import * as React from 'react';
import { useEffect, useRef } from 'react';

import {
  emojiFromElement,
  isEmojiElement,
  NullableElement,
} from '../DomUtils/selectors';
import {
  useActiveSkinToneState,
  useDisallowClickRef,
  useEmojiVariationPickerState,
  useUpdateSuggested,
} from '../components/context/PickerContext';
import { GetEmojiUrl } from '../components/emoji/Emoji';
import {
  useGetEmojiUrlConfig,
  useOnEmojiClickConfig,
} from '../config/useConfig';
import { DataEmoji } from '../dataUtils/DataTypes';
import {
  activeVariationFromUnified,
  emojiHasVariations,
  emojiNames,
  emojiUnified,
} from '../dataUtils/emojiSelectors';
import { parseNativeEmoji } from '../dataUtils/parseNativeEmoji';
import { setsuggested } from '../dataUtils/suggested';
import { EmojiClickData, EmojiStyle, SkinTones } from '../types/exposedTypes';

import { useCloseAllOpenToggles } from './useCloseAllOpenToggles';
import useSetVariationPicker from './useSetVariationPicker';

export function useMouseDownHandlers(
  BodyRef: React.MutableRefObject<NullableElement>
) {
  const mouseDownTimerRef = useRef<undefined | number>();
  const setVariationPicker = useSetVariationPicker();
  const disallowClickRef = useDisallowClickRef();
  const [, setEmojiVariationPicker] = useEmojiVariationPickerState();
  const closeAllOpenToggles = useCloseAllOpenToggles();
  const [activeSkinTone] = useActiveSkinToneState();
  const onEmojiClick = useOnEmojiClickConfig();
  const [, updateSuggested] = useUpdateSuggested();
  const getEmojiUrl = useGetEmojiUrlConfig();

  const onClick = React.useCallback(
    function onClick(event: MouseEvent) {
      if (disallowClickRef.current) {
        return;
      }

      closeAllOpenToggles();

      const [emoji, unified] = emojiFromEvent(event);

      if (!emoji || !unified) {
        return;
      }

      const skinToneToUse =
        activeVariationFromUnified(unified) || activeSkinTone;

      updateSuggested();
      setsuggested(emoji, skinToneToUse);
      onEmojiClick(emojiClickOutput(emoji, skinToneToUse, getEmojiUrl), event);
    },
    [
      activeSkinTone,
      closeAllOpenToggles,
      disallowClickRef,
      onEmojiClick,
      updateSuggested,
      getEmojiUrl,
    ]
  );

  const onMouseDown = React.useCallback(
    function onMouseDown(event: MouseEvent) {
      if (mouseDownTimerRef.current) {
        clearTimeout(mouseDownTimerRef.current);
      }

      const [emoji] = emojiFromEvent(event);

      if (!emoji || !emojiHasVariations(emoji)) {
        return;
      }

      mouseDownTimerRef.current = window?.setTimeout(() => {
        disallowClickRef.current = true;
        mouseDownTimerRef.current = undefined;
        closeAllOpenToggles();
        setVariationPicker(event.target as HTMLElement);
        setEmojiVariationPicker(emoji);
      }, 500);
    },
    [
      disallowClickRef,
      closeAllOpenToggles,
      setVariationPicker,
      setEmojiVariationPicker,
    ]
  );
  const onMouseUp = React.useCallback(
    function onMouseUp() {
      if (mouseDownTimerRef.current) {
        clearTimeout(mouseDownTimerRef.current);
        mouseDownTimerRef.current = undefined;
      } else if (disallowClickRef.current) {
        // The problem we're trying to overcome here
        // is that the emoji has both mouseup and click events
        // and when releasing a mouseup event
        // the click gets triggered too
        // So we're disallowing the click event for a short time

        requestAnimationFrame(() => {
          disallowClickRef.current = false;
        });
      }
    },
    [disallowClickRef]
  );

  useEffect(() => {
    if (!BodyRef.current) {
      return;
    }
    const bodyRef = BodyRef.current;
    bodyRef.addEventListener('click', onClick, {
      passive: true,
    });

    bodyRef.addEventListener('mousedown', onMouseDown, {
      passive: true,
    });
    bodyRef.addEventListener('mouseup', onMouseUp, {
      passive: true,
    });

    return () => {
      bodyRef?.removeEventListener('click', onClick);
      bodyRef?.removeEventListener('mousedown', onMouseDown);
      bodyRef?.removeEventListener('mouseup', onMouseUp);
    };
  }, [BodyRef, onClick, onMouseDown, onMouseUp]);
}

function emojiFromEvent(event: MouseEvent): [DataEmoji, string] | [] {
  const target = event?.target as HTMLElement;
  if (!isEmojiElement(target)) {
    return [];
  }

  return emojiFromElement(target);
}

function emojiClickOutput(
  emoji: DataEmoji,
  activeSkinTone: SkinTones,
  getEmojiUrl: GetEmojiUrl
): EmojiClickData {
  const unified = emojiUnified(emoji, activeSkinTone);
  return {
    activeSkinTone,
    emoji: parseNativeEmoji(unified),
    getImageUrl(emojiStyle: EmojiStyle) {
      return getEmojiUrl(unified, emojiStyle);
    },
    names: emojiNames(emoji),
    unified,
    unifiedWithoutSkinTone: emojiUnified(emoji),
  };
}