"""Author RAG — Email Service Extensions.

Adds email templates required by Phase 1 billing flows:
  - send_welcome: fired on account activation (POST /api/auth/activate)
  - send_password_reset: fired by forgot-password flow
  - send_payment_failed: dunning email (fired by Stripe webhook)
  - send_subscription_cancelled: cancellation confirmation
  - send_token_warning: author approaching budget limit (80% / 95%)

All methods are thin wrappers around _send() — the existing SMTP infrastructure.
"""


def _extend_email_service():
    """Monkey-patch new methods onto EmailService if they don't exist yet."""
    from app.services.email_service import EmailService
    from app.config import get_settings
    cfg = get_settings()

    if not hasattr(EmailService, "send_password_reset"):
        def send_password_reset(self, to_email: str, reset_url: str) -> None:
            """Send HMAC-signed password reset link."""
            self._send(
                to=to_email,
                subject="Reset your ChatBot AI password",
                body=(
                    f"Hi,\n\n"
                    f"Click the link below to reset your password. "
                    f"This link expires in 1 hour.\n\n"
                    f"{reset_url}\n\n"
                    f"If you didn't request a password reset, you can ignore this email.\n\n"
                    f"— The ChatBot AI Team"
                ),
            )
        EmailService.send_password_reset = send_password_reset

    if not hasattr(EmailService, "send_payment_failed"):
        def send_payment_failed(self, to_email: str, author_name: str, grace_days: int = 7) -> None:
            """Dunning email — payment failed, grace period active."""
            self._send(
                to=to_email,
                subject="⚠️ Payment failed — action required",
                body=(
                    f"Hi {author_name},\n\n"
                    f"We couldn't process your subscription payment. "
                    f"Your chatbot will continue working for {grace_days} more days.\n\n"
                    f"Please update your payment method to avoid interruption:\n"
                    f"{cfg.FRONTEND_URL}/dashboard/billing\n\n"
                    f"Questions? Reply to this email.\n\n"
                    f"— The ChatBot AI Team"
                ),
            )
        EmailService.send_payment_failed = send_payment_failed

    if not hasattr(EmailService, "send_subscription_cancelled"):
        def send_subscription_cancelled(self, to_email: str, author_name: str, access_until: str) -> None:
            """Cancellation confirmation — access continues to period end."""
            self._send(
                to=to_email,
                subject="Your subscription has been cancelled",
                body=(
                    f"Hi {author_name},\n\n"
                    f"Your ChatBot AI subscription has been cancelled. "
                    f"You have access until {access_until}.\n\n"
                    f"We'd love to know why you left — reply to this email with feedback.\n\n"
                    f"You can reactivate any time at: {cfg.FRONTEND_URL}/#pricing\n\n"
                    f"— The ChatBot AI Team"
                ),
            )
        EmailService.send_subscription_cancelled = send_subscription_cancelled

    if not hasattr(EmailService, "send_token_warning"):
        def send_token_warning(self, to_email: str, author_name: str, pct_used: int) -> None:
            """Proactive token budget warning (80% or 95%)."""
            threshold = "almost" if pct_used >= 95 else "80%"
            self._send(
                to=to_email,
                subject=f"⚡ You've used {pct_used}% of your monthly AI budget",
                body=(
                    f"Hi {author_name},\n\n"
                    f"You've used {pct_used}% of your monthly token budget. "
                    f"{'Your chatbot may stop responding soon.' if pct_used >= 95 else 'Heads up — you may want to upgrade before month end.'}\n\n"
                    f"Upgrade your plan: {cfg.FRONTEND_URL}/#pricing\n\n"
                    f"Or manage your billing: {cfg.FRONTEND_URL}/dashboard/billing\n\n"
                    f"— The ChatBot AI Team"
                ),
            )
        EmailService.send_token_warning = send_token_warning


# Auto-extend on import
_extend_email_service()