// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
 
using System.Collections.Generic;
using System.Linq;
using System.Net.Http.HPack;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http;
using Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http2;
using Microsoft.Extensions.Primitives;
 
using Xunit;
 
namespace Microsoft.AspNetCore.Server.Kestrel.Core.Tests;
 
public class Http2HeadersEnumeratorTests
{
    [Fact]
    public void CanIterateOverResponseHeaders()
    {
        var responseHeaders = (IHeaderDictionary)new HttpResponseHeaders();
 
        responseHeaders.ContentLength = 9;
        responseHeaders.AcceptRanges = "AcceptRanges!";
        responseHeaders.Age = new StringValues(new[] { "1", "2" });
        responseHeaders.Date = "Date!";
        responseHeaders.GrpcEncoding = "Identity!";
 
        responseHeaders.Append("Name1", "Value1");
        responseHeaders.Append("Name2", "Value2-1");
        responseHeaders.Append("Name2", "Value2-2");
        responseHeaders.Append("Name3", "Value3");
 
        var e = new Http2HeadersEnumerator();
        e.Initialize(responseHeaders);
 
        var headers = GetNormalizedHeaders(e);
 
        Assert.Equal(new[]
        {
                CreateHeaderResult(H2StaticTable.Date, "Date", "Date!"),
                CreateHeaderResult(H2StaticTable.AcceptRanges, "Accept-Ranges", "AcceptRanges!"),
                CreateHeaderResult(H2StaticTable.Age, "Age", "1"),
                CreateHeaderResult(H2StaticTable.Age, "Age", "2"),
                CreateHeaderResult(-1, "Grpc-Encoding", "Identity!"),
                CreateHeaderResult(H2StaticTable.ContentLength, "Content-Length", "9"),
                CreateHeaderResult(-1, "Name1", "Value1"),
                CreateHeaderResult(-1, "Name2", "Value2-1"),
                CreateHeaderResult(-1, "Name2", "Value2-2"),
                CreateHeaderResult(-1, "Name3", "Value3"),
            }, headers);
    }
 
    [Fact]
    public void CanIterateOverResponseTrailers()
    {
        var responseTrailers = (IHeaderDictionary)new HttpResponseTrailers();
 
        responseTrailers.ContentLength = 9;
        responseTrailers.ETag = "ETag!";
 
        responseTrailers.Append("Name1", "Value1");
        responseTrailers.Append("Name2", "Value2-1");
        responseTrailers.Append("Name2", "Value2-2");
        responseTrailers.Append("Name3", "Value3");
 
        var e = new Http2HeadersEnumerator();
        e.Initialize(responseTrailers);
 
        var headers = GetNormalizedHeaders(e);
 
        Assert.Equal(new[]
        {
                CreateHeaderResult(H2StaticTable.ETag, "ETag", "ETag!"),
                CreateHeaderResult(-1, "Name1", "Value1"),
                CreateHeaderResult(-1, "Name2", "Value2-1"),
                CreateHeaderResult(-1, "Name2", "Value2-2"),
                CreateHeaderResult(-1, "Name3", "Value3"),
            }, headers);
    }
 
    [Fact]
    public void Initialize_ChangeHeadersSource_EnumeratorUsesNewSource()
    {
        var responseHeaders = new HttpResponseHeaders();
        responseHeaders.Append("Name1", "Value1");
        responseHeaders.Append("Name2", "Value2-1");
        responseHeaders.Append("Name2", "Value2-2");
 
        var e = new Http2HeadersEnumerator();
        e.Initialize(responseHeaders);
 
        Assert.True(e.MoveNext());
        Assert.Equal("Name1", e.Current.Key);
        Assert.Equal("Value1", e.Current.Value);
        Assert.Equal(-1, e.HPackStaticTableId);
 
        Assert.True(e.MoveNext());
        Assert.Equal("Name2", e.Current.Key);
        Assert.Equal("Value2-1", e.Current.Value);
        Assert.Equal(-1, e.HPackStaticTableId);
 
        Assert.True(e.MoveNext());
        Assert.Equal("Name2", e.Current.Key);
        Assert.Equal("Value2-2", e.Current.Value);
        Assert.Equal(-1, e.HPackStaticTableId);
 
        var responseTrailers = (IHeaderDictionary)new HttpResponseTrailers();
 
        responseTrailers.GrpcStatus = "1";
 
        responseTrailers.Append("Name1", "Value1");
        responseTrailers.Append("Name2", "Value2-1");
        responseTrailers.Append("Name2", "Value2-2");
 
        e.Initialize(responseTrailers);
 
        Assert.True(e.MoveNext());
        Assert.Equal("Grpc-Status", e.Current.Key);
        Assert.Equal("1", e.Current.Value);
        Assert.Equal(-1, e.HPackStaticTableId);
 
        Assert.True(e.MoveNext());
        Assert.Equal("Name1", e.Current.Key);
        Assert.Equal("Value1", e.Current.Value);
        Assert.Equal(-1, e.HPackStaticTableId);
 
        Assert.True(e.MoveNext());
        Assert.Equal("Name2", e.Current.Key);
        Assert.Equal("Value2-1", e.Current.Value);
        Assert.Equal(-1, e.HPackStaticTableId);
 
        Assert.True(e.MoveNext());
        Assert.Equal("Name2", e.Current.Key);
        Assert.Equal("Value2-2", e.Current.Value);
        Assert.Equal(-1, e.HPackStaticTableId);
 
        Assert.False(e.MoveNext());
    }
 
    private (int HPackStaticTableId, string Name, string Value)[] GetNormalizedHeaders(Http2HeadersEnumerator enumerator)
    {
        var headers = new List<(int HPackStaticTableId, string Name, string Value)>();
        while (enumerator.MoveNext())
        {
            headers.Add(CreateHeaderResult(enumerator.HPackStaticTableId, enumerator.Current.Key, enumerator.Current.Value));
        }
        return headers.ToArray();
    }
 
    private static (int HPackStaticTableId, string Key, string Value) CreateHeaderResult(int hPackStaticTableId, string key, string value)
    {
        return (hPackStaticTableId, key, value);
    }
}