Add solver settings display and configuration options to rota detail view

djangorota/rota/forms.py

@@ -415,6 +415,35 @@ class RotaScheduleForm(forms.ModelForm):
             else:
                 self.fields[field_name] = forms.CharField(required=False, initial=initial, label=k.replace("_", " "), help_text=meta.get("help"))
 
+        # Expose solver selection and solver options (JSON) so users can tune
+        # solver behaviour per-rota. Persisted into `RotaSchedule.options` as
+        # keys `solver` (string) and `solver_options` (dict).
+        solver_initial = existing_opts.get("solver", "appsi_highs")
+        solver_opts_initial = existing_opts.get("solver_options", {})
+        try:
+            solver_opts_str = json.dumps(solver_opts_initial, indent=2)
+        except Exception:
+            solver_opts_str = ""
+
+        self.fields["solver"] = forms.CharField(required=False, initial=solver_initial, label="Solver", help_text="Solver plugin name to use (e.g. appsi_highs, scip, gurobi)")
+        # Common solver ratio is surfaced as a dedicated field for convenience
+        # (many workflows tune this). It's stored inside the solver_options
+        # dict under the key 'ratio'. The free-form JSON textarea remains for
+        # advanced options.
+        solver_ratio_initial = None
+        try:
+            if isinstance(solver_opts_initial, dict) and "ratio" in solver_opts_initial:
+                solver_ratio_initial = solver_opts_initial.get("ratio")
+            else:
+                # also accept legacy top-level 'ratio' key in existing_opts
+                solver_ratio_initial = existing_opts.get("ratio")
+        except Exception:
+            solver_ratio_initial = None
+
+        self.fields["solver"] = forms.CharField(required=False, initial=solver_initial, label="Solver", help_text="Solver plugin name to use (e.g. appsi_highs, scip, gurobi)")
+        self.fields["solver_ratio"] = forms.FloatField(required=False, initial=solver_ratio_initial, label="Solver ratio (relative gap)", help_text="Relative MIP gap / ratio (e.g. 0.01 for 1%)")
+        self.fields["solver_options"] = forms.CharField(required=False, widget=forms.Textarea(attrs={"rows": 6}), initial=solver_opts_str, label="Solver options (JSON)", help_text="JSON object of solver-specific options; e.g. {\"seconds\": 60, \"threads\": 4}")
+
     def clean_start_date(self):
         start = self.cleaned_data.get("start_date")
         if start is None:
@@ -506,6 +535,49 @@ class RotaScheduleForm(forms.ModelForm):
         except Exception:
             pass
 
+        # Persist solver selection and options (if provided). Solver options are
+        # stored as a dict under opts['solver_options']. If the user supplied
+        # a JSON string, attempt to parse it; otherwise keep raw value.
+        try:
+            solver_name = self.cleaned_data.get("solver")
+            if solver_name:
+                opts["solver"] = solver_name
+        except Exception:
+            pass
+
+        try:
+            so = self.cleaned_data.get("solver_options")
+            if so is not None and so != "":
+                if isinstance(so, str):
+                    try:
+                        parsed = json.loads(so)
+                    except Exception:
+                        # keep as raw string if parsing fails (non-fatal)
+                        parsed = so
+                else:
+                    parsed = so
+                opts["solver_options"] = parsed
+        except Exception:
+            pass
+
+        # If a dedicated solver_ratio field was provided, inject/override it
+        # into the solver_options dict so it is honoured at runtime. This
+        # ensures the friendly ratio field wins over any value in the JSON
+        # textarea.
+        try:
+            ratio_val = self.cleaned_data.get("solver_ratio")
+            if ratio_val is not None and ratio_val != "":
+                so = opts.get("solver_options")
+                if so is None or not isinstance(so, dict):
+                    so = {}
+                try:
+                    so["ratio"] = float(ratio_val)
+                except Exception:
+                    so["ratio"] = ratio_val
+                opts["solver_options"] = so
+        except Exception:
+            pass
+
         instance.options = opts
 
         if commit: