refactor(manager): reuse parse_model_chain for camerachain validation

Replace manual model validation in CamCreateForm.clean_camerachain()
with parse_model_chain() from ppl_generator. This aligns validation
with the existing pipeline parser and ensures future compatibility
with potential chain syntax changes.

Also includes minor indentation fixes.

Author: COZYTRICKSTER

manager/src/django/forms.py

@@ -190,34 +190,28 @@ def __init__(self, *args, **kwargs):
   def clean_camerachain(self):
     camerachain = self.cleaned_data.get('camerachain', '').strip()
     if not camerachain:
-        return camerachain
+      return camerachain
 
     from pathlib import Path
-    from manager.ppl_generator.model_chain import CameraChainOperations
-    
-    # Load model config
+    from manager.ppl_generator.model_chain import parse_model_chain
+    from manager.ppl_generator import PipelineGenerationValueError, PipelineGenerationNotImplementedError
+
     model_config_path = Path(os.environ.get('MODEL_CONFIGS_FOLDER', '/models/model_configs')) / 'model_config.json'
     if not model_config_path.is_file():
-        raise ValidationError(f"Model config file not found at {model_config_path}")
-    
+      raise ValidationError(f"Model config file not found at {model_config_path}")
+
     try:
-        with open(model_config_path, 'r') as f:
-            model_config = json.load(f)
+      with open(model_config_path, 'r') as f:
+        model_config = json.load(f)
     except (json.JSONDecodeError, IOError) as e:
-        raise ValidationError(f"Error reading model config: {str(e)}")
-    
-    # Extract model names from chain
-    chain_parts = camerachain.replace(CameraChainOperations.PARALLEL.value, CameraChainOperations.SEQUENTIAL.value)
-    model_names = [part.split('=')[0].strip() for part in chain_parts.split(CameraChainOperations.SEQUENTIAL.value) if part.strip()]
-    
-    # Validate models exist
-    missing = [m for m in model_names if m not in model_config]
-    if missing:
-        missing_str = ', '.join(f"'{m}'" for m in missing)
-        available = ', '.join(f"'{m}'" for m in sorted(model_config.keys()))
-        raise ValidationError(f"Error adding camera: Model(s) {missing_str} not found in model config file. Available models: {available}")
+      raise ValidationError(f"Error reading model config: {str(e)}")
+
+    try:
+      parse_model_chain(camerachain, settings.MODEL_ROOT, model_config)
+    except (PipelineGenerationValueError, PipelineGenerationNotImplementedError) as e:
+      raise ValidationError(str(e))
 
-    return camerachain     
+    return camerachain
 
 class ChildSceneForm(forms.ModelForm):
   class Meta: