"""
Verification Service for Email and SMS
Handles sending and verifying codes for user authentication
"""
import random
import string
import smtplib
from email.mime.text import MIMEText
from email.mime.multipart import MIMEMultipart
from datetime import datetime, timedelta
from typing import Optional, Tuple
from sqlalchemy.orm import Session

from ..config import get_settings
from ..models.user import User, VerificationCode

settings = get_settings()


def generate_code(length: int = 6) -> str:
    """Generate a random numeric code"""
    return ''.join(random.choices(string.digits, k=length))


def create_verification_code(
    db: Session,
    code_type: str,  # 'email' or 'phone'
    email: Optional[str] = None,
    phone: Optional[str] = None,
    user_id: Optional[int] = None,
    purpose: str = "verification"
) -> VerificationCode:
    """Create a new verification code"""
    # Invalidate any existing codes for this email/phone
    if email:
        db.query(VerificationCode).filter(
            VerificationCode.email == email,
            VerificationCode.code_type == code_type,
            VerificationCode.verified_at.is_(None)
        ).delete()
    if phone:
        db.query(VerificationCode).filter(
            VerificationCode.phone == phone,
            VerificationCode.code_type == code_type,
            VerificationCode.verified_at.is_(None)
        ).delete()

    # Create new code
    code = VerificationCode(
        user_id=user_id,
        email=email,
        phone=phone,
        code=generate_code(),
        code_type=code_type,
        purpose=purpose,
        expires_at=datetime.utcnow() + timedelta(minutes=settings.VERIFICATION_CODE_EXPIRE_MINUTES)
    )
    db.add(code)
    db.commit()
    db.refresh(code)
    return code


def verify_code(
    db: Session,
    code: str,
    code_type: str,
    email: Optional[str] = None,
    phone: Optional[str] = None
) -> Tuple[bool, str]:
    """
    Verify a code and return (success, message)
    """
    query = db.query(VerificationCode).filter(
        VerificationCode.code_type == code_type,
        VerificationCode.verified_at.is_(None)
    )

    if email:
        query = query.filter(VerificationCode.email == email)
    if phone:
        query = query.filter(VerificationCode.phone == phone)

    verification = query.order_by(VerificationCode.created_at.desc()).first()

    if not verification:
        return False, "No verification code found. Please request a new one."

    # Check if expired
    if datetime.utcnow() > verification.expires_at.replace(tzinfo=None):
        return False, "Verification code has expired. Please request a new one."

    # Check attempts
    if verification.attempts >= verification.max_attempts:
        return False, "Too many failed attempts. Please request a new code."

    # Check code
    if verification.code != code:
        verification.attempts += 1
        db.commit()
        remaining = verification.max_attempts - verification.attempts
        return False, f"Invalid code. {remaining} attempts remaining."

    # Success
    verification.verified_at = datetime.utcnow()
    db.commit()

    return True, "Verification successful"


async def send_email_verification(
    db: Session,
    email: str,
    user_id: Optional[int] = None,
    language: str = "en"
) -> Tuple[bool, str]:
    """Send email verification code"""
    # Check rate limit (1 email per minute)
    recent = db.query(VerificationCode).filter(
        VerificationCode.email == email,
        VerificationCode.code_type == "email",
        VerificationCode.created_at > datetime.utcnow() - timedelta(minutes=1)
    ).first()

    if recent:
        return False, "Please wait 1 minute before requesting another code."

    # Create verification code
    verification = create_verification_code(
        db=db,
        code_type="email",
        email=email,
        user_id=user_id
    )

    # Send email
    try:
        # Email templates by language
        subjects = {
            "en": "AutonetSellCar - Email Verification Code",
            "ko": "AutonetSellCar - 이메일 인증 코드",
            "mn": "AutonetSellCar - Имэйл баталгаажуулах код",
            "ru": "AutonetSellCar - Код подтверждения email"
        }

        bodies = {
            "en": f"""
Hello,

Your verification code is: {verification.code}

This code will expire in {settings.VERIFICATION_CODE_EXPIRE_MINUTES} minutes.

If you didn't request this code, please ignore this email.

Best regards,
AutonetSellCar Team
""",
            "ko": f"""
안녕하세요,

인증 코드: {verification.code}

이 코드는 {settings.VERIFICATION_CODE_EXPIRE_MINUTES}분 후에 만료됩니다.

요청하지 않은 경우 이 이메일을 무시하세요.

감사합니다,
AutonetSellCar 팀
""",
            "mn": f"""
Сайн байна уу,

Таны баталгаажуулах код: {verification.code}

Энэ код {settings.VERIFICATION_CODE_EXPIRE_MINUTES} минутын дараа хүчингүй болно.

Хэрэв та энэ кодыг хүсээгүй бол энэ имэйлийг үл тоомсорлоно уу.

Хүндэтгэсэн,
AutonetSellCar баг
""",
            "ru": f"""
Здравствуйте,

Ваш код подтверждения: {verification.code}

Этот код истечет через {settings.VERIFICATION_CODE_EXPIRE_MINUTES} минут.

Если вы не запрашивали этот код, проигнорируйте это письмо.

С уважением,
Команда AutonetSellCar
"""
        }

        subject = subjects.get(language, subjects["en"])
        body = bodies.get(language, bodies["en"])

        # Check if SMTP is configured
        if not settings.SMTP_USER or not settings.SMTP_PASSWORD:
            # Development mode - just log the code
            print(f"[DEV] Email verification code for {email}: {verification.code}")
            return True, "Verification code sent (dev mode)"

        # Send actual email
        msg = MIMEMultipart()
        msg['From'] = f"{settings.SMTP_FROM_NAME} <{settings.SMTP_FROM_EMAIL or settings.SMTP_USER}>"
        msg['To'] = email
        msg['Subject'] = subject
        msg.attach(MIMEText(body, 'plain', 'utf-8'))

        with smtplib.SMTP(settings.SMTP_HOST, settings.SMTP_PORT) as server:
            server.starttls()
            server.login(settings.SMTP_USER, settings.SMTP_PASSWORD)
            server.send_message(msg)

        return True, "Verification code sent to your email"

    except Exception as e:
        print(f"[ERROR] Failed to send email: {e}")
        return False, f"Failed to send email: {str(e)}"


async def send_sms_verification(
    db: Session,
    phone: str,
    user_id: Optional[int] = None,
    language: str = "en"
) -> Tuple[bool, str]:
    """Send SMS verification code"""
    # Normalize phone number
    phone = phone.strip().replace(" ", "").replace("-", "")
    if not phone.startswith("+"):
        # Assume Mongolia if no country code
        if phone.startswith("9") and len(phone) == 8:
            phone = "+976" + phone

    # Check rate limit (1 SMS per minute)
    recent = db.query(VerificationCode).filter(
        VerificationCode.phone == phone,
        VerificationCode.code_type == "phone",
        VerificationCode.created_at > datetime.utcnow() - timedelta(minutes=1)
    ).first()

    if recent:
        return False, "Please wait 1 minute before requesting another code."

    # Create verification code
    verification = create_verification_code(
        db=db,
        code_type="phone",
        phone=phone,
        user_id=user_id
    )

    # SMS messages by language
    messages = {
        "en": f"AutonetSellCar verification code: {verification.code}. Valid for {settings.VERIFICATION_CODE_EXPIRE_MINUTES} min.",
        "ko": f"AutonetSellCar 인증 코드: {verification.code}. {settings.VERIFICATION_CODE_EXPIRE_MINUTES}분간 유효.",
        "mn": f"AutonetSellCar баталгаажуулах код: {verification.code}. {settings.VERIFICATION_CODE_EXPIRE_MINUTES} мин хүчинтэй.",
        "ru": f"Код подтверждения AutonetSellCar: {verification.code}. Действителен {settings.VERIFICATION_CODE_EXPIRE_MINUTES} мин."
    }

    message = messages.get(language, messages["en"])

    try:
        # Check if Twilio is configured
        if not settings.TWILIO_ACCOUNT_SID or not settings.TWILIO_AUTH_TOKEN:
            # Development mode - just log the code
            print(f"[DEV] SMS verification code for {phone}: {verification.code}")
            return True, "Verification code sent (dev mode)"

        # Send actual SMS via Twilio
        from twilio.rest import Client

        client = Client(settings.TWILIO_ACCOUNT_SID, settings.TWILIO_AUTH_TOKEN)
        client.messages.create(
            body=message,
            from_=settings.TWILIO_PHONE_NUMBER,
            to=phone
        )

        return True, "Verification code sent to your phone"

    except Exception as e:
        print(f"[ERROR] Failed to send SMS: {e}")
        return False, f"Failed to send SMS: {str(e)}"


def mark_email_verified(db: Session, user: User) -> None:
    """Mark user's email as verified"""
    user.email_verified = True
    user.email_verified_at = datetime.utcnow()
    db.commit()


def mark_phone_verified(db: Session, user: User, phone: str) -> None:
    """Mark user's phone as verified and update phone number"""
    user.phone = phone
    user.phone_verified = True
    user.phone_verified_at = datetime.utcnow()
    db.commit()


def is_email_verified(user: User) -> bool:
    """Check if user's email is verified"""
    return user.email_verified


def is_phone_verified(user: User) -> bool:
    """Check if user's phone is verified"""
    return user.phone_verified