'use strict';

var _            = require('lodash');
var inherits     = require('inherits');
var EventEmitter = require('events').EventEmitter;

// Constructor for the builder instance, typically called from
// `knex.builder`, accepting the current `knex` instance,
// and pulling out the `client` and `grammar` from the current
// knex instance.
function SchemaBuilder() {
  this._sequence = [];
  this._errors = [];
}
inherits(SchemaBuilder, EventEmitter);

// Each of the schema builder methods just add to the
// "_sequence" array for consistency.
_.each([
  'createTable', 'createTableIfNotExists', 'createSchema',
  'createSchemaIfNotExists', 'dropSchema', 'dropSchemaIfExists',
  'table', 'alterTable', 'hasTable', 'hasColumn',
  'dropTable', 'renameTable', 'dropTableIfExists', 'raw', 'debug'
], function(method) {
  SchemaBuilder.prototype[method] = function() {
    if (method === 'table') method = 'alterTable';
    this._sequence.push({
      method: method,
      args: _.toArray(arguments)
    });
    return this;
  };
});

SchemaBuilder.prototype.toString = function() {
  return this.toQuery();
};

SchemaBuilder.prototype.toSQL = function() {
  var SchemaCompiler = this.client.SchemaCompiler;
  return new SchemaCompiler(this).toSQL();
};

require('../interface')(SchemaBuilder);

module.exports = SchemaBuilder;