chore: move the go code into a subfolder

apps/api/internal/idp/session.go

@@ -0,0 +1,51 @@
+package idp
+
+import (
+	"context"
+	"time"
+)
+
+// Session is the minimal implementation for a session of a 3rd party authentication [Provider]
+type Session interface {
+	GetAuth(ctx context.Context) (Auth, error)
+	PersistentParameters() map[string]any
+	FetchUser(ctx context.Context) (User, error)
+	ExpiresAt() time.Time
+}
+
+type Auth interface {
+	auth()
+}
+
+type RedirectAuth struct {
+	RedirectURL string
+}
+
+func (r *RedirectAuth) auth() {}
+
+type FormAuth struct {
+	URL    string
+	Fields map[string]string
+}
+
+func (f *FormAuth) auth() {}
+
+// SessionSupportsMigration is an optional extension to the Session interface.
+// It can be implemented to support migrating users, were the initial external id has changed because of a migration of the Provider type.
+// E.g. when a user was linked on a generic OIDC provider and this provider has now been migrated to an AzureAD provider.
+// In this case OIDC used the `sub` claim and Azure now uses the id of the user endpoint, which differ.
+// The RetrievePreviousID will return the `sub` claim again, so that the user can be matched and safely migrated to the new id.
+type SessionSupportsMigration interface {
+	RetrievePreviousID() (previousID string, err error)
+}
+
+func Redirect(redirectURL string) (*RedirectAuth, error) {
+	return &RedirectAuth{RedirectURL: redirectURL}, nil
+}
+
+func Form(url string, fields map[string]string) (*FormAuth, error) {
+	return &FormAuth{
+		URL:    url,
+		Fields: fields,
+	}, nil
+}