'use strict';

var AbstractConnectionManager = require('../abstract/connection-manager')
  , ConnectionManager
  , Utils = require('../../utils')
  , Promise = require('../../promise')
  , sequelizeErrors = require('../../errors')
  , semver = require('semver')
  , dataTypes = require('../../data-types')
  , moment = require('moment-timezone');

ConnectionManager = function(dialect, sequelize) {
  AbstractConnectionManager.call(this, dialect, sequelize);

  this.sequelize = sequelize;
  this.sequelize.config.port = this.sequelize.config.port || 5432;
  try {
    var pgLib;
    if (sequelize.config.dialectModulePath) {
      pgLib = require(sequelize.config.dialectModulePath);
    } else {
      pgLib = require('pg');
    }
    this.lib = sequelize.config.native ? pgLib.native : pgLib;
  } catch (err) {
    if (err.code === 'MODULE_NOT_FOUND') {
      throw new Error('Please install \'' + (sequelize.config.dialectModulePath || 'pg') + '\' module manually');
    }
    throw err;
  }

  this.oidMap = {};
  this.arrayOidMap = {};

  this._oidsFetched = false;
  this.refreshTypeParser(dataTypes.postgres);
};

Utils._.extend(ConnectionManager.prototype, AbstractConnectionManager.prototype);

// Expose this as a method so that the parsing may be updated when the user has added additional, custom types
ConnectionManager.prototype.$refreshTypeParser = function (dataType) {
  var self = this;

  if (dataType.types.postgres.oids) {
    dataType.types.postgres.oids.forEach(function (oid) {
      self.oidMap[oid] = function (value) {
        return dataType.parse(value, oid, self.lib.types.getTypeParser);
      };
    });
  }

  if (dataType.types.postgres.array_oids) {
    dataType.types.postgres.array_oids.forEach(function (oid) {
      self.arrayOidMap[oid] = function (value) {
        return self.lib.types.arrayParser.create(value, function (value) {
          return dataType.parse(value, oid, self.lib.types.getTypeParser);
        }).parse();
      };
    });
  }
};

ConnectionManager.prototype.$clearTypeParser = function () {
  this.oidMap = {};
  this.arrayOidMap = {};
};

ConnectionManager.prototype.getTypeParser = function (oid, format) {
  if (this.oidMap[oid]) {
    return this.oidMap[oid];
  } else if (this.arrayOidMap[oid]) {
    return this.arrayOidMap[oid];
  }

  return this.lib.types.getTypeParser.apply(undefined, arguments);
};

ConnectionManager.prototype.connect = function(config) {
  var self = this
    , connectionConfig = {};

  config.user = config.username;
  connectionConfig = Utils._.pick(config, [
    'user', 'password', 'host', 'database', 'port'
  ]);

  connectionConfig.types = {
    getTypeParser: ConnectionManager.prototype.getTypeParser.bind(this)
  };

  if (config.dialectOptions) {
    Utils._.merge(connectionConfig,
                  Utils._.pick(config.dialectOptions, [
      // see [http://www.postgresql.org/docs/9.3/static/runtime-config-logging.html#GUC-APPLICATION-NAME]
      'application_name',
      // choose the SSL mode with the PGSSLMODE environment variable
      // object format: [https://github.com/brianc/node-postgres/blob/master/lib/connection.js#L79]
      // see also [http://www.postgresql.org/docs/9.3/static/libpq-ssl.html]
      'ssl',
      // In addition to the values accepted by the corresponding server,
      // you can use "auto" to determine the right encoding from the
      // current locale in the client (LC_CTYPE environment variable on Unix systems)
      'client_encoding',
      // !! DONT SET THIS TO TRUE !!
      // (unless you know what you're doing)
      // see [http://www.postgresql.org/message-id/flat/bc9549a50706040852u27633f41ib1e6b09f8339d845@mail.gmail.com#bc9549a50706040852u27633f41ib1e6b09f8339d845@mail.gmail.com]
      'binary'
    ]));
  }

  return new Promise(function (resolve, reject) {
    var connection = new self.lib.Client(connectionConfig)
      , responded = false;

    connection.connect(function(err) {
      if (err) {
        if (err.code) {
          switch (err.code) {
          case 'ECONNREFUSED':
            reject(new sequelizeErrors.ConnectionRefusedError(err));
            break;
          case 'ENOTFOUND':
            reject(new sequelizeErrors.HostNotFoundError(err));
            break;
          case 'EHOSTUNREACH':
            reject(new sequelizeErrors.HostNotReachableError(err));
            break;
          case 'EINVAL':
            reject(new sequelizeErrors.InvalidConnectionError(err));
            break;
          default:
            reject(new sequelizeErrors.ConnectionError(err));
            break;
          }
        } else {
          reject(new sequelizeErrors.ConnectionError(err));
        }
        return;
      }
      responded = true;
      resolve(connection);
    });

    // If we didn't ever hear from the client.connect() callback the connection timeout, node-postgres does not treat this as an error since no active query was ever emitted
    connection.on('end', function () {
      if (!responded) {
        reject(new sequelizeErrors.ConnectionTimedOutError(new Error('Connection timed out')));
      }
    });

    // Don't let a Postgres restart (or error) to take down the whole app
    connection.on('error', function() {
      connection._invalid = true;
    });
  }).tap(function (connection) {
    // Disable escape characters in strings, see https://github.com/sequelize/sequelize/issues/3545
    var query = '';

    if (self.sequelize.options.databaseVersion !== 0 && semver.gte(self.sequelize.options.databaseVersion, '8.2.0')) {
      query += 'SET standard_conforming_strings=on;';
    }

    if (!self.sequelize.config.keepDefaultTimezone) {
      var isZone = !!moment.tz.zone(self.sequelize.options.timezone);
      if (isZone) {
        query += 'SET client_min_messages TO warning; SET TIME ZONE \'' + self.sequelize.options.timezone + '\';';
      } else {
        query += 'SET client_min_messages TO warning; SET TIME ZONE INTERVAL \'' + self.sequelize.options.timezone + '\' HOUR TO MINUTE;';
      }
    }

    // fetch OIDs for Geometry / Hstore / Enum as they are dynamic
    if (!self._oidsFetched) {
      query += 'SELECT typname, typtype, oid, typarray FROM pg_type WHERE (typtype = \'b\' AND typname IN (\'hstore\', \'geometry\', \'geography\')) OR (typtype = \'e\')';
    }

    return new Promise(function (resolve, reject) {
      connection.query(query).on('error', function (err) {
        reject(err);
      }).on('row', function (row) {
        var type;
        if (row.typname === 'geometry') {
          type = dataTypes.postgres.GEOMETRY;
        } else if (row.typname === 'hstore') {
          type = dataTypes.postgres.HSTORE;
        } else if (row.typname === 'geography') {
          type = dataTypes.postgres.GEOGRAPHY;
        } else if (row.typtype === 'e') {
          type = dataTypes.postgres.ENUM;
        }

        type.types.postgres.oids.push(row.oid);
        type.types.postgres.array_oids.push(row.typarray);

        self.$refreshTypeParser(type);
      }).on('end', function () {
        self._oidsFetched = true;

        resolve();
      });
    });
  });
};
ConnectionManager.prototype.disconnect = function(connection) {
  return new Promise(function (resolve, reject) {
    connection.end();
    resolve();
  });
};

ConnectionManager.prototype.validate = function(connection) {
  return connection._invalid === undefined;
};

module.exports = ConnectionManager;