import { ParsingContext } from "../../../chrono";
import { ParsingComponents } from "../../../results";
import { WEEKDAY_DICTIONARY } from "../constants";
import { matchAnyPattern } from "../../../utils/pattern";
import { AbstractParserWithWordBoundaryChecking } from "../../../common/parsers/AbstractParserWithWordBoundary";
import { createParsingComponentsAtWeekday } from "../../../calculation/weekdays";
import { Weekday } from "../../../types";

const PATTERN = new RegExp(
    "(?:(?:\\,|\\(|\\（)\\s*)?" +
        "(?:(questo|questa|quest'|scorso|scorsa|prossimo|prossima)\\s*)?" +
        `(${matchAnyPattern(WEEKDAY_DICTIONARY)}|weekend|fine\\s*settimana)` +
        "(?:\\s*(?:\\,|\\)|\\）))?" +
        "(?:\\s*(scorso|scorsa|prossimo|prossima)(?:\\s*settimana)?)?" +
        "(?=\\W|$)",
    "i"
);

const PREFIX_GROUP = 1;
const WEEKDAY_GROUP = 2;
const POSTFIX_GROUP = 3;

export default class ITWeekdayParser extends AbstractParserWithWordBoundaryChecking {
    innerPattern(): RegExp {
        return PATTERN;
    }

    innerExtract(context: ParsingContext, match: RegExpMatchArray): ParsingComponents | null {
        const prefix = match[PREFIX_GROUP];
        const postfix = match[POSTFIX_GROUP];
        let modifierWord = prefix || postfix;
        modifierWord = modifierWord || "";
        modifierWord = modifierWord.toLowerCase();

        let modifier = null;
        if (modifierWord == "scorso" || modifierWord == "scorsa") {
            modifier = "last";
        } else if (modifierWord == "prossimo" || modifierWord == "prossima") {
            modifier = "next";
        } else if (modifierWord == "questo" || modifierWord == "questa" || modifierWord == "quest'") {
            modifier = "this";
        }

        const weekday_word = match[WEEKDAY_GROUP].toLowerCase();
        let weekday;
        if (WEEKDAY_DICTIONARY[weekday_word] !== undefined) {
            weekday = WEEKDAY_DICTIONARY[weekday_word];
        } else if (weekday_word == "weekend" || weekday_word.match(/fine\s*settimana/)) {
            // 'Questo/prossimo weekend' means the coming Saturday, 'scorso weekend' means last Sunday.
            weekday = modifier == "last" ? Weekday.SUNDAY : Weekday.SATURDAY;
        } else {
            return null;
        }

        return createParsingComponentsAtWeekday(context.reference, weekday, modifier);
    }
}