using CanonSharp.Common.LexicalAnalyzer;
using StringReader = CanonSharp.Common.Reader.StringReader;

namespace CanonSharp.Tests.LexicalAnalyzerTests;

public class ScanTests
{
    [Fact]
    public void ScanTest1()
    {
        LexicalScannerBuilder builder = LexicalScanner.CreateEmptyBuilder();

        LexicalToken token1 = new(RegularExpression.String("ab"), 1);
        builder.DefineToken(token1);

        StringReader reader = new("ab");
        LexicalScanner scanner = builder.Build(reader);

        Assert.True(scanner.TryRead(out LexicalToken? result));
        Assert.Equal(token1, result);
        Assert.Equal("ab", result.LiteralValue);
    }

    [Fact]
    public void ScanTest2()
    {
        LexicalScannerBuilder builder = LexicalScanner.CreateDefaultBuilder();

        LexicalToken stringKeyword = new(RegularExpression.String("string"), 100);
        LexicalToken periodDelimiter = new(RegularExpression.Single('.'), 100);
        LexicalToken semiColonDelimiter = new(RegularExpression.Single(';'), 100);
        LexicalToken identifier = new(RegularExpression.Concatenate(RegularExpression.Range('a', 'z'),
            RegularExpression.Kleene(RegularExpression.Range('a', 'z'))), 0);
        LexicalToken assigner = new(RegularExpression.String(":="), 100);
        builder.DefineToken(stringKeyword);
        builder.DefineToken(periodDelimiter);
        builder.DefineToken(semiColonDelimiter);
        builder.DefineToken(identifier);
        builder.DefineToken(assigner);

        StringReader reader = new("""
                                  string value := origin;
                                  string abc := value.
                                  """);
        LexicalScanner scanner = builder.Build(reader);
        Validate(scanner, [
            stringKeyword,
            identifier,
            assigner,
            identifier,
            semiColonDelimiter,
            stringKeyword,
            identifier,
            assigner,
            identifier,
            periodDelimiter
        ]);

        Assert.False(scanner.TryRead(out _));
    }

    private static void Validate(LexicalScanner scanner, IEnumerable<LexicalToken> expectedTokens)
    {
        foreach (LexicalToken token in expectedTokens)
        {
            Assert.True(scanner.TryRead(out LexicalToken? outToken));
            Assert.NotNull(outToken);
            Assert.Equal(token, outToken);
        }
    }
}