/**
 * Copyright (c) 2020 TypeFox GmbH. All rights reserved.
 * Licensed under the GNU Affero General Public License (AGPL).
 * See License-AGPL.txt in the project root for license information.
 */

import * as chai from 'chai';
const expect = chai.expect;
import { suite, test } from 'mocha-typescript';
import { oneMonthLater } from './timeutil';

@suite()
export class TimeutilSpec {

    @test
    testTimeutil() {
        // targeting a 1st, 1th of Jan => 1st of Feb
        this.isOneMonthLater(new Date(2000, 0, 1), 1, new Date(2000, 1, 1))

        // targeting a 31th, 30th of Apr => 31st of May
        this.isOneMonthLater(new Date(2000, 3, 30), 31, new Date(2000, 4, 31))

        // targeting a 31th, 31th of Mar => 30th of Apr
        this.isOneMonthLater(new Date(2000, 2, 31), 31, new Date(2000, 3, 30))

        // targeting a 30th, 30th of Mar => 30th of Apr
        this.isOneMonthLater(new Date(2000, 2, 30), 30, new Date(2000, 3, 30))

        // next year
        this.isOneMonthLater(new Date(2000, 11, 1), 1, new Date(2001, 0, 1))
        this.isOneMonthLater(new Date(2000, 11, 31), 31, new Date(2001, 0, 31))

        // Feb
        this.isOneMonthLater(new Date(2001, 0, 31), 31, new Date(2001, 1, 28))
        // Feb leap year
        this.isOneMonthLater(new Date(2000, 0, 31), 31, new Date(2000, 1, 29))
    }

    isOneMonthLater(from: Date, day: number, expectation: Date) {
        const later = oneMonthLater(from.toISOString(), day)
        expect(later, `expected ${later} to be equal ${expectation}`).to.be.equal(expectation.toISOString())
    }
}