Use more complex logic for layer/group ordering (#88)

Create a simplified, one-level deep, representation of the QGIS project structure and then use this to determine the desired
ordering of the Felt project. Always specify ordering keys for layers and groups.

felt/core/api_client.py

@@ -10,6 +10,7 @@
     Union,
     Tuple
 )
+from dataclasses import dataclass
 
 from qgis.PyQt.QtCore import (
     QUrl,
@@ -38,6 +39,16 @@
 PLUGIN_VERSION = "0.7.0"
 
 
+@dataclass
+class CreatedGroupDetails:
+    """
+    Encapsulates details of a created layer group
+    """
+    group_id: Optional[str] = None
+    name: Optional[str] = None
+    ordering_key: Optional[int] = None
+
+
 class FeltApiClient:
     """
     Client for the Felt API
@@ -472,8 +483,9 @@ def update_layer_details(self,
 
     def create_layer_groups(self,
                             map_id: str,
-                            layer_group_names: List[str]) \
-            -> QgsNetworkReplyContent:
+                            layer_group_names: List[str],
+                            ordering_keys: Optional[Dict[str, int]] = None) \
+            -> List[CreatedGroupDetails]:
         """
         Creates layer groups for a map
         """
@@ -483,9 +495,49 @@ def create_layer_groups(self,
             version=2
         )
 
+        if not ordering_keys:
+            group_post_data = [
+                {'name': g,
+                 'ordering_key': i} for i, g in enumerate(layer_group_names)
+            ]
+        else:
+            group_post_data = [
+                {'name': g,
+                 'ordering_key': ordering_keys[g] or 0} for g in
+                layer_group_names
+            ]
+
+        reply = QgsNetworkAccessManager.instance().blockingPost(
+            request,
+            json.dumps(group_post_data).encode()
+        )
+
+        return [
+            CreatedGroupDetails(
+                group_id=group['id'],
+                name=group['name'],
+                ordering_key=ordering_keys.get(group['name']))
+            for group in json.loads(reply.content().data().decode())
+        ]
+
+    def apply_layer_groups_updates(self,
+                                   map_id: str,
+                                   group_details: List[CreatedGroupDetails]) \
+            -> QgsNetworkReplyContent:
+        """
+        Updates layer group details
+        """
+        request = self._build_request(
+            self.LAYER_GROUPS_ENDPOINT.format(map_id),
+            {'Content-Type': 'application/json'},
+            version=2
+        )
+
         group_post_data = [
-            {'name': g,
-             'ordering_key': i} for i, g in enumerate(layer_group_names)
+            {'id': g.group_id,
+             'name': g.name,
+             'ordering_key': g.ordering_key} for g in
+            group_details
         ]
 
         return QgsNetworkAccessManager.instance().blockingPost(

felt/core/layer_exporter.py

@@ -87,6 +87,18 @@ class ZippedExportResult:
     qgis_style_xml: str
     style: Optional[LayerStyle] = None
     group_name: Optional[str] = None
+    ordering_key: Optional[int] = None
+
+
+@dataclass
+class ImportByUrlResult:
+    """
+    Results of an import by URL operation
+    """
+    layer_id: Optional[str] = None
+    error_message: Optional[str] = None
+    group_name: Optional[str] = None
+    ordering_key: Optional[int] = None
 
 
 class LayerExporter(QObject):
@@ -178,7 +190,8 @@ def layer_import_url(layer: QgsMapLayer) -> Optional[str]:
 
     @staticmethod
     def import_from_url(layer: QgsMapLayer, target_map: Map,
-                        feedback: Optional[QgsFeedback] = None) -> Dict:
+                        feedback: Optional[QgsFeedback] = None) \
+            -> ImportByUrlResult:
         """
         Imports a layer from URI to the given map
         """
@@ -191,7 +204,16 @@ def import_from_url(layer: QgsMapLayer, target_map: Map,
             blocking=True,
             feedback=feedback
         )
-        return json.loads(reply.content().data().decode())
+        response = json.loads(reply.content().data().decode())
+
+        res = ImportByUrlResult()
+
+        if 'errors' in response:
+            res.error_message = response['errors'][0]['detail']
+            return res
+
+        res.layer_id = response['layer_id']
+        return res
 
     @staticmethod
     def merge_dicts(tgt: Dict, enhancer: Dict) -> Dict: