// 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() {
  var crypto, decrypt, encrypt, exports, getSetRecords, hash, log, redis, replyHandler,
    _this = this;

  log = require('./logging');

  crypto = require('crypto-js');

  redis = require('redis');

  /*
  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, _ref;
    args = args != null ? args : {};
    log(args);
    config = require('./config');
    config(args);
    if ((_ref = _this.db) != null) {
      _ref.quit();
    }
    if (config.isReady()) {
      _this.crypto_key = config.getCryptoKey();
      _this.db = redis.createClient(config.getDBPort(), 'localhost', {
        connect_timeout: 2000
      });
      return _this.db.on('error', function(err) {
        err.addInfo = 'message from DB';
        return log.error('DB', err);
      });
    } else {
      return log.error('DB', 'Initialization failed because of missing config file!');
    }
  };

  /*
  Checks whether the db is connected and passes either an error on failure after
  ten attempts within five seconds, or nothing on success to the callback(err).
  
  @public isConnected( *cb* )
  @param {function} cb
  */


  exports.isConnected = function(cb) {
    var fCheckConnection, numAttempts;
    if (_this.db.connected) {
      return cb();
    } else {
      numAttempts = 0;
      fCheckConnection = function() {
        if (_this.db.connected) {
          log.print('DB', 'Successfully connected to DB!');
          return cb();
        } else if (numAttempts++ < 10) {
          return setTimeout(fCheckConnection, 100);
        } else {
          return cb(new Error('Connection to DB failed!'));
        }
      };
      return setTimeout(fCheckConnection, 100);
    }
  };

  /*
  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);
      }
    };
  };

  /*
  Push an event into the event queue.
  
  @public pushEvent( *oEvent* )
  @param {Object} oEvent
  */


  exports.pushEvent = function(oEvent) {
    if (oEvent) {
      log.print('DB', "Event pushed into the queue: " + oEvent.eventid);
      return _this.db.rpush('event_queue', JSON.stringify(oEvent));
    } else {
      return log.error('DB', 'Why would you give me an empty event...');
    }
  };

  /*
  Pop an event from the event queue and pass it to the callback(err, obj) function.
  
  @public popEvent( *cb* )
  @param {function} cb
  */


  exports.popEvent = function(cb) {
    var makeObj;
    makeObj = function(pcb) {
      return function(err, obj) {
        return pcb(err, JSON.parse(obj));
      };
    };
    return _this.db.lpop('event_queue', makeObj(cb));
  };

  /*
  Purge the event queue.
  
  @public purgeEventQueue()
  */


  exports.purgeEventQueue = function() {
    return _this.db.del('event_queue', replyHandler('purging event queue'));
  };

  /*
  Hashes a string based on SHA-3-512.
  
  @private hash( *plainText* )
  @param {String} plainText
  */


  hash = function(plainText) {
    var err;
    if (plainText == null) {
      return null;
    }
    try {
      return (crypto.SHA3(plainText, {
        outputLength: 512
      })).toString();
    } catch (_error) {
      err = _error;
      err.addInfo = 'during hashing';
      log.error('DB', err);
      return null;
    }
  };

  /*
  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', _this.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', _this.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;
    }
  };

  /*
  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(err, obj) 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(err, obj) function that receives all the retrieved data or an error
  */


  getSetRecords = function(set, fSingle, cb) {
    log.print('DB', "Fetching set records: " + set);
    return _this.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) {
            --semaphore;
            if (err) {
              err.addInfo = "fetching single element: " + prop;
              log.error('DB', err);
            } else if (!data) {
              log.error('DB', new Error("Empty key in DB: " + prop));
            } 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;
      }
    });
  };

  /*
  ## Action Modules
  #TODO Rename Action Modules into something like Action Caller
  */


  /*
  Store a string representation of an action module in the DB.
  
  @public storeActionModule ( *amId, data* )
  @param {String} amId
  @param {String} data
  */


  exports.storeActionModule = function(amId, data) {
    log.print('DB', "storeActionModule: " + amId);
    _this.db.sadd('action-modules', amId, replyHandler("storing action module key " + amId));
    return _this.db.set("action-module:" + amId, data, replyHandler("storing action module " + amId));
  };

  /*
  Query the DB for an action module and pass it to the callback(err, obj) function.
  
  @public getActionModule( *amId, cb* )
  @param {String} amId
  @param {function} cb
  */


  exports.getActionModule = function(amId, cb) {
    log.print('DB', "getActionModule: " + amId);
    return _this.db.get("action-module:" + amId, cb);
  };

  /*
  Fetch all action modules and hand them to the callback(err, obj) function.
  
  @public getActionModules( *cb* )
  @param {function} cb
  */


  exports.getActionModules = function(cb) {
    return getSetRecords('action-modules', exports.getActionModule, cb);
  };

  /*
  Store user-specific action module parameters .
  
  @public storeActionParams( *userId, amId, data* )
  @param {String} userId
  @param {String} amId
  @param {String} data
  */


  exports.storeActionParams = function(userId, amId, data) {
    log.print('DB', "storeActionParams: " + amId + ":" + userId);
    return _this.db.set("action-params:" + amId + ":" + userId, hash(data), replyHandler("storing action params " + amId + ":" + userId));
  };

  /*
  Query the DB for user-specific action module parameters,
  and pass it to the callback(err, obj) function.
  
  @public getActionParams( *userId, amId, cb* )
  @param {String} userId
  @param {String} amId
  @param {function} cb
  */


  exports.getActionParams = function(userId, amId, cb) {
    log.print('DB', "getActionParams: " + amId + ":" + userId);
    return _this.db.get("action-params:" + amId + ":" + userId, function(err, data) {
      return cb(err, decrypt(data));
    });
  };

  /*
  ## Event Modules
  #TODO rename event modules to event puller or something like that
  */


  /*
  Store a string representation of an event module in the DB.
  
  @public storeEventModule( *emId, data* )
  @param {String} emId
  @param {String} data
  */


  exports.storeEventModule = function(emId, data) {
    log.print('DB', "storeEventModule: " + emId);
    _this.db.sadd('event-modules', emId, replyHandler("storing event module key " + emId));
    return _this.db.set('event-module:#{ emId }', data, replyHandler("storing event module " + emId));
  };

  /*
  Query the DB for an event module and pass it to the callback(err, obj) function.
  
  @public getEventModule( *emId, cb* )
  @param {String} emId 
  @param {function} cb
  */


  exports.getEventModule = function(emId, cb) {
    log.print('DB', "getEventModule: " + emId);
    return _this.db.get("event-module:" + emId, cb);
  };

  /*
  Fetch all event modules and pass them to the callback(err, obj) function.
  
  @public getEventModules( *cb* )
  @param {function} cb
  */


  exports.getEventModules = function(cb) {
    return getSetRecords('event-modules', exports.getEventModule, cb);
  };

  /*
  Store a string representation of user-specific parameters for an event module.
  
  @public storeEventParams( *userId, emId, data* )
  @param {String} userId
  @param {String} emId
  @param {Object} data
  */


  exports.storeEventParams = function(userId, emId, data) {
    log.print('DB', "storeEventParams: " + emId + ":" + userId);
    return _this.db.set("event-params:" + emId + ":" + userId, encrypt(data), replyHandler("storing event auth " + emId + ":" + userId));
  };

  /*
  Query the DB for an action module authentication token, associated with a user.
  
  @public getEventAuth( *userId, emId, data* )
  @param {String} userId
  @param {String} emId
  @param {function} cb
  */


  exports.getEventAuth = function(userId, emId, cb) {
    log.print('DB', "getEventAuth: " + emId + ":" + userId);
    return _this.db.get("event-auth:" + emId + ":" + userId, function(err, data) {
      return cb(err, decrypt(data));
    });
  };

  /*
  ## Rules
  */


  /*
  Store a string representation of a rule in the DB.
  
  @public storeRule( *ruleId, userId, data* )
  @param {String} ruleId
  @param {String} userId
  @param {String} data
  */


  exports.storeRule = function(ruleId, userId, data) {
    log.print('DB', "storeRule: " + ruleId);
    _this.db.sadd('rules', "" + ruleId + ":" + userId, replyHandler("storing rule key \"" + ruleId + ":" + userId + "\""));
    _this.db.sadd("user-set:" + userId + ":rules", ruleId, replyHandler("storing rule key to \"user:" + userId + ":rules\""));
    _this.db.sadd("rule-set:" + ruleId + ":users", user, replyHandler("storing user key to \"rule:" + ruleId + ":users\""));
    return _this.db.set("rule:" + ruleId + ":" + userId, data, replyHandler("storing rule \"" + ruleId + ":" + userId + "\""));
  };

  /*
  Query the DB for a rule and pass it to the callback(err, obj) function.
  
  @public getRule( *ruleId, cb* )
  @param {String} ruleId
  @param {function} cb
  */


  exports.getRule = function(ruleId, cb) {
    log.print('DB', "getRule: " + ruleId);
    return _this.db.get("rule:" + ruleId, cb);
  };

  /*
  Fetch all rules from the database and pass them to the callback function.  
  
  @public getRules( *cb* )
  @param {function} cb
  */


  exports.getRules = function(cb) {
    log.print('DB', 'Fetching all Rules');
    return getSetRecords('rules', exports.getRule, cb);
  };

  /*
  Store a user object (needs to be a flat structure).
  
  @public storeUser( *objUser* )
  @param {Object} objUser
  */


  exports.storeUser = function(objUser) {
    log.print('DB', "storeUser: " + objUser.username);
    if (objUser && objUser.username && objUser.password) {
      _this.db.sadd('users', objUser.username, replyHandler("storing user key " + objUser.username));
      objUser.password = hash(objUser.password);
      return _this.db.hmset("user:" + objUser.username, objUser, replyHandler("storing user properties " + objUser.username));
    } else {
      return log.error('DB', new Error('username or password was missing'));
    }
  };

  /*
  Associate a role with a user.
  
  @public storeUserRole( *userId, role* )
  @param {String} userId
  @param {String} role
  */


  exports.storeUserRole = function(userId, role) {
    log.print('DB', "storeUserRole: " + userId + ":" + role);
    _this.db.sadd('roles', role, replyHandler("adding role " + role + " to role index set"));
    _this.db.sadd("user:" + userId + ":roles", role, replyHandler("adding role " + role + " to user " + userId));
    return _this.db.sadd("role:" + role + ":users", userId, replyHandler("adding user " + userId + " to role " + role));
  };

  /*
  Fetch all roles of a user and pass them to the callback(err, obj)
  
  @public getUserRoles( *userId* )
  @param {String} userId
  */


  exports.getUserRoles = function(userId) {
    log.print('DB', "getUserRole: " + userId);
    return _this.db.get("user-roles:" + userId, cb);
  };

  /*
  Fetch all users of a role and pass them to the callback(err, obj)
  
  @public getUserRoles( *role* )
  @param {String} role
  */


  exports.getRoleUsers = function(role) {
    log.print('DB', "getRoleUsers: " + role);
    return _this.db.get("role-users:" + role, cb);
  };

  /*
  Checks the credentials and on success returns the user object to the
  callback(err, obj) function. The password has to be hashed (SHA-3-512)
  beforehand by the instance closest to the user that enters the password,
  because we only store hashes of passwords for safety reasons.
  
  @public loginUser( *userId, password, cb* )
  @param {String} userId
  @param {String} password
  @param {function} cb
  */


  exports.loginUser = function(userId, password, cb) {
    var fCheck;
    log.print('DB', "User \"" + userId + "\" tries to log in");
    fCheck = function(pw) {
      return function(err, obj) {
        if (err) {
          return cb(err);
        } else if (obj && obj.password) {
          if (pw === obj.password) {
            log.print('DB', "User \"" + obj.username + "\" logged in!");
            return cb(null, obj);
          } else {
            return cb(new Error('Wrong credentials!'));
          }
        } else {
          return cb(new Error('User not found!'));
        }
      };
    };
    return _this.db.hgetall("user:" + userId, fCheck(password));
  };

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


  exports.shutDown = function() {
    return _this.db.quit();
  };

}).call(this);