// Copyright: Ankitects Pty Ltd and contributors
// License: GNU AGPL, version 3 or later; http://www.gnu.org/licenses/agpl.html

export enum MatchResult {
    /* Having this be 0 allows for falsy tests */
    NO_MATCH = 0,
    /* Element matches the predicate and may be removed */
    MATCH,
    /* Element matches the predicate, but may not be removed
     * This typically means that the element has other properties which prevent it from being removed */
    KEEP,
    /* Element (or Text) is situated adjacent to a match */
    ALONG,
}

/**
 * Should be pure
 */
export type ElementMatcher = (
    element: Element,
) => Exclude<MatchResult, MatchResult.ALONG>;

/**
 * Is applied to values that match with KEEP
 * Should be idempotent
 */
export type ElementClearer = (element: Element) => boolean;

export const matchTagName =
    (tagName: string): ElementMatcher =>
    (element: Element) => {
        return element.matches(tagName) ? MatchResult.MATCH : MatchResult.NO_MATCH;
    };

export interface FoundMatch {
    element: Element;
    matchType: Exclude<MatchResult, MatchResult.NO_MATCH | MatchResult.ALONG>;
}

export interface FoundAlong {
    element: Element | Text;
    matchType: MatchResult.ALONG;
}

export type FoundAdjacent = FoundMatch | FoundAlong;