Implement adding, editing, and removing time lags to sequence relationships

src/ifcopenshell-python/ifcopenshell/api/sequence/assign_lag_time.py

@@ -1,20 +1,23 @@
 class Usecase:
     def __init__(self, file, **settings):
         self.file = file
-        self.settings = {"rel_sequence": None, "lag_value": None, "duration_type": "NOTEDEFINED"}
+        self.settings = {"rel_sequence": None, "lag_value": None, "duration_type": "NOTDEFINED"}
         for key, value in settings.items():
             self.settings[key] = value
 
     def execute(self):
         lag_value = self.file.createIfcDuration(self.settings["lag_value"])
-        lag_time = self.file.create_entity("IfcLagTime",
+        lag_time = self.file.create_entity(
+            "IfcLagTime",
             **{
-            "DurationType": self.settings["duration_type"],
-            "LagValue": lag_value,
+                "DurationType": self.settings["duration_type"],
+                "LagValue": lag_value,
             }
         )
-        #Can an IfcLagTime entity be used by multiple sequence relationships?
         if self.settings["rel_sequence"].is_a("IfcRelSequence"):
-            if len(self.file.get_inverse(self.settings["rel_sequence"].TimeLag)) == 1:
+            if (
+                self.settings["rel_sequence"].TimeLag
+                and len(self.file.get_inverse(self.settings["rel_sequence"].TimeLag)) == 1
+            ):
                 self.file.remove(self.settings["rel_sequence"].TimeLag)
         self.settings["rel_sequence"].TimeLag = lag_time

src/ifcopenshell-python/ifcopenshell/api/sequence/data.py

@@ -11,6 +11,7 @@ class Data:
     time_periods = {}
     tasks = {}
     task_times = {}
+    lag_times = {}
     sequences = {}
 
     @classmethod
@@ -24,6 +25,7 @@ class Data:
         cls.time_periods = {}
         cls.tasks = {}
         cls.task_times = {}
+        cls.lag_times = {}
         cls.sequences = {}
 
     @classmethod
@@ -39,6 +41,7 @@ class Data:
         cls.load_time_periods()
         cls.load_tasks()
         cls.load_task_times()
+        cls.load_lag_times()
         cls.load_sequences()
         cls.is_loaded = True
 
@@ -158,6 +161,18 @@ class Data:
                     data[key] = ifcopenshell.util.date.ifc2datetime(value)
             cls.task_times[task_time.id()] = data
 
+    @classmethod
+    def load_lag_times(cls):
+        cls.lag_times = {}
+        for lag_time in cls._file.by_type("IfcLagTime"):
+            data = lag_time.get_info()
+            if data["LagValue"]:
+                if data["LagValue"].is_a("IfcDuration"):
+                    data["LagValue"] = ifcopenshell.util.date.ifc2datetime(data["LagValue"].wrappedValue)
+                else:
+                    data["LagValue"] = float(data["LagValue"].wrappedValue)
+            cls.lag_times[lag_time.id()] = data
+
     @classmethod
     def load_sequences(cls):
         cls.sequences = {}

src/ifcopenshell-python/ifcopenshell/api/sequence/edit_lag_time.py

@@ -1,13 +1,18 @@
+import ifcopenshell.util.date
+
+
 class Usecase:
     def __init__(self, file, **settings):
         self.file = file
-        self.settings = {"rel_sequence": None, "attributes": {}}
+        self.settings = {"lag_time": None, "attributes": {}}
         for key, value in settings.items():
             self.settings[key] = value
 
     def execute(self):
         for name, value in self.settings["attributes"].items():
             if name == "LagValue" and value is not None:
-                # TODO: support RatioMeasure
-                value = self.file.createIfcDuration(value)
-            setattr(self.settings["rel_sequence"], name, value)
+                if isinstance(value, float):
+                    value = self.file.createIfcRatioMeasure(value)
+                else:
+                    value = self.file.createIfcDuration(ifcopenshell.util.date.datetime2ifc(value, "IfcDuration"))
+            setattr(self.settings["lag_time"], name, value)

src/ifcopenshell-python/ifcopenshell/api/sequence/unassign_lag_time.py

@@ -8,6 +8,6 @@ class Usecase:
             self.settings[key] = value
 
     def execute(self):
-        if self.settings["rel_sequence"].TimeLag.LagValue:
-            self.file.remove(self.settings["rel_sequence"].TimeLag.LagValue)
-        self.file.remove(self.settings["rel_sequence"].TimeLag)
+        if len(self.file.get_inverse(self.settings["rel_sequence"].TimeLag)) == 1:
+            return self.file.remove(self.settings["rel_sequence"].TimeLag)
+        self.settings["rel_sequence"].TimeLag = None