'use strict';

var _ = require('lodash');

var ColumnNode = require('./node/column');

var OrderByValueNode = require('./node/orderByValue');

var TextNode = require('./node/text');

var valueExpressionMixin = require('./node/valueExpression');

var Column = function(config) {

this.table = config.table;

for (var name in config) {

if (config.hasOwnProperty(name)) {

this[name] = config[name];

}

}

this.asc = this.ascending = this;

this.alias = null;

this.desc = this.descending = new OrderByValueNode({

value : this.toNode(),

direction : new TextNode('DESC')

});

this.dataType = config.dataType;

};

// mix in value expression

_.extend(Column.prototype, valueExpressionMixin());

var contextify = function(base) {

var context = Object.create(Column.prototype);

Object.keys(base).forEach(function (key) {

context[key] = base[key];

});

return context;

};

Column.prototype.value = function(value) {

var context = contextify(this);

context._value = value;

return context;

};

Column.prototype.getValue = function() {

return this._value;

};

Column.prototype.toNode = function() {

// creates a query node from this column

return new ColumnNode(contextify(this));

};

Column.prototype.as = function(alias) {

var context = contextify(this);

context.alias = alias;

return new ColumnNode(context);

};

Column.prototype.arrayAgg = function(alias) {

var context = contextify(this);

context.asArray = true;

context.alias = alias || context.name + 's';

return new ColumnNode(context);

};

Column.prototype.aggregate = function(alias, aggregator) {

var context = contextify(this);

context.aggregator = aggregator.toUpperCase();

context.alias = alias || context.name + '_' + context.aggregator.toLowerCase();

return new ColumnNode(context);

};

Column.prototype.count = function(alias) {

return this.aggregate(alias, 'count');

};

Column.prototype.min = function(alias) {

return this.aggregate(alias, 'min');

};

Column.prototype.max = function(alias) {

return this.aggregate(alias, 'max');

};

Column.prototype.sum = function(alias) {

return this.aggregate(alias, 'sum');

};

Column.prototype.avg = function(alias) {

return this.aggregate(alias, 'avg');

};

Column.prototype.distinct = function() {

var context = contextify(this);

context.distinct = true;

return new ColumnNode(context);

};

Column.prototype.toQuery = function() {

return this.toNode().toQuery();

};

module.exports = Column;