import {
	BufferGeometry,
	Clock,
	Float32BufferAttribute,
	LinearFilter,
	Mesh,
	OrthographicCamera,
	RGBAFormat,
	Vector2,
	WebGLRenderTarget
} from 'three';
import { CopyShader } from '../shaders/CopyShader.js';
import { ShaderPass } from '../postprocessing/ShaderPass.js';
import { MaskPass } from '../postprocessing/MaskPass.js';
import { ClearMaskPass } from '../postprocessing/MaskPass.js';

class EffectComposer {

	constructor( renderer, renderTarget ) {

		this.renderer = renderer;

		if ( renderTarget === undefined ) {

			const parameters = {
				minFilter: LinearFilter,
				magFilter: LinearFilter,
				format: RGBAFormat
			};

			const size = renderer.getSize( new Vector2() );
			this._pixelRatio = renderer.getPixelRatio();
			this._width = size.width;
			this._height = size.height;

			renderTarget = new WebGLRenderTarget( this._width * this._pixelRatio, this._height * this._pixelRatio, parameters );
			renderTarget.texture.name = 'EffectComposer.rt1';

		} else {

			this._pixelRatio = 1;
			this._width = renderTarget.width;
			this._height = renderTarget.height;

		}

		this.renderTarget1 = renderTarget;
		this.renderTarget2 = renderTarget.clone();
		this.renderTarget2.texture.name = 'EffectComposer.rt2';

		this.writeBuffer = this.renderTarget1;
		this.readBuffer = this.renderTarget2;

		this.renderToScreen = true;

		this.passes = [];

		// dependencies

		if ( CopyShader === undefined ) {

			console.error( 'THREE.EffectComposer relies on CopyShader' );

		}

		if ( ShaderPass === undefined ) {

			console.error( 'THREE.EffectComposer relies on ShaderPass' );

		}

		this.copyPass = new ShaderPass( CopyShader );

		this.clock = new Clock();

	}

	swapBuffers() {

		const tmp = this.readBuffer;
		this.readBuffer = this.writeBuffer;
		this.writeBuffer = tmp;

	}

	addPass( pass ) {

		this.passes.push( pass );
		pass.setSize( this._width * this._pixelRatio, this._height * this._pixelRatio );

	}

	insertPass( pass, index ) {

		this.passes.splice( index, 0, pass );
		pass.setSize( this._width * this._pixelRatio, this._height * this._pixelRatio );

	}

	removePass( pass ) {

		const index = this.passes.indexOf( pass );

		if ( index !== - 1 ) {

			this.passes.splice( index, 1 );

		}

	}

	isLastEnabledPass( passIndex ) {

		for ( let i = passIndex + 1; i < this.passes.length; i ++ ) {

			if ( this.passes[ i ].enabled ) {

				return false;

			}

		}

		return true;

	}

	render( deltaTime ) {

		// deltaTime value is in seconds

		if ( deltaTime === undefined ) {

			deltaTime = this.clock.getDelta();

		}

		const currentRenderTarget = this.renderer.getRenderTarget();

		let maskActive = false;

		for ( let i = 0, il = this.passes.length; i < il; i ++ ) {

			const pass = this.passes[ i ];

			if ( pass.enabled === false ) continue;

			pass.renderToScreen = ( this.renderToScreen && this.isLastEnabledPass( i ) );
			pass.render( this.renderer, this.writeBuffer, this.readBuffer, deltaTime, maskActive );

			if ( pass.needsSwap ) {

				if ( maskActive ) {

					const context = this.renderer.getContext();
					const stencil = this.renderer.state.buffers.stencil;

					//context.stencilFunc( context.NOTEQUAL, 1, 0xffffffff );
					stencil.setFunc( context.NOTEQUAL, 1, 0xffffffff );

					this.copyPass.render( this.renderer, this.writeBuffer, this.readBuffer, deltaTime );

					//context.stencilFunc( context.EQUAL, 1, 0xffffffff );
					stencil.setFunc( context.EQUAL, 1, 0xffffffff );

				}

				this.swapBuffers();

			}

			if ( MaskPass !== undefined ) {

				if ( pass instanceof MaskPass ) {

					maskActive = true;

				} else if ( pass instanceof ClearMaskPass ) {

					maskActive = false;

				}

			}

		}

		this.renderer.setRenderTarget( currentRenderTarget );

	}

	reset( renderTarget ) {

		if ( renderTarget === undefined ) {

			const size = this.renderer.getSize( new Vector2() );
			this._pixelRatio = this.renderer.getPixelRatio();
			this._width = size.width;
			this._height = size.height;

			renderTarget = this.renderTarget1.clone();
			renderTarget.setSize( this._width * this._pixelRatio, this._height * this._pixelRatio );

		}

		this.renderTarget1.dispose();
		this.renderTarget2.dispose();
		this.renderTarget1 = renderTarget;
		this.renderTarget2 = renderTarget.clone();

		this.writeBuffer = this.renderTarget1;
		this.readBuffer = this.renderTarget2;

	}

	setSize( width, height ) {

		this._width = width;
		this._height = height;

		const effectiveWidth = this._width * this._pixelRatio;
		const effectiveHeight = this._height * this._pixelRatio;

		this.renderTarget1.setSize( effectiveWidth, effectiveHeight );
		this.renderTarget2.setSize( effectiveWidth, effectiveHeight );

		for ( let i = 0; i < this.passes.length; i ++ ) {

			this.passes[ i ].setSize( effectiveWidth, effectiveHeight );

		}

	}

	setPixelRatio( pixelRatio ) {

		this._pixelRatio = pixelRatio;

		this.setSize( this._width, this._height );

	}

}


class Pass {

	constructor() {

		// if set to true, the pass is processed by the composer
		this.enabled = true;

		// if set to true, the pass indicates to swap read and write buffer after rendering
		this.needsSwap = true;

		// if set to true, the pass clears its buffer before rendering
		this.clear = false;

		// if set to true, the result of the pass is rendered to screen. This is set automatically by EffectComposer.
		this.renderToScreen = false;

	}

	setSize( /* width, height */ ) {}

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

		console.error( 'THREE.Pass: .render() must be implemented in derived pass.' );

	}

}

// Helper for passes that need to fill the viewport with a single quad.

const _camera = new OrthographicCamera( - 1, 1, 1, - 1, 0, 1 );

// https://github.com/mrdoob/three.js/pull/21358

const _geometry = new BufferGeometry();
_geometry.setAttribute( 'position', new Float32BufferAttribute( [ - 1, 3, 0, - 1, - 1, 0, 3, - 1, 0 ], 3 ) );
_geometry.setAttribute( 'uv', new Float32BufferAttribute( [ 0, 2, 0, 0, 2, 0 ], 2 ) );

class FullScreenQuad {

	constructor( material ) {

		this._mesh = new Mesh( _geometry, material );

	}

	dispose() {

		this._mesh.geometry.dispose();

	}

	render( renderer ) {

		renderer.render( this._mesh, _camera );

	}

	get material() {

		return this._mesh.material;

	}

	set material( value ) {

		this._mesh.material = value;

	}

}

export { EffectComposer, Pass, FullScreenQuad };