1 files changed, 34 insertions, 0 deletions
diff --git a/internal/store/store.go b/internal/store/store.go
new file mode 100644
index 0000000..472bb2a
--- /dev/null
+++ b/internal/store/store.go
@@ -0,0 +1,34 @@
+// Package store holds the data models and all SQL queries.
+package store
+
+import (
+	"errors"
+
+	"github.com/jackc/pgx/v5"
+	"github.com/jackc/pgx/v5/pgconn"
+	"github.com/jackc/pgx/v5/pgxpool"
+)
+
+var ErrNotFound = errors.New("not found")
+var ErrConflict = errors.New("already exists")
+
+type Store struct {
+	db *pgxpool.Pool
+}
+
+func New(db *pgxpool.Pool) *Store { return &Store{db: db} }
+
+// wrap maps driver errors onto the store's sentinel errors.
+func wrap(err error) error {
+	if err == nil {
+		return nil
+	}
+	if errors.Is(err, pgx.ErrNoRows) {
+		return ErrNotFound
+	}
+	var pgErr *pgconn.PgError
+	if errors.As(err, &pgErr) && pgErr.Code == "23505" { // unique_violation
+		return ErrConflict
+	}
+	return err
+}