index.js

"use strict";

var https = require('https');
var url = require('url');

var latestAPIVersion = "1.0";

/*
===========
Constructor
===========
*/

function AvaTax(username, password, options) {

	if (typeof username !== "string" || typeof password !== "string") {
		throw new Error("Credentials not supplied for AvaTax");
	}

	this.username = username;
	this.password = password;

	options = options || {};
	//Development or Production
	options.development = options.development || false;
	options.version = options.version || latestAPIVersion;
	options.client = options.client !== undefined ? options.client : "node-avatax";
	options.client = options.client === false ? undefined : options.client;

	if (options.version > latestAPIVersion) {
		console.warn("This library does not support an API version greater than `" + latestAPIVersion + "`. Contact this module's author to allow for newer versions.");
	}

	var authenticationHeader = "Basic " + new Buffer([this.username, this.password].join(":"), 'utf8').toString('base64');

	this.requestOptions = function() {
		var requestOptions = {
			port: 443,//https
			method: 'GET',
			headers: {
				"Content-Type": "application/json",
				"Accept": "application/json",
				"Authorization": authenticationHeader
			}
		};

		requestOptions.host = options.development ? 'development.avalara.net' : 'avatax.avalara.net';
		//allow overriding of host completely
		requestOptions.host = options.host || requestOptions.host;
		
		return requestOptions;
	};

	this.options = options;

	return this;
}


/*
=========
Utilities
=========
*/

AvaTax.prototype._makeRequest = function(requestOptions, requestBody, next) {

	var req = https.request(requestOptions, function(res) {
		
		var responseBody = "";
		res.setEncoding('utf-8');
		
		res.on('data', function(chunk) {
			responseBody += chunk;
		});

		res.on('end', function() {

			var errorText = "AvaTax server error";
			var err;

			var json = null;

			try {
				json = JSON.parse(responseBody);
			} catch (e) {}

			if (res.statusCode >= 400) {

				if (
					json &&
					json.Messages &&
					json.Messages.length &&
					json.Messages[0].Summary
				) {
					errorText = json.Messages[0].Summary;
				}

				err = new Error(errorText);
				err.code = res.statusCode;
			}

			next(err, json);
		});
	});

	req.on('error', next);
	
	req.end(requestBody);
};

/*
========
Validate Address
========
*/

//returns true if all required fields are present
function validateAddressFields(address) {
	return address && (
		(
			address.Line1 !== undefined &&
			address.PostalCode !== undefined
		) || (
			address.Line1 !== undefined &&
			address.City !== undefined &&
			address.Region !== undefined
		)
	);
}

AvaTax.prototype._validateAddress = function(options, next) {

	var requestOptions = this.requestOptions();
	
	requestOptions.path = url.format({
		pathname: "/" + this.options.version + '/address/validate',
		query: options
	});

	this._makeRequest(requestOptions, null, function(err, json) {
		if (err) {
			return next(err);
		}

		if (json.ResultCode === "Error") {
			return next(new Error(json.Messages[0].Summary));
		}

		if (json.ResultCode === "Success") {
			return next(null, json.Address);
		}

		return next(null, json);
	});

};

AvaTax.prototype.validateAddress = function(address, next) {
	
	if (!validateAddressFields(address)) {
		//return an error if both Line+Postal OR Line+City+Region aren't satisfied
		return next(new Error("You must specify at least Line & Postal Code, or Line & City & Region"));
	}

	return AvaTax.prototype._validateAddress.call(this, address, next);
};


/*
========
Tax
========
*/

AvaTax.prototype._estimateTax = function(options, next) {

	options = options || {};

	var requestOptions = this.requestOptions();
	
	requestOptions.path = url.format({
		pathname: "/" + this.options.version + '/tax/' + options.latitude + "," + options.longitude + "/get",
		query: {
			saleamount: options.amount
		}
	});

	this._makeRequest(requestOptions, null, next);
};

AvaTax.prototype.estimateTax = function(latitude, longitude, amount, next) {
	
	if (!isFinite(latitude) || !isFinite(longitude) || !isFinite(amount)) {
		throw new Error("Invalid arguments for `estimateTax`");
	}

	var options = {
		latitude: latitude,
		longitude: longitude,
		amount: amount
	};

	return AvaTax.prototype._estimateTax.call(this, options, next);
};

AvaTax.prototype._getTax = function(options, next) {

	options = options || {};

	var requestBody = JSON.stringify(options, null, '\t');
	var requestOptions = this.requestOptions();
	
	requestOptions.path = url.format({
		pathname: "/" + this.options.version + '/tax/get'
	});
	
	requestOptions.method = "POST";

	this._makeRequest(requestOptions, requestBody, next);
};

AvaTax.prototype.getTax = function(options, next) {
	
	if (!options) {
		throw new Error("Options are missing for `getTax`");
	}
	
	options.DocDate = options.DocDate || new Date();
	options.Commit = options.Commit !== undefined ? options.Commit : false;
	options.CurrencyCode = options.CurrencyCode || "USD";
	options.Client = options.Client !== undefined ? options.Client : this.options.client;
	
	if (options.DocDate instanceof Date) {
		var docDateYear = options.DocDate.getFullYear();
		var docDateMonth = options.DocDate.getMonth() + 1;
		var docDateDate = options.DocDate.getDate();
	
		options.DocDate = [
			docDateYear,
			docDateMonth < 10 ? "0" + docDateMonth : docDateMonth,
			docDateDate < 10 ? "0" + docDateDate : docDateDate
		].join("-");
	}
	
	if (
		options.CustomerCode === undefined ||
		!Array.isArray(options.Lines) ||
		!options.Lines.length ||
		!Array.isArray(options.Addresses) ||
		!options.Addresses.length
	) {
		return next(new Error("Missing required fields"));
	}
	
	var err = null;
	
	options.Lines.some(function(line, index) {
		if (
			line.LineNo === undefined ||
			line.DestinationCode === undefined ||
			line.OriginCode === undefined ||
			!isFinite(line.Qty) ||
			!isFinite(line.Amount)
		) {
			err = new Error("Line indexOf#" + index + " is missing required fields");
			return err;
		}
	});
	
	options.Addresses.some(function(address, index) {
		
		if (
			address.AddressCode === undefined ||
			!(
				validateAddressFields(address) ||
				address.TaxRegionId !== undefined || 
				(
					address.Latitude !== undefined &&
					address.Longitude !== undefined
				)
			)
		) {
			err = next(new Error("Address indexOf#" + index + " is missing required fields"));
			return err;
		}
	});
	
	if (err) {
		return next(err);
	}

	return AvaTax.prototype._getTax.call(this, options, next);
};

module.exports = AvaTax;