def userExists(user):
    statement = f"SELECT EXISTS(SELECT 1 FROM slackDB.Assets WHERE userID LIKE '%{user}%')Assets"
    tempBool  = cursor.execute(statement, args=None)
    conn.commit()
    return tempBool

################################
# Slack Lambda handler.
################################

import sys
import logging
import os
import pymysql
import urllib

# Grab data from the environment.
BOT_TOKEN   = os.environ["BOT_TOKEN"]
ASSET_TABLE = os.environ["ASSET_TABLE"]
REGION_NAME = os.getenv('REGION_NAME', 'us-east-2')

DB_NAME     = "admin"
DB_PASSWORD = "useradmin101"
DB_DATABASE = "slackDB"
RDS_HOST    = "myslackdb.cb6yydo2b9mv.us-east-2.rds.amazonaws.com"
port        = 3306

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

try:
    conn = pymysql.connect(RDS_HOST, user=DB_NAME, passwd=DB_PASSWORD, db=DB_DATABASE, connect_timeout=5)
    cursor = conn.cursor()
except:
    logger.error("ERROR: Unexpected error: Could not connect to MySql instance.")
    sys.exit()

# Define the URL of the targeted Slack API resource.
SLACK_URL = "https://slack.com/api/chat.postMessage"

def userExists(user):
    statement = f"SELECT EXISTS(SELECT 1 FROM slackDB.Assets WHERE userID LIKE '%{user}%')Assets"
    tempBool  = cursor.execute(statement, args=None)
    conn.commit()
    return tempBool

def addUser(user):
    statement = f"INSERT INTO `slackDB`.`Assets` (`userID`, `money`) VALUES ('{user}', '1000')"
    tempBool  = cursor.execute(statement, args=None)
    conn.commit()
    return tempBool

def lambda_handler(data, context):
    # Slack challenge answer.
    if "challenge" in data:
        return data["challenge"]

    # Grab the Slack channel data.
    slack_event    = data['event']
    slack_userID   = slack_event["user"]
    slack_text     = slack_event["text"]
    channel_id     = slack_event["channel"]
    slack_reply    = ""

    # Ignore bot messages.
    if "bot_id" in slack_event:
        slack_reply = ""
    else:
        # Start data sift.
        if slack_text.startswith("!networth"):
            slack_reply = "Your networth is: "
        elif slack_text.startswith("!price"):
            command,asset = text.split()
            slack_reply = f"The price of a(n) {asset} is: "
        elif slack_text.startswith("!addme"):
            if userExists(slack_userID):
                slack_reply = f"User {slack_userID} already exists"
            else:
                slack_reply = f"Adding user {slack_userID}"
                addUser(slack_userID)

        # We need to send back three pieces of information:
        data = urllib.parse.urlencode(
            (
                ("token", BOT_TOKEN),
                ("channel", channel_id),
                ("text", slack_reply)
            )
        )
        data = data.encode("ascii")

        # Construct the HTTP request that will be sent to the Slack API.
        request = urllib.request.Request(
            SLACK_URL,
            data=data,
            method="POST"
        )
        # Add a header mentioning that the text is URL-encoded.
        request.add_header(
            "Content-Type",
            "application/x-www-form-urlencoded"
        )

        # Fire off the request!
        urllib.request.urlopen(request).read()

    # Everything went fine.
    return "200 OK"