/*
 * https://github.com/morethanwords/tweb
 * Copyright (C) 2019-2021 Eduard Kuzmenko
 * https://github.com/morethanwords/tweb/blob/master/LICENSE
 */

import {CustomEmojiRendererElement} from '../lib/richTextProcessor/wrapRichText';
import rootScope from '../lib/rootScope';
import {IS_SAFARI} from '../environment/userAgent';
import {MOUNT_CLASS_TO} from '../config/debug';
import isInDOM from '../helpers/dom/isInDOM';
import RLottiePlayer from '../lib/rlottie/rlottiePlayer';
import indexOfAndSplice from '../helpers/array/indexOfAndSplice';
import forEachReverse from '../helpers/array/forEachReverse';
import idleController from '../helpers/idleController';
import appMediaPlaybackController from './appMediaPlaybackController';
import {fastRaf} from '../helpers/schedulers';

export type AnimationItemGroup = '' | 'none' | 'chat' | 'lock' |
  'STICKERS-POPUP' | 'emoticons-dropdown' | 'STICKERS-SEARCH' | 'GIFS-SEARCH' |
  `CHAT-MENU-REACTIONS-${number}` | 'INLINE-HELPER' | 'GENERAL-SETTINGS' | 'STICKER-VIEWER' | 'EMOJI';
export interface AnimationItem {
  el: HTMLElement,
  group: AnimationItemGroup,
  animation: AnimationItemWrapper
};

export interface AnimationItemWrapper {
  remove: () => void;
  paused: boolean;
  pause: () => any;
  play: () => any;
  autoplay: boolean;
  // onVisibilityChange?: (visible: boolean) => boolean;
};

export class AnimationIntersector {
  private observer: IntersectionObserver;
  private visible: Set<AnimationItem> = new Set();

  private overrideIdleGroups: Set<string>;
  private byGroups: {[group in AnimationItemGroup]?: AnimationItem[]} = {};
  private lockedGroups: {[group in AnimationItemGroup]?: true} = {};
  private onlyOnePlayableGroup: AnimationItemGroup = '';

  private intersectionLockedGroups: {[group in AnimationItemGroup]?: true} = {};
  private videosLocked = false;

  constructor() {
    this.observer = new IntersectionObserver((entries) => {
      // if(rootScope.idle.isIDLE) return;

      for(const entry of entries) {
        const target = entry.target;

        for(const group in this.byGroups) {
          if(this.intersectionLockedGroups[group as AnimationItemGroup]) {
            continue;
          }

          const animation = this.byGroups[group as AnimationItemGroup].find((p) => p.el === target);
          if(!animation) {
            continue;
          }

          if(entry.isIntersecting) {
            this.visible.add(animation);
            this.checkAnimation(animation, false);

            /* if(animation instanceof HTMLVideoElement && animation.dataset.src) {
              animation.src = animation.dataset.src;
              animation.load();
            } */
          } else {
            this.visible.delete(animation);
            this.checkAnimation(animation, true);

            const _animation = animation.animation;
            if(_animation instanceof RLottiePlayer/*  && animation.cachingDelta === 2 */) {
              // console.warn('will clear cache', player);
              _animation.clearCache();
            }/*  else if(animation instanceof HTMLVideoElement && animation.src) {
              animation.dataset.src = animation.src;
              animation.src = '';
              animation.load();
            } */
          }

          break;
        }
      }
    });

    this.overrideIdleGroups = new Set();

    appMediaPlaybackController.addEventListener('play', ({doc}) => {
      if(doc.type === 'round') {
        this.videosLocked = true;
        this.checkAnimations();
      }
    });

    appMediaPlaybackController.addEventListener('pause', () => {
      if(this.videosLocked) {
        this.videosLocked = false;
        this.checkAnimations();
      }
    });

    idleController.addEventListener('change', (idle) => {
      this.checkAnimations(idle);
    });
  }

  public setOverrideIdleGroup(group: string, override: boolean) {
    if(override) this.overrideIdleGroups.add(group);
    else this.overrideIdleGroups.delete(group);
  }

  public getAnimations(element: HTMLElement) {
    const found: AnimationItem[] = [];
    for(const group in this.byGroups) {
      for(const player of this.byGroups[group as AnimationItemGroup]) {
        if(player.el === element) {
          found.push(player);
        }
      }
    }

    return found;
  }

  public removeAnimation(player: AnimationItem) {
    const {el, animation} = player;
    animation.remove();

    if(animation instanceof HTMLVideoElement && IS_SAFARI) {
      setTimeout(() => { // TODO: очистка по очереди, а не все вместе с этим таймаутом
        animation.src = '';
        animation.load();
      }, 1e3);
    }

    const group = this.byGroups[player.group];
    if(group) {
      indexOfAndSplice(group, player);
      if(!group.length) {
        delete this.byGroups[player.group];
      }
    }

    this.observer.unobserve(el);
    this.visible.delete(player);
  }

  public addAnimation(_animation: AnimationItem['animation'], group: AnimationItemGroup = '') {
    if(group === 'none') {
      return;
    }

    let el: HTMLElement;
    if(_animation instanceof RLottiePlayer) {
      el = _animation.el[0];
    } else if(_animation instanceof CustomEmojiRendererElement) {
      el = _animation.canvas;
    } else if(_animation instanceof HTMLElement) {
      el = _animation;
    }

    const animation: AnimationItem = {
      el,
      animation: _animation,
      group
    };

    if(_animation instanceof RLottiePlayer) {
      if(!rootScope.settings.stickers.loop && _animation.loop) {
        _animation.loop = rootScope.settings.stickers.loop;
      }
    }

    (this.byGroups[group as AnimationItemGroup] ??= []).push(animation);
    this.observer.observe(animation.el);
  }

  public checkAnimations(blurred?: boolean, group?: AnimationItemGroup, destroy = false) {
    // if(rootScope.idle.isIDLE) return;

    if(group !== undefined && !this.byGroups[group]) {
      // console.warn('no animation group:', group);
      return;
    }

    const groups = group !== undefined /* && false */ ? [group] : Object.keys(this.byGroups) as AnimationItemGroup[];

    for(const group of groups) {
      const animations = this.byGroups[group];

      forEachReverse(animations, (animation) => {
        this.checkAnimation(animation, blurred, destroy);
      });
    }
  }

  public checkAnimation(player: AnimationItem, blurred = false, destroy = false) {
    const {el, animation, group} = player;
    // return;
    if(destroy || (!this.lockedGroups[group] && !isInDOM(el))) {
      this.removeAnimation(player);
      return;
    }

    if(blurred ||
      (this.onlyOnePlayableGroup && this.onlyOnePlayableGroup !== group) ||
      (animation instanceof HTMLVideoElement && this.videosLocked)
    ) {
      if(!animation.paused) {
        // console.warn('pause animation:', animation);
        animation.pause();
      }
    } else if(animation.paused &&
      this.visible.has(player) &&
      animation.autoplay &&
      (!this.onlyOnePlayableGroup || this.onlyOnePlayableGroup === group) &&
      (!idleController.isIdle || this.overrideIdleGroups.has(player.group))
    ) {
      // console.warn('play animation:', animation);
      animation.play();
    }
  }

  public getOnlyOnePlayableGroup() {
    return this.onlyOnePlayableGroup;
  }

  public setOnlyOnePlayableGroup(group: AnimationItemGroup = '') {
    this.onlyOnePlayableGroup = group;
  }

  public lockGroup(group: AnimationItemGroup) {
    this.lockedGroups[group] = true;
  }

  public unlockGroup(group: AnimationItemGroup) {
    delete this.lockedGroups[group];
    this.checkAnimations(undefined, group);
  }

  public refreshGroup(group: AnimationItemGroup) {
    const animations = this.byGroups[group];
    if(!animations?.length) {
      return;
    }

    animations.forEach((animation) => {
      this.observer.unobserve(animation.el);
    });

    fastRaf(() => {
      animations.forEach((animation) => {
        this.observer.observe(animation.el);
      });
    });
  }

  public lockIntersectionGroup(group: AnimationItemGroup) {
    this.intersectionLockedGroups[group] = true;
  }

  public unlockIntersectionGroup(group: AnimationItemGroup) {
    delete this.intersectionLockedGroups[group];
    this.refreshGroup(group);
  }
}

const animationIntersector = new AnimationIntersector();
MOUNT_CLASS_TO && (MOUNT_CLASS_TO.animationIntersector = animationIntersector);
export default animationIntersector;