import sqlite3
import streamlit_authenticator as stauth

DB_NAME = "users.db"

def init_db(admin_email, admin_password):
    """Initializes the database and creates default admin account if not existing."""
    conn = sqlite3.connect(DB_NAME)
    c = conn.cursor()
    c.execute('''
        CREATE TABLE IF NOT EXISTS users (
            username TEXT PRIMARY KEY,
            name TEXT,
            email TEXT,
            password TEXT,
            status TEXT
        )
    ''')
    
    # Check if admin exists
    c.execute('SELECT * FROM users WHERE username = ?', ('admin',))
    if not c.fetchone():
        hashed_password = stauth.Hasher([admin_password]).generate()[0]
        c.execute(
            'INSERT INTO users (username, name, email, password, status) VALUES (?, ?, ?, ?, ?)',
            ('admin', 'System Admin', admin_email, hashed_password, 'approved')
        )
    conn.commit()
    conn.close()

def verify_password(stored_password, provided_password):
    """Verifies a provided password against the stored hashed password."""
    return stauth.Hasher.check_password(stored_password, provided_password)

def register_user(username, name, email, password):
    """Registers a new user with status 'pending'."""
    conn = sqlite3.connect(DB_NAME)
    c = conn.cursor()
    try:
        hashed_password = stauth.Hasher([password]).generate()[0]
        c.execute(
            'INSERT INTO users (username, name, email, password, status) VALUES (?, ?, ?, ?, ?)',
            (username, name, email, hashed_password, 'pending')
        )
        conn.commit()
        return True, "Registration successful! Awaiting admin approval."
    except sqlite3.IntegrityError:
        return False, "Username already exists."
    finally:
        conn.close()

def get_pending_users():
    """Fetches all users waiting for approval."""
    conn = sqlite3.connect(DB_NAME)
    c = conn.cursor()
    c.execute('SELECT username, name, email FROM users WHERE status = "pending"')
    pending = c.fetchall()
    conn.close()
    return pending

def approve_user(username):
    """Approves a user's login access."""
    conn = sqlite3.connect(DB_NAME)
    c = conn.cursor()
    c.execute('UPDATE users SET status = "approved" WHERE username = ?', (username,))
    conn.commit()
    conn.close()

def reject_user(username):
    """Rejects/Deletes a user's registration request."""
    conn = sqlite3.connect(DB_NAME)
    c = conn.cursor()
    c.execute('DELETE FROM users WHERE username = ?', (username,))
    conn.commit()
    conn.close()

def check_user_status(username):
    """Returns status and hashed password for authentication."""
    conn = sqlite3.connect(DB_NAME)
    c = conn.cursor()
    c.execute('SELECT password, status, name, email FROM users WHERE username = ?', (username,))
    res = c.fetchone()
    conn.close()
    return res