From de0c42faaf1a72f1e850f64bc720fd2e824f8cb8 Mon Sep 17 00:00:00 2001
From: Juliusz Chroboczek <jch@irif.fr>
Date: Sun, 3 Mar 2024 16:45:54 +0100
Subject: [PATCH] Implement "expires" and "not-before" for groups.

---
 README               |  2 ++
 group/description.go |  6 ++++++
 group/group.go       | 16 ++++++++++++++++
 3 files changed, 24 insertions(+)

diff --git a/README b/README
index fbc2418..af1ec64 100644
--- a/README
+++ b/README
@@ -157,6 +157,8 @@ nobody will be able to join the group.  The following fields are allowed:
    a time;
  - `max-history-age`: the time, in seconds, during which chat history is
    kept (default 14400, i.e. 4 hours);
+ - `not-before` and `expires`: the times (in ISO 8601 or RFC 3339 format)
+   between which joining the group is allowed;
  - `allow-recording`: if true, then recording is allowed in this group;
  - `unrestricted-tokens`: if true, then ordinary users (without the "op"
    privilege) are allowed to create tokens;
diff --git a/group/description.go b/group/description.go
index a9b6b48..d2c704e 100644
--- a/group/description.go
+++ b/group/description.go
@@ -46,6 +46,12 @@ type Description struct {
 	// The time for which history entries are kept.
 	MaxHistoryAge int `json:"max-history-age,omitempty"`
 
+	// Time after which joining is no longer allowed
+	Expires *time.Time `json:"expires"`
+
+	// Time before which joining is not allowed
+	NotBefore *time.Time `json:"not-before,omitempty"`
+
 	// Whether users are allowed to log in with an empty username.
 	AllowAnonymous bool `json:"allow-anonymous,omitempty"`
 
diff --git a/group/group.go b/group/group.go
index d1a444c..27e2391 100644
--- a/group/group.go
+++ b/group/group.go
@@ -607,6 +607,22 @@ func AddClient(group string, c Client, creds ClientCredentials) (*Group, error)
 				}
 				return nil, UserError(m)
 			}
+			if g.description.NotBefore != nil ||
+				g.description.Expires != nil {
+				now := time.Now()
+				if g.description.NotBefore != nil &&
+					g.description.NotBefore.After(now) {
+					return nil, UserError(
+						"this group is not open yet",
+					)
+				}
+				if g.description.Expires != nil &&
+					g.description.Expires.Before(now) {
+					return nil, UserError(
+						"this group is closed",
+					)
+				}
+			}
 			if g.description.Autokick {
 				ops := false
 				for _, c := range clients {