/**
 * filesize
 *
 * @copyright 2021 Jason Mulligan <jason.mulligan@avoidwork.com>
 * @license BSD-3-Clause
 * @version 6.4.0
 */
(function (global, factory) {
	typeof exports === 'object' && typeof module !== 'undefined' ? module.exports = factory() :
	typeof define === 'function' && define.amd ? define(factory) :
	(global = typeof globalThis !== 'undefined' ? globalThis : global || self, global.filesize = factory());
}(this, (function () { 'use strict';

	const b = /^(b|B)$/,
		symbol = {
			iec: {
				bits: ["b", "Kib", "Mib", "Gib", "Tib", "Pib", "Eib", "Zib", "Yib"],
				bytes: ["B", "KiB", "MiB", "GiB", "TiB", "PiB", "EiB", "ZiB", "YiB"]
			},
			jedec: {
				bits: ["b", "Kb", "Mb", "Gb", "Tb", "Pb", "Eb", "Zb", "Yb"],
				bytes: ["B", "KB", "MB", "GB", "TB", "PB", "EB", "ZB", "YB"]
			}
		},
		fullform = {
			iec: ["", "kibi", "mebi", "gibi", "tebi", "pebi", "exbi", "zebi", "yobi"],
			jedec: ["", "kilo", "mega", "giga", "tera", "peta", "exa", "zetta", "yotta"]
		},
		roundingFuncs = {
			floor: Math.floor,
			ceil: Math.ceil
		};

	/**
	 * filesize
	 *
	 * @method filesize
	 * @param  {Mixed}   arg        String, Int or Float to transform
	 * @param  {Object}  descriptor [Optional] Flags
	 * @return {String}             Readable file size String
	 */
	function filesize (arg, descriptor = {}) {
		let result = [],
			val = 0,
			e, base, bits, ceil, full, fullforms, locale, localeOptions, neg, num, output, pad, round, u, unix, separator, spacer, standard, symbols, roundingFunc, precision;

		if (isNaN(arg)) {
			throw new TypeError("Invalid number");
		}

		bits = descriptor.bits === true;
		unix = descriptor.unix === true;
		pad = descriptor.pad === true;
		base = descriptor.base || 2;
		round = descriptor.round !== void 0 ? descriptor.round : unix ? 1 : 2;
		locale = descriptor.locale !== void 0 ? descriptor.locale : "";
		localeOptions = descriptor.localeOptions || {};
		separator = descriptor.separator !== void 0 ? descriptor.separator : "";
		spacer = descriptor.spacer !== void 0 ? descriptor.spacer : unix ? "" : " ";
		symbols = descriptor.symbols || {};
		standard = base === 2 ? descriptor.standard || "jedec" : "jedec";
		output = descriptor.output || "string";
		full = descriptor.fullform === true;
		fullforms = descriptor.fullforms instanceof Array ? descriptor.fullforms : [];
		e = descriptor.exponent !== void 0 ? descriptor.exponent : -1;
		roundingFunc = roundingFuncs[descriptor.roundingMethod] || Math.round;
		num = Number(arg);
		neg = num < 0;
		ceil = base > 2 ? 1000 : 1024;
		precision = isNaN(descriptor.precision) === false ? parseInt(descriptor.precision, 10) : 0;

		// Flipping a negative number to determine the size
		if (neg) {
			num = -num;
		}

		// Determining the exponent
		if (e === -1 || isNaN(e)) {
			e = Math.floor(Math.log(num) / Math.log(ceil));

			if (e < 0) {
				e = 0;
			}
		}

		// Exceeding supported length, time to reduce & multiply
		if (e > 8) {
			if (precision > 0) {
				precision += 8 - e;
			}

			e = 8;
		}

		if (output === "exponent") {
			return e;
		}

		// Zero is now a special case because bytes divide by 1
		if (num === 0) {
			result[0] = 0;
			u = result[1] = unix ? "" : symbol[standard][bits ? "bits" : "bytes"][e];
		} else {
			val = num / (base === 2 ? Math.pow(2, e * 10) : Math.pow(1000, e));

			if (bits) {
				val = val * 8;

				if (val >= ceil && e < 8) {
					val = val / ceil;
					e++;
				}
			}

			const p = Math.pow(10, e > 0 ? round : 0);
			result[0] = roundingFunc(val * p) / p;

			if (result[0] === ceil && e < 8 && descriptor.exponent === void 0) {
				result[0] = 1;
				e++;
			}

			u = result[1] = base === 10 && e === 1 ? bits ? "kb" : "kB" : symbol[standard][bits ? "bits" : "bytes"][e];

			if (unix) {
				result[1] = standard === "jedec" ? result[1].charAt(0) : e > 0 ? result[1].replace(/B$/, "") : result[1];

				if (b.test(result[1])) {
					result[0] = Math.floor(result[0]);
					result[1] = "";
				}
			}
		}

		// Decorating a 'diff'
		if (neg) {
			result[0] = -result[0];
		}

		// Setting optional precision
		if (precision > 0) {
			result[0] = result[0].toPrecision(precision);
		}

		// Applying custom symbol
		result[1] = symbols[result[1]] || result[1];

		if (locale === true) {
			result[0] = result[0].toLocaleString();
		} else if (locale.length > 0) {
			result[0] = result[0].toLocaleString(locale, localeOptions);
		} else if (separator.length > 0) {
			result[0] = result[0].toString().replace(".", separator);
		}

		if (pad && Number.isInteger(result[0]) === false && round > 0) {
			const x = separator || ".",
				tmp = result[0].toString().split(x),
				s = tmp[1] || "",
				l = s.length,
				n = round - l;

			result[0] = `${tmp[0]}${x}${s.padEnd(l + n, "0")}`;
		}

		if (full) {
			result[1] = fullforms[e] ? fullforms[e] : fullform[standard][e] + (bits ? "bit" : "byte") + (result[0] === 1 ? "" : "s");
		}

		// Returning Array, Object, or String (default)
		return output === "array" ? result : output === "object" ? {value: result[0], symbol: result[1], exponent: e, unit: u} : result.join(spacer);
	}

	// Partial application for functional programming
	filesize.partial = opt => arg => filesize(arg, opt);

	return filesize;

})));
