from rest_framework import serializers
from ..models import (
    Medication, Prescription, InventoryItem, DispenseRecord,
    MedicationAdministration, DrugInteraction
)


class BaseSerializer(serializers.ModelSerializer):
    """Base serializer with common functionality"""
    
    class Meta:
        fields = ['id']
        read_only_fields = ['created_at', 'updated_at']


class MedicationSerializer(serializers.ModelSerializer):
    """Serializer for Medication model"""
    dosage_form_display = serializers.CharField(source='get_dosage_form_display', read_only=True)
    route_display = serializers.CharField(source='get_route_display', read_only=True)
    controlled_substance_display = serializers.CharField(source='get_controlled_substance_display', read_only=True)
    
    class Meta:
        model = Medication
        fields = [
            'medication_id', 'name', 'generic_name', 'brand_names', 'ndc_number',
            'rxcui', 'dosage_form', 'dosage_form_display', 'strength', 'unit',
            'route', 'route_display', 'manufacturer', 'therapeutic_class',
            'pharmacologic_class', 'controlled_substance', 'controlled_substance_display',
            'dea_schedule', 'pregnancy_category', 'black_box_warning',
            'contraindications', 'side_effects', 'interactions', 'storage_requirements',
            'expiration_tracking', 'lot_tracking', 'is_active', 'created_at', 'updated_at'
        ]
        read_only_fields = ['medication_id', 'created_at', 'updated_at']


class PrescriptionSerializer(serializers.ModelSerializer):
    """Serializer for Prescription model"""
    patient_name = serializers.CharField(source='patient.get_full_name', read_only=True)
    patient_mrn = serializers.CharField(source='patient.mrn', read_only=True)
    prescriber_name = serializers.CharField(source='prescriber.get_full_name', read_only=True)
    medication_name = serializers.CharField(source='medication.name', read_only=True)
    status_display = serializers.CharField(source='get_status_display', read_only=True)
    priority_display = serializers.CharField(source='get_priority_display', read_only=True)
    days_supply = serializers.IntegerField(read_only=True)
    
    class Meta:
        model = Prescription
        fields = [
            'prescription_id', 'prescription_number', 'patient', 'patient_name', 'patient_mrn',
            'prescriber', 'prescriber_name', 'medication', 'medication_name', 'dosage',
            'frequency', 'route', 'quantity', 'quantity_dispensed', 'refills_authorized',
            'refills_remaining', 'days_supply', 'date_prescribed', 'date_filled',
            'expiration_date', 'status', 'status_display', 'priority', 'priority_display',
            'instructions', 'indication', 'notes', 'pharmacy_notes', 'daw_code',
            'generic_substitution_allowed', 'prior_authorization_required',
            'prior_authorization_number', 'insurance_coverage', 'copay_amount',
            'patient_paid_amount', 'insurance_paid_amount', 'created_at', 'updated_at'
        ]
        read_only_fields = [
            'prescription_id', 'prescription_number', 'quantity_dispensed',
            'refills_remaining', 'days_supply', 'created_at', 'updated_at'
        ]


class InventoryItemSerializer(serializers.ModelSerializer):
    """Serializer for InventoryItem model"""
    medication_name = serializers.CharField(source='medication.name', read_only=True)
    status_display = serializers.CharField(source='get_status_display', read_only=True)
    is_low_stock = serializers.BooleanField(read_only=True)
    is_expired = serializers.BooleanField(read_only=True)
    days_until_expiry = serializers.IntegerField(read_only=True)
    
    class Meta:
        model = InventoryItem
        fields = [
            'item_id', 'medication', 'medication_name', 'lot_number', 'expiration_date',
            'quantity_on_hand', 'quantity_allocated', 'quantity_available',
            'unit_cost', 'total_cost', 'reorder_level', 'reorder_quantity',
            'supplier', 'location', 'storage_requirements', 'status', 'status_display',
            'is_low_stock', 'is_expired', 'days_until_expiry', 'last_counted',
            'notes', 'created_at', 'updated_at'
        ]
        read_only_fields = [
            'item_id', 'quantity_available', 'total_cost', 'is_low_stock',
            'is_expired', 'days_until_expiry', 'created_at', 'updated_at'
        ]


class DispenseRecordSerializer(serializers.ModelSerializer):
    """Serializer for DispenseRecord model"""
    prescription_number = serializers.CharField(source='prescription.prescription_number', read_only=True)
    patient_name = serializers.CharField(source='prescription.patient.get_full_name', read_only=True)
    medication_name = serializers.CharField(source='prescription.medication.name', read_only=True)
    dispensed_by_name = serializers.CharField(source='dispensed_by.get_full_name', read_only=True)
    
    class Meta:
        model = DispenseRecord
        fields = [
            'dispense_id', 'prescription', 'prescription_number', 'patient_name',
            'medication_name', 'quantity_dispensed', 'lot_number', 'expiration_date',
            'date_dispensed', 'dispensed_by', 'dispensed_by_name', 'pharmacy_location',
            'patient_counseled', 'counseled_by', 'medication_guide_provided',
            'patient_signature', 'pickup_person', 'pickup_id_verified',
            'delivery_method', 'delivery_address', 'insurance_claim_submitted',
            'copay_collected', 'notes', 'created_at', 'updated_at'
        ]
        read_only_fields = ['dispense_id', 'created_at', 'updated_at']


class MedicationAdministrationSerializer(serializers.ModelSerializer):
    """Serializer for MedicationAdministration model"""
    patient_name = serializers.CharField(source='patient.get_full_name', read_only=True)
    medication_name = serializers.CharField(source='medication.name', read_only=True)
    administered_by_name = serializers.CharField(source='administered_by.get_full_name', read_only=True)
    status_display = serializers.CharField(source='get_status_display', read_only=True)
    
    class Meta:
        model = MedicationAdministration
        fields = [
            'administration_id', 'patient', 'patient_name', 'medication', 'medication_name',
            'dosage_given', 'route_given', 'scheduled_time', 'actual_time',
            'administered_by', 'administered_by_name', 'status', 'status_display',
            'reason_not_given', 'site_of_administration', 'lot_number',
            'expiration_date', 'patient_response', 'adverse_reaction',
            'notes', 'created_at', 'updated_at'
        ]
        read_only_fields = ['administration_id', 'created_at', 'updated_at']


class DrugInteractionSerializer(serializers.ModelSerializer):
    """Serializer for DrugInteraction model"""
    medication1_name = serializers.CharField(source='medication1.name', read_only=True)
    medication2_name = serializers.CharField(source='medication2.name', read_only=True)
    severity_display = serializers.CharField(source='get_severity_display', read_only=True)
    interaction_type_display = serializers.CharField(source='get_interaction_type_display', read_only=True)
    
    class Meta:
        model = DrugInteraction
        fields = [
            'interaction_id', 'medication1', 'medication1_name', 'medication2', 'medication2_name',
            'severity', 'severity_display', 'interaction_type', 'interaction_type_display',
            'description', 'clinical_significance', 'mechanism', 'management_recommendations',
            'references', 'is_active', 'created_at', 'updated_at'
        ]
        read_only_fields = ['interaction_id', 'created_at', 'updated_at']


class PharmacyStatsSerializer(serializers.Serializer):
    """Serializer for pharmacy statistics"""
    total_prescriptions = serializers.IntegerField()
    pending_prescriptions = serializers.IntegerField()
    filled_today = serializers.IntegerField()
    low_stock_items = serializers.IntegerField()
    expired_items = serializers.IntegerField()
    total_medications = serializers.IntegerField()
    controlled_substances = serializers.IntegerField()
    inventory_value = serializers.DecimalField(max_digits=12, decimal_places=2)
    prescription_types = serializers.DictField()
    status_breakdown = serializers.DictField()


class PrescriptionFillSerializer(serializers.Serializer):
    """Serializer for filling prescriptions"""
    prescription_id = serializers.IntegerField()
    quantity_dispensed = serializers.IntegerField()
    lot_number = serializers.CharField()
    expiration_date = serializers.DateField()
    pharmacy_location = serializers.CharField()
    patient_counseled = serializers.BooleanField(default=False)
    counseled_by = serializers.IntegerField(required=False)
    medication_guide_provided = serializers.BooleanField(default=False)
    notes = serializers.CharField(required=False, allow_blank=True)
    
    def validate_prescription_id(self, value):
        """Validate that the prescription exists and can be filled"""
        try:
            prescription = Prescription.objects.get(id=value)
            if prescription.status not in ['PENDING', 'IN_PROGRESS']:
                raise serializers.ValidationError(
                    "Prescription cannot be filled with current status."
                )
            return value
        except Prescription.DoesNotExist:
            raise serializers.ValidationError("Invalid prescription ID.")
    
    def validate_quantity_dispensed(self, value):
        """Validate dispensed quantity"""
        if value <= 0:
            raise serializers.ValidationError("Quantity dispensed must be greater than 0.")
        return value