import {
    PLURAL_SUFFIX,
    SPELLINGS,
    SUFFIX_SPELLINGS,
    WORD_CHARACTERS,
} from "#configuration/constants/vocabulary.constants";

const SPACE = " ";

const spellingOf = function spellingOf(word: string): string {
    const mapped = SPELLINGS.get(word);
    if (mapped !== undefined) {
        return mapped;
    }
    const suffix = SUFFIX_SPELLINGS.find(([british]) => word.endsWith(british));
    return suffix === undefined ? word : word.slice(0, -suffix[0].length) + suffix[1];
};

export const normalizeWord = function normalizeWord(word: string): string {
    const spelled = spellingOf(word.toLowerCase());
    return spelled.endsWith(PLURAL_SUFFIX) ? spelled.slice(0, -1) : spelled;
};

export const wordsOf = function wordsOf(phrase: string): readonly string[] {
    const words: string[] = [];
    let current = "";
    for (const char of phrase.toLowerCase() + SPACE) {
        if (WORD_CHARACTERS.includes(char)) {
            current += char;
            continue;
        }
        if (current.length > 0) {
            words.push(normalizeWord(current));
            current = "";
        }
    }
    return words;
};