package com.displaynone.acss.utils;

import lombok.Getter;
import org.springframework.lang.NonNull;
import org.springframework.lang.Nullable;
import org.springframework.util.Assert;
import org.springframework.util.ObjectUtils;

import java.util.Map;
import java.util.stream.Collector;
import java.util.stream.Collectors;

@Getter
public final class Pair<S, T> {
    private final S first;
    private final T second;

    private Pair(@NonNull S first, @NonNull T second) {
        Assert.notNull(first, "First must not be null");
        Assert.notNull(second, "Second must not be null");

        this.first = first;
        this.second = second;
    }

    public static <S, T> Pair<S, T> of(@NonNull S first, @NonNull T second) {
        return new Pair<>(first, second);
    }

    public static <S, T> Collector<Pair<S, T>, ?, Map<S, T>> toMap() {
        return Collectors.toMap(Pair::getFirst, Pair::getSecond);
    }

    public boolean equals(@Nullable Object object) {
        if (this == object) return true;
        if (!(object instanceof Pair<?, ?> pair)) return false;

        return ObjectUtils.nullSafeEquals(this.first, pair.first) && ObjectUtils.nullSafeEquals(this.second, pair.second);
    }

    public int hashCode() {
        int result = ObjectUtils.nullSafeHashCode(this.first);
        result = 31 * result + ObjectUtils.nullSafeHashCode(this.second);
        return result;
    }

    public String toString() {
        return String.format("%s->%s", this.first, this.second);
    }
}