QoL and metric value inverter

src/physcom/db/schema.py

@@ -44,12 +44,13 @@ CREATE TABLE IF NOT EXISTS metrics (
 );
 
 CREATE TABLE IF NOT EXISTS domain_metric_weights (
-    id        INTEGER PRIMARY KEY AUTOINCREMENT,
-    domain_id INTEGER NOT NULL REFERENCES domains(id),
-    metric_id INTEGER NOT NULL REFERENCES metrics(id),
-    weight    REAL NOT NULL,
-    norm_min  REAL,
-    norm_max  REAL,
+    id              INTEGER PRIMARY KEY AUTOINCREMENT,
+    domain_id       INTEGER NOT NULL REFERENCES domains(id),
+    metric_id       INTEGER NOT NULL REFERENCES metrics(id),
+    weight          REAL NOT NULL,
+    norm_min        REAL,
+    norm_max        REAL,
+    lower_is_better INTEGER NOT NULL DEFAULT 0,
     UNIQUE(domain_id, metric_id)
 );
 
@@ -117,6 +118,23 @@ CREATE INDEX IF NOT EXISTS idx_pipeline_runs_domain ON pipeline_runs(domain_id);
 """
 
 
+def _migrate(conn: sqlite3.Connection) -> None:
+    """Apply incremental migrations for existing databases."""
+    cols = {r[1] for r in conn.execute("PRAGMA table_info(domain_metric_weights)").fetchall()}
+    if "lower_is_better" not in cols:
+        conn.execute(
+            "ALTER TABLE domain_metric_weights ADD COLUMN lower_is_better INTEGER NOT NULL DEFAULT 0"
+        )
+
+    # Backfill: cost_efficiency is lower-is-better in all domains
+    conn.execute(
+        """UPDATE domain_metric_weights SET lower_is_better = 1
+           WHERE lower_is_better = 0
+             AND metric_id IN (SELECT id FROM metrics WHERE name = 'cost_efficiency')"""
+    )
+    conn.commit()
+
+
 def init_db(db_path: str | Path) -> sqlite3.Connection:
     """Create/open the database and ensure all tables exist."""
     db_path = Path(db_path)
@@ -125,5 +143,6 @@ def init_db(db_path: str | Path) -> sqlite3.Connection:
     conn.execute("PRAGMA journal_mode=WAL")
     conn.execute("PRAGMA foreign_keys=ON")
     conn.executescript(DDL)
+    _migrate(conn)
     conn.commit()
     return conn