/**
* @license Apache-2.0
*
* Copyright (c) 2018 The Stdlib Authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
*    http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/

'use strict';

// MODULES //

var isNonNegativeIntegerArray = require( '@stdlib/assert/is-nonnegative-integer-array' ).primitives;
var tic = require( './../../tic' );


// MAIN //

/**
* Returns a high-resolution time difference.
*
* ## Notes
*
* -   Output format: `[seconds, nanoseconds]`.
*
*
* @param {NonNegativeIntegerArray} time - high-resolution time
* @throws {TypeError} must provide a nonnegative integer array
* @throws {RangeError} input array must have length `2`
* @returns {NumberArray} high resolution time difference
*
* @example
* var tic = require( '@stdlib/time/tic' );
*
* var start = tic();
* var delta = toc( start );
* // returns [<number>,<number>]
*/
function toc( time ) {
	var now = tic();
	var sec;
	var ns;
	if ( !isNonNegativeIntegerArray( time ) ) {
		throw new TypeError( 'invalid argument. Must provide an array of nonnegative integers. Value: `' + time + '`.' );
	}
	if ( time.length !== 2 ) {
		throw new RangeError( 'invalid argument. Input array must have length `2`.' );
	}
	sec = now[ 0 ] - time[ 0 ];
	ns = now[ 1 ] - time[ 1 ];
	if ( sec > 0 && ns < 0 ) {
		sec -= 1;
		ns += 1e9;
	}
	else if ( sec < 0 && ns > 0 ) {
		sec += 1;
		ns -= 1e9;
	}
	return [ sec, ns ];
}


// EXPORTS //

module.exports = toc;