Enhance Samsung monitor detection logic and add unit tests for trigger candidate selection

app/hardware.py

@@ -4,6 +4,7 @@ from dataclasses import dataclass, field
 from typing import Protocol
 
 from monitorcontrol import get_monitors
+from app.config import SUPPORTED_TARGET_PORTS
 
 
 ALIENWARE_MODEL_TOKEN = "AW3423DWF"
@@ -86,7 +87,22 @@ class RealMonitorBackend:
         elif not trigger_candidates:
             errors.append("Samsung trigger monitor could not be identified through DDC/CI.")
         else:
-            if samsung_named_candidates:
+            scanned_candidates: list[tuple[object, str, int | None]] = []
+            for monitor, description in trigger_candidates:
+                local_errors: list[str] = []
+                input_code = self._read_input_code(
+                    monitor,
+                    "Samsung trigger candidate monitor",
+                    local_errors,
+                )
+                scanned_candidates.append((monitor, description, input_code))
+
+            selected_index = _select_trigger_candidate_index(
+                [(description, input_code) for _, description, input_code in scanned_candidates]
+            )
+            if selected_index is not None:
+                _, trigger_description, trigger_input_code = scanned_candidates[selected_index]
+            elif samsung_named_candidates:
                 errors.append("Multiple Samsung DDC monitors were detected; trigger monitor is ambiguous.")
             else:
                 errors.append(
@@ -172,3 +188,41 @@ def _is_samsung_description(description: str) -> bool:
     if normalized.startswith("SAM"):
         return True
     return " SAM " in f" {normalized} "
+
+
+def _is_generic_description(description: str) -> bool:
+    normalized = description.upper().strip()
+    return "GENERIC" in normalized or "UNKNOWN" in normalized
+
+
+def _trigger_input_codes() -> set[int]:
+    codes: set[int] = set()
+    for port_spec in SUPPORTED_TARGET_PORTS.values():
+        input_codes = port_spec.get("input_codes", set())
+        codes.update(int(code) for code in input_codes)
+    return codes
+
+
+def _select_trigger_candidate_index(candidates: list[tuple[str, int | None]]) -> int | None:
+    if not candidates:
+        return None
+
+    trigger_codes = _trigger_input_codes()
+    matching = [
+        index
+        for index, (_, input_code) in enumerate(candidates)
+        if input_code is not None and int(input_code) in trigger_codes
+    ]
+    if len(matching) == 1:
+        return matching[0]
+
+    if len(matching) > 1:
+        generic_matches = [index for index in matching if _is_generic_description(candidates[index][0])]
+        if len(generic_matches) == 1:
+            return generic_matches[0]
+
+    generic = [index for index, (description, _) in enumerate(candidates) if _is_generic_description(description)]
+    if len(generic) == 1:
+        return generic[0]
+
+    return None