// @flow
import uniqBy from 'lodash/uniqBy';
import escapeRegExp from 'lodash/escapeRegExp';

import parseCSV from '../../utils/parseCSV';

import type { Option } from './flowTypes';

// Custom input parser for the PillSelectorDropdownField that automatically maps
// a list of comma separated values to their respective Option objects. The parser
// will try to find exact but case-insenstive matches using the option's displayText
// property. If a token does not match displayText, the parser will also try to match
// the string representation of the value property. This last match is useful for country
// codes and other similar use cases.
function defaultInputParser(inputValue: string, options: Array<Option>, selectedOptions: Array<Option>): Array<Option> {
    let mappedOptions;
    const inputTokens = parseCSV(inputValue);

    mappedOptions = inputTokens.map(
        (inputToken: string): Option => {
            const trimmedInputToken = inputToken.replace(/\s/g, '');
            const escapedInputToken = escapeRegExp(trimmedInputToken);
            const regex = new RegExp(`^${escapedInputToken}$`, 'i');

            const existingOption = options.find(
                ({ displayText, value }: Option) =>
                    // Match name without whitespace or commas
                    regex.test(displayText.replace(/\s|,/g, '')) || regex.test(String(value)),
            );
            const mappedOption = existingOption || {
                displayText: inputToken,
                value: inputToken,
            };
            return mappedOption;
        },
    );
    // Remove duplicate values
    mappedOptions = uniqBy(mappedOptions, mappedOption => mappedOption.value);
    // Remove previously selected values
    mappedOptions = mappedOptions.filter(
        mappedOption => !selectedOptions.some(selectedOption => mappedOption.value === selectedOption.value),
    );
    return mappedOptions;
}

export default defaultInputParser;