"use strict";

const utf7 = require('utf7').imap;

const RE_BACKSLASH = /\\/g;
const RE_DBLQUOTE = /"/g;

function escape(str) {
	return str.replace(RE_BACKSLASH, '\\\\').replace(RE_DBLQUOTE, '\\"');
}

module.exports = {
	command: function (strings, ... interpolations) {
		return {
			toCommandString: function () {
				let processedInterpolations = interpolations.map((interpolation) => {
					let isObject = interpolation != null && typeof interpolation === "object";

					if (isObject && interpolation._isRaw) {
						return interpolation.string;
					} else if (isObject && interpolation._is7Bit) {
						return escape(interpolation.string);
					} else if (typeof interpolation === "string") {
						return escape(utf7.encode(interpolation));
					} else {
						throw new Error(`Invalid input into command string: ${interpolation}`);
					}
				});

				let combined = "";

				strings.slice(0, -1).forEach((string, i) => {
					combined += string;
					combined += processedInterpolations[i];
				});

				combined += strings[strings.length - 1];

				return combined;
			}
		};
	},
	unsafeRaw: function (string) {
		return {
			_isRaw: true,
			string: string
		};
	},
	already7Bit: function (string) {
		return {
			_is7Bit: true,
			string: string
		};
	}
};