trade.js

router.post('/trade', function(req, res, next) {
	req.body.quantity = parseInt(req.body.quantity);

	var self = this;

	self.corp = res.locals.corp,
	self.friend = res.locals.friend;

	Order.create({
		friend: self.friend._id,
		corp: self.corp._id,

		quantity: req.body.quantity,
		unfilled: req.body.quantity,

		deposit: 0,

		action: req.body.action,
		type: req.body.type,

		placed: Date.now(),
		expired: gskse.getOrderExpiredDate(req.body.duration),
		filled: gskse.epoch,

		price: req.body.type == 'limit' ? req.body.price : 0,
		deals: [],

		is_filling: true,
	}).then(order => {
		self.order = order;

		if (order.action == 'buy') {
			debug('buy at limit');

			var deposit = order.quantity * order.price;

			res.locals.friend.cash -= deposit;
			res.locals.friend.save().then(friend => {
				order.deposit = deposit;
				order.save();

				return Order.find({ 
					corp: self.corp._id, 
					action: 'sell',
					type: 'limit',
					price: { $lte: order.price },
					unfilled: { $gt: 0 }, 
					expired: { $gt: Date.now() }, 
					is_filling: false,
				}).sort('price');
			}).then(asks => {
				if (!asks || !asks.length) {
					debug('nothing to fill');

					order.is_filling = false;
					return;
				}

				for (var i = 0; i < asks.length; i++) {
					var ask = asks[i];

					var price = ask.price, 
						quantity = ask.unfilled,
						amount = price * quantity;

					dabug('\task [%d] x [%d]', price, quantity);

					if (ask.unfilled < order.unfilled) {  // order unfilled, ask filled
						debug('\t\tdeal: order [unfilled], ask [filled]', price, quantity);

						order.unfilled -= quantity;
						order.deposit -= amount;
						order.deals.push({ order: ask._id, quantity: quantity });
						order.save();

						ask.unfilled = 0;
						ask.deposit += amount;
						ask.deal.push({ order: order._id, quantity: quantity });
						ask.save();
					} else if (ask.unfilled > order.unfilled) {  // order filled, ask unfilled
						debug('\t\tdeal: order [filled], ask [unfilled]', price, quantity);

						order.unfilled = 0;
						order.deposit -= amount;
						order.deals.push({ order: ask._id, quantity: quantity });
						order.save();

						ask.unfilled -= quantity;
						ask.deposit += amount;
						ask.deal.push({ order: order._id, quantity: quantity });
						ask.save();

						break;
					} else {  // order filled, ask filled
						debug('\t\tdeal: order [unfilled], ask [filled]', price, quantity);

						order.unfilled = 0;
						order.deposit -= amount;
						order.deals.push({ order: ask._id, quantity: quantity });
						order.save();

						ask.unfilled = 0;
						ask.deposit += amount;
						ask.deal.push({ order: order._id, quantity: quantity });
						ask.save();

						break;
					}
				}

				if (order.unfilled > 1) {  // order unfilled
					debug('order still unfilled');

					order.is_filling = false;
					order.save();
				}
			});
		} else if (order.action == 'sell') {
			debug('sell at limit');

			Order.find({ 
				corp: self.corp._id,  
				action: 'buy',
				type: 'limit',
				price: { $gte: order.price },
				unfilled: { $gt: 0 }, 
				expired: { $gt: Date.now() }, 
				is_filling: false,
			}).sort('price').then(bids => {
				if (!bids || !bids.length) {
					debug('nothing to fill');

					order.is_filling = false;
					return;
				}

				for (var i = 0; i < bids.length; i++) {
					var bid = bids[i];

					var price = bid.price, 
						quantity = bid.unfilled;

					dabug('\tbid [%d] x [%d]', price, quantity);

					if (bid.unfilled < order.unfilled) {  // order unfilled, bid filled
						debug('\t\tdeal: order [unfilled], bid [filled]', price, quantity);

						order.unfilled -= quantity;
						order.deals.push({ order: bid._id, quantity: quantity });
						order.save();

						bid.unfilled = 0;
						bid.deal.push({ order: order._id, quantity: quantity });
						bid.save();
					} else if (bid.unfilled > order.unfilled) {  // order filled, bid unfilled
						debug('\t\tdeal: order [filled], bid [unfilled]', price, quantity);

						order.unfilled = 0;
						order.deals.push({ order: bid._id, quantity: quantity });
						order.save();

						bid.unfilled -= quantity;
						bid.deal.push({ order: order._id, quantity: quantity });
						bid.save();

						break;
					} else {  // order filled, bid filled
						debug('\t\tdeal: order [unfilled], bid [filled]', price, quantity);

						order.unfilled = 0;
						order.deals.push({ order: bid._id, quantity: quantity });
						order.save();

						bid.unfilled = 0;
						bid.deal.push({ order: order._id, quantity: quantity });
						bid.save();

						break;
					}
				}

				if (order.unfilled > 1) {  // order unfilled
					debug('order still unfilled');

					order.is_filling = false;
					order.save();
				}
			});
		}
	}).catch(err => next(err));
});