import {
  AutocompleteState,
  createAutocomplete,
} from '@algolia/autocomplete-core';
import React from 'react';

import { MAX_QUERY_SIZE } from './constants';
import { DocSearchProps } from './DocSearch';
import { Footer } from './Footer';
import { Hit } from './Hit';
import { ScreenState } from './ScreenState';
import { SearchBox } from './SearchBox';
import { createStoredSearches } from './stored-searches';
import {
  DocSearchHit,
  InternalDocSearchHit,
  StoredDocSearchHit,
} from './types';
import { useSearchClient } from './useSearchClient';
import { useTouchEvents } from './useTouchEvents';
import { useTrapFocus } from './useTrapFocus';
import { groupBy, identity, noop, removeHighlightTags } from './utils';

export interface DocSearchModalProps extends DocSearchProps {
  initialScrollY: number;
  onClose?(): void;
}

export function DocSearchModal({
  appId = 'BH4D9OD16A',
  apiKey,
  indexName,
  placeholder = 'Search docs',
  searchParameters,
  onClose = noop,
  transformItems = identity,
  hitComponent = Hit,
  resultsFooterComponent = () => null,
  navigator,
  initialScrollY = 0,
  transformSearchClient = identity,
  disableUserPersonalization = false,
  initialQuery: initialQueryFromProp = '',
}: DocSearchModalProps) {
  const [state, setState] = React.useState<
    AutocompleteState<InternalDocSearchHit>
  >({
    query: '',
    collections: [],
    completion: null,
    context: {},
    isOpen: false,
    activeItemId: null,
    status: 'idle',
  });

  const containerRef = React.useRef<HTMLDivElement | null>(null);
  const modalRef = React.useRef<HTMLDivElement | null>(null);
  const formElementRef = React.useRef<HTMLDivElement | null>(null);
  const dropdownRef = React.useRef<HTMLDivElement | null>(null);
  const inputRef = React.useRef<HTMLInputElement | null>(null);
  const snippetLength = React.useRef<number>(10);
  const initialQueryFromSelection = React.useRef(
    typeof window !== 'undefined'
      ? window.getSelection()!.toString().slice(0, MAX_QUERY_SIZE)
      : ''
  ).current;
  const initialQuery = React.useRef(
    initialQueryFromProp || initialQueryFromSelection
  ).current;

  const searchClient = useSearchClient(appId, apiKey, transformSearchClient);
  const favoriteSearches = React.useRef(
    createStoredSearches<StoredDocSearchHit>({
      key: `__DOCSEARCH_FAVORITE_SEARCHES__${indexName}`,
      limit: 10,
    })
  ).current;
  const recentSearches = React.useRef(
    createStoredSearches<StoredDocSearchHit>({
      key: `__DOCSEARCH_RECENT_SEARCHES__${indexName}`,
      // We display 7 recent searches and there's no favorites, but only
      // 4 when there are favorites.
      limit: favoriteSearches.getAll().length === 0 ? 7 : 4,
    })
  ).current;

  const saveRecentSearch = React.useCallback(
    function saveRecentSearch(item: InternalDocSearchHit) {
      if (disableUserPersonalization) {
        return;
      }

      // We don't store `content` record, but their parent if available.
      const search = item.type === 'content' ? item.__docsearch_parent : item;

      // We save the recent search only if it's not favorited.
      if (
        search &&
        favoriteSearches
          .getAll()
          .findIndex((x) => x.objectID === search.objectID) === -1
      ) {
        recentSearches.add(search);
      }
    },
    [favoriteSearches, recentSearches, disableUserPersonalization]
  );

  const autocomplete = React.useMemo(
    () =>
      createAutocomplete<
        InternalDocSearchHit,
        React.FormEvent<HTMLFormElement>,
        React.MouseEvent,
        React.KeyboardEvent
      >({
        id: 'docsearch',
        defaultActiveItemId: 0,
        placeholder,
        openOnFocus: true,
        initialState: {
          query: initialQuery,
          context: {
            searchSuggestions: [],
          },
        },
        navigator,
        onStateChange({ state }) {
          setState(state);
        },
        // @ts-ignore Temporarily ignore bad typing in autocomplete-core.
        getSources({ query, state, setContext, setStatus }) {
          if (!query) {
            if (disableUserPersonalization) {
              return [];
            }

            return [
              {
                sourceId: 'recentSearches',
                onSelect({ item, event }) {
                  saveRecentSearch(item);

                  if (!event.shiftKey && !event.ctrlKey && !event.metaKey) {
                    onClose();
                  }
                },
                getItemUrl({ item }) {
                  return item.url;
                },
                getItems() {
                  return recentSearches.getAll();
                },
              },
              {
                sourceId: 'favoriteSearches',
                onSelect({ item, event }) {
                  saveRecentSearch(item);

                  if (!event.shiftKey && !event.ctrlKey && !event.metaKey) {
                    onClose();
                  }
                },
                getItemUrl({ item }) {
                  return item.url;
                },
                getItems() {
                  return favoriteSearches.getAll();
                },
              },
            ];
          }

          return searchClient
            .search<DocSearchHit>([
              {
                query,
                indexName,
                params: {
                  attributesToRetrieve: [
                    'hierarchy.lvl0',
                    'hierarchy.lvl1',
                    'hierarchy.lvl2',
                    'hierarchy.lvl3',
                    'hierarchy.lvl4',
                    'hierarchy.lvl5',
                    'hierarchy.lvl6',
                    'content',
                    'type',
                    'url',
                  ],
                  attributesToSnippet: [
                    `hierarchy.lvl1:${snippetLength.current}`,
                    `hierarchy.lvl2:${snippetLength.current}`,
                    `hierarchy.lvl3:${snippetLength.current}`,
                    `hierarchy.lvl4:${snippetLength.current}`,
                    `hierarchy.lvl5:${snippetLength.current}`,
                    `hierarchy.lvl6:${snippetLength.current}`,
                    `content:${snippetLength.current}`,
                  ],
                  snippetEllipsisText: '…',
                  highlightPreTag: '<mark>',
                  highlightPostTag: '</mark>',
                  hitsPerPage: 20,
                  ...searchParameters,
                },
              },
            ])
            .catch((error) => {
              // The Algolia `RetryError` happens when all the servers have
              // failed, meaning that there's no chance the response comes
              // back. This is the right time to display an error.
              // See https://github.com/algolia/algoliasearch-client-javascript/blob/2ffddf59bc765cd1b664ee0346b28f00229d6e12/packages/transporter/src/errors/createRetryError.ts#L5
              if (error.name === 'RetryError') {
                setStatus('error');
              }

              throw error;
            })
            .then(({ results }) => {
              const { hits, nbHits } = results[0];
              const sources = groupBy(hits, (hit) => removeHighlightTags(hit));

              // We store the `lvl0`s to display them as search suggestions
              // in the "no results" screen.
              if (
                (state.context.searchSuggestions as any[]).length <
                Object.keys(sources).length
              ) {
                setContext({
                  searchSuggestions: Object.keys(sources),
                });
              }

              setContext({ nbHits });

              return Object.values<DocSearchHit[]>(sources).map(
                (items, index) => {
                  return {
                    sourceId: `hits${index}`,
                    onSelect({ item, event }) {
                      saveRecentSearch(item);

                      if (!event.shiftKey && !event.ctrlKey && !event.metaKey) {
                        onClose();
                      }
                    },
                    getItemUrl({ item }) {
                      return item.url;
                    },
                    getItems() {
                      return Object.values(
                        groupBy(items, (item) => item.hierarchy.lvl1)
                      )
                        .map(transformItems)
                        .map((hits) =>
                          hits.map((item) => {
                            return {
                              ...item,
                              // eslint-disable-next-line @typescript-eslint/camelcase
                              __docsearch_parent:
                                item.type !== 'lvl1' &&
                                hits.find(
                                  (siblingItem) =>
                                    siblingItem.type === 'lvl1' &&
                                    siblingItem.hierarchy.lvl1 ===
                                      item.hierarchy.lvl1
                                ),
                            };
                          })
                        )
                        .flat();
                    },
                  };
                }
              );
            });
        },
      }),
    [
      indexName,
      searchParameters,
      searchClient,
      onClose,
      recentSearches,
      favoriteSearches,
      saveRecentSearch,
      initialQuery,
      placeholder,
      navigator,
      transformItems,
      disableUserPersonalization,
    ]
  );

  const { getEnvironmentProps, getRootProps, refresh } = autocomplete;

  useTouchEvents({
    getEnvironmentProps,
    panelElement: dropdownRef.current,
    formElement: formElementRef.current,
    inputElement: inputRef.current,
  });
  useTrapFocus({ container: containerRef.current });

  React.useEffect(() => {
    document.body.classList.add('DocSearch--active');

    return () => {
      document.body.classList.remove('DocSearch--active');

      // IE11 doesn't support `scrollTo` so we check that the method exists
      // first.
      window.scrollTo?.(0, initialScrollY);
    };

    // eslint-disable-next-line react-hooks/exhaustive-deps
  }, []);

  React.useEffect(() => {
    const isMobileMediaQuery = window.matchMedia('(max-width: 750px)');

    if (isMobileMediaQuery.matches) {
      snippetLength.current = 5;
    }
  }, []);

  React.useEffect(() => {
    if (dropdownRef.current) {
      dropdownRef.current.scrollTop = 0;
    }
  }, [state.query]);

  // We don't focus the input when there's an initial query (i.e. Selection
  // Search) because users rather want to see the results directly, without the
  // keyboard appearing.
  // We therefore need to refresh the autocomplete instance to load all the
  // results, which is usually triggered on focus.
  React.useEffect(() => {
    if (initialQuery.length > 0) {
      refresh();

      if (inputRef.current) {
        inputRef.current.focus();
      }
    }
  }, [initialQuery, refresh]);

  // We rely on a CSS property to set the modal height to the full viewport height
  // because all mobile browsers don't compute their height the same way.
  // See https://css-tricks.com/the-trick-to-viewport-units-on-mobile/
  React.useEffect(() => {
    function setFullViewportHeight() {
      if (modalRef.current) {
        const vh = window.innerHeight * 0.01;
        modalRef.current.style.setProperty('--docsearch-vh', `${vh}px`);
      }
    }

    setFullViewportHeight();

    window.addEventListener('resize', setFullViewportHeight);

    return () => {
      window.removeEventListener('resize', setFullViewportHeight);
    };
  }, []);

  return (
    <div
      ref={containerRef}
      {...getRootProps({
        'aria-expanded': true,
      })}
      className={[
        'DocSearch',
        'DocSearch-Container',
        state.status === 'stalled' && 'DocSearch-Container--Stalled',
        state.status === 'error' && 'DocSearch-Container--Errored',
      ]
        .filter(Boolean)
        .join(' ')}
      onMouseDown={(event) => {
        if (event.target === event.currentTarget) {
          onClose();
        }
      }}
    >
      <div className="DocSearch-Modal" ref={modalRef}>
        <header className="DocSearch-SearchBar" ref={formElementRef}>
          <SearchBox
            {...autocomplete}
            state={state}
            autoFocus={initialQuery.length === 0}
            onClose={onClose}
            inputRef={inputRef}
            isFromSelection={
              Boolean(initialQuery) &&
              initialQuery === initialQueryFromSelection
            }
          />
        </header>

        <div className="DocSearch-Dropdown" ref={dropdownRef}>
          <ScreenState
            {...autocomplete}
            indexName={indexName}
            state={state}
            hitComponent={hitComponent}
            resultsFooterComponent={resultsFooterComponent}
            disableUserPersonalization={disableUserPersonalization}
            recentSearches={recentSearches}
            favoriteSearches={favoriteSearches}
            onItemClick={(item) => {
              saveRecentSearch(item);
              onClose();
            }}
            inputRef={inputRef}
          />
        </div>

        <footer className="DocSearch-Footer">
          <Footer />
        </footer>
      </div>
    </div>
  );
}