debit.js

// !debit [field] [action] decrements [field] and runs [action] if [field] > 0
//
// examples (note the '\' to prevent the &{...} from running immediately)
//
//  !debit classactionresource1 %\{Coll|classaction1}
//
//  !debit repeating_classresources_-KBB1UHdMK0ygfFM3AtV_ClassResourceTotal %\{Coll|classaction2}
//
// (I don't know a better way to get repeating classaction ids than inspecting the page)
var DebitModule = DebitModule || (function(){ "use strict"; 

  // catch any thrown warnings and print them
  function catch_warnings(body){
    return function(arg){
      try {
        body.apply( this, arguments );
      } catch(err) {
        if (err["!debit"]) {
          log(err);
          return false;
        } else {
          throw err;
        }
      }
    }
  };

  // break the control flow and pass a warning up the stack
  function warn(msg){
    // XXX: Array.slice is missing
    throw { "!debit": msg, context: Array.prototype.slice.call(arguments, 1) };
  }

  return {
    version: "1.1.0",
    message_re: /^!debit\b(?:\s+(\S+)\s+(\S.*)$)?/m,

    onReady: catch_warnings(function(){
      log('-=> Debit v'+DebitModule.version+' <=-');
      on("chat:message", DebitModule.onMessage);
    }),

    // filter for legal !debit commands and
    // attempt to perform them
    onMessage: catch_warnings(function(msg){
      var match = DebitModule.message_re.exec(msg.content);
      if (!match) return;
    
      (match[1] && match[2]) || 
        warn("Illegal command, expecting \"!debit [field] [action]\"", msg);

      var field = match[1];
      var action = match[2].replace(/\\(.)/g, '$1'); // unescape backslashes

      (msg.selected && msg.selected.length) || 
        warn("Nothing selected", msg);

      var me = msg.who.match(/.+?\b/)[0];
      _.each(msg.selected, function(obj) {
        var character = DebitModule.retrieveCharacter(obj);
        var attribute = DebitModule.retrieveAttribute(character.get("_id"), field);
        var fieldName = DebitModule.fieldName(character.get("_id"), field);
        var debited = DebitModule.attemptDebit(attribute);

        if (debited){
          sendChat( msg.who, '/w ' +  me + ' ' + character.get("name") + " uses a " + fieldName);
          sendChat( character.get("name"), action)
        } else {
          sendChat( msg.who, '/w ' +  me + ' ' + character.get("name") + " doesn't have a " + fieldName + " left to use" );
        }
      });

      return true;
    }),
    
    fieldNamePatterns: [ 
      { regexp: /^(classaction)resource(\d+)$/, replacement: '$1name$2' },
      { regexp: /^(repeating_classresources_-[A-Za-z0-9]{19}_ClassResource)Total$/, replacement: '$1Name' }
    ],

    fieldName: function(character_id, field){
      var p = _.find(DebitModule.fieldNamePatterns, function(p) { return p.regexp.test(field) });
      return p ? DebitModule.retrieveAttribute(character_id, field.replace(p.regexp, p.replacement)).get("current") : field;
    },

    retrieveCharacter: function(obj){
      var graphic = getObj("graphic", obj._id) || 
        warn("No graphic found", obj);
      var character_id = graphic.get("represents") || 
        warn("No character id found", graphic, obj);
      return getObj("character", character_id) || 
        warn("No character found", character_id, graphic, obj);
    },

    // retrieve the attribute named by the field
    retrieveAttribute: function(character_id, field){
      var attributes = findObjs({
        _type: 'attribute',
        _characterid: character_id,
        name: field
      });
      (attributes.length <= 1) || 
        warn("Too many " + field + " attributes found", attributes.length, attributes, character_id );

      return (attributes.length == 1) ? attributes[0] : createObj('attribute', {
        name: field,
        characterid: character_id
      });
    },

    // if the attribute has a positive value,
    // decrement it and return true, otherwise return false
    attemptDebit: function(attribute) {
      var current = attribute.get("current");
      (current || "").toString().match(/^-?\d+$/) ||
        warn("Non-numeric value", current, attribute.get("name"), attribute);

      if (current > 0) {
        attribute.set("current", (current - 1).toString());
        return true;
      }
      return false
    }
  };
})();

on("ready", DebitModule.onReady);