Implement SQLite support check for Chroma's trigram tokenizer, enhancing compatibility with cloud environments. Update README for model command syntax and add pysqlite3-binary to requirements for improved SQLite functionality.

main.py

@@ -8,6 +8,53 @@ from pathlib import Path
 project_root = Path(__file__).parent
 sys.path.insert(0, str(project_root))
 
+
+def _sqlite_supports_trigram(sqlite_module) -> bool:
+    conn = None
+    try:
+        conn = sqlite_module.connect(":memory:")
+        conn.execute("create virtual table t using fts5(content, tokenize='trigram')")
+        return True
+    except Exception:
+        return False
+    finally:
+        if conn is not None:
+            conn.close()
+
+
+def _ensure_sqlite_for_chroma():
+    """
+    Ensure sqlite runtime supports FTS5 trigram tokenizer for Chroma.
+    On some cloud images, system sqlite lacks trigram support.
+    """
+    try:
+        import sqlite3
+    except Exception:
+        return
+
+    if _sqlite_supports_trigram(sqlite3):
+        return
+
+    try:
+        import pysqlite3
+    except Exception as exc:
+        print(
+            "[WARN] sqlite3 does not support trigram tokenizer and pysqlite3 is unavailable: "
+            f"{exc}"
+        )
+        print("[WARN] Chroma may fail and fallback to JSON storage.")
+        return
+
+    if _sqlite_supports_trigram(pysqlite3):
+        sys.modules["sqlite3"] = pysqlite3
+        print("[INFO] sqlite3 switched to pysqlite3 for Chroma trigram support.")
+    else:
+        print("[WARN] pysqlite3 is installed but still lacks trigram tokenizer support.")
+        print("[WARN] Chroma may fail and fallback to JSON storage.")
+
+
+_ensure_sqlite_for_chroma()
+
 from src.core.bot import MyClient, build_intents
 from src.core.config import Config
 from src.utils.logger import setup_logger