Extract cookie config into authn pkg

Signed-off-by: Émile Ré <emile@getprobo.com>

pkg/server/api/authn/cookie.go

@@ -0,0 +1,52 @@
+// Copyright (c) 2025 Probo Inc <hello@getprobo.com>.
+//
+// Permission to use, copy, modify, and/or distribute this software for any
+// purpose with or without fee is hereby granted, provided that the above
+// copyright notice and this permission notice appear in all copies.
+//
+// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
+// REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
+// AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
+// INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
+// LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
+// OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+// PERFORMANCE OF THIS SOFTWARE.
+
+package authn
+
+import (
+	"net/http"
+	"time"
+
+	"go.probo.inc/probo/pkg/coredata"
+	"go.probo.inc/probo/pkg/securecookie"
+)
+
+type Cookie struct {
+	config *securecookie.Config
+}
+
+func (c *Cookie) Set(w http.ResponseWriter, session *coredata.Session) {
+	securecookie.Set(
+		w,
+		c.sessionCookieConfig(time.Until(session.ExpiredAt)),
+		session.ID.String(),
+	)
+}
+
+func NewCookie(config *securecookie.Config) *Cookie {
+	return &Cookie{config}
+}
+
+func (c *Cookie) sessionCookieConfig(maxAge time.Duration) securecookie.Config {
+	return securecookie.Config{
+		Name:     c.config.Name,
+		Secret:   c.config.Secret,
+		Secure:   c.config.Secure,
+		HTTPOnly: c.config.HTTPOnly,
+		SameSite: c.config.SameSite,
+		Path:     c.config.Path,
+		Domain:   c.config.Domain,
+		MaxAge:   int(maxAge.Seconds()),
+	}
+}