using TwitchDownloaderCore.Tools;

namespace TwitchDownloaderCore.Tests.ToolTests
{
    // Important notes: When a TimeSpan less than 24 hours in length is passed to TimeSpanHFormat.Format, TimeSpan.ToString is used instead.
    // ReSharper disable StringLiteralTypo
    public class TimeSpanHFormatTests
    {
        [Fact]
        public void GetFormatWithICustomFormatterReturnsSelf()
        {
            var type = typeof(ICustomFormatter);
            var formatter = TimeSpanHFormat.ReusableInstance;

            var result = formatter.GetFormat(type);

            Assert.Same(formatter, result);
        }

        [Fact]
        public void GetFormatWithNotICustomFormatterReturnsNull()
        {
            var type = typeof(TimeSpanHFormat);
            var formatter = TimeSpanHFormat.ReusableInstance;

            var result = formatter.GetFormat(type);

            Assert.Null(result);
        }

        [Fact]
        public void CustomFormatOverloadMatchesICustomFormatter()
        {
            var timeSpan = new TimeSpan(17, 49, 12);
            const string FORMAT_STRING = @"HH\:mm\:ss";

            var resultICustomFormatter = ((ICustomFormatter)TimeSpanHFormat.ReusableInstance).Format(FORMAT_STRING, timeSpan, null);
            var resultCustom = TimeSpanHFormat.ReusableInstance.Format(FORMAT_STRING, timeSpan);

            Assert.Equal(resultICustomFormatter, resultCustom);
        }

        [Fact]
        public void CorrectlyFormatsNonTimeSpanFormattable()
        {
            const float FLOAT = 3.14159f;
            const string FORMAT_STRING = @"F2";
            const string EXPECTED = @"3.14";

            var resultCustom = TimeSpanHFormat.ReusableInstance.Format(FORMAT_STRING, FLOAT);

            Assert.Equal(EXPECTED, resultCustom);
        }

        [Fact]
        public void CorrectlyFormatsNonTimeSpanNonFormattable()
        {
            var obj = new object();
            const string FORMAT_STRING = "";
            const string EXPECTED = "System.Object";

            var resultCustom = TimeSpanHFormat.ReusableInstance.Format(FORMAT_STRING, obj);

            Assert.Equal(EXPECTED, resultCustom);
        }

        [Fact]
        public void CorrectlyFormatsNull()
        {
            object? obj = null;
            const string FORMAT_STRING = "";
            const string EXPECTED = "";

            var resultCustom = TimeSpanHFormat.ReusableInstance.Format(FORMAT_STRING, obj);

            Assert.Equal(EXPECTED, resultCustom);
        }

        [Fact]
        public void ReturnsTimeSpanToString_WhenFormatIsEmpty()
        {
            var timeSpan = new TimeSpan(17, 49, 12);
            const string FORMAT_STRING = "";
            var expected = timeSpan.ToString();

            var resultCustom = TimeSpanHFormat.ReusableInstance.Format(FORMAT_STRING, timeSpan);

            Assert.Equal(expected, resultCustom);
        }

        [Fact]
        public void ReturnsTimeSpanToString_WhenFormatIsNull()
        {
            var timeSpan = new TimeSpan(17, 49, 12);
            const string FORMAT_STRING = null!;
            var expected = timeSpan.ToString();

            var resultCustom = TimeSpanHFormat.ReusableInstance.Format(FORMAT_STRING, timeSpan);

            Assert.Equal(expected, resultCustom);
        }

        [Fact]
        public void MatchesTimeSpanToString_WhenBigHInFormat()
        {
            var timeSpan = new TimeSpan(17, 49, 12);
            const string FORMAT_STRING = @"HH\:mm\:ss";
            const string EXPECTED = "17:49:12";

            var result = TimeSpanHFormat.ReusableInstance.Format(FORMAT_STRING, timeSpan);

            Assert.Equal(EXPECTED, result);
        }

        [Fact]
        public void MatchesTimeSpanToString_WhenNoBigHInFormat()
        {
            var timeSpan = new TimeSpan(17, 49, 12);
            const string FORMAT_STRING = @"hh\:mm\:ss";
            const string EXPECTED = "17:49:12";

            var result = TimeSpanHFormat.ReusableInstance.Format(FORMAT_STRING, timeSpan);

            Assert.Equal(EXPECTED, result);
        }

        [Fact]
        public void CorrectlyEscapesCharsPrependedByBackslash()
        {
            var timeSpan = new TimeSpan(25, 37, 43);
            const string FORMAT_STRING = @"HH\:mm\:ss";
            const string EXPECTED = "25:37:43";

            var result = TimeSpanHFormat.ReusableInstance.Format(FORMAT_STRING, timeSpan);

            Assert.Equal(EXPECTED, result);
        }

        [Fact]
        public void CorrectlyEscapesSingleCharsContainedWithinQuotes()
        {
            var timeSpan = new TimeSpan(25, 37, 43);
            const string FORMAT_STRING = @"HH'-'mm'-'ss";
            const string EXPECTED = "25-37-43";

            var result = TimeSpanHFormat.ReusableInstance.Format(FORMAT_STRING, timeSpan);

            Assert.Equal(EXPECTED, result);
        }

        [Fact]
        public void CorrectlyEscapesManyCharsContainedWithinQuotes()
        {
            var timeSpan = new TimeSpan(25, 37, 43);
            const string FORMAT_STRING = @"'It has been 'HH' hours.'";
            const string EXPECTED = "It has been 25 hours.";

            var result = TimeSpanHFormat.ReusableInstance.Format(FORMAT_STRING, timeSpan);

            Assert.Equal(EXPECTED, result);
        }

        [Fact]
        public void CorrectlyEscapesEndQuotesPrependedByBackslashes()
        {
            var timeSpan = new TimeSpan(25, 37, 43);
            const string FORMAT_STRING = @"'I\'ll be back in 'H' Hours.'";
            const string EXPECTED = "I'll be back in 25 Hours.";

            var result = TimeSpanHFormat.ReusableInstance.Format(FORMAT_STRING, timeSpan);

            Assert.Equal(EXPECTED, result);
        }

        [Fact]
        public void CorrectlyFormatsTrailingBigH()
        {
            var timeSpan = new TimeSpan(25, 37, 43);
            const string FORMAT_STRING = @"ssmmHH";
            const string EXPECTED = "433725";

            var result = TimeSpanHFormat.ReusableInstance.Format(FORMAT_STRING, timeSpan);

            Assert.Equal(EXPECTED, result);
        }

        [Fact]
        public void CorrectlyFormatsMoreThan2BigH_WhenHoursUnder24()
        {
            var timeSpan = new TimeSpan(23, 37, 43);
            const string FORMAT_STRING = @"HHH";
            const string EXPECTED = "023";

            var result = TimeSpanHFormat.ReusableInstance.Format(FORMAT_STRING, timeSpan);

            Assert.Equal(EXPECTED, result);
        }

        [Fact]
        public void CorrectlyFormatsAbsurdlyLongSequentialBigHFormat()
        {
            var timeSpan = new TimeSpan(25, 37, 43);
            const string FORMAT_STRING = @"HHHHHHHHHHHHHHHHHHHH";
            const string EXPECTED = "00000000000000000025";

            var result = TimeSpanHFormat.ReusableInstance.Format(FORMAT_STRING, timeSpan);

            Assert.Equal(EXPECTED, result);
        }

        [Fact]
        public void CorrectlyFormatsAbsurdlyLongFormatString()
        {
            var timeSpan = new TimeSpan(25, 37, 43);
            const string FORMAT_STRING = "'This is a really long format string. You should never put messages in your format string, but this is a unit test " +
                                         "designed to ensure the unit functions as expected in extreme cases. This class could be exposed to user input someday. " +
                                         "The format string should be at least 256 characters in length, as that is the size of the stackalloc for appending " +
                                         "a regular format string as of writing the test but it could change in the future, we never know. SORRY FOR THE TRAFFIC " +
                                         @"NaM. It is now time to include a big H character to ensure we don\'t fall back on TimeSpan.ToString(). 'H";
            const string EXPECTED = "This is a really long format string. You should never put messages in your format string, but this is a unit test " +
                                    "designed to ensure the unit functions as expected in extreme cases. This class could be exposed to user input someday. " +
                                    "The format string should be at least 256 characters in length, as that is the size of the stackalloc for appending " +
                                    "a regular format string as of writing the test but it could change in the future, we never know. SORRY FOR THE TRAFFIC " +
                                    "NaM. It is now time to include a big H character to ensure we don't fall back on TimeSpan.ToString(). 25";

            var result = TimeSpanHFormat.ReusableInstance.Format(FORMAT_STRING, timeSpan);

            Assert.Equal(EXPECTED, result);
        }

        [Fact]
        public void ThrowsOnImbalancedQuoteMarkEscaping_WhenHoursUnder24()
        {
            var timeSpan = new TimeSpan(23, 37, 43);
            const string FORMAT_STRING = "H\" Imbalanced quote escaping.";
            var expectedExceptionType = typeof(FormatException);
            const string EXPECTED_SOURCE_NAME = nameof(TwitchDownloaderCore);

            var exception = Assert.Throws(expectedExceptionType, () => TimeSpanHFormat.ReusableInstance.Format(FORMAT_STRING, timeSpan));

            // Ensure the FormatException originated from TimeSpanHFormat and not TimeSpan.ToString()
            Assert.IsType<FormatException>(exception);
            Assert.Equal(EXPECTED_SOURCE_NAME, exception.Source);
        }

        [Fact]
        public void ThrowsOnImbalancedQuoteMarkEscaping_When24HoursOrMore()
        {
            var timeSpan = new TimeSpan(24, 37, 43);
            const string FORMAT_STRING = "H\" Imbalanced quote escaping.";
            var expectedExceptionType = typeof(FormatException);
            const string EXPECTED_SOURCE_NAME = nameof(TwitchDownloaderCore);

            var exception = Assert.Throws(expectedExceptionType, () => TimeSpanHFormat.ReusableInstance.Format(FORMAT_STRING, timeSpan));

            // Ensure the FormatException originated from TimeSpanHFormat and not TimeSpan.ToString()
            Assert.IsType<FormatException>(exception);
            Assert.Equal(EXPECTED_SOURCE_NAME, exception.Source);
        }
    }
}