using Azimuth;
using Blacklight.Core;
using Blacklight.Core.Cameras;
using Clave;

namespace Konis.Testbed
{
    /// <summary>
    /// Spawns the demo's effect where the left button goes down, on the ground under the pointer.
    /// </summary>
    public class ClickSpawner : IInputConsumer
    {
        private readonly ParticleDemo demo;
        private readonly WindowHandle window;
        private readonly Camera camera;

        public ClickSpawner(ParticleDemo demo, WindowHandle window, Camera camera)
        {
            this.demo = demo;
            this.window = window;
            this.camera = camera;
        }

        /// <summary>
        /// Gets or sets how many seconds ahead of the click a spawned effect starts.
        /// </summary>
        public float PreWarmSeconds { get; set; }

        /// <summary>
        /// Returns where on the ground a pixel of the window shows, or false when the view can't tell.
        /// </summary>
        public bool TryGroundAt(Vector pixel, out Vector3 position)
        {
            // Pixels put the origin top left with y down.  Projection space is centered with y up.
            var centered = new Vector(pixel.X - window.Width / 2.0, -(pixel.Y - window.Height / 2.0));
            Vector scene = camera.ProjectionToWorld.TransformPoint(centered);

            return demo.Projection.TryUnproject(scene, 0, out position);
        }

        public bool PointerDown(PointerInput input)
        {
            if (input.Buttons != PointerButtons.Left || !TryGroundAt(input.PixelPos, out Vector3 position))
            {
                return false;
            }

            demo.Spawn(position, PreWarmSeconds);

            return true;
        }

        public bool PointerMove(PointerInput input)
        {
            return false;
        }

        public bool PointerUp(PointerInput input)
        {
            return false;
        }

        public bool Wheel(Scalar ticks, Vector pixelPos)
        {
            return false;
        }

        public bool KeyDown(KeyboardSnapshot keyboard)
        {
            return false;
        }

        public bool KeyUp(KeyboardSnapshot keyboard)
        {
            return false;
        }

        public void SyncKeys(KeyboardSnapshot keyboard)
        {
        }

        public void CancelKeys()
        {
        }
    }
}