Add lexical and service-intent indexes

app/intents.py

@@ -0,0 +1,54 @@
+from __future__ import annotations
+
+from app.normalization import normalize_text, tokenize
+from app.typo import word_similarity
+
+SERVICE_INTENTS = {
+    "opening_hours": [
+        ("до", "скольки", "работаете"),
+        ("режим", "работы"),
+        ("график", "работы"),
+    ],
+    "payment": [
+        ("оплата", "картой"),
+        ("оплатить", "картой"),
+        ("наличными", "при", "получении"),
+    ],
+    "location": [
+        ("где", "магазин"),
+        ("адрес", "магазина"),
+        ("как", "доехать"),
+    ],
+    "order_status": [
+        ("статус", "заказа"),
+        ("где", "мой", "заказ"),
+    ],
+    "thanks": [
+        ("спасибо", "заказ", "получил"),
+        ("все", "отлично"),
+    ],
+}
+
+
+def _token_present(expected: str, tokens: tuple[str, ...]) -> bool:
+    for token in tokens:
+        if token == expected:
+            return True
+        if min(len(token), len(expected)) >= 5 and word_similarity(token, expected) >= 0.72:
+            return True
+    return False
+
+
+def detect_service_intent(text: str) -> str | None:
+    """Detect a known non-product intent after product evidence has failed.
+
+    This is deliberately phrase/token based rather than a blacklist of words
+    such as ``подскажите``: those words are valid in product requests too.
+    """
+
+    tokens = tokenize(normalize_text(text), already_normalized=True)
+    for intent, phrases in SERVICE_INTENTS.items():
+        for phrase in phrases:
+            if all(_token_present(expected, tokens) for expected in phrase):
+                return intent
+    return None