"""
Secure Auth App with GitHub-backed Encrypted Storage
Material Design UI with Gradio
"""

import gradio as gr
import bcrypt
from datetime import datetime
from github_storage import read_users, write_users

# Material Design CSS
MATERIAL_CSS = """
@import url('https://fonts.googleapis.com/css2?family=Roboto:wght@300;400;500;700&display=swap');

* {
    font-family: 'Roboto', sans-serif !important;
}

.gradio-container {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%) !important;
    min-height: 100vh !important;
}

.main-container {
    max-width: 420px !important;
    margin: 40px auto !important;
    padding: 0 !important;
}

.auth-card {
    background: white !important;
    border-radius: 16px !important;
    box-shadow: 0 10px 40px rgba(0,0,0,0.2) !important;
    padding: 40px !important;
    margin: 20px !important;
}

.auth-card h1 {
    color: #333 !important;
    font-weight: 500 !important;
    font-size: 28px !important;
    text-align: center !important;
    margin-bottom: 8px !important;
}

.auth-card p {
    color: #666 !important;
    text-align: center !important;
    margin-bottom: 32px !important;
}

.auth-card input {
    border: 2px solid #e0e0e0 !important;
    border-radius: 8px !important;
    padding: 14px 16px !important;
    font-size: 16px !important;
    transition: border-color 0.3s ease !important;
}

.auth-card input:focus {
    border-color: #667eea !important;
    outline: none !important;
}

.primary-btn {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%) !important;
    color: white !important;
    border: none !important;
    border-radius: 8px !important;
    padding: 14px 32px !important;
    font-size: 16px !important;
    font-weight: 500 !important;
    cursor: pointer !important;
    transition: transform 0.2s ease, box-shadow 0.2s ease !important;
    text-transform: uppercase !important;
    letter-spacing: 1px !important;
}

.primary-btn:hover {
    transform: translateY(-2px) !important;
    box-shadow: 0 6px 20px rgba(102, 126, 234, 0.4) !important;
}

.secondary-btn {
    background: transparent !important;
    color: #667eea !important;
    border: 2px solid #667eea !important;
    border-radius: 8px !important;
    padding: 12px 24px !important;
    font-size: 14px !important;
    font-weight: 500 !important;
    cursor: pointer !important;
    transition: all 0.2s ease !important;
}

.secondary-btn:hover {
    background: #667eea !important;
    color: white !important;
}

.error-msg {
    background: #ffebee !important;
    color: #c62828 !important;
    padding: 12px 16px !important;
    border-radius: 8px !important;
    margin: 16px 0 !important;
    font-size: 14px !important;
}

.success-msg {
    background: #e8f5e9 !important;
    color: #2e7d32 !important;
    padding: 12px 16px !important;
    border-radius: 8px !important;
    margin: 16px 0 !important;
    font-size: 14px !important;
}

.welcome-container {
    text-align: center !important;
}

.welcome-container h1 {
    font-size: 32px !important;
    margin-bottom: 16px !important;
}

.welcome-email {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%) !important;
    -webkit-background-clip: text !important;
    -webkit-text-fill-color: transparent !important;
    background-clip: text !important;
    font-size: 24px !important;
    font-weight: 500 !important;
    margin: 24px 0 !important;
}

.avatar-circle {
    width: 100px !important;
    height: 100px !important;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%) !important;
    border-radius: 50% !important;
    margin: 0 auto 24px !important;
    display: flex !important;
    align-items: center !important;
    justify-content: center !important;
    font-size: 40px !important;
    color: white !important;
    font-weight: 500 !important;
}

.link-btn {
    color: #667eea !important;
    background: none !important;
    border: none !important;
    cursor: pointer !important;
    font-size: 14px !important;
    text-decoration: underline !important;
}
"""

def hash_password(password: str) -> str:
    """Hash password using bcrypt."""
    return bcrypt.hashpw(password.encode(), bcrypt.gensalt()).decode()

def verify_password(password: str, hashed: str) -> bool:
    """Verify password against hash."""
    return bcrypt.checkpw(password.encode(), hashed.encode())

def sign_up(email: str, password: str, confirm_password: str):
    """Handle user registration."""
    # Validation
    if not email or not password or not confirm_password:
        return (
            gr.update(visible=True),   # sign_in_container
            gr.update(visible=False),  # sign_up_container
            gr.update(visible=False),  # welcome_container
            "",                         # welcome_email
            gr.update(value="⚠️ All fields are required", visible=True),  # message
        )
    
    if "@" not in email or "." not in email:
        return (
            gr.update(visible=True),
            gr.update(visible=False),
            gr.update(visible=False),
            "",
            gr.update(value="⚠️ Please enter a valid email address", visible=True),
        )
    
    if len(password) < 6:
        return (
            gr.update(visible=True),
            gr.update(visible=False),
            gr.update(visible=False),
            "",
            gr.update(value="⚠️ Password must be at least 6 characters", visible=True),
        )
    
    if password != confirm_password:
        return (
            gr.update(visible=True),
            gr.update(visible=False),
            gr.update(visible=False),
            "",
            gr.update(value="⚠️ Passwords do not match", visible=True),
        )
    
    try:
        # Load existing users
        data = read_users()
        
        # Check if user exists
        if email.lower() in data.get("users", {}):
            return (
                gr.update(visible=True),
                gr.update(visible=False),
                gr.update(visible=False),
                "",
                gr.update(value="⚠️ An account with this email already exists", visible=True),
            )
        
        # Create new user
        data.setdefault("users", {})
        data["users"][email.lower()] = {
            "password_hash": hash_password(password),
            "created_at": datetime.utcnow().isoformat()
        }
        
        # Save to GitHub
        if write_users(data):
            return (
                gr.update(visible=False),
                gr.update(visible=False),
                gr.update(visible=True),
                email,
                gr.update(value="", visible=False),
            )
        else:
            return (
                gr.update(visible=True),
                gr.update(visible=False),
                gr.update(visible=False),
                "",
                gr.update(value="⚠️ Failed to save user data. Please try again.", visible=True),
            )
    except Exception as e:
        return (
            gr.update(visible=True),
            gr.update(visible=False),
            gr.update(visible=False),
            "",
            gr.update(value=f"⚠️ Error: {str(e)}", visible=True),
        )

def sign_in(email: str, password: str):
    """Handle user login."""
    if not email or not password:
        return (
            gr.update(visible=True),
            gr.update(visible=False),
            gr.update(visible=False),
            "",
            gr.update(value="⚠️ Email and password are required", visible=True),
        )
    
    try:
        data = read_users()
        user = data.get("users", {}).get(email.lower())
        
        if not user:
            return (
                gr.update(visible=True),
                gr.update(visible=False),
                gr.update(visible=False),
                "",
                gr.update(value="⚠️ No account found with this email", visible=True),
            )
        
        if not verify_password(password, user["password_hash"]):
            return (
                gr.update(visible=True),
                gr.update(visible=False),
                gr.update(visible=False),
                "",
                gr.update(value="⚠️ Incorrect password", visible=True),
            )
        
        # Success
        return (
            gr.update(visible=False),
            gr.update(visible=False),
            gr.update(visible=True),
            email,
            gr.update(value="", visible=False),
        )
    except Exception as e:
        return (
            gr.update(visible=True),
            gr.update(visible=False),
            gr.update(visible=False),
            "",
            gr.update(value=f"⚠️ Error: {str(e)}", visible=True),
        )

def show_sign_up():
    """Switch to sign up view."""
    return (
        gr.update(visible=False),
        gr.update(visible=True),
        gr.update(visible=False),
        "",
        gr.update(value="", visible=False),
    )

def show_sign_in():
    """Switch to sign in view."""
    return (
        gr.update(visible=True),
        gr.update(visible=False),
        gr.update(visible=False),
        "",
        gr.update(value="", visible=False),
    )

def logout():
    """Handle logout."""
    return (
        gr.update(visible=True),
        gr.update(visible=False),
        gr.update(visible=False),
        "",
        gr.update(value="", visible=False),
    )

# Build the UI
with gr.Blocks(css=MATERIAL_CSS, title="Secure Auth") as demo:
    
    # State for storing current user email
    current_email = gr.State("")
    
    with gr.Column(elem_classes="main-container"):
        
        # Sign In Container
        with gr.Column(visible=True, elem_classes="auth-card") as sign_in_container:
            gr.HTML("<h1>Welcome Back</h1>")
            gr.HTML("<p>Sign in to continue</p>")
            
            sign_in_email = gr.Textbox(
                label="Email",
                placeholder="Enter your email",
                type="email"
            )
            sign_in_password = gr.Textbox(
                label="Password",
                placeholder="Enter your password",
                type="password"
            )
            
            message = gr.HTML("", visible=False, elem_classes="error-msg")
            
            sign_in_btn = gr.Button("Sign In", elem_classes="primary-btn")
            
            gr.HTML("<br>")
            gr.HTML("<p style='text-align: center; color: #666;'>Don't have an account?</p>")
            go_to_sign_up_btn = gr.Button("Create Account", elem_classes="secondary-btn")
        
        # Sign Up Container
        with gr.Column(visible=False, elem_classes="auth-card") as sign_up_container:
            gr.HTML("<h1>Create Account</h1>")
            gr.HTML("<p>Sign up to get started</p>")
            
            sign_up_email = gr.Textbox(
                label="Email",
                placeholder="Enter your email",
                type="email"
            )
            sign_up_password = gr.Textbox(
                label="Password",
                placeholder="Create a password (min 6 characters)",
                type="password"
            )
            sign_up_confirm = gr.Textbox(
                label="Confirm Password",
                placeholder="Confirm your password",
                type="password"
            )
            
            sign_up_btn = gr.Button("Sign Up", elem_classes="primary-btn")
            
            gr.HTML("<br>")
            gr.HTML("<p style='text-align: center; color: #666;'>Already have an account?</p>")
            go_to_sign_in_btn = gr.Button("Sign In", elem_classes="secondary-btn")
        
        # Welcome Container
        with gr.Column(visible=False, elem_classes="auth-card") as welcome_container:
            gr.HTML("<div class='welcome-container'>")
            gr.HTML("<div class='avatar-circle'>👋</div>")
            gr.HTML("<h1>Welcome!</h1>")
            gr.HTML("<p>You're successfully signed in as:</p>")
            welcome_email_display = gr.HTML("<div class='welcome-email'></div>")
            gr.HTML("</div>")
            
            gr.HTML("<br><br>")
            logout_btn = gr.Button("Sign Out", elem_classes="secondary-btn")
    
    # Event handlers
    outputs = [sign_in_container, sign_up_container, welcome_container, current_email, message]
    
    sign_in_btn.click(
        sign_in,
        inputs=[sign_in_email, sign_in_password],
        outputs=outputs
    )
    
    sign_up_btn.click(
        sign_up,
        inputs=[sign_up_email, sign_up_password, sign_up_confirm],
        outputs=outputs
    )
    
    go_to_sign_up_btn.click(
        show_sign_up,
        outputs=outputs
    )
    
    go_to_sign_in_btn.click(
        show_sign_in,
        outputs=outputs
    )
    
    logout_btn.click(
        logout,
        outputs=outputs
    )
    
    # Update welcome email display when current_email changes
    current_email.change(
        lambda email: f"<div class='welcome-email'>{email}</div>",
        inputs=[current_email],
        outputs=[welcome_email_display]
    )

if __name__ == "__main__":
    demo.launch()