer()
        : this._createVanillaRenderer();
  }

  private _createExternalRenderer(): ExternalRenderer {
    const {
      renderer,
      rendererOptions
    } = this._renderExternal!;

    return new (renderer)({ align: this._align, ...rendererOptions });
  }

  private _createVanillaRenderer(): VanillaRenderer {
    const virtual = this.virtualEnabled;

    return new VanillaRenderer({
      align: this._align,
      strategy: virtual
        ? new VirtualRenderingStrategy()
        : new NormalRenderingStrategy({
          providerCtor: VanillaElementProvider
        })
    });
  }

  private _moveToInitialPanel(): void {
    const renderer = this._renderer;
    const control = this._control;
    const camera = this._camera;
    const defaultPanel = renderer.getPanel(this._defaultIndex) || renderer.getPanel(0);

    if (!defaultPanel) return;

    const nearestAnchor = camera.findNearestAnchor(defaultPanel.position);
    const initialPanel = (nearestAnchor && defaultPanel.index !== nearestAnchor.panel.index) ? nearestAnchor.panel : defaultPanel;
    control.setActive(initialPanel, null, false);

    if (!nearestAnchor) {
      throw new FlickingError(ERROR.MESSAGE.POSITION_NOT_REACHABLE(initialPanel.position), ERROR.CODE.POSITION_NOT_REACHABLE);
    }

    let position = initialPanel.position;

    if (!camera.canReach(initialPanel)) {
      position = nearestAnchor.position;
    }

    camera.lookAt(position);
    control.updateInput();
    camera.updateOffset();
  }

  private _initialResize() {
    const viewport = this._viewport;
    const renderer = this._renderer;
    const camera = this._camera;
    const control = this._control;

    this.trigger(new ComponentEvent(EVENTS.BEFORE_RESIZE, {
      width: 0,
      height: 0,
      element: viewport.element
    }));

    viewport.resize();
    renderer.updatePanelSize();
    camera.updateAlignPos();
    camera.updateRange();
    camera.updateAnchors();
    camera.updateOffset();
    control.updateInput();

    const newWidth = viewport.width;
    const newHeight = viewport.height;
    const sizeChanged = newWidth !== 0 || newHeight !== 0;

    this.trigger(new ComponentEvent(EVENTS.AFTER_RESIZE, {
      width: viewport.width,
      height: viewport.height,
      prev: {
        width: 0,
        height: 0
      },
      sizeChanged,
      element: viewport.element
    }));
  }
}

export default Flicking;