FutureMen/Assets/Scripts/Weapons/EnemyBullet/LeviathanBullet.cs

using System;
using System.Collections;
using System.Collections.Generic;
using DG.Tweening;
using DragonLi.Core;
using DragonLi.Frame;
using Unity.VisualScripting;
using UnityEngine;
using Random = UnityEngine.Random;

public class LeviathanBullet : EnemyBullet
{
    [Header("物理参数")]
    private float groundDetectDistance = 0.7f; // 射线检测距离

    private Rigidbody _rb;
    private bool _initialized = false;

    public bool isUpBullet;
    public override void Awake()
    {
        base.Awake();
        _rb = GetComponent<Rigidbody>();
        // 确保物理驱动，重力生效
        _rb.isKinematic = false;
        _rb.useGravity = true;
    }
    
    /// <summary>
    /// 从外部调用，设置初速度以打中 targetPoint
    /// </summary>
    public void Initialize(Vector3 startPos, Vector3 targetPoint, float flightTime)
    {
        transform.position = startPos;

        // 计算初速度
        Vector3 delta = targetPoint - startPos;
        Vector3 g = Physics.gravity;
        Vector3 v0 = delta / flightTime - 0.5f * g * flightTime;
        _rb.velocity = v0;

        // 初始朝向
        if (v0.sqrMagnitude > 0.01f)
            transform.rotation = Quaternion.LookRotation(v0.normalized);
        _initialized = true;
    }
    
    private Vector3 _startPos;
    private Vector3 _targetPos;
    private float   _flightTime;
    private float   _arcHeight;
    private float   _elapsed;
    /// <summary>
    /// 外部调用，初始化一次性发射参数
    /// </summary>
    public void Initialize(Vector3 startPos, Vector3 targetPos, float flightTime, float arcHeight)
    {
        _startPos    = startPos;
        _targetPos   = targetPos;
        _flightTime  = flightTime;
        _arcHeight   = arcHeight;
        _elapsed     = 0f;

        transform.position = _startPos;
        // 初始朝向发射方向
        Vector3 dir = (_targetPos - _startPos).normalized;
        if (dir.sqrMagnitude > 0.01f)
            transform.rotation = Quaternion.LookRotation(dir);
        _initialized = true;
    }
    
    internal override void FixedUpdate()
    {
        if (!_initialized) return;
        if (isUpBullet)
        {
            UpFly();
            return;
        }
        Fly();
    }

    public void Fly()
    {
        // 始终面向速度方向
        Vector3 vel = _rb.velocity;
        if (vel.sqrMagnitude > 0.01f)
            _rb.rotation = Quaternion.LookRotation(vel.normalized);

        // —— 射线检测地面 —— 
        // 从导弹当前点向下发一条短射线，如果击中 groundLayer，就认定触地并爆炸
        float checkDist = groundDetectDistance + vel.magnitude * Time.fixedDeltaTime;
        if (Physics.Raycast(transform.position, Vector3.down, out RaycastHit hit, checkDist, targetHitLayer))
        {
            handlingHit = hit;
            Explode();
        }
    }

    public void UpFly()
    {
        _elapsed += Time.deltaTime;
        float t = Mathf.Clamp01(_elapsed / _flightTime);

        // 1. 直线插值
        Vector3 basePos = Vector3.Lerp(_startPos, _targetPos, t);
        // 2. 正弦叠加高度
        float heightOffset = Mathf.Sin(Mathf.PI * t) * _arcHeight;
        Vector3 curPos = basePos + Vector3.up * heightOffset;
        transform.position = curPos;

        // 3. 调整朝向：面向下一个位置
        float nextT = Mathf.Min(t + 0.02f, 1f);
        Vector3 nextBase = Vector3.Lerp(_startPos, _targetPos, nextT);
        float nextHeight = Mathf.Sin(Mathf.PI * nextT) * _arcHeight;
        Vector3 nextPos = nextBase + Vector3.up * nextHeight;
        Vector3 forwardDir = (nextPos - curPos).normalized;
        if (forwardDir.sqrMagnitude > 0.01f)
            transform.rotation = Quaternion.LookRotation(forwardDir);

        // 4. 到达终点
        if (t >= 1f)
        {
            Explode();
        }
    }
    
    private void Explode()
    {
        // 避免重复触发
        if (!_initialized) return;
        _initialized = false;
        OnFixedUpdate();
        SpawnImpact();
        // 2. 范围伤害
        Collider[] victims = Physics.OverlapSphere(transform.position, explosionRadius, targetHitLayer);
        foreach (var item in victims)
        {
            var damagable = item.GetComponent<IDamagable>();
            if (damagable!= null)
            {
                int randomDamage = GetDamage(out var isCriticalHit);
                damagable.ApplyDamage(randomDamage, isCriticalHit, transform);
            } 
        }
    }
    
    // 辅助调试
    private void OnDrawGizmosSelected()
    {
        // 可视化射线长度和爆炸范围
        Gizmos.color = Color.cyan;
        Gizmos.DrawLine(transform.position, transform.position + Vector3.down * groundDetectDistance);
        Gizmos.color = Color.yellow;
        Gizmos.DrawWireSphere(transform.position, explosionRadius);
    }
}