using UnityEngine;
using UnityEngine.UI;
using System.Collections;

namespace GameFramework
{
    /// <summary>
    /// 魂灵掉落物 —— 敌人被灵灯击杀后掉落。
    /// 从敌人位置飞向 HUD 魂灵计数图标，到达后加分并自毁。
    /// </summary>
    public class SoulDrop : MonoBehaviour
    {
        [Header("飞行参数")]
        [Tooltip("飞向 HUD 的飞行时间（秒）")]
        [SerializeField] private float flyDuration = 0.8f;

        [Tooltip("每个掉落物的分数")]
        [SerializeField] private int scoreValue = 1;

        [Header("延迟")]
        [Tooltip("出生后的随机延迟范围（秒），避免所有掉落物同时起飞")]
        [SerializeField] private float delayMin = 0f;
        [SerializeField] private float delayMax = 0.3f;

        private RectTransform _targetUI;
        private SpriteRenderer _sr;

        private void Awake()
        {
            _sr = GetComponent<SpriteRenderer>();
        }

        /// <summary>
        /// 初始化掉落物：设置目标 UI 并启动飞行协程。
        /// </summary>
        public void Initialize(RectTransform targetUI)
        {
            _targetUI = targetUI;
            StartCoroutine(DelayedFly());
        }

        private IEnumerator DelayedFly()
        {
            // 随机延迟，让掉落物有先后起飞的效果
            float delay = Random.Range(delayMin, delayMax);
            if (delay > 0f)
                yield return new WaitForSeconds(delay);

            yield return StartCoroutine(FlyToHUD());
        }

        private IEnumerator FlyToHUD()
        {
            Vector3 startPos = transform.position;
            Camera cam = Camera.main;
            if (cam == null || _targetUI == null)
            {
                // 降级处理：直接加分
                AddScoreAndDestroy();
                yield break;
            }

            // 目标：HUD 魂灵图标的屏幕位置
            Vector3 targetScreenPos = _targetUI.position;
            // 保持深度一致，避免转换出错
            float depth = Mathf.Abs(cam.WorldToScreenPoint(startPos).z);
            targetScreenPos.z = depth;
            Vector3 targetWorldPos = cam.ScreenToWorldPoint(targetScreenPos);

            float elapsed = 0f;
            while (elapsed < flyDuration)
            {
                elapsed += Time.deltaTime;
                float t = Mathf.Clamp01(elapsed / flyDuration);

                // 带弧度的飞行轨迹（先高后低）
                float arc = Mathf.Sin(t * Mathf.PI) * 0.5f;
                Vector3 pos = Vector3.Lerp(startPos, targetWorldPos, t);
                pos.y += arc;
                transform.position = pos;

                // 逐渐缩小 + 旋转
                float scale = Mathf.Lerp(1f, 0.3f, t);
                transform.localScale = Vector3.one * scale;
                transform.Rotate(0, 0, 360f * Time.deltaTime);

                // 渐隐效果（最后 30% 开始变淡）
                if (_sr != null && t > 0.7f)
                {
                    float fadeT = (t - 0.7f) / 0.3f;
                    _sr.color = new Color(_sr.color.r, _sr.color.g, _sr.color.b, 1f - fadeT);
                }

                yield return null;
            }

            AddScoreAndDestroy();
        }

        private void AddScoreAndDestroy()
        {
            // 确保 ScoreManager 存在（直接从 Gameplay 场景启动时可能没有）
            if (ScoreManager.Instance == null)
            {
                var go = new GameObject("ScoreManager");
                go.AddComponent<ScoreManager>();
                Debug.Log("[SoulDrop] 自动创建 ScoreManager");
            }
            Debug.Log($"[SoulDrop] 加分 +{scoreValue}，当前总分: {ScoreManager.Instance.CurrentScore + scoreValue}");
            ScoreManager.Instance.AddScore(scoreValue);
            Destroy(gameObject);
        }
    }
}