using System.Collections;
using UnityEngine;

public class NoteController : MonoBehaviour
{
    private float speed;
    private bool isMoving = true;
    private bool isInJudgeZone = false; // Documentation text normalized.
    private ParticleSystem hitEffect;
    private Note linkedNote;
    private bool useAbsolutePositioning = false;

    // 去物理判定：用几何阈值复现原 Trigger 的进入/离开时刻。
    private Collider2D _col;
    private float _enterY, _exitY;
    private bool _thresholdsReady;
    
    // For absolute position tracking instead of relative translate
    private Vector3 spawnPosition;
    private float activationTime = -1f;  // When the note should start moving (hitTime - travelTime)
    private float baseSpawnYOffset = 0f; // Initial Y offset from compensation at spawn time

    private void Awake()
    {
        hitEffect = GetComponentInChildren<ParticleSystem>();
        linkedNote = GetComponent<Note>();
        spawnPosition = transform.position;
        _col = GetComponent<Collider2D>();
        // 去物理判定：判定改为几何驱动，音符不再需要 Physics2D 模拟。
        // 关闭 Rigidbody2D 模拟，消除每帧移动 kinematic 刚体触发的物理同步/重叠检测开销。
        // 保留 Collider 组件本身(仅用于读取其 bounds 计算阈值，不参与物理)。
        var rb = GetComponent<Rigidbody2D>();
        if (rb != null) rb.simulated = false;
    }

    private void OnEnable()
    {
        NoteRuntimeTickManager.Register(this);
    }

    private void OnDisable()
    {
        NoteRuntimeTickManager.Unregister(this);
    }

    public void ManualTick(float songTime)
    {
        if (isMoving && useAbsolutePositioning)
        {
            // Use absolute positioning based on elapsed time since activation
            float elapsedSinceActivation = songTime - activationTime;
            float travelDistance = speed * Mathf.Max(0f, elapsedSinceActivation);

            // Position = spawnPoint + initial offset + downward travel
            Vector3 newPos = spawnPosition;
            newPos.y -= (baseSpawnYOffset + travelDistance);
            transform.position = newPos;
        }

        // 去物理判定：用音符 Y 与阈值的比较复现 OnTriggerEnter2D/Exit2D 的进入/离开时刻。
        UpdateJudgeZoneByGeometry();
    }

    private void UpdateJudgeZoneByGeometry()
    {
        if (linkedNote == null) return;
        if (!_thresholdsReady)
        {
            // 判定线捕获后，用音符自身 collider 计算进入/离开阈值(只算一次)。
            if (!JudgeZoneGeometry.LineReady) return;
            if (!JudgeZoneGeometry.TryGetThresholds(_col, transform, out _enterY, out _exitY)) return;
            _thresholdsReady = true;
        }

        float noteY = transform.position.y;
        // 进入：noteY 下降到 ≤ enterY 且尚未进入。
        if (!isInJudgeZone && noteY <= _enterY)
        {
            EnterJudgeZone();
            // 单帧穿透(帧尖峰导致一帧内越过整个判定区)：立即补一次离开，行为与物理一致。
            if (noteY <= _exitY) ExitJudgeZone();
        }
        // 离开：noteY 继续下降到 ≤ exitY 且当前在区内。
        else if (isInJudgeZone && noteY <= _exitY)
        {
            ExitJudgeZone();
        }
    }

    public void SetSpeed(float newSpeed)
    {
        speed = newSpeed;
    }

    public void StopMovement()
    {
        isMoving = false;
    }

    public void PlayHitEffect()
    {
        if (hitEffect != null)
        {
            hitEffect.Play();
        }
    }

    /// <summary>
    /// Configure timing for absolute position tracking.
    /// Call this from NoteSpawner after the note is spawned.
    /// </summary>
    public void ConfigureAbsolutePositioning(Vector3 initialSpawnPos, float hitTime, float travelTime, float initialYOffset)
    {
        spawnPosition = initialSpawnPos;
        activationTime = hitTime - travelTime;
        baseSpawnYOffset = initialYOffset;
        useAbsolutePositioning = true;
        transform.position = GetExpectedPosition(GameplayClock.NowSongTime);
        
        if (JudgeManager.IsDebugEnabled) 
            Debug.Log($"[NoteController] Configured: spawnPos={spawnPosition}, activationTime={activationTime:F3}, initialYOffset={initialYOffset:F4}");
    }

    public Vector3 GetExpectedPosition(float time)
    {
        float elapsedSinceActivation = time - activationTime;
        float travelDistance = speed * Mathf.Max(0f, elapsedSinceActivation);
        Vector3 newPos = spawnPosition;
        newPos.y -= (baseSpawnYOffset + travelDistance);
        return newPos;
    }

    public void ResetState()
    {
        speed = 0f;
        isMoving = true;
        isInJudgeZone = false;
        activationTime = -1f;
        baseSpawnYOffset = 0f;
        spawnPosition = transform.position;
        useAbsolutePositioning = false;
        _thresholdsReady = false; // 池化复用：下次重新计算阈值。
        
        if (hitEffect != null)
        {
            hitEffect.Stop();
            hitEffect.Clear();
        }
    }

    // 进入判定区(原 OnTriggerEnter2D 逻辑，保持完全一致)。
    private void EnterJudgeZone()
    {
        if (linkedNote == null) return;
        isInJudgeZone = true;
        // register note by instance id so TrackKeyManager can prioritize
        // tap notes are short notes without hold
        TrackKeyManager.Instance.RegisterKey(linkedNote.GetTrackIndex(), linkedNote.GetCachedInstanceId(), "tap", linkedNote.HitTime);
    }

    // 离开判定区(原 OnTriggerExit2D 逻辑，保持完全一致)。
    private void ExitJudgeZone()
    {
        if (linkedNote == null) return;
        isInJudgeZone = false;
        TrackKeyManager.Instance.UnregisterKey(linkedNote.GetTrackIndex(), linkedNote.GetCachedInstanceId());
        linkedNote.SetJudgeZone(isInJudgeZone);
    }

    /// <summary>
    /// Query Note whether it's in judge zone
    /// </summary>
    public bool IsInJudgeZone()
    {
        return isInJudgeZone;
    }
}