using System.Collections;
using UnityEngine;
using BaseGames.Combat;
using BaseGames.Core;
using BaseGames.Core.Pool;

namespace BaseGames.Enemies.Abilities
{
    /// <summary>
    /// 远程射弹能力（扇形 / 弹幕）。
    /// 每段攻击按 projectileFireT 触发，从池中生成 projectileCount 个抛射物，
    /// 按 spreadAngleDeg 均布角度。
    /// </summary>
    public sealed class ProjectileAttackAbility : EnemyAbilityBase
    {
        [Header("发射点（为空则使用本物体位置）")]
        [SerializeField] private Transform _muzzle;

        [Header("行为")]
        [SerializeField] private bool _faceTargetOnStart = true;

        private IObjectPoolService _pool;

        protected override void Awake()
        {
            base.Awake();
            if (_muzzle == null) _muzzle = _transform;
        }

        protected override IEnumerator ExecuteCoroutine()
        {
            _pool ??= ServiceLocator.GetOrDefault<IObjectPoolService>();
            var seq = _config != null ? _config.attackSequence : null;
            if (seq == null || seq.Length == 0) yield break;

            if (_faceTargetOnStart && _enemy != null && _enemy.PlayerTransform != null)
                FaceTarget(_enemy.PlayerTransform);

            for (int i = 0; i < seq.Length; i++)
            {
                var atk = seq[i];
                if (atk == null) continue;
                yield return PlayShot(atk);
                if (atk.postDelay > 0f) yield return EnemyAbilityWaits.Get(atk.postDelay);
            }
        }

        private IEnumerator PlayShot(EnemyAttackSO atk)
        {
            Phase = AbilityRunState.Active;
            float duration = atk.fallbackDuration;
            if (atk.clip != null && _animancer != null)
            {
                var state = _animancer.Play(atk.clip);
                if (state != null && state.Length > 0f) duration = state.Length;
            }

            float fireAbs = atk.projectileFireT * duration;
            float t = 0f;
            bool fired = false;

            while (t < duration)
            {
                t += Time.deltaTime;
                if (!fired && t >= fireAbs)
                {
                    SpawnVolley(atk);
                    fired = true;
                }
                yield return null;
            }
            if (!fired) SpawnVolley(atk);
        }

        private void SpawnVolley(EnemyAttackSO atk)
        {
            if (_pool == null || atk.projectileConfig == null) return;
            var cfg = atk.projectileConfig;
            if (string.IsNullOrEmpty(cfg.PoolKey)) return;

            Vector2 baseDir = GetAimDirection();
            int count = Mathf.Max(1, atk.projectileCount);
            float spread = atk.spreadAngleDeg;
            float startAngle = -spread * 0.5f;
            float step = count > 1 ? spread / (count - 1) : 0f;

            var src    = atk.damageSource != null ? atk.damageSource : cfg.DamageSource;
            int layer  = gameObject.layer;

            for (int i = 0; i < count; i++)
            {
                float angle = startAngle + step * i;
                Vector2 dir = Rotate(baseDir, angle);

                var go = _pool.Spawn(cfg.PoolKey, _muzzle.position, Quaternion.identity);
                if (go == null)
                {
                    Debug.LogWarning($"[ProjectileAttackAbility] 对象池 '{cfg.PoolKey}' 无法获取弹体，请检查池配置或容量。", this);
                    continue;
                }
                var proj = go.GetComponent<Projectile>();
                if (proj == null)
                {
                    Debug.LogWarning($"[ProjectileAttackAbility] 弹体 '{go.name}' 缺少 Projectile 组件，请检查 Prefab 配置。", this);
                    continue;
                }
                var info = DamageInfo.From(src, dir, _muzzle.position, layer, proj);
                proj.Initialize(cfg, info, dir, layer);
            }
        }

        private Vector2 GetAimDirection()
        {
            if (_enemy != null && _enemy.PlayerTransform != null)
                return ((Vector2)_enemy.PlayerTransform.position - (Vector2)_muzzle.position).normalized;
            return _transform.localScale.x >= 0f ? Vector2.right : Vector2.left;
        }

        private static Vector2 Rotate(Vector2 v, float degrees)
        {
            float rad = degrees * Mathf.Deg2Rad;
            float c = Mathf.Cos(rad), s = Mathf.Sin(rad);
            return new Vector2(v.x * c - v.y * s, v.x * s + v.y * c);
        }
    }
}