feat(gitea): typed error mapping from http status

internal/gitea/errors.go

@@ -0,0 +1,34 @@
+package gitea
+
+import (
+	"errors"
+	"fmt"
+)
+
+var (
+	ErrPermissionDenied = errors.New("permission denied")
+	ErrNotFound         = errors.New("not found")
+	ErrConflict         = errors.New("conflict")
+	ErrValidation       = errors.New("validation failed")
+	ErrUpstream         = errors.New("upstream gitea error")
+)
+
+// MapStatus returns nil for 2xx, otherwise a typed error wrapping the response body.
+func MapStatus(status int, body []byte) error {
+	if status >= 200 && status < 300 {
+		return nil
+	}
+	switch {
+	case status == 401, status == 403:
+		return fmt.Errorf("%w: %s", ErrPermissionDenied, body)
+	case status == 404:
+		return fmt.Errorf("%w: %s", ErrNotFound, body)
+	case status == 409:
+		return fmt.Errorf("%w: %s", ErrConflict, body)
+	case status == 422:
+		return fmt.Errorf("%w: %s", ErrValidation, body)
+	case status >= 500:
+		return fmt.Errorf("%w (status %d)", ErrUpstream, status)
+	}
+	return fmt.Errorf("unexpected status %d: %s", status, body)
+}