using sc.modeling.splines.runtime;
using System.Collections.Generic;
using Unity.VisualScripting;
using UnityEngine;
using UnityEngine.Splines;
using UVC.Data.Core;

public enum conveyorType
{
    partial,
    overall
}
public class ConveyorComponent : ComponentBase
{
    public List<ConveyorTarget> ConveyorQueue = new List<ConveyorTarget>();
    public Stack<ConveyorTarget> WaitingQueue = new Stack<ConveyorTarget>();
    public List<SplineMesher> mesher = new List<SplineMesher>();
    SplineContainer spline;
    float duration = 3f;

    // === 추가: 슬롯 기반 제어 ===
    public conveyorType type = conveyorType.overall;
    public int segmentCount = 10;           // 칸 개수
    public float borderEpsilon = 1e-4f;     // 경계 떨림 방지
    bool[] occupancy;                       // 프레임 점유 캐시

    // Start is called once before the first execution of Update after the MonoBehaviour is created
    void Start()
    {
        spline = GetComponent<SplineContainer>();
        occupancy = new bool[Mathf.Max(1, segmentCount)];
        EntityManager.Instance.OnEntityDestroyed += UnSetEntity;
    }

    // Update is called once per frame
    void Update()
    {
        /*
        if (Input.GetKeyDown(KeyCode.G))
        {
            GameObject target = GameObject.CreatePrimitive(PrimitiveType.Cube);
            var cTraget = target.AddComponent<ConveyorTarget>();
            cTraget.Progress = 0f;
            ConveyorQueue.Add(cTraget);
        }

        if (Input.GetKeyDown(KeyCode.S))
        {
            // 출구에서 한 개 배출
            if (WaitingQueue.Count > 0)
            {
                var target = WaitingQueue.Pop();
                Destroy(target.gameObject);
            }
        }

        if (type == conveyorType.overall)
        {
            if (WaitingQueue.Count < 1)
            {
                SetProgress(Time.deltaTime / duration);
                MoveOnConveyor();
            }
        }
        else // partial
        {
            SetProgress(Time.deltaTime / duration);
            MoveOnConveyor();
        }
        */
        SetProgress(Time.deltaTime / duration);
        MoveOnConveyor();
    }


    void SetConveyorEntity(Entity entity)
    {
        var cTarget = entity.gameObject.GetComponent<ConveyorTarget>();
        cTarget.transform.SetParent(this.transform, worldPositionStays: false);
        cTarget.Progress = 0f;
        ConveyorQueue.Add(cTarget);
    }

    public void SetModelData(DataObject datas)
    {
        var data = datas.GetDataObject("data");
        var entityId = data.GetString("entity_id_original");
        var entity = EntityManager.Instance.GetEntity(entityId,this);
        if (entity == null)
        {
            Debug.Log(entityId);
            Debug.Log(entity);
        }
        duration = (float)data.GetFloat("travel_time");
        SetConveyorEntity(entity);
    }

    public void UnSetEntity(Entity entity)
    {
        var cTarget = entity.gameObject.GetComponent<ConveyorTarget>();
        if (ConveyorQueue.Contains(cTarget))
        {
            ConveyorQueue.Remove(cTarget);
        }
    }

    public void UnSetModelData(DataObject datas)
    {
        var data = datas.GetDataObject("data");
        var entityId = data.GetString("entity_id_original");
        var entity = EntityManager.Instance.GetEntity(entityId,this);
        var cTarget = entity.gameObject.GetComponent<ConveyorTarget>();
        if (ConveyorQueue.Contains(cTarget))
        {
            ConveyorQueue.Remove(cTarget);
        }
    }
    void SetProgress(float progress)
    {
        if (ConveyorQueue.Count == 0) return;

        if (type == conveyorType.overall)
        {
            // 기존: 전 화물 동일 진행
            foreach (var target in ConveyorQueue)
            {
                target.Progress += progress;
                if (target.Progress > 1f) target.Progress = 1f;
            }
        }
        else
        {
            // 슬롯 기반: 끝 칸이 막혀 있어도 압축 전진
            PartialAdvance(progress);
        }
    }

    void MoveOnConveyor()
    {
        Spline s = spline.Splines[0];

        for (int i = ConveyorQueue.Count - 1; i >= 0; i--)
        {
            var target = ConveyorQueue[i];
            Vector3 localPos = SplineUtility.EvaluatePosition(s, target.Progress);
            target.transform.position = localPos;
            target.transform.position += new Vector3(0, 1f, -0.275f);

            // 끝(1.0) 도달 → WaitingQueue로 이동(배출 대기)
            if (target.Progress >= 1f)
            {
                ConveyorQueue.RemoveAt(i);
                WaitingQueue.Push(target);
            }
        }
    }

    // === 한 칸씩 채우는 압축 로직 ===
    void PartialAdvance(float delta)
    {
        // 끝에 가까운 순서로 처리 → 뒤따르는 한계 계산이 정확
        ConveyorQueue.Sort((a, b) => b.Progress.CompareTo(a.Progress));

        int cellCount = Mathf.Max(1, segmentCount);
        float cell = 1f / cellCount;

        if (occupancy == null || occupancy.Length != cellCount)
            occupancy = new bool[cellCount];
        System.Array.Clear(occupancy, 0, occupancy.Length);

        // ★ 중요: 출구가 막혀 있으면 마지막 칸을 항상 점유된 것으로 간주
        if (WaitingQueue.Count > 0)
            occupancy[cellCount - 1] = true;

        foreach (var t in ConveyorQueue)
        {
            float desired = Mathf.Min(1f, t.Progress + delta);

            int currCell = CellIndex(t.Progress, cellCount);
            int wantCell = CellIndex(desired, cellCount);

            int allowedCell = currCell;
            // 앞칸이 비어 있으면 한 칸 더, 또 비어 있으면 또 한 칸… 식으로 최대 전진
            for (int c = currCell + 1; c <= wantCell && c < cellCount; c++)
            {
                if (occupancy[c]) break;
                allowedCell = c;
            }

            // 허용 칸의 끝 경계 직전까지
            float maxProg = Mathf.Min(desired, CellEnd(allowedCell, cellCount) - borderEpsilon);

            // 마지막 칸이면 1.0까지 허용(도달 시 MoveOnConveyor에서 대기열로 이동)
            if (allowedCell == cellCount - 1)
                maxProg = Mathf.Min(desired, 1f);

            t.Progress = Mathf.Clamp01(maxProg);

            // 점유 표시
            int newCell = CellIndex(t.Progress, cellCount);
            occupancy[newCell] = true;
        }
    }

    int CellIndex(float progress, int cellCount)
    {
        float cell = 1f / cellCount;
        int idx = Mathf.FloorToInt(progress / cell);
        return Mathf.Clamp(idx, 0, cellCount - 1);
    }
    float CellEnd(int cellIndex, int cellCount)
    {
        float cell = 1f / cellCount;
        return (cellIndex + 1) * cell;
    }

    void UpdateKnot(BezierKnot knot, int index, int splineIndex)
    {
        spline.Splines[splineIndex].SetKnot(index, knot);
    }

    void UpdateMesh()
    {
        foreach (var m in mesher)
        {
            m.Rebuild();
        }
    }
}