Add a config option for maximum signup in advance

We now have `signup_advance_hours` in the configuration that
only allows signup for shifts so many hours in the future.
A notice is displayed in the shift view for shifts in the
far future, together with an info notice on when signup for
that shift will be possible.

In addition, we now have a new shift state `NOT_YET` for this
purpose so we do not have to abuse `SHIFT_ENDED` anymore for
`signup_requires_arrival` as well.

2 files changed, 9 insertions, 0 deletions

diff --git a/includes/model/ShiftSignupState.php b/includes/model/ShiftSignupState.php
index 8d588de3..a2618cf1 100644
--- a/includes/model/ShiftSignupState.php
+++ b/includes/model/ShiftSignupState.php
@@ -39,6 +39,11 @@ class ShiftSignupState
     const SHIFT_ENDED = 'SHIFT_ENDED';
 
     /**
+     * Shift is not available yet
+     */
+    const NOT_YET = 'NOT_YET';
+
+    /**
      * User is already signed up
      */
     const SIGNED_UP = 'SIGNED_UP';
diff --git a/includes/model/Shifts_model.php b/includes/model/Shifts_model.php
index 6f422c32..6bb17cf2 100644
--- a/includes/model/Shifts_model.php
+++ b/includes/model/Shifts_model.php
@@ -325,6 +325,10 @@ function Shift_signup_allowed_angel(
         return new ShiftSignupState(ShiftSignupState::NOT_ARRIVED, $free_entries);
     }
 
+    if (config('signup_advance_hours') && $shift['start'] > time() + config('signup_advance_hours') * 3600) {
+        return new ShiftSignupState(ShiftSignupState::NOT_YET, $free_entries);
+    }
+
     if (empty($user_shifts)) {
         $user_shifts = Shifts_by_user($user->id);
     }