/**
* @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 isPositiveInteger = require( '@stdlib/assert/is-positive-integer' );
var isObject = require( '@stdlib/assert/is-plain-object' );
var isBoolean = require( '@stdlib/assert/is-boolean' ).isPrimitive;
var hasOwnProp = require( '@stdlib/assert/has-own-property' );
var roundn = require( '@stdlib/math/base/special/roundn' );


// MAIN //

/**
* Pretty-print output of test.
*
* @param {Object} [opts] - options object
* @param {PositiveInteger} [opts.digits=4] - number of digits after the decimal point
* @param {boolean} [opts.decision=true] - boolean indicating whether to print the test decision
* @throws {TypeError} options argument must be an object
* @throws {TypeError} must provide valid options
* @returns {string} formatted output
*/
function print( opts ) { // eslint-disable-line stdlib/no-redeclare
	/* eslint-disable no-invalid-this */
	var decision;
	var dgts;
	var str;

	dgts = 4;
	decision = true;
	if ( arguments.length > 0 ) {
		if ( !isObject( opts ) ) {
			throw new TypeError( 'invalid argument. First argument must be an options object. Value: `' + opts + '`.' );
		}
		if ( hasOwnProp( opts, 'digits' ) ) {
			if ( !isPositiveInteger( opts.digits ) ) {
				throw new TypeError( 'invalid option. `digits` option must be a positive integer. Option: `' + opts.digits + '`.' );
			}
			dgts = opts.digits;
		}
		if ( hasOwnProp( opts, 'decision' ) ) {
			if ( !isBoolean( opts.decision ) ) {
				throw new TypeError( 'invalid option. `decision` option must be a boolean primitive. Option: `' + opts.decision + '`.' );
			}
			decision = opts.decision;
		}
	}
	str = '';
	str += this.method;
	str += '\n\n';
	str += 'Alternative hypothesis: ';
	if ( this.method === 'Paired t-test' ) {
		str += 'True difference in means is ';
	} else {
		str += 'True mean is ';
	}
	switch ( this.alternative ) {
	case 'two-sided':
	default:
		str += 'not equal to ';
		break;
	case 'less':
		str += 'less than ';
		break;
	case 'greater':
		str += 'greater than ';
		break;
	}
	str += this.nullValue;
	str += '\n\n';
	str += '    pValue: ' + roundn( this.pValue, -dgts ) + '\n';
	str += '    statistic: ' + roundn( this.statistic, -dgts ) + '\n';
	str += '    df: ' + this.df + '\n';
	str += '    ' + ((1.0-this.alpha)*100) + '% confidence interval: [' +
		roundn( this.ci[0], -dgts ) +
		',' +
		roundn( this.ci[1], -dgts ) +
	']';
	str += '\n\n';
	if ( decision ) {
		str += 'Test Decision: ';
		if ( this.rejected ) {
			str += 'Reject null in favor of alternative at ' + (this.alpha*100) + '% significance level';
		} else {
			str += 'Fail to reject null in favor of alternative at ' + (this.alpha*100) + '% significance level';
		}
		str += '\n';
	}
	return str;
}


// EXPORTS //

module.exports = print;