//================================================================
/**
 * @packageDocumentation
 * @module std.internal
 */
//================================================================
import { HashBuckets } from "./HashBuckets";

import { IHashSet } from "../../base/container/IHashSet";
import { Comparator } from "../functional/Comparator";
import { Hasher } from "../functional/Hasher";

/**
 * Hash buckets for set containers
 *
 * @author Jeongho Nam - https://github.com/samchon
 */
export class SetHashBuckets<
    Key,
    Unique extends boolean,
    Source extends IHashSet<Key, Unique, Source>,
> extends HashBuckets<Key, IHashSet.Iterator<Key, Unique, Source>> {
    private source_: IHashSet<Key, Unique, Source>;
    private readonly key_eq_: Comparator<Key>;

    /* ---------------------------------------------------------
        CONSTRUCTORS
    --------------------------------------------------------- */
    /**
     * Initializer Constructor
     *
     * @param source Source set container
     * @param hasher Hash function
     * @param pred Equality function
     */
    public constructor(
        source: IHashSet<Key, Unique, Source>,
        hasher: Hasher<Key>,
        pred: Comparator<Key>,
    ) {
        super(fetcher, hasher);

        this.source_ = source;
        this.key_eq_ = pred;
    }

    /**
     * @internal
     */
    public static _Swap_source<
        Key,
        Unique extends boolean,
        Source extends IHashSet<Key, Unique, Source>,
    >(
        x: SetHashBuckets<Key, Unique, Source>,
        y: SetHashBuckets<Key, Unique, Source>,
    ): void {
        [x.source_, y.source_] = [y.source_, x.source_];
    }

    /* ---------------------------------------------------------
        FINDERS
    --------------------------------------------------------- */
    public key_eq(): Comparator<Key> {
        return this.key_eq_;
    }

    public find(val: Key): IHashSet.Iterator<Key, Unique, Source> {
        const index: number = this.hash_function()(val) % this.length();
        const bucket: IHashSet.Iterator<Key, Unique, Source>[] = this.at(index);

        for (const it of bucket) if (this.key_eq_(it.value, val)) return it;

        return this.source_.end();
    }
}

function fetcher<
    Key,
    Unique extends boolean,
    Source extends IHashSet<Key, Unique, Source>,
>(elem: IHashSet.Iterator<Key, Unique, Source>): Key {
    return elem.value;
}