gistfile1.txt

/**
 * @api {get} /chat/one Retrieve one chat.
 * @apiName GetOneChat
 * @apiGroup Chat
 *
 * @apiParam {int} [chatId] Providing chatId alone is sufficient. Else provide travellerId, shopperId and requestId.
 * @apiParam {int} [travellerId] 
 * @apiParam {int} [shopperId] 
 * @apiParam {int} [requestId] 
 *
 * @apiSuccess {Bool} success success flag.
 * @apiSuccess {JSON} chat
 */
router.get('/one', function(req, res) {

    var errLocation = fname + ' index/one';

    var where = {};

    
    var chatId = req.query.chatId;
    if (chatId) {

        // case 1: using chatId
        if (!parseInt(chatId)) {
            return res.status(400).send({
                success: false,
                message: 'An error has occurred, please try again.',
                debug: {
                    message: '`chatId` parameter is not valid.'
                }
            });

        }
        where.chatId = chatId;

        
    } else {

        // case 2: using travellerId, shopperId and requestId as a set.
        var travellerId = req.query.travellerId,
            shopperId = req.query.shopperId,
            requestId = req.query.requestId;

        if (!travellerId || !parseInt(travellerId)) {
            return res.status(400).send({
                success: false,
                message: 'An error has occurred, please try again.',
                debug: {
                    message: '`travellerId` parameter is not valid.'
                }
            });
        }

        if (!shopperId || !parseInt(shopperId)) {
            return res.status(400).send({
                success: false,
                message: 'An error has occurred, please try again.',
                debug: {
                    message: '`shopperId` parameter is not valid.'
                }
            });
        }

        if (!requestId || !parseInt(requestId)) {
            return res.status(400).send({
                success: false,
                message: 'An error has occurred, please try again.',
                debug: {
                    message: '`requestId` parameter is not valid.'
                }
            });
        }

        where.User_userId__shopper = shopperId;
        where.User_userId__traveller = travellerId;
        where.Request_requestId = requestId;

    }


    DB.Chat.findOne({
        where: where,
        include: [{
            model: DB.User,
            as: 'Traveller'
        }, {
            model: DB.User,
            as: 'Shopper'
        }, {
            model: DB.ChatLine
        }, {
            model: DB.Request
        }],
        order: [
            [{ model: DB.ChatLine }, 'lineId', 'DESC']
        ]
    }).then(function(chat) {

        if (!chat) {
            return res.status(400).send({
                success: false, 
                message: 'An error has occurred, please try again.',
                debug: {
                    message: '`chat` was not found.'
                }
            });
        }

        res.send({ success: true, message: '', chat: chat });

        // update the unseen counter to zero for this chat.
        // don't return this branch to the main promise chain, to isolate error handling.
        chat.unseenCounter = 0;
        chat.save().catch(function(err) {
            ERR_HANDLER(err, null, {
                printTrace: true,
                useUUID: true,
                errLocation: errLocation
            });
        });

    }).catch(function(err) {

        ERR_HANDLER(err, res, {
            printTrace: true,
            useUUID: true,
            errLocation: errLocation
        });

    });
});