using System.Collections;
using UnityEngine;

public class ArcherSkill : UnitSkill
{
    [Min(1)]
    public int volleyArrowCount = 3;

    [Min(0f)]
    public float volleyArrowDamageMultiplier = 0.7f;

    [Min(0f)]
    public float volleyArrowInterval = 0.15f;

    private Coroutine volleyCoroutine;

    public override void ReleaseSkill()
    {
        if (volleyCoroutine != null)
        {
            StopCoroutine(volleyCoroutine);
        }

        volleyCoroutine = StartCoroutine(FireVolley());
    }

    private IEnumerator FireVolley()
    {
        for (int i = 0; i < volleyArrowCount; i++)
        {
            // 三连射优先攻击当前目标；目标阵亡后剩余箭矢改打最近敌人。
            GameObject volleyTarget = unit.Target != null ? unit.Target : FindNearestOpponent();
            if (volleyTarget == null)
            {
                break;
            }

            unit.FireSkillProjectile(volleyTarget, volleyArrowDamageMultiplier);
            yield return new WaitForSeconds(volleyArrowInterval);
        }

        volleyCoroutine = null;
    }

    private GameObject FindNearestOpponent()
    {
        string opponentTag = unit.OpponentTag;
        if (string.IsNullOrEmpty(opponentTag))
        {
            return null;
        }

        GameObject nearestOpponent = null;
        float nearestSqrDistance = float.PositiveInfinity;
        GameObject[] opponents = GameObject.FindGameObjectsWithTag(opponentTag);
        foreach (GameObject opponent in opponents)
        {
            if (opponent == null || opponent.transform.root == unit.transform.root)
            {
                continue;
            }

            float sqrDistance = (opponent.transform.position - unit.transform.position).sqrMagnitude;
            if (sqrDistance < nearestSqrDistance)
            {
                nearestSqrDistance = sqrDistance;
                nearestOpponent = opponent;
            }
        }

        return nearestOpponent;
    }
}