// Generated by CoffeeScript 1.6.3
/*

DB Interface
============
>Handles the connection to the database and provides functionalities for
>event/action modules, rules and the encrypted storing of authentication tokens.
>General functionality as a wrapper for the module holds initialization,
>encryption/decryption, the retrieval of modules and shut down.
>
>The general structure for linked data is that the key is stored in a set.
>By fetching all set entries we can then fetch all elements, which is
>automated in this function.
>For example modules of the same group, e.g. action modules are registered in an
>unordered set in the database, from where they can be retrieved again. For example
>a new action module has its ID (e.g 'probinder') first registered in the set
>'action_modules' and then stored in the db with the key 'action\_module\_' + ID
>(e.g. action\_module\_probinder). 
>
*/


(function() {
  'use strict';
  /* Grab all required modules*/

  var crypto, crypto_key, db, decrypt, encrypt, exports, getSetRecords, log, redis, replyHandler;

  redis = require('redis');

  crypto = require('crypto');

  log = require('./logging');

  crypto_key = null;

  db = null;

  /*
  ##Module call
  
  Initializes the DB connection. Requires a valid configuration file which contains
  a db port and a crypto key.
  @param {Object} args
  */


  exports = module.exports = function(args) {
    var config;
    args = args != null ? args : {};
    log(args);
    config = require('./config');
    config(args);
    crypto_key = config.getCryptoKey();
    db = redis.createClient(config.getDBPort(), 'localhost', {
      connect_timeout: 2000
    });
    return db.on("error", function(err) {
      err.addInfo = 'message from DB';
      return log.error('DB', err);
    });
  };

  /*
  Checks whether the db is connected and calls the callback function if successful,
  or an error after ten attempts within five seconds.
  
  @public isConnected( *cb* )
  @param {function} cb
  */


  exports.isConnected = function(cb) {
    var fCheckConnection, numAttempts;
    if (db.connected) {
      return cb();
    } else {
      numAttempts = 0;
      fCheckConnection = function() {
        var e;
        if (db.connected) {
          log.print('DB', 'Successfully connected to DB!');
          return cb();
        } else if (numAttempts++ < 10) {
          return setTimeout(fCheckConnection, 500);
        } else {
          e = new Error('Connection to DB failed!');
          log.error('DB', e);
          return cb(e);
        }
      };
      return setTimeout(fCheckConnection, 500);
    }
  };

  /*
  Encrypts a string using the crypto key from the config file, based on aes-256-cbc.
  
  @private encrypt( *plainText* )
  @param {String} plainText
  */


  encrypt = function(plainText) {
    var enciph, err, et;
    if (plainText == null) {
      return null;
    }
    try {
      enciph = crypto.createCipher('aes-256-cbc', crypto_key);
      et = enciph.update(plainText, 'utf8', 'base64');
      return et + enciph.final('base64');
    } catch (_error) {
      err = _error;
      err.addInfo = 'during encryption';
      log.error('DB', err);
      return null;
    }
  };

  /*
  Decrypts an encrypted string and hands it back on success or null.
  
  @private decrypt( *crypticText* )
  @param {String} crypticText
  */


  decrypt = function(crypticText) {
    var deciph, dt, err;
    if (crypticText == null) {
      return null;
    }
    try {
      deciph = crypto.createDecipher('aes-256-cbc', crypto_key);
      dt = deciph.update(crypticText, 'base64', 'utf8');
      return dt + deciph.final('utf8');
    } catch (_error) {
      err = _error;
      err.addInfo = 'during decryption';
      log.error('DB', err);
      return null;
    }
  };

  /*
  Abstracts logging for simple action replies from the DB.
  
  @private replyHandler( *action* )
  @param {String} action
  */


  replyHandler = function(action) {
    return function(err, reply) {
      if (err) {
        err.addInfo = 'during "' + action + '"';
        return log.error('DB', err);
      } else {
        return log.print('DB', action + ': ' + reply);
      }
    };
  };

  /*
  Fetches all linked data set keys from a linking set, fetches the single data objects
  via the provided function and returns the results to the callback function.
  
  @private getSetRecords( *set, fSingle, cb* )
  @param {String} set the set name how it is stored in the DB
  @param {function} fSingle a function to retrieve a single data element per set entry
  @param {function} cb the callback function that receives all the retrieved data or an error
  */


  getSetRecords = function(set, funcSingle, cb) {
    return db != null ? db.smembers(set, function(err, arrReply) {
      var fCallback, objReplies, reply, semaphore, _i, _len, _results;
      if (err) {
        err.addInfo = 'fetching ' + set;
        return log.error('DB', err);
      } else if (arrReply.length === 0) {
        return cb();
      } else {
        semaphore = arrReply.length;
        objReplies = {};
        setTimeout(function() {
          if (semaphore > 0) {
            return cb(new Error('Timeout fetching ' + set));
          }
        }, 2000);
        fCallback = function(prop) {
          return function(err, data) {
            if (err) {
              err.addInfo = 'fetching single element: ' + prop;
              return log.error('DB', err);
            } else {
              objReplies[prop] = data;
              if (--semaphore === 0) {
                return cb(null, objReplies);
              }
            }
          };
        };
        _results = [];
        for (_i = 0, _len = arrReply.length; _i < _len; _i++) {
          reply = arrReply[_i];
          _results.push(fSingle(reply, fCallback(reply)));
        }
        return _results;
      }
    }) : void 0;
  };

  /*
  @Function shutDown()
  
  Shuts down the db link.
  */


  /*exports.shutDown = function() { if(db) db.quit(); };
  */


  /*
  ## Action Modules
  
  @Function storeActionModule
  Store a string representation of an action module in the DB.
  @param {String} id the unique identifier of the module
  @param {String} data the string representation
  */


  /*exports.storeActionModule = function(id, data) {
    if(db) {
      db.sadd('action_modules', id, replyHandler('storing action module key ' + id));
      db.set('action_module_' + id, data, replyHandler('storing action module ' + id));
    }
  };
  */


  /*
  @Function getActionModule(id, cb)
  Query the DB for an action module.
  @param {String} id the module id
  @param {function} cb the cb to receive the answer (err, obj)
  */


  /*exports.getActionModule = function(id, cb) {
    if(cb && db) db.get('action_module_' + id, cb);
  };
  */


  /*
  @Function getActionModules(cb)
  Fetch all action modules.
  @param {function} cb the cb to receive the answer (err, obj)
  */


  /*exports.getActionModules = function(cb) {
    getSetRecords('action_modules', exports.getActionModule, cb);
  };
  */


  /*
  @Function storeActionModuleAuth(id, data)
  Store a string representation of the authentication parameters for an action module.
  @param {String} id the unique identifier of the module
  @param {String} data the string representation
  */


  /*exports.storeActionModuleAuth = function(id, data) {
    if(data && db) {
      db.sadd('action_modules_auth', id, replyHandler('storing action module auth key ' + id));
      db.set('action_module_' + id +'_auth', encrypt(data), replyHandler('storing action module auth ' + id));
    }
  };
  */


  /*
  @Function getActionModuleAuth(id, cb)
  Query the DB for an action module authentication token.
  @param {String} id the module id
  @param {function} cb the cb to receive the answer (err, obj)
  */


  /*exports.getActionModuleAuth = function(id, cb) {
    if(cb && db) db.get('action_module_' + id + '_auth', function(id) {
      return function(err, txt) { cb(err, decrypt(txt, 'action_module_' + id + '_auth')); };
    }(id));
  };
  */


  /*
  ## Event Modules
  
  @Function storeEventModule(id, data)
  Store a string representation of an event module in the DB.
  @param {String} id the unique identifier of the module
  @param {String} data the string representation
  */


  /*exports.storeEventModule = function(id, data) {
    if(db) {
      db.sadd('event_modules', id, replyHandler('storing event module key ' + id));
      db.set('event_module_' + id, data, replyHandler('storing event module ' + id));
    }
  };
  */


  /*
  @Function getEventModule(id, cb)
  Query the DB for an event module.
  @param {String} id the module id
  @param {function} cb the cb to receive the answer (err, obj)
  */


  /*exports.getEventModule = function(id, cb) {
    if(cb && db) db.get('event_module_' + id, cb);
  };
  */


  /*
  @Function getEventModules(cb)
  Fetch all event modules.
  @param {function} cb the cb that receives the arguments (err, obj)
  */


  /*exports.getEventModules = function(cb) {
    getSetRecords('event_modules', exports.getEventModule, cb);
  };
  */


  /*
  @Function storeEventModuleAuth(id, data)
  Store a string representation of he authentication parameters for an event module.
  @param {String} id the unique identifier of the module
  @param {String} data the string representation
  */


  /*exports.storeEventModuleAuth = function(id, data) {
    if(data && db) {
      db.sadd('event_modules_auth', id, replyHandler('storing event module auth key ' + id));
      db.set('event_module_' + id +'_auth', encrypt(data), replyHandler('storing event module auth ' + id));
    }
  };
  */


  /*
  @Function getEventModuleAuth(id, cb)
  
  Query the DB for an event module authentication token.
  @param {String} id the module id
  @param {function} cb the cb to receive the answer (err, obj)
  */


  /*exports.getEventModuleAuth = function(id, cb) {
    if(cb) db.get('event_module_' + id +'_auth',  function(id) {
      return function(err, txt) { cb(err, decrypt(txt, 'event_module_' + id + '_auth')); };
    }(id));
  };
  */


  /*
  ## Rules
  
  @Function storeRule(id, data)
  
  Store a string representation of a rule in the DB.
  @param {String} id the unique identifier of the rule
  @param {String} data the string representation
  */


  /*exports.storeRule = function(id, data) {
    if(db) {
      db.sadd('rules', id, replyHandler('storing rule key ' + id));
      db.set('rule_' + id, data, replyHandler('storing rule ' + id));
    }
  };
  */


  /*
  @Function getRule(id, cb)
  
  Query the DB for a rule.
  @param {String} id the rule id
  @param {function} cb the cb to receive the answer (err, obj)
  */


  /*exports.getRule = function(id, cb) {
    if(db) db.get('rule_' + id, cb);
  };
  */


  /*
  @Function getRules(cb)
  
  Fetch all rules from the database.  
  @param {function} cb
  */


  /*exports.getRules = function(cb) {
    getSetRecords('rules', exports.getRule, cb);
  };
  */


  /*
  @Function storeUser
  
  @param {Object} objUser
  @param {function} cb
  */


  /*exports.storeUser = function(objUser, cb) {
    if(db && objUser && objUser.username && objUser.password) {
      db.sadd('users', objUser.username, replyHandler('storing user key ' + objUser.username));
      objUser.password = encrypt(objUser.password);
      db.set('user:' + objUser.username, objUser, replyHandler('storing user properties ' + objUser.username));
    }
  };
  */


  /*
  Checks the credentials and on success returns the user object.
  @param {Object} objUser
  @param {function} cb
  */


  /* exports.loginUser = function(username, password, cb) {
    if(typeof cb !== 'function') return;
    if(db) db.get('user:' + username, function(p) {
      return function(err, obj) {
        if(err) cb(err);
        else if(encrypt(obj.password) === p) cb(null, obj);
        else cb(new Error('Wrong credentials!'));
      };
    }(password));
    else cb(new Error('No database link available!'));
  };
  */


}).call(this);