using System.Text.Json;
using BenchmarkDotNet.Attributes;
using BenchmarkDotNet.Running;

BenchmarkRunner.Run<StringLookupBenchmark>();

[MemoryDiagnoser]
public class StringLookupBenchmark
{
    private readonly Dictionary<string, string> _cached = new(StringComparer.OrdinalIgnoreCase)
    {
        ["Echo"] = "Echo"
    };

    private readonly Utf8HashLookup _utf8Lookup = new Utf8HashLookup();

    public StringLookupBenchmark()
    {
        _utf8Lookup.Add("Echo");
    }

    private static ReadOnlySpan<byte> Payload => "{\"target\": \"echo\"}"u8;

    [Benchmark]
    public string StringLookup()
    {
        var reader = new Utf8JsonReader(Payload);
        reader.Read(); // Start object
        reader.Read(); // property name
        reader.Read(); // property value
        var target = reader.GetString()!;
        reader.Read(); // end object
        _cached.TryGetValue(target, out var value);
        return value!;
    }

    [Benchmark]
    public string Uf8Lookup()
    {
        var reader = new Utf8JsonReader(Payload);
        reader.Read(); // Start object
        reader.Read(); // property name
        reader.Read(); // property value
        var target = reader.ValueSpan;
        reader.Read(); // end object
        _utf8Lookup.TryGetValue(target, out var value);
        return value!;
    }
}