import { Nullable } from "babylonjs/types";
import { serializeAsVector3, serialize, SerializationHelper } from "babylonjs/Misc/decorators";
import { Vector3, Matrix } from "babylonjs/Maths/math.vector";
import { IAnimatable } from 'babylonjs/Animations/animatable.interface';
import { BaseTexture } from "babylonjs/Materials/Textures/baseTexture";
import { EffectFallbacks } from "babylonjs/Materials/effect";
import { MaterialDefines } from "babylonjs/Materials/materialDefines";
import { MaterialHelper } from "babylonjs/Materials/materialHelper";
import { PushMaterial } from "babylonjs/Materials/pushMaterial";
import { VertexBuffer } from "babylonjs/Meshes/buffer";
import { AbstractMesh } from "babylonjs/Meshes/abstractMesh";
import { SubMesh } from "babylonjs/Meshes/subMesh";
import { Mesh } from "babylonjs/Meshes/mesh";
import { Scene } from "babylonjs/scene";
import { _TypeStore } from 'babylonjs/Misc/typeStore';

import "./sky.fragment";
import "./sky.vertex";

/** @hidden */
class SkyMaterialDefines extends MaterialDefines {
    public CLIPPLANE = false;
    public CLIPPLANE2 = false;
    public CLIPPLANE3 = false;
    public CLIPPLANE4 = false;
    public POINTSIZE = false;
    public FOG = false;
    public VERTEXCOLOR = false;
    public VERTEXALPHA = false;

    constructor() {
        super();
        this.rebuild();
    }
}

/**
 * This is the sky material which allows to create dynamic and texture free effects for skyboxes.
 * @see https://doc.babylonjs.com/extensions/sky
 */
export class SkyMaterial extends PushMaterial {
    /**
     * Defines the overall luminance of sky in interval ]0, 1[.
     */
    @serialize()
    public luminance: number = 1.0;

    /**
    * Defines the amount (scattering) of haze as opposed to molecules in atmosphere.
    */
    @serialize()
    public turbidity: number = 10.0;

    /**
     * Defines the sky appearance (light intensity).
     */
    @serialize()
    public rayleigh: number = 2.0;

    /**
     * Defines the mieCoefficient in interval [0, 0.1] which affects the property .mieDirectionalG.
     */
    @serialize()
    public mieCoefficient: number = 0.005;

    /**
     * Defines the amount of haze particles following the Mie scattering theory.
     */
    @serialize()
    public mieDirectionalG: number = 0.8;

    /**
     * Defines the distance of the sun according to the active scene camera.
     */
    @serialize()
    public distance: number = 500;

    /**
     * Defines the sun inclination, in interval [-0.5, 0.5]. When the inclination is not 0, the sun is said
     * "inclined".
     */
    @serialize()
    public inclination: number = 0.49;

    /**
     * Defines the solar azimuth in interval [0, 1]. The azimuth is the angle in the horizontal plan between
     * an object direction and a reference direction.
     */
    @serialize()
    public azimuth: number = 0.25;

    /**
     * Defines the sun position in the sky on (x,y,z). If the property .useSunPosition is set to false, then
     * the property is overriden by the inclination and the azimuth and can be read at any moment.
     */
    @serializeAsVector3()
    public sunPosition: Vector3 = new Vector3(0, 100, 0);

    /**
     * Defines if the sun position should be computed (inclination and azimuth) according to the given
     * .sunPosition property.
     */
    @serialize()
    public useSunPosition: boolean = false;

    /**
     * Defines an offset vector used to get a horizon offset.
     * @example skyMaterial.cameraOffset.y = camera.globalPosition.y // Set horizon relative to 0 on the Y axis
     */
    @serialize()
    public cameraOffset: Vector3 = Vector3.Zero();

    // Private members
    private _cameraPosition: Vector3 = Vector3.Zero();

    private _renderId: number;

    /**
     * Instantiates a new sky material.
     * This material allows to create dynamic and texture free
     * effects for skyboxes by taking care of the atmosphere state.
     * @see https://doc.babylonjs.com/extensions/sky
     * @param name Define the name of the material in the scene
     * @param scene Define the scene the material belong to
     */
    constructor(name: string, scene: Scene) {
        super(name, scene);
    }

    /**
     * Specifies if the material will require alpha blending
     * @returns a boolean specifying if alpha blending is needed
     */
    public needAlphaBlending(): boolean {
        return (this.alpha < 1.0);
    }

    /**
     * Specifies if this material should be rendered in alpha test mode
     * @returns false as the sky material doesn't need alpha testing.
     */
    public needAlphaTesting(): boolean {
        return false;
    }

    /**
     * Get the texture used for alpha test purpose.
     * @returns null as the sky material has no texture.
     */
    public getAlphaTestTexture(): Nullable<BaseTexture> {
        return null;
    }

    /**
     * Get if the submesh is ready to be used and all its information available.
     * Child classes can use it to update shaders
     * @param mesh defines the mesh to check
     * @param subMesh defines which submesh to check
     * @param useInstances specifies that instances should be used
     * @returns a boolean indicating that the submesh is ready or not
     */
    public isReadyForSubMesh(mesh: AbstractMesh, subMesh: SubMesh, useInstances?: boolean): boolean {
        if (this.isFrozen) {
            if (this._wasPreviouslyReady && subMesh.effect) {
                return true;
            }
        }

        if (!subMesh._materialDefines) {
            subMesh._materialDefines = new SkyMaterialDefines();
        }

        var defines = <SkyMaterialDefines>subMesh._materialDefines;
        var scene = this.getScene();

        if (!this.checkReadyOnEveryCall && subMesh.effect) {
            if (this._renderId === scene.getRenderId()) {
                return true;
            }
        }

        MaterialHelper.PrepareDefinesForMisc(mesh, scene, false, this.pointsCloud, this.fogEnabled, false, defines);

        // Attribs
        MaterialHelper.PrepareDefinesForAttributes(mesh, defines, true, false);

        // Get correct effect
        if (defines.isDirty) {
            defines.markAsProcessed();

            scene.resetCachedMaterial();

            // Fallbacks
            var fallbacks = new EffectFallbacks();
            if (defines.FOG) {
                fallbacks.addFallback(1, "FOG");
            }

            //Attributes
            var attribs = [VertexBuffer.PositionKind];

            if (defines.VERTEXCOLOR) {
                attribs.push(VertexBuffer.ColorKind);
            }

            var shaderName = "sky";

            var join = defines.toString();
            subMesh.setEffect(scene.getEngine().createEffect(shaderName,
                attribs,
                ["world", "viewProjection", "view",
                    "vFogInfos", "vFogColor", "pointSize", "vClipPlane", "vClipPlane2", "vClipPlane3", "vClipPlane4",
                    "luminance", "turbidity", "rayleigh", "mieCoefficient", "mieDirectionalG", "sunPosition",
                    "cameraPosition", "cameraOffset"
                ],
                [],
                join, fallbacks, this.onCompiled, this.onError), defines);
        }

        if (!subMesh.effect || !subMesh.effect.isReady()) {
            return false;
        }

        this._renderId = scene.getRenderId();
        this._wasPreviouslyReady = true;

        return true;
    }

    /**
     * Binds the submesh to this material by preparing the effect and shader to draw
     * @param world defines the world transformation matrix
     * @param mesh defines the mesh containing the submesh
     * @param subMesh defines the submesh to bind the material to
     */
    public bindForSubMesh(world: Matrix, mesh: Mesh, subMesh: SubMesh): void {
        var scene = this.getScene();

        var defines = <SkyMaterialDefines>subMesh._materialDefines;
        if (!defines) {
            return;
        }

        var effect = subMesh.effect;
        if (!effect) {
            return;
        }
        this._activeEffect = effect;

        // Matrices
        this.bindOnlyWorldMatrix(world);
        this._activeEffect.setMatrix("viewProjection", scene.getTransformMatrix());

        if (this._mustRebind(scene, effect)) {

            MaterialHelper.BindClipPlane(this._activeEffect, scene);

            // Point size
            if (this.pointsCloud) {
                this._activeEffect.setFloat("pointSize", this.pointSize);
            }
        }

        // View
        if (scene.fogEnabled && mesh.applyFog && scene.fogMode !== Scene.FOGMODE_NONE) {
            this._activeEffect.setMatrix("view", scene.getViewMatrix());
        }

        // Fog
        MaterialHelper.BindFogParameters(scene, mesh, this._activeEffect);

        // Sky
        var camera = scene.activeCamera;
        if (camera) {
            var cameraWorldMatrix = camera.getWorldMatrix();
            this._cameraPosition.x = cameraWorldMatrix.m[12];
            this._cameraPosition.y = cameraWorldMatrix.m[13];
            this._cameraPosition.z = cameraWorldMatrix.m[14];
            this._activeEffect.setVector3("cameraPosition", this._cameraPosition);
        }

        this._activeEffect.setVector3("cameraOffset", this.cameraOffset);

        if (this.luminance > 0) {
            this._activeEffect.setFloat("luminance", this.luminance);
        }

        this._activeEffect.setFloat("turbidity", this.turbidity);
        this._activeEffect.setFloat("rayleigh", this.rayleigh);
        this._activeEffect.setFloat("mieCoefficient", this.mieCoefficient);
        this._activeEffect.setFloat("mieDirectionalG", this.mieDirectionalG);

        if (!this.useSunPosition) {
            var theta = Math.PI * (this.inclination - 0.5);
            var phi = 2 * Math.PI * (this.azimuth - 0.5);

            this.sunPosition.x = this.distance * Math.cos(phi);
            this.sunPosition.y = this.distance * Math.sin(phi) * Math.sin(theta);
            this.sunPosition.z = this.distance * Math.sin(phi) * Math.cos(theta);
        }

        this._activeEffect.setVector3("sunPosition", this.sunPosition);

        this._afterBind(mesh, this._activeEffect);
    }

    /**
     * Get the list of animatables in the material.
     * @returns the list of animatables object used in the material
     */
    public getAnimatables(): IAnimatable[] {
        return [];
    }

    /**
     * Disposes the material
     * @param forceDisposeEffect specifies if effects should be forcefully disposed
     */
    public dispose(forceDisposeEffect?: boolean): void {
        super.dispose(forceDisposeEffect);
    }

    /**
     * Makes a duplicate of the material, and gives it a new name
     * @param name defines the new name for the duplicated material
     * @returns the cloned material
     */
    public clone(name: string): SkyMaterial {
        return SerializationHelper.Clone<SkyMaterial>(() => new SkyMaterial(name, this.getScene()), this);
    }

    /**
     * Serializes this material in a JSON representation
     * @returns the serialized material object
     */
    public serialize(): any {
        var serializationObject = SerializationHelper.Serialize(this);
        serializationObject.customType = "BABYLON.SkyMaterial";
        return serializationObject;
    }

    /**
     * Gets the current class name of the material e.g. "SkyMaterial"
     * Mainly use in serialization.
     * @returns the class name
     */
    public getClassName(): string {
        return "SkyMaterial";
    }

    /**
     * Creates a sky material from parsed material data
     * @param source defines the JSON representation of the material
     * @param scene defines the hosting scene
     * @param rootUrl defines the root URL to use to load textures and relative dependencies
     * @returns a new sky material
     */
    public static Parse(source: any, scene: Scene, rootUrl: string): SkyMaterial {
        return SerializationHelper.Parse(() => new SkyMaterial(source.name, scene), source, scene, rootUrl);
    }
}

_TypeStore.RegisteredTypes["BABYLON.SkyMaterial"] = SkyMaterial;