chore: sync from fn-registry agent

db.go

@@ -0,0 +1,77 @@
+package main
+
+import (
+	"database/sql"
+	"embed"
+	"fmt"
+
+	"fn-registry/functions/infra"
+)
+
+//go:embed migrations/*.sql
+var migrationsFS embed.FS
+
+type DB struct{ conn *sql.DB }
+
+func openDB(path string) (*DB, error) {
+	conn, err := infra.SQLiteOpen(path, "")
+	if err != nil {
+		return nil, err
+	}
+	if err := infra.ApplyMigrations(conn, migrationsFS, "migrations/*.sql"); err != nil {
+		conn.Close()
+		return nil, fmt.Errorf("migrate: %w", err)
+	}
+	return &DB{conn: conn}, nil
+}
+
+func (d *DB) Close() error { return d.conn.Close() }
+
+type tableCount struct {
+	Name string
+	Rows int64
+}
+
+func (d *DB) tableCounts() ([]tableCount, error) {
+	tables := []string{"sessions", "calls", "code_writes", "test_runs", "e2e_runs_fn", "violations", "patterns", "function_versions", "copied_code"}
+	out := make([]tableCount, 0, len(tables))
+	for _, t := range tables {
+		var n int64
+		if err := d.conn.QueryRow("SELECT COUNT(*) FROM " + t).Scan(&n); err != nil {
+			return nil, fmt.Errorf("count %s: %w", t, err)
+		}
+		out = append(out, tableCount{Name: t, Rows: n})
+	}
+	return out, nil
+}
+
+type funcStat struct {
+	FunctionID      string
+	CallsTotal      int64
+	Calls7d         int64
+	ErrorsTotal     int64
+	ErrorRate       float64
+	MeanDurationMs  float64
+	LastUsedAt      sql.NullInt64
+}
+
+func (d *DB) topFunctions(limit int) ([]funcStat, error) {
+	rows, err := d.conn.Query(`
+		SELECT function_id, calls_total, calls_7d, errors_total, error_rate, mean_duration_ms, last_used_at
+		FROM function_stats
+		ORDER BY calls_total DESC
+		LIMIT ?`, limit)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+	var out []funcStat
+	for rows.Next() {
+		var s funcStat
+		if err := rows.Scan(&s.FunctionID, &s.CallsTotal, &s.Calls7d, &s.ErrorsTotal, &s.ErrorRate, &s.MeanDurationMs, &s.LastUsedAt); err != nil {
+			return nil, err
+		}
+		out = append(out, s)
+	}
+	return out, rows.Err()
+}