import streamlit as st
import pandas as pd
import csv
import os
from sklearn.datasets import load_iris
from sklearn.ensemble import RandomForestClassifier
from sklearn.model_selection import train_test_split
from sklearn.metrics import accuracy_score
from datetime import datetime
import time

# Load user credentials from CSV
def load_users():
    try:
        df = pd.read_csv("users.csv")
        return dict(zip(df['username'], df['password']))
    except FileNotFoundError:
        st.error("users.csv file not found.")
        return {}
    
# Save new user to CSV
def add_user_to_csv(username, password):
    # Read existing users
    with open("users.csv", mode='r', newline='') as file:
        users = list(csv.reader(file))
    
    # Check if the username already exists
    for user in users:
        if user[0] == username:
            print(f"User {username} already exists.")
            return
    
    # If not, append the new user
    with open("users.csv", mode='a', newline='') as file:
        writer = csv.writer(file)
        writer.writerow([username, password])
    st.info(f"User {username} added.")
#def add_user_to_csv(username, password):
#    with open("users.csv", mode='a', newline='') as file:
#        writer = csv.writer(file)
#        writer.writerow([username, password])

# Log session to CSV
def log_session_to_csv(username, start_time, end_time):
    duration = end_time - start_time
    row = [username, start_time.strftime('%Y-%m-%d %H:%M:%S'),
           end_time.strftime('%Y-%m-%d %H:%M:%S'), str(duration)]

    file_exists = os.path.isfile("session_log.csv")

    with open("session_log.csv", mode='a', newline='') as file:
        writer = csv.writer(file)
        if not file_exists:
            writer.writerow(["Username", "Login Time", "Logout Time", "Duration"])
        writer.writerow(row)

# Display session logs
def show_logs():
    if os.path.exists("session_log.csv"):
        df = pd.read_csv("session_log.csv")
        st.subheader("Session Logs")
        st.dataframe(df)
    else:
        st.info("No session logs found yet.")

# Load credentials once
USER_CREDENTIALS = load_users()

# Initialize session state
if 'logged_in' not in st.session_state:
    st.session_state.logged_in = False
if 'current_user' not in st.session_state:
    st.session_state.current_user = None
if 'start_time' not in st.session_state:
    st.session_state.start_time = None
if 'end_time' not in st.session_state:
    st.session_state.end_time = None

# Login function
def login():
    st.title("Login")

    username = st.text_input("Username")
    password = st.text_input("Password", type="password")

    if st.button("Login"):
        if username in USER_CREDENTIALS and USER_CREDENTIALS[username] == password:
            st.success("Login successful!")
            st.session_state.logged_in = True
            st.session_state.current_user = username
            st.session_state.start_time = datetime.now()
            st.rerun()
        else:
            st.error("Invalid username or password")
    if st.button("Register"):
        if username and password:
            if username not in USER_CREDENTIALS:
                add_user_to_csv(username, password)
                st.success(f"User {username} successfully registered!")
                st.session_state.logged_in = True
                st.session_state.current_user = username
                st.session_state.start_time = datetime.now()
            
                st.rerun()
            else:
                st.error("Username already exists. Please choose another.")
        else:
            st.error("Both username and password are required.")

   
       
# Logout function
def logout():
    st.session_state.end_time = datetime.now()
    log_session_to_csv(
        st.session_state.current_user,
        st.session_state.start_time,
        st.session_state.end_time
    )
    st.session_state.logged_in = False
    st.session_state.current_user = None
    st.rerun()

# Main app after login
def app():
    st.title(f"Welcome, {st.session_state.current_user}!")

    if st.button("Train Random Forest Model"):
        iris = load_iris()
        X_train, X_test, y_train, y_test = train_test_split(
            iris.data, iris.target, test_size=0.3, random_state=42)

        model = RandomForestClassifier()
        model.fit(X_train, y_train)
        predictions = model.predict(X_test)
        acc = accuracy_score(y_test, predictions)

        st.success(f"Model trained. Accuracy: {acc:.2f}")

    if st.button("Logout"):
        logout()

    if st.session_state.start_time and st.session_state.end_time:
        duration = st.session_state.end_time - st.session_state.start_time
       # st.info(f"last Session Duration: {duration}")

    if st.checkbox("Show session log"):
        show_logs()

# Main controller
def main():
    if st.session_state.logged_in:
        app()
    else:
        login()

if __name__ == "__main__":
    main()