'use strict';

// Oracle Migrator
// ------
module.exports = function(client) {

var _        = require('lodash');
var Migrator = require('../../migrate');
var inherits = require('inherits');
var Promise  = require('../../promise');

function Migrator_Oracle() {
  this.client = client;
  Migrator.apply(this, arguments);
}
inherits(Migrator_Oracle, Migrator);

// Create the migration table, if it doesn't already exist.
Migrator_Oracle.prototype._createMigrationTable = function(tableName) {
  return this.knex.schema.createTable(tableName, function(t) {
    t.timestamp('migration_time').primary().nullable(false);
    t.string('name');
    t.integer('batch');
  });
};

// Lists all migrations that have been completed for the current db, as an array.
Migrator_Oracle.prototype._listCompleted = Promise.method(function() {
  var tableName = this.config.tableName;
  return this._ensureTable(tableName)
    .bind(this)
    .then(function () {
      return this.knex(tableName).orderBy('migration_time').select('name');
    })
    .then(function(migrations) {
      return _.pluck(migrations, 'name');
    });
});

// Get the last batch of migrations, by name, ordered by insert migration_time
// in reverse order.
Migrator_Oracle.prototype._getLastBatch = function() {
  var tableName = this.config.tableName;
  return this.knex(tableName)
    .where('batch', function() {
      this.select().max('batch').from(tableName);
    })
    .orderBy('migration_time', 'desc');
};

client.Migrator = Migrator_Oracle;

};