Initial commit

internal/db/db.go

@@ -0,0 +1,65 @@
+package db
+
+import (
+	"database/sql"
+	_ "embed"
+	"fmt"
+
+	_ "modernc.org/sqlite"
+)
+
+//go:embed schema.sql
+var schemaSQL string
+
+func Open(path string) (*sql.DB, error) {
+	dsn := fmt.Sprintf("file:%s?_pragma=journal_mode(WAL)&_pragma=foreign_keys(ON)&_pragma=busy_timeout(5000)", path)
+	conn, err := sql.Open("sqlite", dsn)
+	if err != nil {
+		return nil, fmt.Errorf("open sqlite: %w", err)
+	}
+	if err := conn.Ping(); err != nil {
+		conn.Close()
+		return nil, fmt.Errorf("ping sqlite: %w", err)
+	}
+	if _, err := conn.Exec(schemaSQL); err != nil {
+		conn.Close()
+		return nil, fmt.Errorf("apply schema: %w", err)
+	}
+	if err := addColumnIfMissing(conn, "items", "min_price", "REAL"); err != nil {
+		conn.Close()
+		return nil, err
+	}
+	if err := addColumnIfMissing(conn, "items", "exclude_keywords", "TEXT"); err != nil {
+		conn.Close()
+		return nil, err
+	}
+	if err := addColumnIfMissing(conn, "results", "matched_query", "TEXT"); err != nil {
+		conn.Close()
+		return nil, err
+	}
+	return conn, nil
+}
+
+func addColumnIfMissing(conn *sql.DB, table, column, typ string) error {
+	rows, err := conn.Query(fmt.Sprintf(`PRAGMA table_info(%s)`, table))
+	if err != nil {
+		return fmt.Errorf("inspect %s: %w", table, err)
+	}
+	defer rows.Close()
+	for rows.Next() {
+		var cid int
+		var name, ctype string
+		var notnull, pk int
+		var dflt sql.NullString
+		if err := rows.Scan(&cid, &name, &ctype, &notnull, &dflt, &pk); err != nil {
+			return err
+		}
+		if name == column {
+			return nil
+		}
+	}
+	if _, err := conn.Exec(fmt.Sprintf(`ALTER TABLE %s ADD COLUMN %s %s`, table, column, typ)); err != nil {
+		return fmt.Errorf("add column %s.%s: %w", table, column, err)
+	}
+	return nil
+}