add: add admin panel api for user

core/apps/admin_panel/serializers/user.py

@@ -0,0 +1,40 @@
+from django.db import transaction
+
+from rest_framework import serializers
+
+from core.apps.accounts.models import User
+
+
+class UserSerializer(serializers.ModelSerializer):
+    class Meta:
+        model = User
+        fields = [
+            'id', 'first_name', 'last_name', 'username', 'password'
+        ]
+        extra_kwargs = {'id': {'read_only': True}, 'password': {'write_only': True}}
+
+    def validate_username(self, value):
+        if User.objects.filter(username=value).exists():
+            raise serializers.ValidationError("User with this username already exists")
+        return value
+    
+    def create(self, validated_data):
+        with transaction.atomic():
+            user = User.objects.create(
+                first_name=validated_data.get('first_name'),
+                last_name=validated_data.get('last_name'),
+                username=validated_data.get('username'),
+            )
+            user.set_password(validated_data.get('password'))
+            user.save()
+            return user
+        
+    def update(self, instance, validated_data):
+        with transaction.atomic():
+            instance.username = validated_data.get('username', instance.username)
+            instance.first_name = validated_data.get('first_name', instance.first_name)
+            instance.last_name = validated_data.get('last_name', instance.last_name)
+            if validated_data.get('password'):
+                instance.set_password(validated_data.get('password'))
+            instance.save()
+            return instance