import { addToWorklet } from "./WorkletGlobalScope";

const delayLine = /* javascript */ `
	/**
	 * A multichannel buffer for use within an AudioWorkletProcessor as a delay line
	 */
	class DelayLine {
		
		constructor(size, channels) {
			this.buffer = [];
			this.writeHead = []
			this.size = size;

			// create the empty channels
			for (let i = 0; i < channels; i++) {
				this.buffer[i] = new Float32Array(this.size);
				this.writeHead[i] = 0;
			}
		}

		/**
		 * Push a value onto the end
		 * @param channel number
		 * @param value number
		 */
		push(channel, value) {
			this.writeHead[channel] += 1;
			if (this.writeHead[channel] > this.size) {
				this.writeHead[channel] = 0;
			}
			this.buffer[channel][this.writeHead[channel]] = value;
		}

		/**
		 * Get the recorded value of the channel given the delay
		 * @param channel number
		 * @param delay number delay samples
		 */
		get(channel, delay) {
			let readHead = this.writeHead[channel] - Math.floor(delay);
			if (readHead < 0) {
				readHead += this.size;
			}
			return this.buffer[channel][readHead];
		}
	}
`;

addToWorklet(delayLine);