/**
 * 项目禁用原生 Set（小游戏运行时对部分 Set 用法不稳定）。
 * 用 Map<K, true> 表示成员集合；迭代时 yield key（与 Set 一致，而非 Map 的 [key, value]）。
 */
export type MembershipSet<K> = Map<K, true>;
export type ReadonlyMembershipSet<K> = ReadonlyMap<K, true>;

function bindMembershipIterator<K>(set: Map<K, true>): MembershipSet<K> {
    // Map 默认 for-of 迭代 [key,value]；覆盖为仅 yield key（与 Set 一致）
    (set as { [Symbol.iterator]?: () => IterableIterator<K> })[Symbol.iterator] = () => set.keys();
    return set;
}

export function createMembershipSet<K>(): MembershipSet<K> {
    return bindMembershipIterator(new Map<K, true>());
}

export function membershipAdd<K>(set: MembershipSet<K>, key: K): MembershipSet<K> {
    set.set(key, true);
    return set;
}

export function membershipHas<K>(set: ReadonlyMembershipSet<K>, key: K): boolean {
    return set.has(key);
}

export function membershipDelete<K>(set: MembershipSet<K>, key: K): boolean {
    return set.delete(key);
}

export function membershipClear<K>(set: MembershipSet<K>): void {
    set.clear();
}

export function membershipFromArray<K>(items: Iterable<K>): MembershipSet<K> {
    const set = createMembershipSet<K>();
    for (const item of items) {
        set.set(item, true);
    }
    return set;
}

export function membershipToArray<K>(set: ReadonlyMembershipSet<K>): K[] {
    return [...set];
}

/** 去重数组（替代 Array.from(new Set(...)) / [...new Set(...)]） */
export function membershipDedupeArray<K>(items: Iterable<K>): K[] {
    return membershipToArray(membershipFromArray(items));
}

export function membershipForEach<K>(set: ReadonlyMembershipSet<K>, fn: (key: K) => void): void {
    for (const key of set) {
        fn(key);
    }
}