import { PerspectiveProjection, AssetBase, Transform } from '@awayjs/core';

import { TextureBase } from '@awayjs/renderer';

import { TextureProjectorEvent } from '../events/TextureProjectorEvent';

/**
 * TextureProjector is an object in the scene that can be used to project textures onto geometry. To do so,
 * the object's material must have a ProjectiveTextureMethod method added to it with a TextureProjector object
 * passed in the constructor.
 * This can be used for various effects apart from acting like a normal projector, such as projecting fake shadows
 * unto a surface, the impact of light coming through a stained glass window, ...
 *
 * @see away3d.materials.methods.ProjectiveTextureMethod
 */
export class TextureProjector extends AssetBase {
	private _transform: Transform;

	public static assetType: string = '[asset TextureProjector]';

	private _projection: PerspectiveProjection;
	private _texture: TextureBase;

	public get transform(): Transform {
		return this._transform;
	}

	public set transform(value: Transform) {
		if (this._transform == value)
			return;

		this._transform = value;
	}

	/**
	 * Creates a new TextureProjector object.
	 * @param texture The texture to be projected on the geometry. Since any point that is projected out of the range
	 * of the projector's cone is clamped to the texture's edges, the edges should be entirely neutral.
	 */
	constructor(texture: TextureBase, transform: Transform = null) {
		super();

		this._transform = transform || new Transform();

		this._projection = new PerspectiveProjection();
		this._projection.transform = this._transform;

		this._texture = texture;

		// const width: number = (<Image2D> texture.getImageAt(0)).width;
		// const height: number = (<Image2D> texture.getImageAt(0)).height;
	}

	/**
	 *
	 */
	public get projection(): PerspectiveProjection {
		return this._projection;
	}

	public get assetType(): string {
		return TextureProjector.assetType;
	}

	/**
	 * The texture to be projected on the geometry.
	 * IMPORTANT: Since any point that is projected out of the range of the projector's cone is clamped to the texture's edges,
	 * the edges should be entirely neutral. Depending on the blend mode, the neutral color is:
	 * White for MULTIPLY,
	 * Black for ADD,
	 * Transparent for MIX
	 */
	public get texture(): TextureBase {
		return this._texture;
	}

	public set texture(value: TextureBase) {
		if (value == this._texture)
			return;

		this._texture = value;

		// const width: number = (<Image2D> value.getImageAt(0)).width;
		// const height: number = (<Image2D> value.getImageAt(0)).height;

		this.dispatchEvent(new TextureProjectorEvent(TextureProjectorEvent.TEXTURE_CHANGE));
	}
}