# (SS,27/08/15) Python script to update Express Music stock levels from separate MySQL databased called seanic
# Version of Python must be 3.4 or greater

import datetime
import mysql.connector
import sys
import smtplib
from email.mime.multipart import MIMEMultipart
from email.mime.text import MIMEText
import email.utils
  
      
def do_stock_update():   
    # get the source records
    LSQL = """SELECT Stock_Levels.System_Code, SUM(Stock_Level - Allocated) AS StockLevel, RRP
      FROM Stock_Levels
      INNER JOIN Product ON Product.System_Code = Stock_Levels.System_Code
      GROUP BY System_Code"""
    cursor_source.execute(LSQL)
    
    # empty the existing destination table
    cursor_destin.execute("TRUNCATE TABLE seanic_stock_levels")
    
    # copy the records from source to destination
    for row in cursor_source.fetchall(): 
      LSQL = "INSERT INTO seanic_stock_levels VALUES " + str(tuple(row));
      cursor_destin.execute(LSQL)
      
    # update the stocks levels in products table if different to seanic and product isn't disabled 
    LSQL = """UPDATE products p, seanic_stock_levels s 
      SET p.NumInStock = s.Stock_Level
      WHERE s.System_Code = p.ProductCode AND
      NOT p.ProductDisabled AND p.NumInStock <> s.Stock_Level"""
    cursor_destin.execute(LSQL)
    print_log("Product records updated: " + str(cursor_destin.rowcount))
    
    # count products where prices don't match seanic
    LSQL = """SELECT COUNT(*) FROM products p
      INNER JOIN seanic_stock_levels s ON s.System_Code = p.ProductCode
      WHERE NOT p.ProductDisabled AND p.StdPrice <> s.RRP AND COALESCE(p.SalePrice, 0) <> s.RRP"""
    cursor_destin.execute(LSQL)
    result = cursor_destin.fetchone()
    print_log("Product records with different prices: " + str(result[0]))

def set_alert(AAlert):
    global FAlert # required to modify a global 
    FAlert = AAlert
      
def get_alert():
    return FAlert
      
def print_log(AText):
    global FPrintLog # required to modify a global
    print(AText)
    FPrintLog = FPrintLog + AText + '\r\n'
      
def send_email_text(ABody, ASubject, AFrom, ATo, ABcc):
    # Create a text/plain message
    msg = MIMEText(ABody)

    # header    
    if get_alert():
        msg['Subject'] = 'ALERT!!! ' + ASubject
    else:
        msg['Subject'] = ASubject
    msg['From'] = AFrom
    msg['To'] = ATo
    msg['Date'] = email.utils.formatdate(localtime=True)
    if get_alert():       
        msg['X-Priority'] = '2'
            
    # send the messsage using localhost
    s = smtplib.SMTP('localhost')
    s.sendmail(AFrom, [ATo, ABcc], msg.as_string())
    s.quit()
     
 
FAlert = False  # global used to set alert
FPrintLog = ""  # global used to hold log that is also the email body 
        
start = datetime.datetime.now()
print_log('Started: ' + start.strftime('%Y-%m-%d %H:%M:%S'))
print_log('')

try:
  # open source connection seanic database
  cnx_source = None
  cursor_source = None
  cnx_source = mysql.connector.connect(user='elvis_presley', password='Su5p1ci0u5',
                                host='data.seanicretail.co.uk',
                                database='Express_Music')                              
  cursor_source = cnx_source.cursor()

  # open destination connection
  cnx_destin = None
  cursor_destin = None
  cnx_destin = mysql.connector.connect(user='expressmusic', password='bsharp',
                                host='localhost',
                                database='expressmusic')
  cursor_destin = cnx_destin.cursor()

  do_stock_update();
except:
  set_alert(True)
  print_log("Error:")
  print_log(str(sys.exc_info()))
  #raise

finally:
  # close connections if they were opened
  if cursor_destin:
    cursor_destin.close()
  if cnx_destin:
    cnx_destin.commit()
    cnx_destin.close()
  if cursor_source:
    cursor_source.close()
  if cnx_source:
    cnx_source.close()

finish = datetime.datetime.now()
time_taken = finish - start
print_log('')
print_log('Finished: ' + finish.strftime('%Y-%m-%d %H:%M:%S'))
print_log('Time taken: %0.3f seconds' % (time_taken.seconds + time_taken.microseconds / 1E6))


# send the text as an email, from address stock-update@expressmusicstore.co.uk doesn't actually exist as valid mailbox
send_email_text(FPrintLog, 'Express Music Stock Level Update Result', 'stock-update@expressmusicstore.co.uk', 'surinder@itpartnership.com', '')