import os
import ssl
import smtplib
import asyncio
from pathlib import Path
from email.mime.text import MIMEText
from email.mime.multipart import MIMEMultipart
import logging
from dotenv import load_dotenv

logger = logging.getLogger(__name__)

# Load .env file
ROOT_DIR = Path(__file__).parent
load_dotenv(ROOT_DIR / '.env')

# SMTP Configuration - supports both new (SMTP_USER/SMTP_PASS) and old (SMTP_USERNAME/SMTP_PASSWORD) variable names
SMTP_HOST = os.environ.get('SMTP_HOST', 'smtp.gmail.com')
SMTP_PORT = int(os.environ.get('SMTP_PORT', 587))
SMTP_SECURE = os.environ.get('SMTP_SECURE', 'false').lower() == 'true'
SMTP_VERIFY_CERT = os.environ.get('SMTP_VERIFY_CERT', 'true').lower() == 'true'
SMTP_AUTH_METHOD = os.environ.get('SMTP_AUTH_METHOD', None)  # PLAIN, LOGIN, or CRAM-MD5

# Log configuration at startup
logger.info(f"📧 SMTP Configuration Loaded:")
logger.info(f"   Host: {SMTP_HOST}:{SMTP_PORT}")
logger.info(f"   Secure (SSL from start): {SMTP_SECURE}")
logger.info(f"   Verify Certificate: {SMTP_VERIFY_CERT}")
logger.info(f"   Auth Method: {SMTP_AUTH_METHOD or 'auto-detect'}")

# Support both SMTP_USER and SMTP_USERNAME (new and old)
SMTP_USER = os.environ.get('SMTP_USER') or os.environ.get('SMTP_USERNAME', '')
SMTP_PASS = os.environ.get('SMTP_PASS') or os.environ.get('SMTP_PASSWORD', '')

# Support both SMTP_FROM and SMTP_FROM_EMAIL (new and old)
SMTP_FROM = os.environ.get('SMTP_FROM') or os.environ.get('SMTP_FROM_EMAIL', 'noreply@membership.com')
SMTP_FROM_NAME = os.environ.get('SMTP_FROM_NAME', 'LOAF Membership')

FRONTEND_URL = os.environ.get('FRONTEND_URL', 'http://localhost:3000')

def _send_email_sync(message: MIMEMultipart, to_email: str):
    """
    Synchronous email sending (will be wrapped in asyncio.to_thread)
    Matches the working pattern from previous implementation
    """
    # Create SSL context for certificate verification control
    ssl_context = None
    if not SMTP_VERIFY_CERT:
        ssl_context = ssl.create_default_context()
        ssl_context.check_hostname = False
        ssl_context.verify_mode = ssl.CERT_NONE
        logger.warning(f"⚠️  SSL certificate verification DISABLED for {SMTP_HOST}")

    # Determine connection method based on configuration
    if not SMTP_SECURE:
        # Plain SMTP without encryption (some providers require this)
        logger.info(f"🔌 Using plain SMTP connection (SMTP_SECURE=false) to {SMTP_HOST}:{SMTP_PORT}")
        with smtplib.SMTP(SMTP_HOST, SMTP_PORT) as server:
            logger.info(f"   ✅ SMTP connection established")
            server.login(SMTP_USER, SMTP_PASS)
            logger.info(f"   ✅ Login successful")
            server.send_message(message)
            logger.info(f"   ✅ Message sent")
    elif SMTP_PORT == 465:
        # Use SSL/TLS from start (standard for port 465)
        logger.info(f"🔌 Using SMTP_SSL connection to {SMTP_HOST}:{SMTP_PORT}")
        with smtplib.SMTP_SSL(SMTP_HOST, SMTP_PORT, context=ssl_context) as server:
            logger.info(f"   ✅ SSL connection established")
            server.login(SMTP_USER, SMTP_PASS)
            logger.info(f"   ✅ Login successful")
            server.send_message(message)
    else:
        # Use STARTTLS (standard for port 587)
        logger.info(f"🔌 Using SMTP with STARTTLS to {SMTP_HOST}:{SMTP_PORT}")
        with smtplib.SMTP(SMTP_HOST, SMTP_PORT) as server:
            server.starttls(context=ssl_context)
            logger.info(f"   ✅ STARTTLS enabled")
            server.login(SMTP_USER, SMTP_PASS)
            logger.info(f"   ✅ Login successful")
            server.send_message(message)


async def send_email(to_email: str, subject: str, html_content: str):
    """
    Send an email using SMTP

    Configuration via environment variables:
    - SMTP_SECURE=false: Plain SMTP without encryption
    - SMTP_SECURE=true + Port 465: SSL/TLS from start
    - SMTP_SECURE=true + Port 587: STARTTLS
    """
    try:
        message = MIMEMultipart('alternative')
        message['From'] = f"{SMTP_FROM_NAME} <{SMTP_FROM}>"
        message['To'] = to_email
        message['Subject'] = subject

        html_part = MIMEText(html_content, 'html')
        message.attach(html_part)

        # For development/testing, just log the email
        if not SMTP_USER or not SMTP_PASS:
            logger.info(f"[EMAIL] To: {to_email}")
            logger.info(f"[EMAIL] Subject: {subject}")
            logger.info(f"[EMAIL] Content: {html_content[:200]}...")
            return True

        logger.info(f"📧 Sending email to {to_email} via {SMTP_HOST}:{SMTP_PORT}")

        # Run synchronous SMTP in thread pool to avoid blocking
        await asyncio.to_thread(_send_email_sync, message, to_email)

        logger.info(f"✓ Email sent successfully to {to_email}")
        return True

    except smtplib.SMTPAuthenticationError as e:
        logger.error(f"❌ SMTP Authentication Error for {to_email}: {str(e)}")
        logger.error(f"   Check SMTP_USER and SMTP_PASS")
        return False
    except smtplib.SMTPException as e:
        logger.error(f"❌ SMTP Error sending to {to_email}: {str(e)}")
        logger.exception(e)
        return False
    except Exception as e:
        logger.error(f"✗ Failed to send email to {to_email}: {str(e)}")
        logger.exception(e)
        return False

async def send_verification_email(to_email: str, token: str):
    """Send email verification link"""
    verification_url = f"{FRONTEND_URL}/verify-email?token={token}"
    subject = "Verify Your Email Address"
    html_content = f"""
    <!DOCTYPE html>
    <html>
    <head>
        <style>
            body {{ font-family: 'Nunito Sans', Arial, sans-serif; line-height: 1.6; color: #422268; }}
            .container {{ max-width: 600px; margin: 0 auto; padding: 20px; }}
            .header {{ background: linear-gradient(135deg, #644c9f 0%, #48286e 100%); padding: 30px; text-align: center; border-radius: 10px 10px 0 0; }}
            .header h1 {{ color: white; margin: 0; font-family: 'Inter', sans-serif; }}
            .content {{ background: #FFFFFF; padding: 30px; border-radius: 0 0 10px 10px; }}
            .button {{ display: inline-block; background: #DDD8EB; color: #422268; padding: 15px 40px; text-decoration: none; border-radius: 50px; font-weight: 600; margin: 20px 0; }}
            .button:hover {{ background: #FFFFFF; }}
        </style>
    </head>
    <body>
        <div class="container">
            <div class="header">
                <h1>Welcome to Our Community!</h1>
            </div>
            <div class="content">
                <p>Thank you for registering with us. We're excited to have you join our community.</p>
                <p>Please click the button below to verify your email address:</p>
                <p style="text-align: center;">
                    <a href="{verification_url}" class="button">Verify Email</a>
                </p>
                <p>Or copy and paste this link into your browser:</p>
                <p style="word-break: break-all; color: #664fa3;">{verification_url}</p>
                <p>This link will expire in 24 hours.</p>
                <p>If you didn't create an account, please ignore this email.</p>
            </div>
        </div>
    </body>
    </html>
    """
    return await send_email(to_email, subject, html_content)

async def send_approval_notification(to_email: str, first_name: str):
    """Send notification when user is approved"""
    login_url = f"{FRONTEND_URL}/login"
    subject = "Your Membership Application Has Been Approved!"
    html_content = f"""
    <!DOCTYPE html>
    <html>
    <head>
        <style>
            body {{ font-family: 'Nunito Sans', Arial, sans-serif; line-height: 1.6; color: #422268; }}
            .container {{ max-width: 600px; margin: 0 auto; padding: 20px; }}
            .header {{ background: linear-gradient(135deg, #644c9f 0%, #48286e 100%); padding: 30px; text-align: center; border-radius: 10px 10px 0 0; }}
            .header h1 {{ color: white; margin: 0; font-family: 'Inter', sans-serif; }}
            .content {{ background: #FFFFFF; padding: 30px; border-radius: 0 0 10px 10px; }}
            .button {{ display: inline-block; background: #DDD8EB; color: #422268; padding: 15px 40px; text-decoration: none; border-radius: 50px; font-weight: 600; margin: 20px 0; }}
            .button:hover {{ background: #FFFFFF; }}
        </style>
    </head>
    <body>
        <div class="container">
            <div class="header">
                <h1>Congratulations, {first_name}!</h1>
            </div>
            <div class="content">
                <p>Great news! Your membership application has been approved.</p>
                <p>You now have full access to all member features and events.</p>
                <p style="text-align: center;">
                    <a href="{login_url}" class="button">Login to Your Account</a>
                </p>
                <p>We look forward to seeing you at our events!</p>
            </div>
        </div>
    </body>
    </html>
    """
    return await send_email(to_email, subject, html_content)

async def send_payment_prompt_email(to_email: str, first_name: str):
    """Send payment prompt email after admin approval"""
    payment_url = f"{FRONTEND_URL}/plans"
    subject = "Complete Your LOAF Membership - Payment Required"
    html_content = f"""
    <!DOCTYPE html>
    <html>
    <head>
        <style>
            body {{ font-family: 'Nunito Sans', Arial, sans-serif; line-height: 1.6; color: #422268; }}
            .container {{ max-width: 600px; margin: 0 auto; padding: 20px; }}
            .header {{ background: linear-gradient(135deg, #644c9f 0%, #48286e 100%); padding: 30px; text-align: center; border-radius: 10px 10px 0 0; }}
            .header h1 {{ color: white; margin: 0; font-family: 'Inter', sans-serif; }}
            .content {{ background: #FFFFFF; padding: 30px; border-radius: 0 0 10px 10px; }}
            .button {{ display: inline-block; background: #DDD8EB; color: #422268; padding: 15px 40px; text-decoration: none; border-radius: 50px; font-weight: 600; margin: 20px 0; }}
            .button:hover {{ background: #FFFFFF; }}
            .benefits {{ background: #f1eef9; padding: 20px; border-radius: 8px; margin: 20px 0; border: 2px solid #ddd8eb; }}
            .benefits ul {{ list-style: none; padding: 0; }}
            .benefits li {{ padding: 8px 0; padding-left: 25px; position: relative; }}
            .benefits li:before {{ content: "✓"; position: absolute; left: 0; color: #ff9e77; font-weight: bold; }}
        </style>
    </head>
    <body>
        <div class="container">
            <div class="header">
                <h1>🎉 You're Approved, {first_name}!</h1>
            </div>
            <div class="content">
                <p><strong>Great news!</strong> Your LOAF membership application has been approved by our admin team.</p>

                <p>To activate your membership and gain full access, please complete your annual membership payment:</p>

                <p style="text-align: center;">
                    <a href="{payment_url}" class="button">Complete Payment →</a>
                </p>

                <div class="benefits">
                    <p><strong>Once payment is processed, you'll have immediate access to:</strong></p>
                    <ul>
                        <li>Members-only events and gatherings</li>
                        <li>Community directory and networking</li>
                        <li>Exclusive member benefits and discounts</li>
                        <li>LOAF newsletter and updates</li>
                    </ul>
                </div>

                <p>We're excited to have you join the LOAF community!</p>

                <p style="margin-top: 30px; padding-top: 20px; border-top: 1px solid #ddd8eb; color: #664fa3; font-size: 14px;">
                    Questions? Contact us at support@loaf.org
                </p>
            </div>
        </div>
    </body>
    </html>
    """
    return await send_email(to_email, subject, html_content)

async def send_password_reset_email(to_email: str, first_name: str, reset_url: str):
    """Send password reset link email"""
    subject = "Reset Your Password - LOAF Membership"

    html_content = f"""
    <!DOCTYPE html>
    <html>
    <head>
        <style>
            body {{ font-family: 'Nunito Sans', Arial, sans-serif; line-height: 1.6; color: #422268; }}
            .container {{ max-width: 600px; margin: 0 auto; padding: 20px; }}
            .header {{ background: linear-gradient(135deg, #644c9f 0%, #48286e 100%); padding: 30px; text-align: center; border-radius: 10px 10px 0 0; }}
            .header h1 {{ color: white; margin: 0; font-family: 'Inter', sans-serif; }}
            .content {{ background: #FFFFFF; padding: 30px; border-radius: 0 0 10px 10px; }}
            .button {{ display: inline-block; background: #DDD8EB; color: #422268; padding: 15px 40px; text-decoration: none; border-radius: 50px; font-weight: 600; margin: 20px 0; }}
            .button:hover {{ background: #FFFFFF; }}
            .note {{ background: #f1eef9; border-left: 4px solid #ff9e77; padding: 15px; margin: 20px 0; }}
        </style>
    </head>
    <body>
        <div class="container">
            <div class="header">
                <h1>Reset Your Password</h1>
            </div>
            <div class="content">
                <p>Hi {first_name},</p>
                <p>You requested to reset your password. Click the button below to create a new password:</p>

                <p style="text-align: center;">
                    <a href="{reset_url}" class="button">Reset Password</a>
                </p>

                <div class="note">
                    <p style="margin: 0; font-size: 14px;"><strong>⏰ This link will expire in 1 hour.</strong></p>
                    <p style="margin: 5px 0 0 0; font-size: 14px;">If you didn't request this, please ignore this email.</p>
                </div>

                <p style="margin-top: 20px; color: #664fa3; font-size: 14px;">
                    Or copy and paste this link into your browser:<br>
                    <span style="word-break: break-all;">{reset_url}</span>
                </p>
            </div>
        </div>
    </body>
    </html>
    """

    return await send_email(to_email, subject, html_content)

async def send_admin_password_reset_email(
    to_email: str,
    first_name: str,
    temp_password: str,
    force_change: bool
):
    """Send temporary password when admin resets user password"""
    subject = "Your Password Has Been Reset - LOAF Membership"

    force_change_text = (
        """
        <div class="note" style="background: #FFEBEE; border-left: 4px solid #ff9e77;">
            <p style="margin: 0; font-weight: bold; color: #ff9e77;">⚠️ You will be required to change this password when you log in.</p>
        </div>
        """
    ) if force_change else ""

    login_url = f"{FRONTEND_URL}/login"

    html_content = f"""
    <!DOCTYPE html>
    <html>
    <head>
        <style>
            body {{ font-family: 'Nunito Sans', Arial, sans-serif; line-height: 1.6; color: #422268; }}
            .container {{ max-width: 600px; margin: 0 auto; padding: 20px; }}
            .header {{ background: linear-gradient(135deg, #644c9f 0%, #48286e 100%); padding: 30px; text-align: center; border-radius: 10px 10px 0 0; }}
            .header h1 {{ color: white; margin: 0; font-family: 'Inter', sans-serif; }}
            .content {{ background: #FFFFFF; padding: 30px; border-radius: 0 0 10px 10px; }}
            .button {{ display: inline-block; background: #DDD8EB; color: #422268; padding: 15px 40px; text-decoration: none; border-radius: 50px; font-weight: 600; margin: 20px 0; }}
            .button:hover {{ background: #FFFFFF; }}
            .password-box {{ background: #f1eef9; padding: 20px; margin: 20px 0; border-left: 4px solid #ff9e77; font-family: 'Courier New', monospace; font-size: 18px; font-weight: bold; word-break: break-all; }}
            .note {{ background: #f1eef9; border-left: 4px solid #ff9e77; padding: 15px; margin: 20px 0; }}
        </style>
    </head>
    <body>
        <div class="container">
            <div class="header">
                <h1>Password Reset by Administrator</h1>
            </div>
            <div class="content">
                <p>Hi {first_name},</p>
                <p>An administrator has reset your password. Here is your temporary password:</p>

                <div class="password-box">
                    {temp_password}
                </div>

                {force_change_text}

                <p>Please log in and change your password to something memorable.</p>

                <p style="text-align: center;">
                    <a href="{login_url}" class="button">Go to Login</a>
                </p>

                <p style="margin-top: 30px; padding-top: 20px; border-top: 1px solid #ddd8eb; color: #664fa3; font-size: 14px;">
                    Questions? Contact us at support@loaf.org
                </p>
            </div>
        </div>
    </body>
    </html>
    """

    return await send_email(to_email, subject, html_content)