using System.IO;
using System.Text.RegularExpressions;
using BenchmarkDotNet.Attributes;
using BenchmarkDotNet.Engines;
using ParadoxSaveParser.Lib;
using PCRE;

namespace ParadoxSaveParser.Benchmarks;

/// <summary>
///     In-process engines, all extracting <c>countries.*.technology</c> from the same 110 MB save.
///     Input is preloaded into memory, so disk I/O is not part of any measurement.
/// </summary>
[MemoryDiagnoser]
[SimpleJob(RunStrategy.Monitoring, launchCount: 1, warmupCount: 1, iterationCount: 5)]
public class ExtractionBenchmarks
{
    private byte[] _pdx = null!;
    private string _pdxText = null!;
    private byte[] _json = null!;
    private SearchExpressionCompilation _query = null!;

    private Regex _technologyBlock = null!;
    private Regex _pathAwareCompiled = null!;
    private Regex _pathAwareNonBacktracking = null!;
    private Regex _countriesBlock = null!;
    private PcreRegex _pcrePathAware = null!;

    [GlobalSetup]
    public void Setup()
    {
        _pdx = BenchData.PdxBytes;
        _pdxText = BenchData.PdxText;
        _json = File.ReadAllBytes(BenchData.JsonPath);
        _query = new SearchExpressionCompilation(BenchData.PdxQuery);

        _technologyBlock = new Regex(Extractors.TechnologyBlockPattern, RegexOptions.Compiled);
        _pathAwareCompiled = new Regex(Extractors.PathAwarePattern, RegexOptions.Compiled);
        _pathAwareNonBacktracking = new Regex(Extractors.PathAwarePattern, RegexOptions.NonBacktracking);
        _countriesBlock = new Regex(Extractors.CountriesBlockPattern, RegexOptions.Compiled);
        _pcrePathAware = new PcreRegex(Extractors.PathAwarePattern, PcreOptions.Compiled);
    }

    [Benchmark(Baseline = true, Description = "SearchExpression (this project)")]
    public long SearchExpression() => Extractors.SearchExpression(_pdx, _query);

    [Benchmark(Description = "Full parse, then select")]
    public long FullParse() => Extractors.FullParseThenSelect(_pdx);

    [Benchmark(Description = ".NET Regex path aware, compiled")]
    public long RegexPathAwareCompiled() => Extractors.RegexScan(_pathAwareCompiled, _pdxText);

    [Benchmark(Description = ".NET Regex path aware, NonBacktracking")]
    public long RegexPathAwareNonBacktracking() => Extractors.RegexScan(_pathAwareNonBacktracking, _pdxText);

    [Benchmark(Description = ".NET Regex balanced block + inner scan")]
    public long RegexBalancedTwoStage() => Extractors.RegexTwoStage(_countriesBlock, _technologyBlock, _pdxText);

    [Benchmark(Description = "PCRE.NET path aware, JIT compiled")]
    public long PcrePathAware() => Extractors.PcreScan(_pcrePathAware, _pdxText);

    [Benchmark(Description = "Utf8JsonReader over JSON twin")]
    public long Utf8JsonReader() => Extractors.Utf8JsonReaderScan(_json);

    [Benchmark(Description = "JsonDocument over JSON twin")]
    public long JsonDocument() => Extractors.JsonDocumentScan(_json);
}