from django.core.mail import EmailMultiAlternatives
from django.template.loader import render_to_string
from django.conf import settings
from django.utils import timezone
import pytz
from datetime import datetime

class EmailService:
    
    @staticmethod
    def _format_datetime_for_user(dt, user_timezone='UTC'):
        if not dt:
            return ''
        
        try:
            user_tz = pytz.timezone(user_timezone or 'UTC')
            
            if timezone.is_naive(dt):
                dt = timezone.make_aware(dt, pytz.UTC)
            
            local_dt = dt.astimezone(user_tz)
            
            formatted = local_dt.strftime('%B %d, %Y at %I:%M %p %Z')
            
            return formatted
        except Exception as e:
            print(f"Error formatting datetime: {e}")
            return dt.strftime('%B %d, %Y at %I:%M %p UTC')
    
    @staticmethod
    def send_admin_notification(appointment):
        subject = f"New Appointment Request from {appointment.full_name}"
        
        context = {
            'appointment': appointment,
            'preferred_dates': appointment.get_preferred_dates_display(),
            'preferred_times': appointment.get_preferred_time_slots_display(),
            'admin_dashboard_url': "https://attunehearttherapy.com/admin/dashboard"
        }
        
        html_message = render_to_string('emails/admin_notification.html', context)
        
        admin_email = getattr(settings, 'ADMIN_EMAIL', 'admin@attunehearttherapy.com')
        
        try:
            email = EmailMultiAlternatives(
                subject=subject,
                body="Please view this email in an HTML-compatible client.",
                from_email=settings.DEFAULT_FROM_EMAIL,
                to=[admin_email],
            )
            email.attach_alternative(html_message, "text/html")
            email.send(fail_silently=False)
            return True
        except Exception as e:
            print(f"Failed to send admin notification: {e}")
            return False
    
    @staticmethod
    def send_appointment_scheduled(appointment):
        subject = "Your Appointment Has Been Scheduled"
        
        user_timezone = getattr(appointment, 'user_timezone', 'UTC')
        
        formatted_datetime = EmailService._format_datetime_for_user(
            appointment.scheduled_datetime,
            user_timezone
        )
        
        context = {
            'appointment': appointment,
            'scheduled_datetime': formatted_datetime,
            'user_dashboard_url': f"{settings.FRONTEND_URL}/dashboard" if hasattr(settings, 'FRONTEND_URL') else '/dashboard/',
            'settings': {
                'SITE_NAME': getattr(settings, 'SITE_NAME', 'Attune Heart Therapy')
            }
        }
        
        html_message = render_to_string('emails/appointment_scheduled.html', context)
        
        try:
            email = EmailMultiAlternatives(
                subject=subject,
                body=f"Your appointment has been scheduled for {formatted_datetime}. Please view this email in an HTML-compatible client for more details.",
                from_email=settings.DEFAULT_FROM_EMAIL,
                to=[appointment.email],
            )
            email.attach_alternative(html_message, "text/html")
            email.send(fail_silently=False)
            return True
        except Exception as e:
            print(f"Failed to send scheduled notification: {e}")
            return False
    
    @staticmethod
    def send_appointment_rejected(appointment):
        subject = "Update on Your Appointment Request"
        
        context = {
            'appointment': appointment,
            'rejection_reason': appointment.rejection_reason or "No specific reason provided.",
            'user_dashboard_url': f"{settings.FRONTEND_URL}/dashboard" if hasattr(settings, 'FRONTEND_URL') else '/dashboard/',
            'settings': {
                'SITE_NAME': getattr(settings, 'SITE_NAME', 'Attune Heart Therapy')
            }
        }
        
        html_message = render_to_string('emails/appointment_rejected.html', context)
        
        try:
            email = EmailMultiAlternatives(
                subject=subject,
                body="Please view this email in an HTML-compatible client.",
                from_email=settings.DEFAULT_FROM_EMAIL,
                to=[appointment.email],
            )
            email.attach_alternative(html_message, "text/html")
            email.send(fail_silently=False)
            return True
        except Exception as e:
            print(f"Failed to send rejection notification: {e}")
            return False
    
    @staticmethod
    def send_appointment_reminder(appointment, hours_before=24):
        subject = "Reminder: Your Upcoming Appointment"
        
        user_timezone = getattr(appointment, 'user_timezone', 'UTC')
        formatted_datetime = EmailService._format_datetime_for_user(
            appointment.scheduled_datetime,
            user_timezone
        )
        
        context = {
            'appointment': appointment,
            'scheduled_datetime': formatted_datetime,
            'hours_before': hours_before,
            'join_url': appointment.get_participant_join_url() if hasattr(appointment, 'get_participant_join_url') else None,
            'settings': {
                'SITE_NAME': getattr(settings, 'SITE_NAME', 'Attune Heart Therapy')
            }
        }
        
        html_message = render_to_string('emails/appointment_reminder.html', context)
        
        try:
            email = EmailMultiAlternatives(
                subject=subject,
                body=f"This is a reminder that you have an appointment scheduled for {formatted_datetime}.",
                from_email=settings.DEFAULT_FROM_EMAIL,
                to=[appointment.email],
            )
            email.attach_alternative(html_message, "text/html")
            email.send(fail_silently=False)
            return True
        except Exception as e:
            print(f"Failed to send reminder notification: {e}")
            return False