From 39d072d0ca91313397c6509d703cf18355c09efb Mon Sep 17 00:00:00 2001
From: "Sigma Dimensions (Yass)" <79010126+myoualid@users.noreply.github.com>
Date: Wed, 23 Aug 2023 21:19:16 +0100
Subject: [PATCH] Calculates the number of resources based on required
 person-hours.

---
 .../api/resource/calculate_resource_usage.py  | 71 +++++++++++++++++++
 .../ifcopenshell/util/resource.py             |  6 ++
 2 files changed, 77 insertions(+)
 create mode 100644 src/ifcopenshell-python/ifcopenshell/api/resource/calculate_resource_usage.py

diff --git a/src/ifcopenshell-python/ifcopenshell/api/resource/calculate_resource_usage.py b/src/ifcopenshell-python/ifcopenshell/api/resource/calculate_resource_usage.py
new file mode 100644
index 0000000000..1137b23cf3
--- /dev/null
+++ b/src/ifcopenshell-python/ifcopenshell/api/resource/calculate_resource_usage.py
@@ -0,0 +1,71 @@
+# IfcOpenShell - IFC toolkit and geometry engine
+# Copyright (C) 2021 Dion Moult <dion@thinkmoult.com>
+#
+# This file is part of IfcOpenShell.
+#
+# IfcOpenShell is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Lesser General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# IfcOpenShell is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with IfcOpenShell.  If not, see <http://www.gnu.org/licenses/>.
+
+import math
+import ifcopenshell.api
+import ifcopenshell.util.date
+import ifcopenshell.util.element
+import ifcopenshell.util.resource
+
+
+class Usecase:
+    def __init__(self, file, resource=None):
+        """Calculates the number of resources required to perform scheduled work on a task.
+        """
+        self.file = file
+        self.settings = {"resource": resource}
+
+    def execute(self):
+        metrics = ifcopenshell.util.constraint.has_metric_constraints(
+            self.settings["resource"], "Usage.ScheduleUsage"
+        )
+        if (
+            metrics
+            and metrics[0].ConstraintGrade == "HARD"
+            and metrics[0].Benchmark == "EQUALTO"
+        ):
+            return
+        if (
+            not self.settings["resource"].Usage
+            or not self.settings["resource"].Usage.ScheduleWork
+        ):
+            return
+
+        task = ifcopenshell.util.resource.get_task_assignments(
+            self.settings["resource"]
+        )
+        if not task or not task.TaskTime:
+            return
+
+        if not task.TaskTime.DurationType or task.TaskTime.DurationType == "WORKTIME":
+            hours_per_day = 8
+        else:
+            hours_per_day = 24
+
+        task_duration = ifcopenshell.util.date.ifc2datetime(
+            task.TaskTime.ScheduleDuration
+        )
+        seconds = task_duration.days * hours_per_day * 60 * 60
+        seconds += task_duration.seconds
+
+        person_hours = ifcopenshell.util.date.ifc2datetime(
+            self.settings["resource"].Usage.ScheduleWork
+        )
+
+        required_resources = person_hours.total_seconds() / seconds
+        self.settings["resource"].Usage.ScheduleUsage = float(required_resources)
diff --git a/src/ifcopenshell-python/ifcopenshell/util/resource.py b/src/ifcopenshell-python/ifcopenshell/util/resource.py
index 477a4e2af6..f4ce388dc5 100644
--- a/src/ifcopenshell-python/ifcopenshell/util/resource.py
+++ b/src/ifcopenshell-python/ifcopenshell/util/resource.py
@@ -84,6 +84,12 @@ def get_parametric_resource_products(resource):
             products.append(rel2.RelatingProduct)
     return products
 
+def get_task_assignments(resource):
+    for rel in resource.HasAssignments or []:
+        if not rel.is_a("IfcRelAssignsToProcess"):
+            continue
+        return rel.RelatingProcess
+
 
 def get_resource_required_work(resource):
     productivity = get_productivity(resource)