dlna_dms fixes from code review (#67796)

homeassistant/components/dlna_dms/util.py

@@ -0,0 +1,27 @@
+"""Small utility functions for the dlna_dms integration."""
+from __future__ import annotations
+
+from homeassistant.core import HomeAssistant
+from homeassistant.util import slugify
+
+from .const import CONF_SOURCE_ID, DOMAIN
+
+
+def generate_source_id(hass: HomeAssistant, name: str) -> str:
+    """Generate a unique source ID."""
+    other_entries = hass.config_entries.async_entries(DOMAIN)
+    other_source_ids: set[str] = {
+        other_source_id
+        for entry in other_entries
+        if (other_source_id := entry.data.get(CONF_SOURCE_ID))
+    }
+
+    source_id_base = slugify(name)
+    if source_id_base not in other_source_ids:
+        return source_id_base
+
+    tries = 1
+    while (suggested_source_id := f"{source_id_base}_{tries}") in other_source_ids:
+        tries += 1
+
+    return suggested_source_id