import streamlit as st
import json
import os
import random
import string

if 'username' not in st.session_state:
   st.session_state.username = ''
if 'scratch_pad' not in st.session_state:
   st.session_state.scratch_pad = ''

history_file = 'user_history.json'
if not os.path.exists(history_file):
   with open(history_file, 'w') as file:
       json.dump({}, file)

with open(history_file, 'r') as file:
   user_history = json.load(file)

def save_session(username, password):
   st.session_state.username = username
   st.session_state.scratch_pad = st.session_state.scratch_pad
   user_history[username] = {
       'password': password,
       'scratch_pad': st.session_state.scratch_pad
   }
   with open(history_file, 'w') as file:
       json.dump(user_history, file)

def register_user(username, password):
   if username not in user_history:
       save_session(username, password)
       st.success("User registered successfully!")
   else:
       st.warning("Username already exists. Please choose a different username.")

def login_user(username, password):
   if username in user_history:
       stored_password = user_history[username]['password']
       if password == stored_password:
           st.session_state.username = username
           st.session_state.scratch_pad = user_history[username]['scratch_pad']
           st.success("Logged in successfully!")
           return True
       else:
           st.error("Incorrect password. Please try again.")
   else:
       st.warning("Username not found. Please register first.")
   return False

def reset_password(username):
   if username in user_history:
       new_password = ''.join(random.choices(string.ascii_letters + string.digits, k=8))
       user_history[username]['password'] = new_password
       with open(history_file, 'w') as file:
           json.dump(user_history, file)
       st.success(f"Password reset successful. Your new password is: {new_password}")
   else:
       st.warning("Username not found.")

st.title("Welcome to My App")

if st.session_state.username:
   st.subheader(f"Welcome back, {st.session_state.username}!")
   scratch_pad = st.text_area("Scratch Pad", value=st.session_state.scratch_pad, height=200)
   if st.button("💾 Save"):
       save_session(st.session_state.username, user_history[st.session_state.username]['password'])
   if st.button("🔑 Reset Password"):
       reset_password(st.session_state.username)
else:
   username = st.text_input("Username:")
   password = st.text_input("Password:", type="password")
   col1, col2 = st.columns(2)
   with col1:
       if st.button("🔑 Login"):
           if login_user(username, password):
               st.experimental_rerun()
   with col2:
       if st.button("📝 Register"):
           register_user(username, password)