using System;
using UnityEngine;
using UnityEngine.UI;

/// <summary>
/// Binds five pre-authored UI touch regions to the existing gameplay input path.
/// This script does not create runtime objects. You assign the region RectTransforms
/// in the inspector, and it ensures each one has an Image raycast target plus a
/// TrackTouchRegion configured with the matching track index.
/// </summary>
[DisallowMultipleComponent]
public class TrackTouchRegionLayoutController : MonoBehaviour
{
    [Serializable]
    public class RegionBinding
    {
        [Range(0, 4)]
        public int trackIndex;

        [Tooltip("Pre-authored UI region to bind. Assign in inspector.")]
        public RectTransform regionObject;

        [Tooltip("Optional debug tint. Alpha 0 keeps the region invisible while preserving raycasts.")]
        public Color debugTint = new Color(1f, 1f, 1f, 0f);
    }

    [Header("Behavior")]
    public bool bindOnStart = true;
    public bool mobileOnly = true;

    [Header("Prebound Regions")]
    public RegionBinding[] regions = new RegionBinding[5];

    private void Reset()
    {
        EnsureDefaultBindings();
    }

    private void Awake()
    {
        EnsureDefaultBindings();
    }

    private void Start()
    {
        if (!bindOnStart)
        {
            return;
        }

        if (mobileOnly && !Application.isMobilePlatform)
        {
            return;
        }

        ApplyBindings();
    }

    [ContextMenu("Apply Touch Region Bindings")]
    public void ApplyBindings()
    {
        EnsureDefaultBindings();

        for (int i = 0; i < regions.Length; i++)
        {
            BindRegion(regions[i], i);
        }
    }

    private void EnsureDefaultBindings()
    {
        if (regions == null || regions.Length != 5)
        {
            regions = new RegionBinding[5];
        }

        for (int i = 0; i < regions.Length; i++)
        {
            if (regions[i] == null)
            {
                regions[i] = new RegionBinding();
            }

            regions[i].trackIndex = Mathf.Clamp(i, 0, 4);
        }
    }

    private static void BindRegion(RegionBinding binding, int fallbackTrackIndex)
    {
        if (binding == null || binding.regionObject == null)
        {
            return;
        }

        int trackIndex = Mathf.Clamp(binding.trackIndex, 0, 4);
        if (trackIndex != fallbackTrackIndex)
        {
            trackIndex = Mathf.Clamp(trackIndex, 0, 4);
        }

        Image image = binding.regionObject.GetComponent<Image>();
        if (image == null)
        {
            image = binding.regionObject.gameObject.AddComponent<Image>();
        }

        image.color = binding.debugTint;
        image.raycastTarget = true;

        TrackTouchRegion touchRegion = binding.regionObject.GetComponent<TrackTouchRegion>();
        if (touchRegion == null)
        {
            touchRegion = binding.regionObject.gameObject.AddComponent<TrackTouchRegion>();
        }

        touchRegion.trackIndex = trackIndex;
    }
}