using System.Collections.Generic;
using UnityEngine;

public enum BuildAxis
{
    X, // YZ plane
    Y, // XZ plane (horizontal)
    Z  // XY plane
}

public class VirtualPlatformManager : MonoBehaviour
{
    private static VirtualPlatformManager instance;

    [Header("Platform Settings")]
    [SerializeField] private float platformThickness = 0.1f;

    [Header("Visual Settings")]
    [SerializeField] private bool showGrid = true;
    [SerializeField] private float gridSpacing = 1f;
    [SerializeField] private int gridExtent = 50; // How many grid lines from center
    [SerializeField] private float lineWidth = 0.5f;
    [SerializeField] private Color gridColor = new Color(1f, 1f, 1f, 0.3f);
    [SerializeField] private Material gridMaterial;

    [Header("Current Platform")]
    [SerializeField] private BuildAxis currentAxis = BuildAxis.Y;
    [SerializeField] private float currentDistance = 0f;

    private List<LineRenderer> gridLines = new List<LineRenderer>();

    private GameObject currentPlatform;
    private GameObject gridVisual;
    private GameObject colliderObj;
    private BoxCollider platformCollider;
    private Camera mainCamera;

    private void Awake()
    {
        if (instance == null) instance = this;
        else Destroy(this.gameObject);
    }
    public static VirtualPlatformManager getInstance() => instance;

    private void Start()
    {
        mainCamera = Camera.main;

        if (gridMaterial == null)
        {
            gridMaterial = new Material(Shader.Find("Sprites/Default"));
        }

        CreatePlatform();
    }

    private void LateUpdate()
    {
        if (showGrid && gridVisual != null)
        {
            UpdateGridPosition();
        }

        // Update collider position and size to match grid
        if (platformCollider != null)
        {
            UpdateColliderPosition();
        }
    }

    private void UpdateGridPosition()
    {
        Vector3 cameraPos = mainCamera.transform.position;
        Vector3 planeOrigin = GetPlatformOrigin();
        Vector3 axis1, axis2;
        GetPlatformAxes(out axis1, out axis2);

        Vector3 relativePos = cameraPos - planeOrigin;
        float coord1 = Mathf.Round(Vector3.Dot(relativePos, axis1) / gridSpacing) * gridSpacing;
        float coord2 = Mathf.Round(Vector3.Dot(relativePos, axis2) / gridSpacing) * gridSpacing;

        Vector3 gridCenter = planeOrigin + axis1 * coord1 + axis2 * coord2;

        UpdateGridLines(gridCenter, axis1, axis2);
    }

    private void UpdateColliderPosition()
    {
        Vector3 cameraPos = mainCamera.transform.position;
        Vector3 planeOrigin = GetPlatformOrigin();
        Vector3 axis1, axis2;
        GetPlatformAxes(out axis1, out axis2);

        // Project camera position onto the plane
        Vector3 relativePos = cameraPos - planeOrigin;
        float coord1 = Vector3.Dot(relativePos, axis1);
        float coord2 = Vector3.Dot(relativePos, axis2);

        // Center collider on camera's projected position
        Vector3 colliderCenter = planeOrigin + axis1 * coord1 + axis2 * coord2;
        colliderObj.transform.position = colliderCenter;

        // Make collider large enough to cover the grid
        float colliderSize = gridExtent * gridSpacing * 2f;
        platformCollider.size = new Vector3(colliderSize, platformThickness, colliderSize);
    }

    private void UpdateGridLines(Vector3 center, Vector3 axis1, Vector3 axis2)
    {
        int lineIndex = 0;

        // Update lines along axis1
        for (int i = -gridExtent; i <= gridExtent; i++)
        {
            Vector3 offset = axis2 * (i * gridSpacing);
            Vector3 start = center + offset - axis1 * (gridExtent * gridSpacing);
            Vector3 end = center + offset + axis1 * (gridExtent * gridSpacing);

            if (lineIndex < gridLines.Count)
            {
                gridLines[lineIndex].SetPosition(0, start);
                gridLines[lineIndex].SetPosition(1, end);
            }
            lineIndex++;
        }

        // Update lines along axis2
        for (int i = -gridExtent; i <= gridExtent; i++)
        {
            Vector3 offset = axis1 * (i * gridSpacing);
            Vector3 start = center + offset - axis2 * (gridExtent * gridSpacing);
            Vector3 end = center + offset + axis2 * (gridExtent * gridSpacing);

            if (lineIndex < gridLines.Count)
            {
                gridLines[lineIndex].SetPosition(0, start);
                gridLines[lineIndex].SetPosition(1, end);
            }
            lineIndex++;
        }
    }

    public void SwitchToAxis(BuildAxis axis)
    {
        currentAxis = axis;
        RecreatePlatform();
    }

    public void MovePlatform(float delta)
    {
        currentDistance += delta;
        UpdatePlatformDistance();
    }

    public void SetPlatformDistance(float distance)
    {
        currentDistance = distance;
        UpdatePlatformDistance();
    }

    private void UpdatePlatformDistance()
    {
        // Just update the rotation/orientation without recreating everything
        SetupPlatformTransform();
    }

    private void RecreatePlatform()
    {
        if (currentPlatform != null)
            Destroy(currentPlatform);
        if (gridVisual != null)
            Destroy(gridVisual);

        CreatePlatform();
    }

    private void CreatePlatform()
    {
        // Create container
        currentPlatform = new GameObject($"Platform_{currentAxis}_{currentDistance}");
        currentPlatform.transform.parent = transform;

        // Create invisible collider platform
        colliderObj = new GameObject("Collider");
        colliderObj.transform.parent = currentPlatform.transform;
        colliderObj.layer = LayerMask.NameToLayer("World");

        platformCollider = colliderObj.AddComponent<BoxCollider>();

        // Position and orient the platform based on axis
        SetupPlatformTransform();

        // Create visual grid if enabled
        if (showGrid)
        {
            CreateGridVisual();
        }
    }

    private void CreateGridVisual()
    {
        gridVisual = new GameObject("GridVisual");
        gridVisual.transform.parent = currentPlatform.transform;

        // Pre-create all line renderers
        int totalLines = (gridExtent * 2 + 1) * 2;
        gridLines.Clear();

        for (int i = 0; i < totalLines; i++)
        {
            LineRenderer line = CreateLine(Vector3.zero, Vector3.zero);
            gridLines.Add(line);
        }
    }

    private void SetupPlatformTransform()
    {
        Vector3 rotation = Vector3.zero;

        switch (currentAxis)
        {
            case BuildAxis.X: // YZ plane
                rotation = new Vector3(0, 0, 90);
                break;

            case BuildAxis.Y: // XZ plane (horizontal)
                rotation = Vector3.zero;
                break;

            case BuildAxis.Z: // XY plane
                rotation = new Vector3(90, 0, 0);
                break;
        }

        colliderObj.transform.rotation = Quaternion.Euler(rotation);

        // Initial position will be updated in LateUpdate
        UpdateColliderPosition();
    }

    private LineRenderer CreateLine(Vector3 start, Vector3 end)
    {
        GameObject lineObj = new GameObject("GridLine");
        lineObj.transform.parent = gridVisual.transform;

        LineRenderer line = lineObj.AddComponent<LineRenderer>();

        line.material = gridMaterial;
        line.startColor = gridColor;
        line.endColor = gridColor;
        line.startWidth = lineWidth;
        line.endWidth = lineWidth;
        line.positionCount = 2;
        line.SetPosition(0, start);
        line.SetPosition(1, end);
        line.useWorldSpace = true;

        return line;
    }

    private Vector3 GetPlatformOrigin()
    {
        switch (currentAxis)
        {
            case BuildAxis.X:
                return new Vector3(currentDistance, 0, 0);
            case BuildAxis.Y:
                return new Vector3(0, currentDistance, 0);
            case BuildAxis.Z:
                return new Vector3(0, 0, currentDistance);
            default:
                return Vector3.zero;
        }
    }

    private void GetPlatformAxes(out Vector3 axis1, out Vector3 axis2)
    {
        switch (currentAxis)
        {
            case BuildAxis.X: // YZ plane
                axis1 = Vector3.up;
                axis2 = Vector3.forward;
                break;
            case BuildAxis.Y: // XZ plane
                axis1 = Vector3.right;
                axis2 = Vector3.forward;
                break;
            case BuildAxis.Z: // XY plane
                axis1 = Vector3.right;
                axis2 = Vector3.up;
                break;
            default:
                axis1 = Vector3.right;
                axis2 = Vector3.up;
                break;
        }
    }

    public void ToggleGridVisibility(bool visible)
    {
        showGrid = visible;
        if (gridVisual != null)
            gridVisual.SetActive(visible);
    }

    public BuildAxis GetCurrentAxis() => currentAxis;
    public float GetCurrentDistance() => currentDistance;
    public Vector3 GetPlatformPosition() => GetPlatformOrigin();
}