// @flow

import React, { useCallback, useContext, useEffect, useRef } from 'react';
import { TreeDispatcherContext, TreeStateContext } from './TreeContext';
import Button from '../Button';
import ButtonIcon from '../ButtonIcon';
import Icon from '../Icon';

import styles from './SearchInput.css';

type Props = {||};

export default function SearchInput(props: Props) {
  const { searchIndex, searchResults, searchText } = useContext(
    TreeStateContext
  );
  const dispatch = useContext(TreeDispatcherContext);

  const inputRef = useRef<HTMLInputElement | null>(null);

  const handleTextChange = useCallback(
    ({ currentTarget }) =>
      dispatch({ type: 'SET_SEARCH_TEXT', payload: currentTarget.value }),
    [dispatch]
  );
  const resetSearch = useCallback(
    () => dispatch({ type: 'SET_SEARCH_TEXT', payload: '' }),
    [dispatch]
  );

  const handleKeyDown = useCallback(
    event => {
      // For convenience, let up/down arrow keys change Tree selection.
      switch (event.key) {
        case 'ArrowDown':
          dispatch({ type: 'SELECT_NEXT_ELEMENT_IN_TREE' });
          event.preventDefault();
          break;
        case 'ArrowUp':
          dispatch({ type: 'SELECT_PREVIOUS_ELEMENT_IN_TREE' });
          event.preventDefault();
          break;
        default:
          break;
      }
    },
    [dispatch]
  );

  const handleInputKeyPress = useCallback(
    ({ key }) => {
      if (key === 'Enter') {
        dispatch({ type: 'GO_TO_NEXT_SEARCH_RESULT' });
      }
    },
    [dispatch]
  );

  // Auto-focus search input
  useEffect(() => {
    if (inputRef.current === null) {
      return () => {};
    }

    const handleWindowKey = (event: KeyboardEvent) => {
      const { key, metaKey } = event;
      if (key === 'f' && metaKey) {
        if (inputRef.current !== null) {
          inputRef.current.focus();
          event.preventDefault();
          event.stopPropagation();
        }
      }
    };

    // It's important to listen to the ownerDocument to support the browser extension.
    // Here we use portals to render individual tabs (e.g. Profiler),
    // and the root document might belong to a different window.
    const ownerDocument = inputRef.current.ownerDocument;
    ownerDocument.addEventListener('keydown', handleWindowKey);

    return () => ownerDocument.removeEventListener('keydown', handleWindowKey);
  }, [inputRef]);

  return (
    <div className={styles.SearchInput}>
      <Icon className={styles.InputIcon} type="search" />
      <input
        className={styles.Input}
        onChange={handleTextChange}
        onKeyDown={handleKeyDown}
        onKeyPress={handleInputKeyPress}
        placeholder="Search (text or /regex/)"
        ref={inputRef}
        value={searchText}
      />
      {!!searchText && (
        <span className={styles.IndexLabel}>
          {Math.min(searchIndex + 1, searchResults.length)} |{' '}
          {searchResults.length}
        </span>
      )}
      <div className={styles.LeftVRule} />
      <Button
        className={styles.IconButton}
        disabled={!searchText}
        onClick={() => dispatch({ type: 'GO_TO_PREVIOUS_SEARCH_RESULT' })}
        title="Scroll to previous search result"
      >
        <ButtonIcon type="up" />
      </Button>
      <Button
        className={styles.IconButton}
        disabled={!searchText}
        onClick={() => dispatch({ type: 'GO_TO_NEXT_SEARCH_RESULT' })}
        title="Scroll to next search result"
      >
        <ButtonIcon type="down" />
      </Button>
      <Button
        className={styles.IconButton}
        disabled={!searchText}
        onClick={resetSearch}
        title="Reset search"
      >
        <ButtonIcon type="close" />
      </Button>
    </div>
  );
}