XFESystem

using XFESystem.Console;
using XfeConsoleApi = XFEExtension.NetCore.XFEConsole.XFEConsole;

namespace XFESystem.ManagedRuntime;

/// <summary>Console API calls are bound to one guest terminal, never to host stdout or files.</summary>
public sealed class TerminalManagedConsole(TerminalTextWriter writer) : IManagedConsole
{
    private ConsoleColor _foreground = ConsoleColor.Cyan, _background = ConsoleColor.Black;
    private int _written;
    public ConsoleColor ForegroundColor
    {
        get => _foreground;
        set { var color = TerminalColor.FromConsoleColor(value); _foreground = value; Control($"\u001b[38;2;{color.Red};{color.Green};{color.Blue}m"); }
    }
    public ConsoleColor BackgroundColor
    {
        get => _background;
        set { var color = TerminalColor.FromConsoleColor(value); _background = value; Control($"\u001b[48;2;{color.Red};{color.Green};{color.Blue}m"); }
    }
    public void ResetColor() { _foreground = ConsoleColor.Cyan; _background = ConsoleColor.Black; Control("\u001b[0m"); }
    public void Write(string value) { Limit(value.Length); writer.Write(value); }
    public void WriteLine(string value) { Limit(value.Length + 2); writer.Write(value); writer.Write("\r\n"); }
    public void XfeWriteLine(string value)
    {
        Limit(value.Length + 2);
        var oldWriter = XfeConsoleApi.CurrentConsoleTextWriter;
        bool oldDebug = XfeConsoleApi.ShowInDebug, oldLocal = XfeConsoleApi.ShowInLocalConsole, oldLog = XfeConsoleApi.EnableLog;
        try
        {
            XfeConsoleApi.CurrentConsoleTextWriter = new(writer);
            XfeConsoleApi.ShowInDebug = false; XfeConsoleApi.ShowInLocalConsole = true; XfeConsoleApi.EnableLog = false;
            XfeConsoleApi.WriteLine(value);
        }
        catch
        {
            Restore();
            throw;
        }
        Restore();
        // The current native exception unwinder does not execute finally clauses.
        void Restore()
        {
            XfeConsoleApi.CurrentConsoleTextWriter = oldWriter;
            XfeConsoleApi.ShowInDebug = oldDebug; XfeConsoleApi.ShowInLocalConsole = oldLocal; XfeConsoleApi.EnableLog = oldLog;
        }
    }
    private void Control(string sequence) { Limit(sequence.Length); writer.Write(sequence); }
    private void Limit(int count)
    {
        if (count > ManagedRuntimeCapabilities.MaxOutputCharacters - _written) throw new InvalidOperationException("Managed console output limit exceeded.");
        _written += count;
    }
}