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

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

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

export function DocSearchModal({
  appId = 'BH4D9OD16A',
  apiKey,
  indexName,
  placeholder = 'Search docs',
  searchParameters,
  onClose = noop,
  transformItems = (x) => x,
  hitComponent = Hit,
  navigator,
}: DocSearchModalProps) {
  const [state, setState] = React.useState<
    AutocompleteState<InternalDocSearchHit>
  >({
    query: '',
    suggestions: [],
  } as any);

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

  const searchClient = useSearchClient(appId, apiKey);
  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) {
      // 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]
  );

  const autocomplete = React.useMemo(
    () =>
      createAutocomplete<
        InternalDocSearchHit,
        React.FormEvent<HTMLFormElement>,
        React.MouseEvent,
        React.KeyboardEvent
      >({
        id: 'docsearch',
        defaultHighlightedIndex: 0,
        autoFocus: true,
        placeholder,
        openOnFocus: true,
        initialState: {
          query: initialQuery,
          context: {
            searchSuggestions: [],
          },
        },
        navigator,
        onStateChange({ state }) {
          setState(state as any);
        },
        // @ts-ignore Temporarily ignore bad typing in autocomplete-core.
        getSources({ query, state, setContext, setStatus }) {
          if (!query) {
            return [
              {
                onSelect({ suggestion }) {
                  saveRecentSearch(suggestion);
                  onClose();
                },
                getSuggestionUrl({ suggestion }) {
                  return suggestion.url;
                },
                getSuggestions() {
                  return recentSearches.getAll();
                },
              },
              {
                onSelect({ suggestion }) {
                  saveRecentSearch(suggestion);
                  onClose();
                },
                getSuggestionUrl({ suggestion }) {
                  return suggestion.url;
                },
                getSuggestions() {
                  return favoriteSearches.getAll();
                },
              },
            ];
          }

          return getAlgoliaHits({
            searchClient,
            queries: [
              {
                indexName,
                query,
                params: {
                  attributesToRetrieve: [
                    'hierarchy.lvl0',
                    'hierarchy.lvl1',
                    'hierarchy.lvl2',
                    'hierarchy.lvl3',
                    'hierarchy.lvl4',
                    'hierarchy.lvl5',
                    'hierarchy.lvl6',
                    'content',
                    'type',
                    'url',
                  ],
                  attributesToSnippet: [
                    `hierarchy.lvl1:${snipetLength.current}`,
                    `hierarchy.lvl2:${snipetLength.current}`,
                    `hierarchy.lvl3:${snipetLength.current}`,
                    `hierarchy.lvl4:${snipetLength.current}`,
                    `hierarchy.lvl5:${snipetLength.current}`,
                    `hierarchy.lvl6:${snipetLength.current}`,
                    `content:${snipetLength.current}`,
                  ],
                  snippetEllipsisText: '…',
                  highlightPreTag: '<mark>',
                  highlightPostTag: '</mark>',
                  hitsPerPage: 20,
                  distinct: 4,
                  ...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((hits: DocSearchHit[]) => {
              const sources = groupBy(hits, (hit) => hit.hierarchy.lvl0);

              // 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),
                });
              }

              return Object.values<DocSearchHit[]>(sources).map((items) => {
                return {
                  onSelect({ suggestion }) {
                    saveRecentSearch(suggestion);
                    onClose();
                  },
                  getSuggestionUrl({ suggestion }) {
                    return suggestion.url;
                  },
                  getSuggestions() {
                    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,
    ]
  );

  const { getEnvironmentProps, getRootProps, refresh } = autocomplete;

  useTouchEvents({
    getEnvironmentProps,
    dropdownElement: dropdownRef.current,
    searchBoxElement: searchBoxRef.current,
    inputElement: inputRef.current,
  });
  useTrapFocus({ container: containerRef.current });

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

    return () => {
      document.body.classList.remove('DocSearch--active');
      document.body.scrollTop = scrollY.current;
    };
  }, []);

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

    if (isMobileMediaQuery.matches) {
      snipetLength.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();
    }
  }, [initialQuery, refresh]);

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

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

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