add web service

internal/storage/storage.go

@@ -0,0 +1,52 @@
+package storage
+
+import (
+	"context"
+	"database/sql"
+	"fmt"
+
+	_ "modernc.org/sqlite"
+)
+
+type Storage struct {
+	db *sql.DB
+}
+
+func Open(path string) (*Storage, error) {
+	db, err := sql.Open("sqlite", path+"?_pragma=journal_mode(wal)&_pragma=busy_timeout(5000)")
+	if err != nil {
+		return nil, fmt.Errorf("open sqlite: %w", err)
+	}
+
+	if err := db.Ping(); err != nil {
+		db.Close()
+		return nil, fmt.Errorf("ping sqlite: %w", err)
+	}
+
+	s := &Storage{db: db}
+	if err := s.migrate(context.Background()); err != nil {
+		db.Close()
+		return nil, fmt.Errorf("migrate: %w", err)
+	}
+
+	return s, nil
+}
+
+func (s *Storage) Close() error {
+	return s.db.Close()
+}
+
+func (s *Storage) migrate(ctx context.Context) error {
+	const ddl = `
+		CREATE TABLE IF NOT EXISTS show_history (
+			id        INTEGER PRIMARY KEY AUTOINCREMENT,
+			memo_name TEXT    NOT NULL,
+			shown_at  INTEGER NOT NULL,
+			tier      INTEGER NOT NULL DEFAULT 0
+		);
+		CREATE INDEX IF NOT EXISTS idx_show_history_memo ON show_history(memo_name);
+		CREATE INDEX IF NOT EXISTS idx_show_history_shown_at ON show_history(shown_at);
+	`
+	_, err := s.db.ExecContext(ctx, ddl)
+	return err
+}