using UnityEngine;

namespace MazeGen
{
    /// <summary>
    /// Placeholder visual for a Room: a flat tinted square sized to the room's radius.
    /// Swap this out for real prefabs later without touching generation logic.
    /// </summary>
    [RequireComponent(typeof(SpriteRenderer))]
    public class RoomView : MonoBehaviour
    {
        private static Sprite _sharedSquareSprite;

        public static Sprite SharedSquareSprite
        {
            get
            {
                if (_sharedSquareSprite == null)
                {
                    var tex = Texture2D.whiteTexture;
                    _sharedSquareSprite = Sprite.Create(
                        tex, new Rect(0, 0, tex.width, tex.height),
                        new Vector2(0.5f, 0.5f), tex.width);
                }
                return _sharedSquareSprite;
            }
        }

        public Room RoomData { get; private set; }

        public void Initialize(Room room)
        {
            RoomData = room;

            // Elbow-connector hallways know both doors they join - render as a stretched
            // strip along that path instead of a small square, so the corridor actually
            // looks like it spans the gap between the two rooms it connects.
            if (room.Kind == RoomKind.Hallway && room.CorridorWaypoints != null && room.CorridorWaypoints.Length >= 2)
            {
                GetComponent<SpriteRenderer>().enabled = false;
                Color color = ColorFor(room.Kind);
                for (int i = 0; i < room.CorridorWaypoints.Length - 1; i++)
                    SpawnCorridorSegment(room.CorridorWaypoints[i], room.CorridorWaypoints[i + 1], room.Radius, color);
                return;
            }

            transform.position = room.Position;
            transform.localScale = Vector3.one * (room.Radius * 2f);

            var sr = GetComponent<SpriteRenderer>();
            sr.sprite = SharedSquareSprite;
            sr.color = ColorFor(room.Kind);
        }

        private void SpawnCorridorSegment(Vector2 a, Vector2 b, float radius, Color color)
        {
            Vector2 mid = (a + b) * 0.5f;
            float length = Vector2.Distance(a, b);
            if (length < 0.01f) return;
            float angle = Mathf.Atan2(b.y - a.y, b.x - a.x) * Mathf.Rad2Deg;

            var segmentGO = new GameObject("CorridorSegment");
            segmentGO.transform.SetParent(transform, false);
            segmentGO.transform.position = new Vector3(mid.x, mid.y, transform.position.z);
            segmentGO.transform.rotation = Quaternion.Euler(0f, 0f, angle);
            segmentGO.transform.localScale = new Vector3(length, radius * 2f, 1f);

            var sr = segmentGO.AddComponent<SpriteRenderer>();
            sr.sprite = SharedSquareSprite;
            sr.color = color;
        }

        private static Color ColorFor(RoomKind kind)
        {
            switch (kind)
            {
                case RoomKind.Start: return new Color(0.2f, 0.6f, 1f);
                case RoomKind.Exit: return new Color(1f, 0.3f, 0.3f);
                case RoomKind.Hallway: return new Color(0.6f, 0.6f, 0.6f);
                default: return new Color(0.3f, 0.8f, 0.4f);
            }
        }
    }
}