import gradio as gr
import sqlite3
import os

DB_PATH = "temp.db"

# --- Database Setup ---
def init_db():
    conn = sqlite3.connect(DB_PATH)
    cursor = conn.cursor()
    cursor.execute("""
        CREATE TABLE IF NOT EXISTS users (
            id INTEGER PRIMARY KEY AUTOINCREMENT,
            username TEXT UNIQUE,
            password TEXT
        )
    """)
    conn.commit()
    conn.close()

init_db()

# --- Functions ---
def signup(username, password):
    if not username or not password:
        return "⚠️ Please enter both username and password."
    conn = sqlite3.connect(DB_PATH)
    cursor = conn.cursor()
    try:
        cursor.execute("INSERT INTO users (username, password) VALUES (?, ?)", (username, password))
        conn.commit()
        conn.close()
        return "✅ Signup successful! Please login."
    except sqlite3.IntegrityError:
        conn.close()
        return "❌ Username already exists. Try another."

def login(username, password):
    if username == "1234" and password == "1234":
        return "✅ Admin logged in! You can download the database.", "Admin"
    
    conn = sqlite3.connect(DB_PATH)
    cursor = conn.cursor()
    cursor.execute("SELECT * FROM users WHERE username=? AND password=?", (username, password))
    user = cursor.fetchone()
    conn.close()
    
    if user:
        return f"✅ Welcome, {username}!", username
    else:
        return "❌ Invalid credentials.", None

def logout():
    return "✅ Logged out successfully!", None

def download_db():
    if os.path.exists(DB_PATH):
        return DB_PATH
    return None

# --- Gradio UI ---
with gr.Blocks() as demo:
    gr.Markdown("## 🔐 Simple Login System with Signup & DB Download")

    with gr.Tab("Signup"):
        signup_user = gr.Textbox(label="Username")
        signup_pass = gr.Textbox(label="Password", type="password")
        signup_btn = gr.Button("Signup")
        signup_out = gr.Textbox(label="Signup Status", interactive=False)

        signup_btn.click(signup, inputs=[signup_user, signup_pass], outputs=signup_out)

    with gr.Tab("Login"):
        login_user = gr.Textbox(label="Username")
        login_pass = gr.Textbox(label="Password", type="password")
        login_btn = gr.Button("Login")
        login_status = gr.Textbox(label="Login Status", interactive=False)
        current_user = gr.State()  # store logged-in user

        login_btn.click(login, inputs=[login_user, login_pass], outputs=[login_status, current_user])

    with gr.Tab("Home"):
        home_status = gr.Textbox(label="Home Status", interactive=False)
        logout_btn = gr.Button("Logout")
        download_btn = gr.File(label="Download DB", interactive=False)

        # logout clears user
        logout_btn.click(logout, outputs=[home_status, current_user])

        # allow admin to download DB
        login_btn.click(fn=lambda u: "Welcome Home!" if u else "❌ Please login first.",
                        inputs=current_user, outputs=home_status)

        login_btn.click(fn=lambda u: download_db() if u == "Admin" else None,
                        inputs=current_user, outputs=download_btn)

demo.launch()