var AWS = require("aws-sdk");
var docClient = new AWS.DynamoDB.DocumentClient();

exports.handler = async (event, context, callback) => {
	var lockStatus = event.Details.ContactData.Attributes.LockStatus;
	var last4digits = event.Details.ContactData.Attributes.Last4Digits;
	var paramsQuery = {
		TableName: 'CreditCard',
		IndexName : "phoneNumber-cardNumber-index",
        FilterExpression: "contains(#cardNumber, :cardNumber)",
  		ExpressionAttributeNames: {
            "#cardNumber": "cardNumber",
        },
        ExpressionAttributeValues: {
            ":cardNumber": last4digits
        }
 	};
 	try {
        const response = await docClient.scan(paramsQuery).promise();
        const length = response.Items.length;
        if (length > 0) {
            for (var i = 0; i < length; i++) {
                if (response.Items[i].cardNumber.endsWith(last4digits) === true) {
                    paramsQuery = {
                		TableName: 'CreditCard',
                		Key: {
                		    "phoneNumber": response.Items[i].phoneNumber,
                		    "cardNumber": response.Items[i].cardNumber
                		},
                        UpdateExpression: "set #lock = :lockStatus",
                        ExpressionAttributeValues:{
                            ":lockStatus": lockStatus
                        },
                        ExpressionAttributeNames: {
                            '#lock': "lock"
                        },
                        ReturnValues:"UPDATED_NEW"
                 	};
                 	await docClient.update(paramsQuery).promise();
                 	callback(null, buildResponse(true, lockStatus));
                }
            }
        } else {
            callback(null, buildResponse(true));
        }
    } catch (err) {
        console.log(err)
        context.fail(buildResponse(false));
    }
};

function buildResponse(isSuccess, lockStatus) {
 	if (isSuccess) {
  		return {
			lock: lockStatus,
			lambdaResult: "Success"
		};
 	}
	else {
  		console.log("Lambda returned error to Connect");
  		return { lambdaResult: "Error" };
 	}
}