import pandas as pd
import numpy as np 
import re
def preprocess(data):
  pattern = r'\d{1,2}/\d{1,2}/\d{2,4},\s\d{1,2}:\d{2}\s?(?:AM|PM|am|pm|[AaPp][Mm])\s-\s'

  
  message=re.split(pattern,data)[1:]
  print(message)

  dates=re.findall(pattern,data)


  df=pd.DataFrame({'user_message':message,'message_date':dates})
  df["message_date"]=pd.to_datetime(df['message_date'], format="%d/%m/%Y, %I:%M\u202f%p - ")
  df.rename(columns={'message_date':'date'},inplace=True)

 

  users = []
  messages = []
  for message in df['user_message']:
    entry= re.split('([\w\W]+?):\s', message)
    if entry [1:]:# user name
      users.append(entry[1])
      messages.append(entry[2])
    else:
      users.append('group_notification')
      messages.append(entry[0])
  df['user'] = users
  df['message'] = messages
  df.drop(columns=['user_message'], inplace=True)

  df['year']=df["date"].dt.year

  df['month']=df['date'].dt.month_name()


  df['day']=df['date'].dt.day

  df['hour']=df['date'].dt.hour

  df['min']=df['date'].dt.minute

  df['month_num']=df['date'].dt.month


  return df