using System;
using System.Collections.Generic;
using Microsoft.Xna.Framework;

namespace MonoGame.Extended.Tilemaps
{
    /// <summary>
    /// Represents a closed polygonal object in a tilemap.
    /// </summary>
    public class TilemapPolygonObject : TilemapObject
    {
        /// <summary>
        /// Gets or sets the vertices of the polygon relative to the object's position.
        /// </summary>
        public Vector2[] Points { get; set; }

        /// <summary>
        /// Gets the vertices of the polygon in world coordinates.
        /// </summary>
        public IEnumerable<Vector2> WorldPoints
        {
            get
            {
                foreach (var point in Points)
                {
                    yield return Position + point;
                }
            }
        }

        /// <inheritdoc/>
        public override RectangleF Bounds
        {
            get
            {
                if (Points == null || Points.Length == 0)
                    return new RectangleF(Position.X, Position.Y, 0, 0);

                // Calculate bounding box from all world points
                float minX = float.MaxValue;
                float minY = float.MaxValue;
                float maxX = float.MinValue;
                float maxY = float.MinValue;

                foreach (var worldPoint in WorldPoints)
                {
                    minX = Math.Min(minX, worldPoint.X);
                    minY = Math.Min(minY, worldPoint.Y);
                    maxX = Math.Max(maxX, worldPoint.X);
                    maxY = Math.Max(maxY, worldPoint.Y);
                }

                return new RectangleF(minX, minY, maxX - minX, maxY - minY);
            }
        }

        // NOTE: Will use BoundingPolygon2D

        /// <summary>
        /// Initializes a new instance of the <see cref="TilemapPolygonObject"/> class.
        /// </summary>
        /// <param name="id">The unique identifier for the object.</param>
        /// <param name="position">The position of the object (origin point).</param>
        /// <param name="points">The vertices of the polygon relative to the position.</param>
        public TilemapPolygonObject(int id, Vector2 position, Vector2[] points) : base(id, position)
        {
            Points = points;
        }
    }
}