import { EventDispatcher } from '../core/EventDispatcher.js';
import {
	MirroredRepeatWrapping,
	ClampToEdgeWrapping,
	RepeatWrapping,
	UnsignedByteType,
	RGBAFormat,
	LinearMipmapLinearFilter,
	LinearFilter,
	UVMapping,
	NoColorSpace,
} from '../constants.js';
import * as MathUtils from '../math/MathUtils.js';
import { Vector2 } from '../math/Vector2.js';
import { Matrix3 } from '../math/Matrix3.js';
import { Source } from './Source.js';

let _textureId = 0;

class Texture extends EventDispatcher {

	constructor( image = Texture.DEFAULT_IMAGE, mapping = Texture.DEFAULT_MAPPING, wrapS = ClampToEdgeWrapping, wrapT = ClampToEdgeWrapping, magFilter = LinearFilter, minFilter = LinearMipmapLinearFilter, format = RGBAFormat, type = UnsignedByteType, anisotropy = Texture.DEFAULT_ANISOTROPY, colorSpace = NoColorSpace ) {

		super();

		this.isTexture = true;

		Object.defineProperty( this, 'id', { value: _textureId ++ } );

		this.uuid = MathUtils.generateUUID();

		this.name = '';

		this.source = new Source( image );
		this.mipmaps = [];

		this.mapping = mapping;
		this.channel = 0;

		this.wrapS = wrapS;
		this.wrapT = wrapT;

		this.magFilter = magFilter;
		this.minFilter = minFilter;

		this.anisotropy = anisotropy;

		this.format = format;
		this.internalFormat = null;
		this.type = type;

		this.offset = new Vector2( 0, 0 );
		this.repeat = new Vector2( 1, 1 );
		this.center = new Vector2( 0, 0 );
		this.rotation = 0;

		this.matrixAutoUpdate = true;
		this.matrix = new Matrix3();

		this.generateMipmaps = true;
		this.premultiplyAlpha = false;
		this.flipY = true;
		this.unpackAlignment = 4;	// valid values: 1, 2, 4, 8 (see http://www.khronos.org/opengles/sdk/docs/man/xhtml/glPixelStorei.xml)

		this.colorSpace = colorSpace;

		this.userData = {};

		this.version = 0;
		this.onUpdate = null;

		this.isRenderTargetTexture = false; // indicates whether a texture belongs to a render target or not
		this.needsPMREMUpdate = false; // indicates whether this texture should be processed by PMREMGenerator or not (only relevant for render target textures)

	}

	get image() {

		return this.source.data;

	}

	set image( value = null ) {

		this.source.data = value;

	}

	updateMatrix() {

		this.matrix.setUvTransform( this.offset.x, this.offset.y, this.repeat.x, this.repeat.y, this.rotation, this.center.x, this.center.y );

	}

	clone() {

		return new this.constructor().copy( this );

	}

	copy( source ) {

		this.name = source.name;

		this.source = source.source;
		this.mipmaps = source.mipmaps.slice( 0 );

		this.mapping = source.mapping;
		this.channel = source.channel;

		this.wrapS = source.wrapS;
		this.wrapT = source.wrapT;

		this.magFilter = source.magFilter;
		this.minFilter = source.minFilter;

		this.anisotropy = source.anisotropy;

		this.format = source.format;
		this.internalFormat = source.internalFormat;
		this.type = source.type;

		this.offset.copy( source.offset );
		this.repeat.copy( source.repeat );
		this.center.copy( source.center );
		this.rotation = source.rotation;

		this.matrixAutoUpdate = source.matrixAutoUpdate;
		this.matrix.copy( source.matrix );

		this.generateMipmaps = source.generateMipmaps;
		this.premultiplyAlpha = source.premultiplyAlpha;
		this.flipY = source.flipY;
		this.unpackAlignment = source.unpackAlignment;
		this.colorSpace = source.colorSpace;

		this.userData = JSON.parse( JSON.stringify( source.userData ) );

		this.needsUpdate = true;

		return this;

	}

	toJSON( meta ) {

		const isRootObject = ( meta === undefined || typeof meta === 'string' );

		if ( ! isRootObject && meta.textures[ this.uuid ] !== undefined ) {

			return meta.textures[ this.uuid ];

		}

		const output = {

			metadata: {
				version: 4.6,
				type: 'Texture',
				generator: 'Texture.toJSON'
			},

			uuid: this.uuid,
			name: this.name,

			image: this.source.toJSON( meta ).uuid,

			mapping: this.mapping,
			channel: this.channel,

			repeat: [ this.repeat.x, this.repeat.y ],
			offset: [ this.offset.x, this.offset.y ],
			center: [ this.center.x, this.center.y ],
			rotation: this.rotation,

			wrap: [ this.wrapS, this.wrapT ],

			format: this.format,
			internalFormat: this.internalFormat,
			type: this.type,
			colorSpace: this.colorSpace,

			minFilter: this.minFilter,
			magFilter: this.magFilter,
			anisotropy: this.anisotropy,

			flipY: this.flipY,

			generateMipmaps: this.generateMipmaps,
			premultiplyAlpha: this.premultiplyAlpha,
			unpackAlignment: this.unpackAlignment

		};

		if ( Object.keys( this.userData ).length > 0 ) output.userData = this.userData;

		if ( ! isRootObject ) {

			meta.textures[ this.uuid ] = output;

		}

		return output;

	}

	dispose() {

		this.dispatchEvent( { type: 'dispose' } );

	}

	transformUv( uv ) {

		if ( this.mapping !== UVMapping ) return uv;

		uv.applyMatrix3( this.matrix );

		if ( uv.x < 0 || uv.x > 1 ) {

			switch ( this.wrapS ) {

				case RepeatWrapping:

					uv.x = uv.x - Math.floor( uv.x );
					break;

				case ClampToEdgeWrapping:

					uv.x = uv.x < 0 ? 0 : 1;
					break;

				case MirroredRepeatWrapping:

					if ( Math.abs( Math.floor( uv.x ) % 2 ) === 1 ) {

						uv.x = Math.ceil( uv.x ) - uv.x;

					} else {

						uv.x = uv.x - Math.floor( uv.x );

					}

					break;

			}

		}

		if ( uv.y < 0 || uv.y > 1 ) {

			switch ( this.wrapT ) {

				case RepeatWrapping:

					uv.y = uv.y - Math.floor( uv.y );
					break;

				case ClampToEdgeWrapping:

					uv.y = uv.y < 0 ? 0 : 1;
					break;

				case MirroredRepeatWrapping:

					if ( Math.abs( Math.floor( uv.y ) % 2 ) === 1 ) {

						uv.y = Math.ceil( uv.y ) - uv.y;

					} else {

						uv.y = uv.y - Math.floor( uv.y );

					}

					break;

			}

		}

		if ( this.flipY ) {

			uv.y = 1 - uv.y;

		}

		return uv;

	}

	set needsUpdate( value ) {

		if ( value === true ) {

			this.version ++;
			this.source.needsUpdate = true;

		}

	}

}

Texture.DEFAULT_IMAGE = null;
Texture.DEFAULT_MAPPING = UVMapping;
Texture.DEFAULT_ANISOTROPY = 1;

export { Texture };