﻿// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.

using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.Logging.Abstractions;
using Microsoft.Net.Http.Headers;

namespace Microsoft.AspNetCore.Internal;

public class RangeHelperTests
{
    [Theory]
    [InlineData(1, 2)]
    [InlineData(2, 3)]
    public void NormalizeRange_ReturnsNullWhenRangeStartEqualsOrGreaterThanLength(long start, long end)
    {
        // Arrange & Act
        var normalizedRange = RangeHelper.NormalizeRange(new RangeItemHeaderValue(start, end), 1);

        // Assert
        Assert.Null(normalizedRange);
    }

    [Fact]
    public void NormalizeRange_ReturnsNullWhenRangeEndEqualsZero()
    {
        // Arrange & Act
        var normalizedRange = RangeHelper.NormalizeRange(new RangeItemHeaderValue(null, 0), 1);

        // Assert
        Assert.Null(normalizedRange);
    }

    [Theory]
    [InlineData(0, null, 0, 2)]
    [InlineData(0, 0, 0, 0)]
    public void NormalizeRange_ReturnsNormalizedRange(long? start, long? end, long? normalizedStart, long? normalizedEnd)
    {
        // Arrange & Act
        var normalizedRange = RangeHelper.NormalizeRange(new RangeItemHeaderValue(start, end), 3);

        // Assert
        Assert.Equal(normalizedStart, normalizedRange.From);
        Assert.Equal(normalizedEnd, normalizedRange.To);
    }

    [Fact]
    public void NormalizeRange_ReturnsRangeWithNoChange()
    {
        // Arrange & Act
        var normalizedRange = RangeHelper.NormalizeRange(new RangeItemHeaderValue(1, 3), 4);

        // Assert
        Assert.Equal(1, normalizedRange.From);
        Assert.Equal(3, normalizedRange.To);
    }

    [Theory]
    [InlineData(null)]
    [InlineData("")]
    public void ParseRange_ReturnsNullWhenRangeHeaderNotProvided(string range)
    {
        // Arrange
        var httpContext = new DefaultHttpContext();
        httpContext.Request.Headers.Range = range;

        // Act
        var (isRangeRequest, parsedRangeResult) = RangeHelper.ParseRange(httpContext, httpContext.Request.GetTypedHeaders(), 10, NullLogger.Instance);

        // Assert
        Assert.False(isRangeRequest);
        Assert.Null(parsedRangeResult);
    }

    [Theory]
    [InlineData("1-2, 3-4")]
    [InlineData("1-2, ")]
    public void ParseRange_ReturnsNullWhenMultipleRangesProvidedInRangeHeader(string range)
    {
        // Arrange
        var httpContext = new DefaultHttpContext();
        httpContext.Request.Headers.Range = range;

        // Act
        var (isRangeRequest, parsedRangeResult) = RangeHelper.ParseRange(httpContext, httpContext.Request.GetTypedHeaders(), 10, NullLogger.Instance);

        // Assert
        Assert.False(isRangeRequest);
        Assert.Null(parsedRangeResult);
    }

    [Fact]
    public void ParseRange_ReturnsSingleRangeWhenInputValid()
    {
        // Arrange
        var httpContext = new DefaultHttpContext();
        var range = new RangeHeaderValue(1, 2);
        httpContext.Request.Headers.Range = range.ToString();

        // Act
        var (isRangeRequest, parsedRange) = RangeHelper.ParseRange(httpContext, httpContext.Request.GetTypedHeaders(), 4, NullLogger.Instance);

        // Assert
        Assert.True(isRangeRequest);
        Assert.Equal(1, parsedRange.From);
        Assert.Equal(2, parsedRange.To);
    }
}
