using System.Text;
using Syntax;
using Syntax.Typing.BoundNode;

namespace Generation.QBE;

internal class QBEWriter
{
    private readonly StringBuilder _builder = new();
    private int _currentLine = -1;

    public QBEWriter(string debugFile)
    {
        _builder.AppendLine($"dbgfile \"{debugFile}\"");
        _builder.AppendLine();
    }

    public void StartFunction(string signature)
    {
        _currentLine = -1;
        _builder.Append(signature);
        _builder.AppendLine(" {");
        _builder.AppendLine("@start");
    }

    public void EndFunction()
    {
        _builder.AppendLine("}");
    }

    private void WriteDebugLocation(SourceSpan span)
    {
        var line = span.Start.Line;

        if (_currentLine != line)
        {
            _builder.AppendLine($"    dbgloc {line}");
            _currentLine = line;
        }
    }

    public void WriteDebugLocation(BoundNode node)
    {
        var firstToken = node.Tokens.FirstOrDefault();
        if (firstToken != null)
        {
            WriteDebugLocation(firstToken.Span);
        }
    }

    public void Indented(string value)
    {
        _builder.Append('\t');
        _builder.AppendLine(value);
    }

    public void Comment(string comment)
    {
        _builder.AppendLine("# " + comment);
    }

    public void WriteLine(string text)
    {
        _builder.AppendLine(text);
    }

    public void Write(string text)
    {
        _builder.Append(text);
    }

    public void NewLine()
    {
        _builder.AppendLine();
    }

    public override string ToString()
    {
        return _builder.ToString();
    }
}