using Azimuth;
using Prism;

namespace Konis.Testbed
{
    /// <summary>
    /// The effects the testbed offers.  Sizes and speeds are in world units, which are pixels at the camera's starting
    /// zoom, and the ground is the plane of altitude zero.
    /// </summary>
    public static class Effects
    {
        private static GradientDef Tint(Gradient gradient)
        {
            return new GradientDef { Gradient = gradient };
        }

        private static Color Rgb(int red, int green, int blue)
        {
            return Color.FromArgb(255, red, green, blue);
        }

        public static readonly Effect Fire = new Effect("Fire", new StandardEmitterDef
        {
            Name = "Fire",
            Capacity = 500,
            Rate = 140,
            Lifetime = new Variation(0.6, 1.0),
            Speed = new Variation(20, 50),
            Heading = new Variation(0, 1),
            Elevation = new Variation(0.2, 0.3),
            AngularVelocity = new Variation(-0.5, 0.5),
            Size = new Variation(16, 26),
            Gravity = -30,
            Drag = 0.5,
            SizeOverLife = fraction => 1.0 - 0.8 * fraction,
            AlphaOverLife = fraction => 1.0 - fraction,
            TintOverLife = Tint(new Gradient(
                GradientSpace.LinearLight,
                new GradientStop(0, Rgb(255, 240, 150)),
                new GradientStop(0.4, Rgb(255, 140, 30)),
                new GradientStop(1, Rgb(150, 20, 10)))),
        }, additive: true);

        public static readonly Effect Smoke = new Effect("Smoke", new StandardEmitterDef
        {
            Name = "Smoke",
            Capacity = 400,
            Rate = 30,
            Lifetime = new Variation(3, 5),
            Speed = new Variation(10, 25),
            Heading = new Variation(0, 1),
            Elevation = new Variation(0.2, 0.3),
            AngularVelocity = new Variation(-0.1, 0.1),
            Size = new Variation(14, 20),
            Gravity = -8,
            Drag = 0.3,
            SizeOverLife = fraction => 1.0 + 3.0 * fraction,
            AlphaOverLife = fraction => 0.5 * Scalar.Min(1.0, fraction * 8.0) * (1.0 - fraction),
            TintOverLife = Tint(Gradient.Constant(Rgb(170, 170, 175))),
        }, additive: false);

        public static readonly Effect Fountain = new Effect("Fountain", new StandardEmitterDef
        {
            Name = "Fountain",
            Capacity = 800,
            Rate = 160,
            Lifetime = new Variation(1.6, 2.0),
            Speed = new Variation(150, 190),
            Heading = new Variation(0, 1),
            Elevation = new Variation(0.21, 0.26),
            Size = new Variation(6, 10),
            Gravity = 220,
            AlphaOverLife = fraction => 1.0 - 0.6 * fraction,
            TintOverLife = Tint(Gradient.Between(Rgb(200, 235, 255), Rgb(60, 140, 230))),
        }, additive: false);

        public static readonly Effect Sparks = new Effect("Sparks", new StandardEmitterDef
        {
            Name = "Sparks",
            Capacity = 300,
            Rate = 800,
            Lifespan = 0.15,
            Lifetime = new Variation(0.5, 1.2),
            Speed = new Variation(80, 260),
            Heading = new Variation(0, 1),
            Elevation = new Variation(0.02, 0.25),
            Size = new Variation(5, 9),
            Gravity = 260,
            Drag = 1.0,
            AlphaOverLife = fraction => 1.0 - fraction,
            TintOverLife = Tint(Gradient.Between(Rgb(255, 250, 200), Rgb(255, 110, 20))),
        }, additive: true);

        public static readonly Effect Spinner = new Effect("Spinner", new StandardEmitterDef
        {
            Name = "Spinner",
            Capacity = 200,
            Rate = 60,
            Lifetime = 2.5,
            Speed = 70,
            Heading = new Variation(0, 1),
            Elevation = 0,
            AngularVelocity = new Variation(0.5, 1.5),
            Size = 28,
            Drag = 0.6,
            AlphaOverLife = fraction => 1.0 - fraction,
            TintOverLife = Tint(Gradient.Between(Rgb(120, 255, 160), Rgb(40, 120, 255))),
        }, additive: false);

        /// <summary>
        /// Gets every effect, in the order the testbed lists them.
        /// </summary>
        public static readonly Effect[] All = { Fire, Smoke, Fountain, Sparks, Spinner };

        /// <summary>
        /// Returns whether the effect that runs <paramref name="def"/> is blended additively.
        /// </summary>
        public static bool IsAdditive(EmitterDef def)
        {
            for (int i = 0; i < All.Length; i++)
            {
                if (ReferenceEquals(All[i].Def, def))
                {
                    return All[i].Additive;
                }
            }

            return false;
        }
    }
}