(function(){
  if (!("$TDP" in window)){
    console.error("Missing $TDP");
  }
  
  const validatePluginObject = function(pluginObject){
    if (!("$token" in pluginObject)){
      throw "Invalid plugin object.";
    }
  };
  
  //
  // Block: Setup a simple JavaScript object configuration loader.
  //
  window.TDPF_loadConfigurationFile = function(pluginObject, fileNameUser, fileNameDefault, onSuccess, onFailure){
    validatePluginObject(pluginObject);
    
    let identifier = pluginObject.$id;
    let token = pluginObject.$token;
    
    $TDP.checkFileExists(token, fileNameUser).then(exists => {
      let fileName = exists ? fileNameUser : fileNameDefault;
      
      (exists ? $TDP.readFile(token, fileName, true) : $TDP.readFileRoot(token, fileName)).then(contents => {
        let obj;
        
        try{
          obj = eval("(" + contents + ")");
        }catch(err){
          if (!(onFailure && onFailure(err))){
            $TD.alert("warning", "Problem loading '" + fileName + "' file for '" + identifier + "' plugin, the JavaScript syntax is invalid: " + err.message);
          }
          
          return;
        }
        
        onSuccess && onSuccess(obj);
      }).catch(err => {
        if (!(onFailure && onFailure(err))){
          $TD.alert("warning", "Problem loading '" + fileName + "' file for '" + identifier + "' plugin: " + err.message);
        }
      });
    }).catch(err => {
      if (!(onFailure && onFailure(err))){
        $TD.alert("warning", "Problem checking '" + fileNameUser + "' file for '" + identifier + "' plugin: " + err.message);
      }
    });
  };
  
  //
  // Block: Setup a function to add/remove custom CSS.
  //
  window.TDPF_createCustomStyle = function(pluginObject){
    validatePluginObject(pluginObject);
    
    let element = document.createElement("style");
    element.id = "plugin-" + pluginObject.$id + "-"+Math.random().toString(36).substring(2, 7);
    document.head.appendChild(element);
    
    return {
      insert: (rule) => element.sheet.insertRule(rule, 0),
      remove: () => element.remove(),
      element: element
    };
  };
})();