/**
 * MySet
 * @author guobin201314@gmail.com on 2019-03-09
 */
export class MySet {
    private readonly collection: any[];

    constructor() {
        this.collection = [];
    }

    has(el: any): boolean {
        return this.collection.indexOf(el, 0) !== -1;
    }

    values(): any[] {
        return this.collection;
    }

    add(el: any): boolean {
        if (this.has(el)) {
            return false;
        } else {
            this.collection.push(el);
            return true;
        }
    }

    size(): number {
        return this.collection.length;
    }

    remove(el: any): boolean {
        if (this.has(el)) {
            const index = this.collection.indexOf(el);
            this.collection.splice(index, 1);
            return true;
        } else {
            return false;
        }
    }

    /**
     * 并集
     * @param otherSet
     */
    public union(otherSet: MySet): Set<any> {
        const unionSet = new Set();
        const firstSet = this.values();
        const secondSet = otherSet.values();
        firstSet.forEach(el => unionSet.add(el));
        secondSet.forEach(el => unionSet.add(el));
        return unionSet;
    }

    /**
     * 交集
     * @param otherSet
     */
    public intersection(otherSet: MySet): Set<any> {
        const intersection = new Set();
        const first = this.values();
        first.forEach(el => {
            if (otherSet.has(el)) {
                intersection.add(el);
            }
        });
        return intersection;
    }

    /**
     * 差集
     * @param otherSet
     */
    public difference(otherSet: MySet): Set<any> {
        const difference = new Set();
        const first = this.values();
        first.forEach(el => {
            if (!otherSet.has(el)) {
                difference.add(el);
            }
        });
        return difference;
    }

    /**
     * 子集
     * @param otherSet
     */
    public subset(otherSet: MySet): boolean {
        const first = this.values();
        return first.every(value => {
            return otherSet.has(value);
        });
    }
}