"""
DRF Serializers for Core app.
"""

from rest_framework import serializers
from django.contrib.auth import get_user_model
from .models import Patient, Clinic, File, SubFile, Consent, Attachment, AuditLog

User = get_user_model()


class UserSerializer(serializers.ModelSerializer):
    """Serializer for User model."""
    
    full_name = serializers.CharField(source='get_full_name', read_only=True)
    role_display = serializers.CharField(source='get_role_display', read_only=True)
    
    class Meta:
        model = User
        fields = [
            'id', 'username', 'email', 'first_name', 'last_name', 'full_name',
            'role', 'role_display', 'phone', 'is_active', 'date_joined'
        ]
        read_only_fields = ['id', 'date_joined']


class PatientListSerializer(serializers.ModelSerializer):
    """Lightweight serializer for patient lists."""
    
    full_name = serializers.CharField(source='get_full_name', read_only=True)
    age = serializers.IntegerField(source='get_age', read_only=True)
    
    class Meta:
        model = Patient
        fields = [
            'id', 'mrn', 'first_name_en', 'last_name_en',
            'full_name', 'date_of_birth', 'age', 'gender',
            'phone', 'is_active'
        ]
        read_only_fields = ['id', 'mrn']


class PatientDetailSerializer(serializers.ModelSerializer):
    """Detailed serializer for patient detail views."""
    
    full_name = serializers.CharField(source='get_full_name', read_only=True)
    age = serializers.IntegerField(source='get_age', read_only=True)
    tenant_name = serializers.CharField(source='tenant.name', read_only=True)
    
    class Meta:
        model = Patient
        fields = [
            'id', 'tenant', 'tenant_name', 'mrn',
            'first_name_en', 'middle_name_en', 'last_name_en',
            'first_name_ar', 'middle_name_ar', 'last_name_ar',
            'full_name', 'date_of_birth', 'age', 'gender',
            'nationality', 'national_id', 'passport_number',
            'phone', 'email', 'address',
            'caregiver_name', 'caregiver_relationship', 'caregiver_phone',
            'emergency_contact_name', 'emergency_contact_phone',
            'is_active', 'notes',
            'created_at', 'updated_at'
        ]
        read_only_fields = ['id', 'mrn', 'created_at', 'updated_at']


class PatientCreateUpdateSerializer(serializers.ModelSerializer):
    """Serializer for creating/updating patients."""
    
    class Meta:
        model = Patient
        fields = [
            'first_name_en', 'middle_name_en', 'last_name_en',
            'first_name_ar', 'middle_name_ar', 'last_name_ar',
            'date_of_birth', 'gender', 'nationality',
            'national_id', 'passport_number',
            'phone', 'email', 'address',
            'caregiver_name', 'caregiver_relationship', 'caregiver_phone',
            'emergency_contact_name', 'emergency_contact_phone',
            'notes'
        ]
    
    def validate(self, data):
        """Validate patient data."""
        # Ensure at least one name is provided
        if not data.get('first_name_en') and not data.get('first_name_ar'):
            raise serializers.ValidationError(
                "At least one name (English or Arabic) must be provided."
            )
        return data


class ClinicSerializer(serializers.ModelSerializer):
    """Serializer for Clinic model."""
    
    specialty_display = serializers.CharField(source='get_specialty_display', read_only=True)
    
    class Meta:
        model = Clinic
        fields = [
            'id', 'name_en', 'name_ar', 'specialty', 'specialty_display',
            'description', 'is_active'
        ]
        read_only_fields = ['id']


class FileSerializer(serializers.ModelSerializer):
    """Serializer for File model."""
    
    patient_name = serializers.CharField(source='patient.get_full_name', read_only=True)
    
    class Meta:
        model = File
        fields = [
            'id', 'patient', 'patient_name', 'file_number',
            'opened_date', 'is_active', 'notes',
            'created_at', 'updated_at'
        ]
        read_only_fields = ['id', 'file_number', 'created_at', 'updated_at']


class SubFileSerializer(serializers.ModelSerializer):
    """Serializer for SubFile model."""
    
    patient_name = serializers.CharField(source='file.patient.get_full_name', read_only=True)
    clinic_name = serializers.CharField(source='clinic.name_en', read_only=True)
    
    class Meta:
        model = SubFile
        fields = [
            'id', 'file', 'patient_name', 'clinic', 'clinic_name',
            'subfile_number', 'opened_date', 'is_active',
            'created_at', 'updated_at'
        ]
        read_only_fields = ['id', 'subfile_number', 'created_at', 'updated_at']


class ConsentSerializer(serializers.ModelSerializer):
    """Serializer for Consent model."""
    
    patient_name = serializers.CharField(source='patient.get_full_name', read_only=True)
    consent_type_display = serializers.CharField(source='get_consent_type_display', read_only=True)
    signed_by_name = serializers.CharField(source='signed_by.get_full_name', read_only=True)
    
    class Meta:
        model = Consent
        fields = [
            'id', 'patient', 'patient_name', 'consent_type', 'consent_type_display',
            'consent_text', 'signature_data', 'signed_by', 'signed_by_name',
            'signed_at', 'is_valid', 'notes',
            'created_at'
        ]
        read_only_fields = ['id', 'created_at']


class AttachmentSerializer(serializers.ModelSerializer):
    """Serializer for Attachment model."""
    
    uploaded_by_name = serializers.CharField(source='uploaded_by.get_full_name', read_only=True)
    file_size_display = serializers.SerializerMethodField()
    
    class Meta:
        model = Attachment
        fields = [
            'id', 'file', 'title', 'description', 'category',
            'uploaded_by', 'uploaded_by_name', 'uploaded_at',
            'file_size_display'
        ]
        read_only_fields = ['id', 'uploaded_at']
    
    def get_file_size_display(self, obj):
        """Return human-readable file size."""
        if obj.file:
            size = obj.file.size
            for unit in ['B', 'KB', 'MB', 'GB']:
                if size < 1024.0:
                    return f"{size:.1f} {unit}"
                size /= 1024.0
        return "0 B"


class AuditLogSerializer(serializers.ModelSerializer):
    """Serializer for AuditLog model."""
    
    user_name = serializers.CharField(source='user.get_full_name', read_only=True)
    action_display = serializers.CharField(source='get_action_display', read_only=True)
    
    class Meta:
        model = AuditLog
        fields = [
            'id', 'user', 'user_name', 'action', 'action_display',
            'model_name', 'object_id', 'object_repr',
            'changes', 'ip_address', 'user_agent',
            'timestamp'
        ]
        read_only_fields = ['id', 'timestamp']