import {
	HalfFloatType,
	NearestFilter,
	NoBlending,
	ShaderMaterial,
	UniformsUtils,
	WebGLRenderTarget
} from 'three';
import { Pass, FullScreenQuad } from './Pass.js';
import { CopyShader } from '../shaders/CopyShader.js';
import { AfterimageShader } from '../shaders/AfterimageShader.js';

class AfterimagePass extends Pass {

	constructor( damp = 0.96 ) {

		super();

		this.shader = AfterimageShader;

		this.uniforms = UniformsUtils.clone( this.shader.uniforms );

		this.uniforms[ 'damp' ].value = damp;

		this.textureComp = new WebGLRenderTarget( window.innerWidth, window.innerHeight, {
			magFilter: NearestFilter,
			type: HalfFloatType
		} );

		this.textureOld = new WebGLRenderTarget( window.innerWidth, window.innerHeight, {
			magFilter: NearestFilter,
			type: HalfFloatType
		} );

		this.compFsMaterial = new ShaderMaterial( {

			uniforms: this.uniforms,
			vertexShader: this.shader.vertexShader,
			fragmentShader: this.shader.fragmentShader

		} );

		this.compFsQuad = new FullScreenQuad( this.compFsMaterial );

		const copyShader = CopyShader;

		this.copyFsMaterial = new ShaderMaterial( {
			uniforms: UniformsUtils.clone( copyShader.uniforms ),
			vertexShader: copyShader.vertexShader,
			fragmentShader: copyShader.fragmentShader,
			blending: NoBlending,
			depthTest: false,
			depthWrite: false
		} );

		this.copyFsQuad = new FullScreenQuad( this.copyFsMaterial );

	}

	render( renderer, writeBuffer, readBuffer/*, deltaTime, maskActive*/ ) {

		this.uniforms[ 'tOld' ].value = this.textureOld.texture;
		this.uniforms[ 'tNew' ].value = readBuffer.texture;

		renderer.setRenderTarget( this.textureComp );
		this.compFsQuad.render( renderer );

		this.copyFsQuad.material.uniforms.tDiffuse.value = this.textureComp.texture;

		if ( this.renderToScreen ) {

			renderer.setRenderTarget( null );
			this.copyFsQuad.render( renderer );

		} else {

			renderer.setRenderTarget( writeBuffer );

			if ( this.clear ) renderer.clear();

			this.copyFsQuad.render( renderer );

		}

		// Swap buffers.
		const temp = this.textureOld;
		this.textureOld = this.textureComp;
		this.textureComp = temp;
		// Now textureOld contains the latest image, ready for the next frame.

	}

	setSize( width, height ) {

		this.textureComp.setSize( width, height );
		this.textureOld.setSize( width, height );

	}

	dispose() {

		this.textureComp.dispose();
		this.textureOld.dispose();

		this.compFsMaterial.dispose();
		this.copyFsMaterial.dispose();

		this.compFsQuad.dispose();
		this.copyFsQuad.dispose();

	}

}

export { AfterimagePass };
