using System;
using System.Runtime.InteropServices;
using System.Text;

public static class ComNativeWrapper
{
    private const string Dll = "ComNative"; // имя файла в Plugins/x86_64 без .dll

    // --- Порты (Unicode) ---
    [DllImport(Dll, CallingConvention = CallingConvention.Cdecl, CharSet = CharSet.Unicode)]
    public static extern int Serial_ListPortsLength();

    [DllImport(Dll, CallingConvention = CallingConvention.Cdecl, CharSet = CharSet.Unicode)]
    public static extern int Serial_ListPorts(StringBuilder buffer, int bufferChars);

    // --- Открытие/закрытие ---
    [DllImport(Dll, CallingConvention = CallingConvention.Cdecl, CharSet = CharSet.Unicode)]
    public static extern int Serial_Open(string portName, int baud, int dataBits, int parity, int stopBits,
                                         int readTimeoutMs, int writeTimeoutMs);

    [DllImport(Dll, CallingConvention = CallingConvention.Cdecl)]
    public static extern int Serial_Close(int handleId);

    [DllImport(Dll, CallingConvention = CallingConvention.Cdecl)]
    public static extern int Serial_CloseAll(); // NEW

    // --- Запись/чтение (строкой) ---
    [DllImport(Dll, CallingConvention = CallingConvention.Cdecl, CharSet = CharSet.Ansi)]
    public static extern int Serial_WriteStringUTF8(int handleId, string utf8, int appendNewline);

    // byte[]-вариант к той же native-функции (EntryPoint), чтобы избежать маршаллинга StringBuilder
    [DllImport(Dll, CallingConvention = CallingConvention.Cdecl, EntryPoint = "Serial_ReadLineUTF8")]
    public static extern int Serial_ReadLineUTF8_bytes(int handleId, byte[] buffer, int bufferSize);

    // --- Ошибка (Unicode) ---
    [DllImport(Dll, CallingConvention = CallingConvention.Cdecl, CharSet = CharSet.Unicode)]
    public static extern int Serial_GetLastErrorW(StringBuilder buffer, int bufferChars);

    public static string GetLastError()
    {
        int need = Serial_GetLastErrorW(null, 0);
        var sb = new StringBuilder(Math.Max(need, 1));
        int r = Serial_GetLastErrorW(sb, sb.Capacity);
        return (r < 0) ? $"err({r})" : sb.ToString();
    }

    public static string[] ListPorts()
    {
        int need = Serial_ListPortsLength();
        if (need <= 1) return Array.Empty<string>();
        var sb = new StringBuilder(need);
        int r = Serial_ListPorts(sb, sb.Capacity);
        if (r < 0) return Array.Empty<string>();
        string joined = sb.ToString();
        return string.IsNullOrWhiteSpace(joined) ? Array.Empty<string>() : joined.Split(';');
    }
}