From feb3b03a39c57e19a30501893e74966e4ba4e122 Mon Sep 17 00:00:00 2001
From: Abdessamad Derraz <3028866+Abdess@users.noreply.github.com>
Date: Sat, 17 Oct 2026 12:44:22 +0200
Subject: [PATCH] fix: suggest the nearest system or emulator name

---
 scripts/common.py              | 16 +++++++++++++++-
 scripts/generate_pack.py       |  7 +++----
 scripts/verify.py              |  7 +++----
 tests/test_system_selection.py | 12 ++++++++++++
 4 files changed, 33 insertions(+), 9 deletions(-)

diff --git a/scripts/common.py b/scripts/common.py
index a34c3b63..2234d7b5 100644
--- a/scripts/common.py
+++ b/scripts/common.py
@@ -350,6 +350,20 @@ def list_registered_platforms(
     return platforms
 
 
+def suggest_names(typed: list[str], available: list[str], listing_flag: str) -> str:
+    """The closest known names to what was typed, and how to see them all.
+
+    The hints showed the first ten or twenty names of the alphabet behind a
+    "..." whatever was typed: sony-playstaton listed 3do to apple-iie.
+    """
+    import difflib  # noqa: PLC0415
+
+    close = sorted({m for name in typed
+                    for m in difflib.get_close_matches(name, available, n=3, cutoff=0.6)})
+    hint = f"Did you mean: {', '.join(close)}? " if close else ""
+    return f"{hint}{listing_flag} lists all {len(available)}."
+
+
 def require_platform(name: str, platforms_dir: str = "platforms") -> None:
     """Exit with a usable message when no platform answers to a name.
 
@@ -1345,7 +1359,7 @@ def select_emulator_profiles(
             )
             raise ProfileSelectionError(
                 f"emulator '{name}' not found\n"
-                f"Available: {', '.join(available[:10])}..."
+                + suggest_names([name], available, "--list-emulators")
             )
         profile = all_profiles[name]
         kind = profile.get("type", "libretro")
diff --git a/scripts/generate_pack.py b/scripts/generate_pack.py
index aafd2c9f..a28a39c7 100644
--- a/scripts/generate_pack.py
+++ b/scripts/generate_pack.py
@@ -30,6 +30,7 @@ from pathlib import Path
 sys.path.insert(0, os.path.dirname(__file__))
 from common import resolve_platform_cores as _platform_cores
 from common import (
+    suggest_names,
     require_platform,
     apply_target_overrides,
     archive_entry,
@@ -1646,10 +1647,8 @@ def generate_system_pack(
                 f"No emulators found for system(s): {', '.join(system_ids)}",
                 file=sys.stderr,
             )
-        print(
-            f"Available systems: {', '.join(sorted(all_systems)[:20])}...",
-            file=sys.stderr,
-        )
+        print(suggest_names(system_ids, sorted(all_systems), "--list-systems"),
+              file=sys.stderr)
         return None
 
     # Named like the platform's --system tag: one spelling of a system is
diff --git a/scripts/verify.py b/scripts/verify.py
index 7ea224b2..31d283f1 100644
--- a/scripts/verify.py
+++ b/scripts/verify.py
@@ -34,6 +34,7 @@ import slots
 
 sys.path.insert(0, os.path.dirname(__file__))
 from common import (
+    suggest_names,
     require_platform,
     archive_entry,
     archive_members,
@@ -1849,10 +1850,8 @@ def verify_system(
                 f"No emulators found for system(s): {', '.join(system_ids)}",
                 file=sys.stderr,
             )
-        print(
-            f"Available systems: {', '.join(sorted(all_systems)[:20])}...",
-            file=sys.stderr,
-        )
+        print(suggest_names(system_ids, sorted(all_systems), "--list-systems"),
+              file=sys.stderr)
         sys.exit(1)
 
     return verify_emulator(
diff --git a/tests/test_system_selection.py b/tests/test_system_selection.py
index 9fc1b221..e9adfc9a 100644
--- a/tests/test_system_selection.py
+++ b/tests/test_system_selection.py
@@ -163,5 +163,17 @@ class ExclusionNotesListedOnAsk(unittest.TestCase):
         self.assertRegex(verbose, r"No external files \(\d+\):")
         self.assertLess(len(plain.splitlines()), len(verbose.splitlines()))
 
+
+class ATypoGetsTheNearestNames(unittest.TestCase):
+    """The hint listed the first names of the alphabet behind "...":
+    sony-playstaton was answered with 3do to apple-iie."""
+
+    def test_suggestions_follow_the_typed_name(self):
+        hint = common.suggest_names(["sony-playstaton"],
+                                    ["3do", "apple-ii", "sony-playstation"], "--list-systems")
+        self.assertEqual(hint, "Did you mean: sony-playstation? --list-systems lists all 3.")
+        self.assertEqual(common.suggest_names(["zzz"], ["3do"], "--list-systems"),
+                         "--list-systems lists all 1.")
+
 if __name__ == "__main__":
     unittest.main()