// 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.Linq;
using Xunit;

namespace Microsoft.Net.Http.Headers
{
    public class RangeHeaderValueTest
    {
        [Fact]
        public void Ctor_InvalidRange_Throw()
        {
            Assert.Throws<ArgumentOutOfRangeException>(() => new RangeHeaderValue(5, 2));
        }

        [Fact]
        public void Unit_GetAndSetValidAndInvalidValues_MatchExpectation()
        {
            var range = new RangeHeaderValue();
            range.Unit = "myunit";
            Assert.Equal("myunit", range.Unit);

            Assert.Throws<ArgumentException>(() => range.Unit = null);
            Assert.Throws<ArgumentException>(() => range.Unit = "");
            Assert.Throws<FormatException>(() => range.Unit = " x");
            Assert.Throws<FormatException>(() => range.Unit = "x ");
            Assert.Throws<FormatException>(() => range.Unit = "x y");
        }

        [Fact]
        public void ToString_UseDifferentRanges_AllSerializedCorrectly()
        {
            var range = new RangeHeaderValue();
            range.Unit = "myunit";
            range.Ranges.Add(new RangeItemHeaderValue(1, 3));
            Assert.Equal("myunit=1-3", range.ToString());

            range.Ranges.Add(new RangeItemHeaderValue(5, null));
            range.Ranges.Add(new RangeItemHeaderValue(null, 17));
            Assert.Equal("myunit=1-3, 5-, -17", range.ToString());
        }

        [Fact]
        public void GetHashCode_UseSameAndDifferentRanges_SameOrDifferentHashCodes()
        {
            var range1 = new RangeHeaderValue(1, 2);
            var range2 = new RangeHeaderValue(1, 2);
            range2.Unit = "BYTES";
            var range3 = new RangeHeaderValue(1, null);
            var range4 = new RangeHeaderValue(null, 2);
            var range5 = new RangeHeaderValue();
            range5.Ranges.Add(new RangeItemHeaderValue(1, 2));
            range5.Ranges.Add(new RangeItemHeaderValue(3, 4));
            var range6 = new RangeHeaderValue();
            range6.Ranges.Add(new RangeItemHeaderValue(3, 4)); // reverse order of range5
            range6.Ranges.Add(new RangeItemHeaderValue(1, 2));

            Assert.Equal(range1.GetHashCode(), range2.GetHashCode());
            Assert.NotEqual(range1.GetHashCode(), range3.GetHashCode());
            Assert.NotEqual(range1.GetHashCode(), range4.GetHashCode());
            Assert.NotEqual(range1.GetHashCode(), range5.GetHashCode());
            Assert.Equal(range5.GetHashCode(), range6.GetHashCode());
        }

        [Fact]
        public void Equals_UseSameAndDifferentRanges_EqualOrNotEqualNoExceptions()
        {
            var range1 = new RangeHeaderValue(1, 2);
            var range2 = new RangeHeaderValue(1, 2);
            range2.Unit = "BYTES";
            var range3 = new RangeHeaderValue(1, null);
            var range4 = new RangeHeaderValue(null, 2);
            var range5 = new RangeHeaderValue();
            range5.Ranges.Add(new RangeItemHeaderValue(1, 2));
            range5.Ranges.Add(new RangeItemHeaderValue(3, 4));
            var range6 = new RangeHeaderValue();
            range6.Ranges.Add(new RangeItemHeaderValue(3, 4)); // reverse order of range5
            range6.Ranges.Add(new RangeItemHeaderValue(1, 2));
            var range7 = new RangeHeaderValue(1, 2);
            range7.Unit = "other";

            Assert.False(range1.Equals(null), "bytes=1-2 vs. <null>");
            Assert.True(range1.Equals(range2), "bytes=1-2 vs. BYTES=1-2");
            Assert.False(range1.Equals(range3), "bytes=1-2 vs. bytes=1-");
            Assert.False(range1.Equals(range4), "bytes=1-2 vs. bytes=-2");
            Assert.False(range1.Equals(range5), "bytes=1-2 vs. bytes=1-2,3-4");
            Assert.True(range5.Equals(range6), "bytes=1-2,3-4 vs. bytes=3-4,1-2");
            Assert.False(range1.Equals(range7), "bytes=1-2 vs. other=1-2");
        }

        [Fact]
        public void Parse_SetOfValidValueStrings_ParsedCorrectly()
        {
            CheckValidParse(" bytes=1-2 ", new RangeHeaderValue(1, 2));

            var expected = new RangeHeaderValue();
            expected.Unit = "custom";
            expected.Ranges.Add(new RangeItemHeaderValue(null, 5));
            expected.Ranges.Add(new RangeItemHeaderValue(1, 4));
            CheckValidParse("custom = -  5 , 1 - 4 ,,", expected);

            expected = new RangeHeaderValue();
            expected.Unit = "custom";
            expected.Ranges.Add(new RangeItemHeaderValue(1, 2));
            CheckValidParse(" custom = 1 - 2", expected);

            expected = new RangeHeaderValue();
            expected.Ranges.Add(new RangeItemHeaderValue(1, 2));
            expected.Ranges.Add(new RangeItemHeaderValue(3, null));
            expected.Ranges.Add(new RangeItemHeaderValue(null, 4));
            CheckValidParse("bytes =1-2,,3-, , ,-4,,", expected);
        }

        [Fact]
        public void Parse_SetOfInvalidValueStrings_Throws()
        {
            CheckInvalidParse("bytes=1-2x"); // only delimiter ',' allowed after last range
            CheckInvalidParse("x bytes=1-2");
            CheckInvalidParse("bytes=1-2.4");
            CheckInvalidParse(null);
            CheckInvalidParse(string.Empty);

            CheckInvalidParse("bytes=1");
            CheckInvalidParse("bytes=");
            CheckInvalidParse("bytes");
            CheckInvalidParse("bytes 1-2");
            CheckInvalidParse("bytes= ,,, , ,,");
        }

        [Fact]
        public void TryParse_SetOfValidValueStrings_ParsedCorrectly()
        {
            CheckValidTryParse(" bytes=1-2 ", new RangeHeaderValue(1, 2));

            var expected = new RangeHeaderValue();
            expected.Unit = "custom";
            expected.Ranges.Add(new RangeItemHeaderValue(null, 5));
            expected.Ranges.Add(new RangeItemHeaderValue(1, 4));
            CheckValidTryParse("custom = -  5 , 1 - 4 ,,", expected);
        }

        [Fact]
        public void TryParse_SetOfInvalidValueStrings_ReturnsFalse()
        {
            CheckInvalidTryParse("bytes=1-2x"); // only delimiter ',' allowed after last range
            CheckInvalidTryParse("x bytes=1-2");
            CheckInvalidTryParse("bytes=1-2.4");
            CheckInvalidTryParse(null);
            CheckInvalidTryParse(string.Empty);
        }

        #region Helper methods

        private void CheckValidParse(string input, RangeHeaderValue expectedResult)
        {
            var result = RangeHeaderValue.Parse(input);
            Assert.Equal(expectedResult, result);
        }

        private void CheckInvalidParse(string input)
        {
            Assert.Throws<FormatException>(() => RangeHeaderValue.Parse(input));
        }

        private void CheckValidTryParse(string input, RangeHeaderValue expectedResult)
        {
            RangeHeaderValue result = null;
            Assert.True(RangeHeaderValue.TryParse(input, out result));
            Assert.Equal(expectedResult, result);
        }

        private void CheckInvalidTryParse(string input)
        {
            RangeHeaderValue result = null;
            Assert.False(RangeHeaderValue.TryParse(input, out result));
            Assert.Null(result);
        }

        #endregion
    }
}
