Module.cs

// SPDX-FileCopyrightText: © 2023 YorVeX, https://github.com/YorVeX
// SPDX-License-Identifier: MIT

using System.Runtime.InteropServices;
using System.Text;
using ObsInterop;
namespace ObsCSharpExample;

public enum ObsLogLevel : int
{
  Error = ObsBase.LOG_ERROR,
  Warning = ObsBase.LOG_WARNING,
  Info = ObsBase.LOG_INFO,
  Debug = ObsBase.LOG_DEBUG
}

public static class Module
{
  const bool DebugLog = true; // set this to true and recompile to get debug messages from this plug-in only (unlike getting the full log spam when enabling debug log globally in OBS)
  const string DefaultLocale = "en-US";
  public static string ModuleName = "ObsCSharpExample";
  static string _locale = DefaultLocale;
  static unsafe obs_module* _obsModule = null;
  public static unsafe obs_module* ObsModule { get => _obsModule; }
  static unsafe text_lookup* _textLookupModule = null;

  #region Helper methods
  public static unsafe void Log(string text, ObsLogLevel logLevel = ObsLogLevel.Info)
  {
    if (DebugLog && (logLevel == ObsLogLevel.Debug))
      logLevel = ObsLogLevel.Info;
    // need to escape %, otherwise they are treated as format items, but since we provide null as arguments list this crashes OBS
    fixed (byte* logMessagePtr = Encoding.UTF8.GetBytes("[" + ModuleName + "] " + text.Replace("%", "%%")))
      ObsBase.blog((int)logLevel, (sbyte*)logMessagePtr);
  }

  public static byte[] ObsText(string identifier, params object[] args)
  {
    return Encoding.UTF8.GetBytes(string.Format(ObsTextString(identifier), args));
  }

  public static byte[] ObsText(string identifier)
  {
    return Encoding.UTF8.GetBytes(ObsTextString(identifier));
  }

  public static string ObsTextString(string identifier, params object[] args)
  {
    return string.Format(ObsTextString(identifier), args);
  }

  public static unsafe string ObsTextString(string identifier)
  {
    fixed (byte* lookupVal = Encoding.UTF8.GetBytes(identifier))
    {
      sbyte* lookupResult = null;
      ObsTextLookup.text_lookup_getstr(_textLookupModule, (sbyte*)lookupVal, &lookupResult);
      var resultString = Marshal.PtrToStringUTF8((IntPtr)lookupResult);
      if (string.IsNullOrEmpty(resultString))
        return "<MissingLocale:" + _locale + ":" + identifier + ">";
      else
        return resultString;
    }
  }

  public static unsafe string GetString(sbyte* obsString)
  {
    string managedString = Marshal.PtrToStringUTF8((IntPtr)obsString)!;
    ObsBmem.bfree(obsString);
    return managedString;
  }

  #endregion Helper methods

  #region Event handlers
  [UnmanagedCallersOnly(CallConvs = new[] { typeof(System.Runtime.CompilerServices.CallConvCdecl) })]
  public static unsafe void ToolsMenuItemClicked(void* private_data)
  {
    SettingsDialog.Show();
  }

  [UnmanagedCallersOnly(CallConvs = new[] { typeof(System.Runtime.CompilerServices.CallConvCdecl) })]
  public static unsafe void FrontendEvent(obs_frontend_event eventName, void* private_data)
  {
    Log("FrontendEvent called", ObsLogLevel.Debug);
    switch (eventName)
    {
      case ObsInterop.obs_frontend_event.OBS_FRONTEND_EVENT_FINISHED_LOADING:
        fixed (byte* menuItemText = "C# Example Output"u8)
          ObsFrontendApi.obs_frontend_add_tools_menu_item((sbyte*)menuItemText, &ToolsMenuItemClicked, null);
        break;
      case ObsInterop.obs_frontend_event.OBS_FRONTEND_EVENT_EXIT:
        Log("OBS exiting, stopping output...", ObsLogLevel.Debug);
        Output.Stop();
        break;
    }
  }
  #endregion Event handlers

  #region OBS module API methods
  [UnmanagedCallersOnly(EntryPoint = "obs_module_set_pointer", CallConvs = new[] { typeof(System.Runtime.CompilerServices.CallConvCdecl) })]
  public static unsafe void obs_module_set_pointer(obs_module* obsModulePointer)
  {
    Log("obs_module_set_pointer called", ObsLogLevel.Debug);
    ModuleName = System.Reflection.Assembly.GetExecutingAssembly().GetName().Name!;
    _obsModule = obsModulePointer;
  }

  [UnmanagedCallersOnly(EntryPoint = "obs_module_ver", CallConvs = new[] { typeof(System.Runtime.CompilerServices.CallConvCdecl) })]
  public static uint obs_module_ver()
  {
    var major = (uint)Obs.Version.Major;
    var minor = (uint)Obs.Version.Minor;
    var patch = (uint)Obs.Version.Build;
    var version = (major << 24) | (minor << 16) | patch;
    return version;
  }

  [UnmanagedCallersOnly(EntryPoint = "obs_module_load", CallConvs = new[] { typeof(System.Runtime.CompilerServices.CallConvCdecl) })]
  public static unsafe bool obs_module_load()
  {
    Log("Loading module...", ObsLogLevel.Debug);

    ObsFrontendApi.obs_frontend_add_event_callback(&FrontendEvent, null);

    SettingsDialog.Register();

    Filter.Register();

    Source.Register();

    Output.Register();
    Output.Create();

    Log("Module loaded.", ObsLogLevel.Debug);
    return true;
  }

  [UnmanagedCallersOnly(EntryPoint = "obs_module_post_load", CallConvs = new[] { typeof(System.Runtime.CompilerServices.CallConvCdecl) })]
  public static void obs_module_post_load()
  {
    Log("obs_module_post_load called", ObsLogLevel.Debug);
  }

  [UnmanagedCallersOnly(EntryPoint = "obs_module_unload", CallConvs = new[] { typeof(System.Runtime.CompilerServices.CallConvCdecl) })]
  public static void obs_module_unload()
  {
    Log("obs_module_unload called", ObsLogLevel.Debug);
    SettingsDialog.Save();
    SettingsDialog.Dispose();
    Output.Dispose();
  }

  [UnmanagedCallersOnly(EntryPoint = "obs_module_set_locale", CallConvs = new[] { typeof(System.Runtime.CompilerServices.CallConvCdecl) })]
  public static unsafe void obs_module_set_locale(char* locale)
  {
    Log("obs_module_set_locale called", ObsLogLevel.Debug);
    var localeString = Marshal.PtrToStringUTF8((IntPtr)locale);
    if (!string.IsNullOrEmpty(localeString))
    {
      _locale = localeString;
      Log("Locale is set to: " + _locale, ObsLogLevel.Debug);
    }
    if (_textLookupModule != null)
      ObsTextLookup.text_lookup_destroy(_textLookupModule);
    fixed (byte* defaultLocale = Encoding.UTF8.GetBytes(DefaultLocale), currentLocale = Encoding.UTF8.GetBytes(_locale))
      _textLookupModule = Obs.obs_module_load_locale(_obsModule, (sbyte*)defaultLocale, (sbyte*)currentLocale);
  }

  [UnmanagedCallersOnly(EntryPoint = "obs_module_free_locale", CallConvs = new[] { typeof(System.Runtime.CompilerServices.CallConvCdecl) })]
  public static unsafe void obs_module_free_locale()
  {
    if (_textLookupModule != null)
      ObsTextLookup.text_lookup_destroy(_textLookupModule);
    _textLookupModule = null;
    Log("obs_module_free_locale called", ObsLogLevel.Debug);
  }
  #endregion OBS module API methods

}