random select recursive solution for bundle constraints

app/helpers/solver_helper.py

@@ -56,6 +56,22 @@ def build_constraints(solver_run: SolverRun, problem: LpProblem, items: list[Ite
     logging.error(error)
     raise ItemGenerationError("Bundle min and/or max larger than bundle amount provided", error.args[0])
 
+def get_random_bundles(total_form_items: int, total_bundles: int, bundles: list[Bundle], found_bundles = False) -> list[Bundle]:
+  selected_bundles = None
+  total_bundle_items = 0
+
+  while found_bundles == False:
+    selected_bundles = sample(bundles, total_bundles)
+    total_bundle_items = sum(bundle.count for bundle in selected_bundles)
+
+    if total_bundle_items <= total_form_items:
+      found_bundles = True
+
+  if found_bundles == True:
+    return selected_bundles
+  else:
+    return get_random_bundles(total_form_items, total_bundles - 1, bundles)
+
 def valid_bundle_combinations(total_form_items: int, total_bundles: int, min_bundles: int, bundles: list[Bundle], selected_bundle_combinations: list[list[Bundle]] = []) -> list[list[Bundle]]:
   if total_bundles < min_bundles:
     return selected_bundle_combinations

app/services/loft_service.py

@@ -74,33 +74,36 @@ class LoftService(Base):
         response_id=random.randint(100, 5000),
         forms=[]
       )
-      
+
       # initiate problem
       problem = None
       count = 0
+
       if bundle_constraint:
-        # generate valid bundle combinations
-        bundle_combinations = solver_helper.valid_bundle_combinations(
-                                self.solver_run.total_form_items, 
-                                int(bundle_constraint.maximum), 
-                                int(bundle_constraint.minimum),
-                                self.solver_run.bundles)
+        # # generate valid bundle combinations
+        # bundle_combinations = solver_helper.valid_bundle_combinations(
+        #                         self.solver_run.total_form_items,
+        #                         int(bundle_constraint.maximum),
+        #                         int(bundle_constraint.minimum),
+        #                         self.solver_run.bundles)
 
-        # scramble bundle_combinations to ensure distinctiveness for each form generated
-        random.shuffle(bundle_combinations)
+        # # scramble bundle_combinations to ensure distinctiveness for each form generated
+        # random.shuffle(bundle_combinations)
 
-        for bundles in bundle_combinations:
-          problem = self.solve_problem(items, bundles)
-          
-          # if optimal solution found, break loop
-          if LpStatus[problem.status] == 'Optimal':
-            break
+        # for bundles in bundle_combinations:
+        #   problem = self.solve(items, bundles)
+
+        #   # if optimal solution found, break loop
+        #   if LpStatus[problem.status] == 'Optimal':
+        #     break
+        bundles_amount = random.randint(int(bundle_constraint.minimum), int(bundle_constraint.maximum))
+        problem = self.recursive_solve(items, bundles_amount)
       else: # no bundles
-        problem = self.solve_problem(items)
-      
+        problem = self.solve(items)
+
       # successfull form, increment and exit out of loop
       f += 1
-            
+
       # add return items and create as a form
       form_items = service_helper.solution_items(problem.variables(), self.solver_run)
 
@@ -108,8 +111,22 @@ class LoftService(Base):
       solution.forms.append(Form.create(form_items, self.solver_run, LpStatus[problem.status]))
 
       return solution
-  
-  def solve_problem(self, items: list[Item], bundles: list[Bundle] or None = None) -> LpProblem:
+
+  def recursive_solve(self, items, bundles_amount, attempts = 1000) -> LpProblem:
+    selected_bundles = solver_helper.get_random_bundles(
+                                        self.solver_run.total_form_items,
+                                        bundles_amount,
+                                        self.solver_run.bundles)
+
+    problem = self.solve(items, selected_bundles)
+
+    # if optimal solution found, break loop
+    if LpStatus[problem.status] == 'Optimal' or attempts == 0:
+      return problem
+    else:
+      return self.recursive_solve(items, max, attempts - 1)
+
+  def solve(self, items: list[Item], bundles: list[Bundle] or None = None) -> LpProblem:
     # create problem
     problem = LpProblem("ata-form-generate", LpMinimize)