using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class FootprintHintManager : MonoBehaviour
{
    [Header("VR Player Reference")]
    [Tooltip("XR OriginÀÇ Main Camera TransformÀ» ³Ö´Â °ÍÀ» ÃßõÇÕ´Ï´Ù.")]
    [SerializeField] private Transform playerTarget;

    [Header("Footprint Prefabs")]
    [SerializeField] private GameObject leftFootPrefab;
    [SerializeField] private GameObject rightFootPrefab;

    [Header("Footprint Settings")]
    [SerializeField] private int footprintCount = 6;
    [SerializeField] private float spacing = 0.45f;
    [SerializeField] private float sideOffset = 0.13f;
    [SerializeField] private float showTime = 2f;
    [SerializeField] private bool startWithLeftFoot = true;

    [Header("Ground Settings")]
    [SerializeField] private bool useGroundRaycast = true;
    [SerializeField] private LayerMask groundMask = ~0;
    [SerializeField] private float raycastHeight = 2f;
    [SerializeField] private float raycastDistance = 5f;
    [SerializeField] private float groundOffset = 0.03f;
    [SerializeField] private float fallbackGroundY = 0f;

    private readonly List<GameObject> spawnedFootprints = new List<GameObject>();
    private Coroutine footprintRoutine;

    public void ShowFootprints(MazeDirection direction)
    {
        if (footprintRoutine != null)
            StopCoroutine(footprintRoutine);

        footprintRoutine = StartCoroutine(ShowFootprintRoutine(direction));
    }

    private IEnumerator ShowFootprintRoutine(MazeDirection direction)
    {
        ClearFootprints();

        if (playerTarget == null)
        {
            Debug.LogWarning("FootprintHintManager: Player Target is missing.");
            footprintRoutine = null;
            yield break;
        }

        if (leftFootPrefab == null || rightFootPrefab == null)
        {
            Debug.LogWarning("FootprintHintManager: Left Foot Prefab or Right Foot Prefab is missing.");
            footprintRoutine = null;
            yield break;
        }

        Vector3 moveDirection = GetWorldDirection(direction);

        if (moveDirection == Vector3.zero)
        {
            footprintRoutine = null;
            yield break;
        }

        Vector3 sideDirection = Vector3.Cross(Vector3.up, moveDirection).normalized;

        for (int i = 0; i < footprintCount; i++)
        {
            bool isLeftFoot = startWithLeftFoot ? i % 2 == 0 : i % 2 != 0;

            GameObject prefabToUse = isLeftFoot ? leftFootPrefab : rightFootPrefab;

            float forwardDistance = spacing * (i + 1);
            float leftRightOffset = isLeftFoot ? -sideOffset : sideOffset;

            Vector3 spawnPosition =
                playerTarget.position +
                moveDirection * forwardDistance +
                sideDirection * leftRightOffset;

            Quaternion spawnRotation = Quaternion.LookRotation(moveDirection, Vector3.up);

            PlaceOnGround(ref spawnPosition, ref spawnRotation, moveDirection);

            GameObject footprint = Instantiate(
                prefabToUse,
                spawnPosition,
                spawnRotation
            );

            spawnedFootprints.Add(footprint);
        }

        yield return new WaitForSeconds(showTime);

        ClearFootprints();
        footprintRoutine = null;
    }

    private Vector3 GetWorldDirection(MazeDirection direction)
    {
        Vector3 forward = playerTarget.forward;
        Vector3 right = playerTarget.right;

        forward.y = 0f;
        right.y = 0f;

        forward.Normalize();
        right.Normalize();

        switch (direction)
        {
            case MazeDirection.Forward:
                return forward;

            case MazeDirection.Backward:
                return -forward;

            case MazeDirection.Left:
                return -right;

            case MazeDirection.Right:
                return right;

            case MazeDirection.None:
            default:
                return Vector3.zero;
        }
    }

    private void PlaceOnGround(
        ref Vector3 position,
        ref Quaternion rotation,
        Vector3 moveDirection
    )
    {
        if (!useGroundRaycast)
        {
            position.y = fallbackGroundY + groundOffset;
            return;
        }

        Vector3 rayStart = position + Vector3.up * raycastHeight;

        if (Physics.Raycast(rayStart, Vector3.down, out RaycastHit hit, raycastDistance, groundMask))
        {
            position = hit.point + hit.normal * groundOffset;

            Vector3 projectedForward =
                Vector3.ProjectOnPlane(moveDirection, hit.normal).normalized;

            if (projectedForward.sqrMagnitude > 0.001f)
                rotation = Quaternion.LookRotation(projectedForward, hit.normal);
        }
        else
        {
            position.y = fallbackGroundY + groundOffset;
        }
    }

    public void ClearFootprints()
    {
        foreach (GameObject footprint in spawnedFootprints)
        {
            if (footprint != null)
                Destroy(footprint);
        }

        spawnedFootprints.Clear();
    }
}