import * as MathUtils from '../math/MathUtils.js';
import { StaticDrawUsage } from '../constants.js';

class InterleavedBuffer {

	constructor( array, stride ) {

		this.isInterleavedBuffer = true;

		this.array = array;
		this.stride = stride;
		this.count = array !== undefined ? array.length / stride : 0;

		this.usage = StaticDrawUsage;
		this.updateRange = { offset: 0, count: - 1 };

		this.version = 0;

		this.uuid = MathUtils.generateUUID();

	}

	onUploadCallback() {}

	set needsUpdate( value ) {

		if ( value === true ) this.version ++;

	}

	setUsage( value ) {

		this.usage = value;

		return this;

	}

	copy( source ) {

		this.array = new source.array.constructor( source.array );
		this.count = source.count;
		this.stride = source.stride;
		this.usage = source.usage;

		return this;

	}

	copyAt( index1, attribute, index2 ) {

		index1 *= this.stride;
		index2 *= attribute.stride;

		for ( let i = 0, l = this.stride; i < l; i ++ ) {

			this.array[ index1 + i ] = attribute.array[ index2 + i ];

		}

		return this;

	}

	set( value, offset = 0 ) {

		this.array.set( value, offset );

		return this;

	}

	clone( data ) {

		if ( data.arrayBuffers === undefined ) {

			data.arrayBuffers = {};

		}

		if ( this.array.buffer._uuid === undefined ) {

			this.array.buffer._uuid = MathUtils.generateUUID();

		}

		if ( data.arrayBuffers[ this.array.buffer._uuid ] === undefined ) {

			data.arrayBuffers[ this.array.buffer._uuid ] = this.array.slice( 0 ).buffer;

		}

		const array = new this.array.constructor( data.arrayBuffers[ this.array.buffer._uuid ] );

		const ib = new this.constructor( array, this.stride );
		ib.setUsage( this.usage );

		return ib;

	}

	onUpload( callback ) {

		this.onUploadCallback = callback;

		return this;

	}

	toJSON( data ) {

		if ( data.arrayBuffers === undefined ) {

			data.arrayBuffers = {};

		}

		// generate UUID for array buffer if necessary

		if ( this.array.buffer._uuid === undefined ) {

			this.array.buffer._uuid = MathUtils.generateUUID();

		}

		if ( data.arrayBuffers[ this.array.buffer._uuid ] === undefined ) {

			data.arrayBuffers[ this.array.buffer._uuid ] = Array.from( new Uint32Array( this.array.buffer ) );

		}

		//

		return {
			uuid: this.uuid,
			buffer: this.array.buffer._uuid,
			type: this.array.constructor.name,
			stride: this.stride
		};

	}

}

export { InterleavedBuffer };