import streamlit as st
import sqlite3
from passlib.hash import bcrypt
import pandas as pd
import re
import warnings
warnings.filterwarnings("ignore", message="module 'bcrypt' has no attribute '__about__'")
if "is_starting" not in st.session_state:
    st.session_state["is_starting"] = True

if "authenticated" not in st.session_state:
    st.session_state["authenticated"] = False

#from pages.About import show_about
#from pages.Text_prompt import show_text_prompt
#from pages.Multimodal import show_multimodal
#from pages.Settings import show_settings

if "authenticated" not in st.session_state:
    st.session_state["authenticated"] = False

def create_usertable():
    conn = sqlite3.connect('users.db')
    c = conn.cursor()
    c.execute('CREATE TABLE IF NOT EXISTS userstable(username TEXT, password BLOB)')
    c.execute('CREATE TABLE IF NOT EXISTS system_instructions(username TEXT PRIMARY KEY, instruction TEXT)')
    c.execute('CREATE TABLE IF NOT EXISTS user_prompts(id INTEGER PRIMARY KEY AUTOINCREMENT, username TEXT, prompt_time TEXT, prompt_type TEXT)')
    conn.commit()
    conn.close()

def add_userdata(username, password):
    conn = sqlite3.connect('users.db')
    c = conn.cursor()
    c.execute('INSERT INTO userstable(username, password) VALUES (?,?)', (username, password))
    conn.commit()
    conn.close()

def login_user(username, password):
    conn = sqlite3.connect('users.db')
    c = conn.cursor()
    c.execute('SELECT password FROM userstable WHERE username =?', (username,))
    stored_hash = c.fetchone()
    conn.close()
    
    if stored_hash:
        stored_hash = stored_hash[0]
        return check_hashes(password, stored_hash)
    else:
        return False

def view_all_users():
    conn = sqlite3.connect('users.db')
    c = conn.cursor()
    c.execute('SELECT * FROM userstable')
    data = c.fetchall()
    conn.close()
    return data

# --- Hashing ---
def make_hashes(password):
    return bcrypt.hash(password)

def check_hashes(password, hashed_text):
    return bcrypt.verify(password, hashed_text)

# --- Authentication ---
def authenticate(username, password):
    return login_user(username, password)

def logout():
    del st.session_state["authenticated"]
    del st.session_state["username"]
    del st.session_state["page"]

# --- Initialize session state ---
if "authenticated" not in st.session_state:
    st.session_state["authenticated"] = False
if "username" not in st.session_state:
    st.session_state["username"] = None
if "page" not in st.session_state:
    st.session_state["page"] = "login"

# --- Login page ---
def login_page():
    st.title("WVSU Exam Maker")
    st.subheader("User Login")
    username = st.text_input("User Name")
    password = st.text_input("Password", type='password')
    if st.button("Login"):
        result = authenticate(username.lower(), password)
        if result:
            st.session_state["authenticated"] = True
            st.session_state["username"] = username
            st.success("Logged In as {}".format(username))
            st.session_state["page"] = "main"
            st.session_state["is_starting"] = False
            st.rerun()
        else:
            st.warning("Incorrect Username/Password")

    st.write("Don't have an account? Click Signup.")
    # --- Signup button ---
    if st.button("Signup"):
        st.session_state["page"] = "signup"
        st.rerun()

# --- Signup page ---
def signup_page():
    st.subheader("Create New Account")
    new_user = st.text_input("Username")
    new_password = st.text_input("Password", type='password')
    
    # Display password requirements
    st.write("Password Requirements:")
    st.write("* Minimum length: 8 characters")
    st.write("* Mix of uppercase and lowercase letters")
    st.write("* At least one number")
    st.write("* At least one special character")
    
    # Validate password strength
    col1, col2 = st.columns([1, 1])
    if col1.button("Signup"):
        password_strength = validate_password(new_password)
        if password_strength:
            # Check if username already exists
            conn = sqlite3.connect('users.db')
            c = conn.cursor()
            c.execute('SELECT * FROM userstable WHERE username=?', (new_user,))
            existing_user = c.fetchone()
            conn.close()
            
            if existing_user:
                st.error("Username already exists. Please choose a different username.")
            else:
                hashed_new_password = make_hashes(new_password.encode("utf-8"))
                add_userdata(new_user, hashed_new_password)
                st.success("You have successfully created a valid Account")
                st.info("Go to Login Menu to login")
                st.session_state["page"] = "login"
                st.rerun()
        else:
            st.error("Password does not meet the requirements.")
    if col2.button("Cancel"):
        st.session_state["page"] = "login"
        st.rerun()

# --- Validate password strength ---
def validate_password(password):
    # Define password requirements
    min_length = 8
    has_uppercase = re.search(r"[A-Z]", password)
    has_lowercase = re.search(r"[a-z]", password)
    has_number = re.search(r"\d", password)
    has_symbol = re.search(r"[!@#$%^&*()_+=-{};:'<>,./?]", password)
    
    # Check if password meets all requirements
    if (len(password) >= min_length and 
        has_uppercase and 
        has_lowercase and 
        has_number and 
        has_symbol):
        return True
    else:
        return False

# --- Manage users page ---
def manage_users_page():
    st.subheader("User Management")
    user_result = view_all_users()
    clean_db = pd.DataFrame(user_result, columns=["Username", "Password"])
    st.dataframe(clean_db)

# --- Main app ---
def main():
    create_usertable()

    if st.session_state["page"] == "login":
        login_page()
    elif st.session_state["page"] == "signup":
        signup_page()
    else:

        msg = """
# Welcome to the WVSU Exam Maker!

We are excited to introduce you to the WVSU Exam Maker, a cutting-edge tool designed to assist faculty members of West Visayas State University in creating comprehensive exams with ease.

### Empowering Teachers, Enhancing Education

With the WVSU Exam Maker, you can generate high-quality exam questions in various formats, saving you time and effort. Our innovative app leverages the latest AI technology from Google Gemini 2 to help you create exams that are both effective and engaging.

### Explore the Possibilities

• **Streamline exam creation**: Generate questions in multiple formats, including Multiple Choice, True or False, Short Response, and Essay.
• **Enhance exam accuracy**: Review and refine AI-generated questions to ensure accuracy and relevance.
• **Simplify exam preparation**: Use our intuitive interface to define exam requirements and upload reference materials.

### Get Started Today!

We invite you to explore the WVSU Exam Maker and discover how it can support your teaching and assessment needs. 

Thank you for using the WVSU Exam Maker!
"""
        st.markdown(msg)
    
        # Display username and logout button on every page
        st.sidebar.write(f"Welcome, {st.session_state['username']}")
        if st.sidebar.button("Logout"):
            logout()
            st.rerun()

 
if __name__ == "__main__":
    main()