'use strict';

import _ from 'underscore';
import NumberUtil from '../utils/number.js';
import ValidateMixin from '../mixin/validate.js';
import SetOptionsMixin from '../mixin/set-options.js';
import HandleGeneratorMixin from '../mixin/handle-generator.js';

/**
 * @param {object} [options]
 * @param {number} [options.startIndex]
 * @param {number} [options.endIndex}] 
 * @param {boolean} [options.lazyEvaluation=true]
 * @param {number} [option.maxTickDuration=10]
 */
function ADL(options = {}) {
	if (!new.target) throw new Error('ERROR: ADL() must be called with new');

	this._options = {
		startIndex: null,
		endIndex: null,
		lazyEvaluation: true,
		maxTickDuration: 10,
	}

	let m = [SetOptionsMixin, ValidateMixin, HandleGeneratorMixin];
	Object.assign(this, ...m);
	this.setOptions(options);
	this._collection = [];
}

ADL.prototype = {

	setValues(values) {
		if (!Array.isArray(values)) {
			throw new Error('ERROR: values param is not an array');
		}

		this._collection = values;
	},

	calculate() {
		this._validate(this._collection, this._options);
		return this._handleGenerator(this._compute());
	},

	_compute: function* () {
		let results = [];

		let convertToResultItem = (close, mfMultiplier, mfVolume, adl) => {
			return {
				price: close,
				mfMultiplier,
				mfVolume,
				adl: Math.round(adl),
			};
		};

		let { startIndex, endIndex, lazyEvaluation } = this._options;

		if (_.isNull(startIndex)) startIndex = 0;
		if (_.isNull(endIndex)) endIndex = this._collection.length - 1;

		for (let i = startIndex; i <= endIndex; i++) {
			let item = this._collection[i];
			let mfMultiplier = ((item.close - item.low) - (item.high - item.close)) / (item.high - item.low);
			mfMultiplier = NumberUtil.roundTo(mfMultiplier, 4);
			let mfVolume = Math.round(mfMultiplier * item.volume);

			let prevAdl = 0;
			if (i != startIndex) prevAdl = results[results.length - 1].adl;
			let adl = prevAdl + mfVolume;
			let resultItem = convertToResultItem(item.close, mfMultiplier, mfVolume, adl);
			results.push(resultItem);
			if (lazyEvaluation) yield resultItem;
		}

		return results;
	},

};

export default ADL;