using BenchmarkDotNet.Attributes;
using CanonSharp.Benchmark.Canon.Core;
using CanonSharp.Benchmark.Canon.Core.Abstractions;
using CanonSharp.Benchmark.Canon.Core.GrammarParser;
using CanonSharp.Benchmark.Canon.Core.LexicalParser;
using CanonSharp.Benchmark.Canon.Core.SyntaxNodes;
using CanonSharp.Pascal.Parser;
using CanonSharp.Pascal.Scanner;

namespace CanonSharp.Benchmark.Benchmarks;

public class GrammarParserBenchmark
{
    private readonly List<string> _inputFiles = [];

    // CanonSharp
    private readonly LexicalScanner _scanner = new();
    private readonly GrammarParser _parser = new();

    // Canon
    private readonly IGrammarParser _grammarParser = GeneratedGrammarParser.Instance;

    public GrammarParserBenchmark()
    {
        _inputFiles.AddRange(ReadOpenSet());
    }

    [Benchmark]
    [ArgumentsSource(nameof(InputFiles))]
    public Pascal.SyntaxTree.Program CanonSharpParse(int index)
    {
        IEnumerable<LexicalToken> tokens = _scanner.Tokenize(new StringReadState(_inputFiles[index]));
        return _parser.Parse(tokens);
    }

    [Benchmark]
    [ArgumentsSource(nameof(InputFiles))]
    public ProgramStruct CanonParse(int index)
    {
        Lexer lexer = new();
        IEnumerable<SemanticToken> tokens = lexer.Tokenize(new StringSourceReader(_inputFiles[index]));

        return _grammarParser.Analyse(tokens);
    }

    public IEnumerable<object> InputFiles()
    {
        for (int i = 0; i < _inputFiles.Count; i++)
        {
            yield return i;
        }
    }

    private static List<string> ReadOpenSet()
    {
        DirectoryInfo baseDirectory = new("/home/ricardo/Documents/Code/CSharp/CanonSharp/OpenSet");
        if (!baseDirectory.Exists)
        {
            throw new InvalidOperationException("Can't find 'OpenSet' directory.");
        }

        List<string> result = [];

        foreach (FileInfo file in baseDirectory.EnumerateFiles())
        {
            using StreamReader reader = file.OpenText();

            result.Add(reader.ReadToEnd());
        }

        return result;
    }
}