Fix: auto-detect Things DB container dir instead of hardcoding suffix (#1)

The ThingsData-XXXXX directory suffix under the group container is
randomized per Things install, so the hardcoded ThingsData-C1ON7 path
fails on every other machine with 'Cannot open database because the
directory does not exist'.

Resolve the DB path at runtime: honor a THINGS_DB_PATH override, else
scan the group container for the live ThingsData-* dir, else fall back
to the legacy hardcoded path so error messages stay informative.

Author: kaufmanhenry

src/lib/constants.js

@@ -2,11 +2,37 @@
 
 const path = require('path');
 const os = require('os');
+const fs = require('fs');
 
-const DB_PATH = path.join(
+const GROUP_CONTAINER = path.join(
   os.homedir(),
-  'Library/Group Containers/JLMPQHK86H.com.culturedcode.ThingsMac/ThingsData-C1ON7/Things Database.thingsdatabase/main.sqlite'
+  'Library/Group Containers/JLMPQHK86H.com.culturedcode.ThingsMac'
 );
+const DB_LEAF = 'Things Database.thingsdatabase/main.sqlite';
+
+// The `ThingsData-XXXXX` directory suffix is randomized per Things install, so
+// it cannot be hardcoded. Resolution order:
+//   1. THINGS_DB_PATH env var (explicit override)
+//   2. Auto-detect the live DB under the group container (skipping Backups)
+//   3. Fall back to the original hardcoded path (so errors stay informative)
+function resolveDbPath() {
+  if (process.env.THINGS_DB_PATH) return process.env.THINGS_DB_PATH;
+
+  try {
+    const candidates = fs
+      .readdirSync(GROUP_CONTAINER)
+      .filter((name) => name.startsWith('ThingsData-'))
+      .map((name) => path.join(GROUP_CONTAINER, name, DB_LEAF))
+      .filter((p) => fs.existsSync(p));
+    if (candidates.length) return candidates[0];
+  } catch {
+    // Group container missing — fall through to the legacy default.
+  }
+
+  return path.join(GROUP_CONTAINER, 'ThingsData-C1ON7', DB_LEAF);
+}
+
+const DB_PATH = resolveDbPath();
 
 const TYPE = { TASK: 0, PROJECT: 1, HEADING: 2 };
 const STATUS = { OPEN: 0, CANCELED: 2, COMPLETED: 3 };