"""
ShopDB Email API
================
Flask API for sending emails via SMTP with STARTTLS support.
Designed to be called from Classic ASP pages that cannot handle STARTTLS.

Environment Variables:
    SMTP_HOST     - SMTP server hostname
    SMTP_PORT     - SMTP port (default: 587)
    SMTP_USER     - SMTP username
    SMTP_PASS     - SMTP password
    SMTP_FROM     - Default from address (optional)
    API_KEY       - Simple API key for authentication (optional)
    DB_HOST       - MySQL host for distribution groups (default: 192.168.122.1)
    DB_USER       - MySQL username (default: 570005354)
    DB_PASS       - MySQL password
    DB_NAME       - MySQL database (default: shopdb)

Usage from ASP:
    Set http = Server.CreateObject("MSXML2.ServerXMLHTTP.6.0")
    http.open "POST", "http://localhost:5000/api/send", False
    http.setRequestHeader "Content-Type", "application/json"
    http.send "{""to"":""user@example.com"",""subject"":""Test"",""message"":""Hello""}"
"""

import os
import smtplib
import logging
from email.mime.text import MIMEText
from email.mime.multipart import MIMEMultipart
from flask import Flask, request, jsonify
from functools import wraps

# Optional MySQL support for distribution groups
try:
    import mysql.connector
    MYSQL_AVAILABLE = True
except ImportError:
    MYSQL_AVAILABLE = False

app = Flask(__name__)

# Configure logging
logging.basicConfig(
    level=logging.INFO,
    format='%(asctime)s - %(levelname)s - %(message)s'
)
logger = logging.getLogger(__name__)

# Configuration from environment
SMTP_HOST = os.environ.get('SMTP_HOST', '')
SMTP_PORT = int(os.environ.get('SMTP_PORT', '587'))
SMTP_USER = os.environ.get('SMTP_USER', '')
SMTP_PASS = os.environ.get('SMTP_PASS', '')
SMTP_FROM = os.environ.get('SMTP_FROM', SMTP_USER)
API_KEY = os.environ.get('API_KEY', '')

# Database config for distribution groups
DB_HOST = os.environ.get('DB_HOST', '192.168.122.1')
DB_PORT = int(os.environ.get('DB_PORT', '3306'))
DB_USER = os.environ.get('DB_USER', '570005354')
DB_PASS = os.environ.get('DB_PASS', '570005354')
DB_NAME = os.environ.get('DB_NAME', 'shopdb')


def require_api_key(f):
    """Optional API key authentication decorator."""
    @wraps(f)
    def decorated(*args, **kwargs):
        if API_KEY:
            provided_key = request.headers.get('X-API-Key') or request.args.get('api_key')
            if provided_key != API_KEY:
                return jsonify({'success': False, 'error': 'Invalid or missing API key'}), 401
        return f(*args, **kwargs)
    return decorated


def get_db_connection():
    """Get MySQL database connection."""
    if not MYSQL_AVAILABLE:
        return None
    try:
        return mysql.connector.connect(
            host=DB_HOST,
            port=DB_PORT,
            user=DB_USER,
            password=DB_PASS,
            database=DB_NAME
        )
    except Exception as e:
        logger.error(f"Database connection failed: {e}")
        return None


def send_email(to_addresses, subject, message, html=False, from_addr=None):
    """
    Send email via SMTP with STARTTLS.

    Args:
        to_addresses: Single email or list of emails
        subject: Email subject
        message: Email body (plain text or HTML)
        html: If True, send as HTML email
        from_addr: Optional from address (defaults to SMTP_FROM)

    Returns:
        tuple: (success: bool, error_message: str or None)
    """
    if not SMTP_HOST or not SMTP_USER or not SMTP_PASS:
        return False, "SMTP not configured. Set SMTP_HOST, SMTP_USER, SMTP_PASS environment variables."

    # Normalize to list
    if isinstance(to_addresses, str):
        to_addresses = [to_addresses]

    # Filter empty addresses
    to_addresses = [addr.strip() for addr in to_addresses if addr and addr.strip()]

    if not to_addresses:
        return False, "No valid recipient addresses provided"

    from_addr = from_addr or SMTP_FROM

    try:
        # Create message
        if html:
            msg = MIMEMultipart('alternative')
            msg.attach(MIMEText(message, 'html'))
        else:
            msg = MIMEText(message, 'plain')

        msg['Subject'] = subject
        msg['From'] = from_addr
        msg['To'] = ', '.join(to_addresses)

        # Connect and send
        logger.info(f"Connecting to {SMTP_HOST}:{SMTP_PORT}")

        with smtplib.SMTP(SMTP_HOST, SMTP_PORT, timeout=30) as server:
            server.ehlo()
            server.starttls()
            server.ehlo()
            server.login(SMTP_USER, SMTP_PASS)
            server.sendmail(from_addr, to_addresses, msg.as_string())

        logger.info(f"Email sent successfully to {to_addresses}")
        return True, None

    except smtplib.SMTPAuthenticationError as e:
        error = f"SMTP authentication failed: {e}"
        logger.error(error)
        return False, error
    except smtplib.SMTPException as e:
        error = f"SMTP error: {e}"
        logger.error(error)
        return False, error
    except Exception as e:
        error = f"Failed to send email: {e}"
        logger.error(error)
        return False, error


@app.route('/api/health', methods=['GET'])
def health_check():
    """Health check endpoint."""
    smtp_configured = bool(SMTP_HOST and SMTP_USER and SMTP_PASS)
    return jsonify({
        'status': 'ok',
        'smtp_configured': smtp_configured,
        'mysql_available': MYSQL_AVAILABLE
    })


@app.route('/api/send', methods=['POST'])
@require_api_key
def send_email_endpoint():
    """
    Send an email.

    Request JSON:
        {
            "to": "email@example.com" or ["email1@example.com", "email2@example.com"],
            "subject": "Email subject",
            "message": "Email body",
            "html": false,  // optional, default false
            "from": "sender@example.com"  // optional
        }

    Response JSON:
        {"success": true} or {"success": false, "error": "error message"}
    """
    try:
        data = request.get_json()

        if not data:
            return jsonify({'success': False, 'error': 'No JSON data provided'}), 400

        to_addresses = data.get('to')
        subject = data.get('subject', '')
        message = data.get('message', '')
        html = data.get('html', False)
        from_addr = data.get('from')

        if not to_addresses:
            return jsonify({'success': False, 'error': 'Missing "to" field'}), 400

        if not subject:
            return jsonify({'success': False, 'error': 'Missing "subject" field'}), 400

        if not message:
            return jsonify({'success': False, 'error': 'Missing "message" field'}), 400

        success, error = send_email(to_addresses, subject, message, html, from_addr)

        if success:
            return jsonify({'success': True})
        else:
            return jsonify({'success': False, 'error': error}), 500

    except Exception as e:
        logger.error(f"Error in send endpoint: {e}")
        return jsonify({'success': False, 'error': str(e)}), 500


@app.route('/api/send-to-group', methods=['POST'])
@require_api_key
def send_to_distribution_group():
    """
    Send email to a distribution group from the database.

    Request JSON:
        {
            "group_id": 1,  // or "group_name": "IT Support"
            "subject": "Email subject",
            "message": "Email body",
            "html": false
        }
    """
    if not MYSQL_AVAILABLE:
        return jsonify({'success': False, 'error': 'MySQL connector not installed'}), 500

    try:
        data = request.get_json()

        if not data:
            return jsonify({'success': False, 'error': 'No JSON data provided'}), 400

        group_id = data.get('group_id')
        group_name = data.get('group_name')
        subject = data.get('subject', '')
        message = data.get('message', '')
        html = data.get('html', False)

        if not group_id and not group_name:
            return jsonify({'success': False, 'error': 'Missing group_id or group_name'}), 400

        # Look up distribution group
        conn = get_db_connection()
        if not conn:
            return jsonify({'success': False, 'error': 'Database connection failed'}), 500

        try:
            cursor = conn.cursor(dictionary=True)

            if group_id:
                cursor.execute(
                    "SELECT email FROM distributiongroups WHERE distributiongroupid = %s AND isactive = 1",
                    (group_id,)
                )
            else:
                cursor.execute(
                    "SELECT email FROM distributiongroups WHERE name = %s AND isactive = 1",
                    (group_name,)
                )

            result = cursor.fetchone()

            if not result:
                return jsonify({'success': False, 'error': 'Distribution group not found or inactive'}), 404

            to_address = result['email']

        finally:
            cursor.close()
            conn.close()

        success, error = send_email(to_address, subject, message, html)

        if success:
            return jsonify({'success': True, 'sent_to': to_address})
        else:
            return jsonify({'success': False, 'error': error}), 500

    except Exception as e:
        logger.error(f"Error in send-to-group endpoint: {e}")
        return jsonify({'success': False, 'error': str(e)}), 500


@app.route('/api/groups', methods=['GET'])
@require_api_key
def list_distribution_groups():
    """List all active distribution groups."""
    if not MYSQL_AVAILABLE:
        return jsonify({'success': False, 'error': 'MySQL connector not installed'}), 500

    conn = get_db_connection()
    if not conn:
        return jsonify({'success': False, 'error': 'Database connection failed'}), 500

    try:
        cursor = conn.cursor(dictionary=True)
        cursor.execute(
            "SELECT distributiongroupid, name, email FROM distributiongroups WHERE isactive = 1 ORDER BY name"
        )
        groups = cursor.fetchall()
        return jsonify({'success': True, 'groups': groups})
    except Exception as e:
        logger.error(f"Error listing groups: {e}")
        return jsonify({'success': False, 'error': str(e)}), 500
    finally:
        cursor.close()
        conn.close()


if __name__ == '__main__':
    # Check configuration
    if not SMTP_HOST:
        logger.warning("SMTP_HOST not set - email sending will fail")
    if not SMTP_USER:
        logger.warning("SMTP_USER not set - email sending will fail")
    if not SMTP_PASS:
        logger.warning("SMTP_PASS not set - email sending will fail")

    logger.info(f"Starting Email API on port 5000")
    logger.info(f"SMTP: {SMTP_HOST}:{SMTP_PORT}")

    app.run(host='0.0.0.0', port=5000, debug=False)