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

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

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

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

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

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

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

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

        for (const it of bucket) if (this.key_eq_(it.first, key)) return it;

        return this.source_.end();
    }
}

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