from rest_framework import serializers
from .models import AdminWeeklyAvailability, AppointmentRequest
from django.utils import timezone
from datetime import datetime, timedelta
import json

class AdminWeeklyAvailabilitySerializer(serializers.ModelSerializer):
    available_days_display = serializers.SerializerMethodField()
    
    class Meta:
        model = AdminWeeklyAvailability
        fields = ['id', 'available_days', 'available_days_display', 'created_at', 'updated_at']
    
    def get_available_days_display(self, obj):
        days_map = dict(AdminWeeklyAvailability.DAYS_OF_WEEK)
        return [days_map[day] for day in obj.available_days]

class AppointmentRequestSerializer(serializers.ModelSerializer):
    full_name = serializers.ReadOnlyField()
    formatted_created_at = serializers.ReadOnlyField()
    formatted_scheduled_datetime = serializers.ReadOnlyField()
    preferred_dates_display = serializers.ReadOnlyField()
    preferred_time_slots_display = serializers.ReadOnlyField()
    has_jitsi_meeting = serializers.ReadOnlyField()
    jitsi_meet_url = serializers.ReadOnlyField()
    jitsi_room_id = serializers.ReadOnlyField()
    can_join_meeting = serializers.ReadOnlyField()
    meeting_status = serializers.ReadOnlyField()
    
    class Meta:
        model = AppointmentRequest
        fields = [
            'id', 'first_name', 'last_name', 'email', 'phone', 'reason',
            'preferred_dates', 'preferred_time_slots', 'status',
            'scheduled_datetime', 'scheduled_duration', 'rejection_reason', 
            'jitsi_meet_url', 'jitsi_room_id', 'created_at', 'updated_at',
            'full_name', 'formatted_created_at', 'formatted_scheduled_datetime',
            'preferred_dates_display', 'preferred_time_slots_display',
            'has_jitsi_meeting', 'can_join_meeting', 'meeting_status'
        ]
        read_only_fields = [
            'id', 'status', 'scheduled_datetime', 'scheduled_duration', 
            'rejection_reason', 'jitsi_meet_url', 'jitsi_room_id', 
            'created_at', 'updated_at'
        ]

class AppointmentRequestCreateSerializer(serializers.ModelSerializer):
    class Meta:
        model = AppointmentRequest
        fields = [
            'first_name', 'last_name', 'email', 'phone', 'reason',
            'preferred_dates', 'preferred_time_slots'
        ]
    
    def validate_preferred_dates(self, value):
        if not value or len(value) == 0:
            raise serializers.ValidationError("At least one preferred date is required.")
        
        today = timezone.now().date()
        for date_str in value:
            try:
                date_obj = datetime.strptime(date_str, '%Y-%m-%d').date()
                if date_obj < today:
                    raise serializers.ValidationError("Preferred dates cannot be in the past.")
            except ValueError:
                raise serializers.ValidationError(f"Invalid date format: {date_str}. Use YYYY-MM-DD.")
        
        return value
    
    def validate_preferred_time_slots(self, value):
        if not value or len(value) == 0:
            raise serializers.ValidationError("At least one time slot is required.")
        
        valid_slots = ['morning', 'afternoon', 'evening']
        for slot in value:
            if slot not in valid_slots:
                raise serializers.ValidationError(f"Invalid time slot: {slot}. Must be one of {valid_slots}.")
        
        return value

class AppointmentScheduleSerializer(serializers.Serializer):
    scheduled_datetime = serializers.DateTimeField()
    scheduled_duration = serializers.IntegerField(default=60, min_value=30, max_value=240)
    
    def validate_scheduled_datetime(self, value):
        if value <= timezone.now():
            raise serializers.ValidationError("Scheduled datetime must be in the future.")
        return value
    
    def validate_scheduled_duration(self, value):
        if value < 30:
            raise serializers.ValidationError("Duration must be at least 30 minutes.")
        if value > 240:
            raise serializers.ValidationError("Duration cannot exceed 4 hours.")
        return value

class AppointmentRejectSerializer(serializers.Serializer):
    rejection_reason = serializers.CharField(required=False, allow_blank=True)