// Copyright (c) .NET Foundation. All rights reserved.
// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.

using System;
using System.Collections.Generic;
using Xunit;

namespace Microsoft.Net.Http.Headers
{
    public class DateParserTest
    {
        [Theory]
        [MemberData(nameof(ValidStringData))]
        public void TryParse_SetOfValidValueStrings_ParsedCorrectly(string input, DateTimeOffset expected)
        {
            // We don't need to validate all possible date values, since they're already tested in HttpRuleParserTest.
            // Just make sure the parser calls HttpRuleParser methods correctly.
            Assert.True(HeaderUtilities.TryParseDate(input, out var result));
            Assert.Equal(expected, result);
        }

        public static IEnumerable<object[]> ValidStringData()
        {
            yield return new object[] { "Tue, 15 Nov 1994 08:12:31 GMT", new DateTimeOffset(1994, 11, 15, 8, 12, 31, TimeSpan.Zero) };
            yield return new object[] { "      Sunday, 06-Nov-94 08:49:37 GMT   ", new DateTimeOffset(1994, 11, 6, 8, 49, 37, TimeSpan.Zero) };
            yield return new object[] { " Tue,\r\n 15 Nov\r\n 1994 08:12:31 GMT   ", new DateTimeOffset(1994, 11, 15, 8, 12, 31, TimeSpan.Zero) };
            yield return new object[] { "Sat, 09-Dec-2017 07:07:03 GMT ", new DateTimeOffset(2017, 12, 09, 7, 7, 3, TimeSpan.Zero) };
        }

        [Theory]
        [MemberData(nameof(InvalidStringData))]
        public void TryParse_SetOfInvalidValueStrings_ReturnsFalse(string input)
        {
            Assert.False(HeaderUtilities.TryParseDate(input, out var result));
            Assert.Equal(new DateTimeOffset(), result);
        }

        public static IEnumerable<object[]> InvalidStringData()
        {
            yield return new object[] { null };
            yield return new object[] { string.Empty };
            yield return new object[] { "  " };
            yield return new object[] { "!!Sunday, 06-Nov-94 08:49:37 GMT" };
        }

        [Fact]
        public void ToString_UseDifferentValues_MatchExpectation()
        {
            Assert.Equal("Sat, 31 Jul 2010 15:38:57 GMT",
                HeaderUtilities.FormatDate(new DateTimeOffset(2010, 7, 31, 15, 38, 57, TimeSpan.Zero)));

            Assert.Equal("Fri, 01 Jan 2010 01:01:01 GMT",
                HeaderUtilities.FormatDate(new DateTimeOffset(2010, 1, 1, 1, 1, 1, TimeSpan.Zero)));
        }
    }
}