from rest_framework import serializers
from django.contrib.auth import get_user_model
from .models import FolderStructure, FolderPermission, FolderBookmark, FolderActivity

User = get_user_model()


class FolderStructureSerializer(serializers.ModelSerializer):
    """Serializer for folder structures."""
    
    path = serializers.CharField(source='get_path', read_only=True)
    children = serializers.SerializerMethodField()
    email_count = serializers.SerializerMethodField()
    unread_count = serializers.SerializerMethodField()
    permissions = serializers.SerializerMethodField()
    
    class Meta:
        model = FolderStructure
        fields = '__all__'
        read_only_fields = ('user', 'created_at', 'updated_at')
    
    def get_children(self, obj):
        children = obj.get_children()
        return FolderStructureSerializer(children, many=True, context=self.context).data
    
    def get_email_count(self, obj):
        # This would need to be implemented based on your email folder relationship
        return 0
    
    def get_unread_count(self, obj):
        # This would need to be implemented based on your email folder relationship
        return 0
    
    def get_permissions(self, obj):
        if obj.is_shared:
            permissions = obj.permissions.all()
            return FolderPermissionSerializer(permissions, many=True).data
        return []


class FolderPermissionSerializer(serializers.ModelSerializer):
    """Serializer for folder permissions."""
    
    user_name = serializers.CharField(source='user.get_full_name', read_only=True)
    user_email = serializers.CharField(source='user.email', read_only=True)
    granted_by_name = serializers.CharField(source='granted_by.get_full_name', read_only=True)
    
    class Meta:
        model = FolderPermission
        fields = '__all__'
        read_only_fields = ('granted_by', 'granted_at')


class FolderBookmarkSerializer(serializers.ModelSerializer):
    """Serializer for folder bookmarks."""
    
    folder_name = serializers.CharField(source='folder.name', read_only=True)
    folder_path = serializers.CharField(source='folder.get_path', read_only=True)
    
    class Meta:
        model = FolderBookmark
        fields = '__all__'
        read_only_fields = ('user', 'created_at')


class FolderActivitySerializer(serializers.ModelSerializer):
    """Serializer for folder activities."""
    
    user_name = serializers.CharField(source='user.get_full_name', read_only=True)
    user_email = serializers.CharField(source='user.email', read_only=True)
    folder_name = serializers.CharField(source='folder.name', read_only=True)
    
    class Meta:
        model = FolderActivity
        fields = '__all__'
        read_only_fields = ('created_at',)


class FolderCreateSerializer(serializers.ModelSerializer):
    """Serializer for creating folders."""
    
    class Meta:
        model = FolderStructure
        fields = ('name', 'description', 'parent', 'folder_type', 'color', 'icon', 'sort_order')
    
    def validate_name(self, value):
        user = self.context['request'].user
        parent = self.initial_data.get('parent')
        
        # Check for duplicate names in the same parent folder
        if FolderStructure.objects.filter(
            user=user, 
            name=value, 
            parent_id=parent
        ).exists():
            raise serializers.ValidationError("A folder with this name already exists in the same location.")
        
        return value


class FolderShareSerializer(serializers.Serializer):
    """Serializer for sharing folders."""
    
    user_email = serializers.EmailField()
    permission = serializers.ChoiceField(choices=FolderPermission.PERMISSION_CHOICES)
    
    def validate_user_email(self, value):
        user = self.context['request'].user
        if value == user.email:
            raise serializers.ValidationError("You cannot share a folder with yourself.")
        
        try:
            User.objects.get(email=value)
        except User.DoesNotExist:
            raise serializers.ValidationError("User with this email does not exist.")
        
        return value


class FolderMoveSerializer(serializers.Serializer):
    """Serializer for moving folders."""
    
    new_parent = serializers.IntegerField(required=False, allow_null=True)
    new_sort_order = serializers.IntegerField(required=False)
    
    def validate_new_parent(self, value):
        if value is not None:
            user = self.context['request'].user
            try:
                folder = FolderStructure.objects.get(id=value, user=user)
                return folder
            except FolderStructure.DoesNotExist:
                raise serializers.ValidationError("Parent folder does not exist or you don't have access to it.")
        return None