using MycroForge.Core.CodeGen;

namespace MycroForge.CLI.CodeGen;

public class DbEnvModifier
{
    private readonly Source _source;
    private readonly string _importPath;
    private readonly string _className;
    private SourceMatch? _lastImport;

    public DbEnvModifier(string source, string importPath, string className)
    {
        _source = new Source(source);
        _importPath = importPath;
        _className = className;
    }

    public string Rewrite()
    {
        InsertEntityImport();

        return _source.Text;
    }

    private void InsertEntityImport()
    {
        _lastImport = _source
            .FindAll($@"from\s+{Features.Db.FeatureName}\.entities(?:\..+)+\s*import\s+.+\s")
            .LastOrDefault();
        
        if (_lastImport is null)
            throw new Exception("Could not find import insertion point.");

        _source.InsertSingleLine(
            _lastImport.EndIndex,
            $"from {_importPath} import {_className}\n"
        );
    }
}