"""
This sample demonstrates an implementation of the Lex Code Hook Interface
in order to serve a sample bot which manages reservations for hotel rooms and car rentals.
Bot, Intent, and Slot models which are compatible with this sample can be found in the Lex Console
as part of the 'BookTrip' template.

For instructions on how to set up and test this bot, as well as additional samples,
visit the Lex Getting Started documentation http://docs.aws.amazon.com/lex/latest/dg/getting-started.html.
"""

import json
import datetime
import time
import os
import dateutil.parser
import logging
import uuid
import boto3
from boto3.dynamodb.conditions import Key, Attr

logger = logging.getLogger()
logger.setLevel(logging.DEBUG)

# --- Main handler ---

def lambda_handler(event, context):
    """
    Route the incoming request based on intent.
    The JSON body of the request is provided in the event slot.
    """
        
    # By default, treat the user request as coming from the America/New_York time zone.
    os.environ['TZ'] = 'America/New_York'
    time.tzset()
    logger.debug('event.bot.name={}'.format(event['bot']['name']))
    logger.debug('event={}'.format(event))
    
    session_attributes = event['sessionAttributes']
    
    if session_attributes is None:
        session_attributes = {}
    
        
    session_attributes['lastIntent'] = event['currentIntent']['name']
#    session_attributes['submitterName'] = event['currentIntent']['slots']['first_name']
    

    
    #before closing the intent, save the case info to a database table
    record = getFromDB(event['currentIntent']['slots'])
    slots = event['currentIntent']['slots']
    if record is None:
        response_string = "We were unable to locate support case "+ event['currentIntent']['slots']['ticket_id'] + " please your your case id and try again."    
    else:
        updateStatus(slots['ticket_id'],slots['status'])
        response_string = 'We have found and updated your support case. The status is now '+ slots['status'] + ' and was last updated '+ time.strftime('%Y-%m-%d %H:%M:%S', time.localtime(float(record['LastUpdatedDate'])))    
        
    return close(session_attributes, 'Fulfilled', {'contentType': 'PlainText','content': response_string})


def getFromDB(slots):

    dynamodb = boto3.resource('dynamodb')
    db_table_name = os.environ['DynamoDB_Table_Name']
    table = dynamodb.Table(db_table_name)
    
    logger.debug("looking up key CaseId="+slots['ticket_id'])
   
    response = table.query(KeyConditionExpression=Key('CaseId').eq(slots['ticket_id']))
    logger.debug(str(response)) 

    
    return response['Items'][0]
    
def updateStatus(ticketId,updatedStatus):
    logger.debug("changing status to="+updatedStatus)
    dynamodb = boto3.resource('dynamodb')
    db_table_name = os.environ['DynamoDB_Table_Name']
    table = dynamodb.Table(db_table_name)
    response = table.update_item(
    Key={
        'CaseId': ticketId,
    },
    UpdateExpression="set #st = :r, LastUpdatedDate = :l",
    ExpressionAttributeValues={
        ':r':updatedStatus,
        ':l':str(time.time())
    },
    ExpressionAttributeNames={
        '#st':'Status'
    },
    ReturnValues="UPDATED_NEW")
    
    logger.debug('finished changing status to='+updatedStatus)

    
    
def close(session_attributes, fulfillment_state, message):
    response = {
        'sessionAttributes': session_attributes,
        'dialogAction': {
            'type': 'Close',
            'fulfillmentState': fulfillment_state,
            'message': message
        }
    }
    
    logger.debug('<<SupportBot>> "Lambda fulfillment function response = \n' + str(response)) 

    return response