'use strict';

// Oracle Client
// -------
var _                 = require('lodash')
var inherits          = require('inherits')
var Client            = require('../../client')
var Promise           = require('../../promise')
var ReturningHelper   = require('./utils').ReturningHelper
var Formatter         = require('./formatter')
var assign            = require('lodash/object/assign')

var QueryCompiler     = require('./query/compiler')
var SchemaCompiler    = require('./schema/compiler')
var ColumnBuilder     = require('./schema/columnbuilder')
var ColumnCompiler    = require('./schema/columncompiler')
var TableCompiler     = require('./schema/tablecompiler')
var OracleQueryStream = require('./stream')

// Always initialize with the "QueryBuilder" and "QueryCompiler"
// objects, which extend the base 'lib/query/builder' and
// 'lib/query/compiler', respectively.
function Client_Oracle(config) {
  Client.call(this, config)
}
inherits(Client_Oracle, Client)

assign(Client_Oracle.prototype, {

  dialect: 'oracle',

  driverName: 'oracle',

  Formatter: Formatter,

  QueryCompiler: QueryCompiler,

  SchemaCompiler: SchemaCompiler,

  ColumnBuilder: ColumnBuilder,

  ColumnCompiler: ColumnCompiler,

  TableCompiler: TableCompiler,

  // Get a raw connection, called by the `pool` whenever a new
  // connection needs to be added to the pool.
  acquireRawConnection: function() {
    var client = this
    return new Promise(function(resolver, rejecter) {
      client.driver.connect(client.connectionSettings,
        function(err, connection) {
          if (err) return rejecter(err)
          if (client.connectionSettings.prefetchRowCount) {
            connection.setPrefetchRowCount(client.connectionSettings.prefetchRowCount)
          }
          resolver(connection)
        })
    })
  },

  // Used to explicitly close a connection, called internally by the pool
  // when a connection times out or the pool is shutdown.
  destroyRawConnection: function(connection, cb) {
    connection.close()
    cb()
  },

  // Return the database for the Oracle client.
  database: function() {
    return this.connectionSettings.database
  },

  // Position the bindings for the query.
  positionBindings: function(sql) {
    var questionCount = 0
    return sql.replace(/\?/g, function() {
      questionCount += 1
      return ':' + questionCount
    })
  },

  _stream: function(connection, obj, stream, options) {
    obj.sql = this.positionBindings(obj.sql);
    return new Promise(function (resolver, rejecter) {
      stream.on('error', rejecter);
      stream.on('end', resolver);
      var queryStream = new OracleQueryStream(connection, obj.sql, obj.bindings, options);
      queryStream.pipe(stream)
    });
  },

  // Runs the query on the specified connection, providing the bindings
  // and any other necessary prep work.
  _query: function(connection, obj) {

    // convert ? params into positional bindings (:1)
    obj.sql = this.client.positionBindings(obj.sql);
    
    obj.bindings = obj.bindings || [];

    if (!obj.sql) throw new Error('The query is empty');

    return new Promise(function(resolver, rejecter) {
      connection.execute(obj.sql, obj.bindings, function(err, response) {
        if (err) return rejecter(err);

        if (obj.returning) {
          var rowIds = obj.outParams.map(function (v, i) {
            return response['returnParam' + (i ? i : '')];
          });

          return connection.execute(obj.returningSql, rowIds, function (err, subres) {
            if (err) return rejecter(err);
            obj.response = subres;
            resolver(obj);
          });

        } else {
          obj.response = response;
          resolver(obj);
        }
      });
    });
  },

  // Process the response as returned from the query.
  processResponse: function(obj, runner) {
    var response = obj.response;
    var method   = obj.method;
    if (obj.output) return obj.output.call(runner, response);
    switch (method) {
      case 'select':
      case 'pluck':
      case 'first':
        response = helpers.skim(response);
        if (obj.method === 'pluck') response = _.pluck(response, obj.pluck);
        return obj.method === 'first' ? response[0] : response;
      case 'insert':
      case 'del':
      case 'update':
      case 'counter':
        if (obj.returning) {
          if (obj.returning.length > 1 || obj.returning[0] === '*') {
            return response;
          }
          // return an array with values if only one returning value was specified
          return _.flatten(_.map(response, _.values));
        }
        return response.updateCount;
      default:
        return response;
    }
  }  

})

Client_Oracle.__proto__ = Client

module.exports = Client_Oracle