using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Graphics;
using RecrownedAthenaeum.Camera;
using System;

namespace RecrownedAthenaeum.Render
{
    /// <summary>
    /// Renders rectangles using the <see cref="PrimitiveBatch"/>.
    /// </summary>
    public class RectangleRenderer : IDisposable
    {
        private bool disposed;
        /// <summary>
        /// The <see cref="PrimitiveBatch"/> used. Needs to be disposed.
        /// </summary>
        private readonly PrimitiveBatch primitiveBatch;

        /// <summary>
        /// Creates a rectangle renderer with the given <see cref="PrimitiveBatch"/>.
        /// </summary>
        /// <param name="camera">Camera to use for <see cref="PrimitiveBatch"/>. Default will use <see cref="Configuration"/>.</param>
        /// <param name="graphicsDevice">Graphics device to use. Default will use <see cref="Configuration"/>.</param>
        public RectangleRenderer(Camera2D camera = null, GraphicsDevice graphicsDevice = null)
        {
            primitiveBatch = new PrimitiveBatch(camera, graphicsDevice, 4);
        }

        /// <summary>
        /// Disposes the rectangle renderer.
        /// </summary>
        public void Dispose()
        {
            Dispose(true);
        }

        /// <summary>
        /// Overridable for dispose.
        /// </summary>
        /// <param name="disposing">True when its a player calling the dispose.</param>
        public virtual void Dispose(bool disposing)
        {
            if (disposed) throw new ObjectDisposedException(GetType().Name);
            if (disposing)
            {
                primitiveBatch.Dispose();
            }
            disposed = true;
        }

        /// <summary>
        /// Draws a basic rectangle given bottom left and top right.
        /// </summary>
        /// <param name="x">X coordinate of bottom left.</param>
        /// <param name="y">Y coordinate of bottom left.</param>
        /// <param name="width">Width of rectangle.</param>
        /// <param name="height">Height of rectangle.</param>
        /// <param name="color">Color of all vertices of this rectangle.</param>
        /// <param name="rotation">Rotation of rectangle. Default is 0 radians.</param>
        /// <param name="filled">If this rectangle should be filled.</param>
        public void Draw(int x, int y, int width, int height, Color color, double rotation = 0, bool filled = false)
        {
            primitiveBatch.Begin(filled ? PrimitiveType.TriangleStrip : PrimitiveType.LineStrip);

            Vector2[] corners = new Vector2[4];

            double topRightAngleFromOrig = Math.Atan((double)height / width);
            corners[0] = new Vector2(x, y);
            corners[1] = new Vector2(x + (float)Math.Cos(rotation) * width, y + (float)Math.Sin(rotation) * width);
            float origDiagonalHypotenuse = (float)Math.Sqrt((width * width) + (height * height));
            corners[2] = new Vector2(x + (float)Math.Cos(topRightAngleFromOrig + rotation) * origDiagonalHypotenuse, y + (float)Math.Sin(topRightAngleFromOrig + rotation) * origDiagonalHypotenuse);
            corners[3] = new Vector2(x - (float)(Math.Cos((Math.PI / 2f) - rotation) * height), y + (float)(Math.Sin((Math.PI / 2f) - rotation) * height));

            if (filled)
            {
                primitiveBatch.AddVertex(corners[1], color);
                primitiveBatch.AddVertex(corners[2], color);
                primitiveBatch.AddVertex(corners[0], color);
                primitiveBatch.AddVertex(corners[3], color);
            }
            else
            {
                primitiveBatch.AddVertex(corners[0], color);
                primitiveBatch.AddVertex(corners[1], color);
                primitiveBatch.AddVertex(corners[2], color);
                primitiveBatch.AddVertex(corners[3], color);
            }

            primitiveBatch.End();
        }
    }
}