guis/views: Introduce GcalAgendaViewItem

GcalAgendaViewItem is an auxiliary object that will be used instead of
the raw events by GcalAgendaViewDay in a later commit to construct the
event widgets inside the main ListView of the agenda view as opposed to
a creating them inside of a `GtkListBox` inside each row of the
ListView.

Holding a reference to the event widget will be necessary in later
commits, so when a ListView row is activated, we can query its model of
GcalAgendaViewItem's with the given activated position, and pass the
correct item's event widget to `gcal_view_event_activated ()`

Part-of: <https://gitlab.gnome.org/GNOME/gnome-calendar/-/merge_requests/809>

src/gui/views/gcal-agenda-view-item.c

@@ -0,0 +1,227 @@
+/*
+ * gcal-agenda-view-item.c
+ *
+ * Copyright 2026 Zelda Ahmed <zoeyahmed10@proton.me>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ */
+
+#include "gcal-agenda-view-item.h"
+#include "gcal-date-time-utils.h"
+
+struct _GcalAgendaViewItem
+{
+  GObject parent_instance;
+
+  GcalEvent       *event;
+  GcalEventWidget *event_widget;
+
+};
+
+G_DEFINE_FINAL_TYPE (GcalAgendaViewItem, gcal_agenda_view_item, G_TYPE_OBJECT)
+
+enum
+{
+  PROP_0,
+  PROP_EVENT,
+  PROP_EVENT_WIDGET,
+  N_PROPS
+};
+
+static GParamSpec *properties[N_PROPS];
+
+static void
+gcal_agenda_view_item_dispose (GObject *object)
+{
+  GcalAgendaViewItem *self = GCAL_AGENDA_VIEW_ITEM (object);
+
+  g_clear_object (&self->event_widget);
+  g_clear_object (&self->event);
+
+  G_OBJECT_CLASS (gcal_agenda_view_item_parent_class)->dispose (object);
+}
+
+static void
+gcal_agenda_view_item_get_property (GObject *object,
+                                    guint prop_id,
+                                    GValue *value,
+                                    GParamSpec *pspec)
+{
+  GcalAgendaViewItem *self = GCAL_AGENDA_VIEW_ITEM (object);
+
+  switch (prop_id)
+    {
+    case PROP_EVENT:
+      g_value_set_object (value, gcal_agenda_view_item_get_event (self));
+      break;
+
+    case PROP_EVENT_WIDGET:
+      g_value_set_object (value, gcal_agenda_view_item_get_event_widget (self));
+      break;
+
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+    }
+}
+
+static void
+gcal_agenda_view_item_set_property (GObject *object,
+                                    guint prop_id,
+                                    const GValue *value,
+                                    GParamSpec *pspec)
+{
+  GcalAgendaViewItem *self = GCAL_AGENDA_VIEW_ITEM (object);
+
+  switch (prop_id)
+    {
+    case PROP_EVENT:
+      gcal_agenda_view_item_set_event (self, g_value_get_object (value));
+      break;
+    case PROP_EVENT_WIDGET:
+      gcal_agenda_view_item_set_event_widget (self, g_value_get_object (value));
+      break;
+
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+    }
+}
+
+static void
+gcal_agenda_view_item_class_init (GcalAgendaViewItemClass *klass)
+{
+  GObjectClass *object_class = G_OBJECT_CLASS (klass);
+
+  object_class->dispose = gcal_agenda_view_item_dispose;
+  object_class->get_property = gcal_agenda_view_item_get_property;
+  object_class->set_property = gcal_agenda_view_item_set_property;
+
+  /**
+   * GcalAgendaViewItem:event:
+   *
+   * The event that will be presented by the item's row.
+   */
+  properties [PROP_EVENT] =
+    g_param_spec_object ("event", NULL, NULL,
+                         GCAL_TYPE_EVENT,
+                         G_PARAM_READWRITE | G_PARAM_EXPLICIT_NOTIFY | G_PARAM_STATIC_STRINGS);
+  /**
+   * GcalAgendaViewItem:event:
+   *
+   * The event widget representing the item in the #GcalAgendaView.
+   *
+   * This should be passed into `gcal_view_event_activated`
+   * when the `::activated` signal is emitted on the item's row.
+   */
+  properties [PROP_EVENT_WIDGET] =
+    g_param_spec_object ("event-widget", NULL, NULL,
+                         GCAL_TYPE_EVENT_WIDGET,
+                         G_PARAM_READWRITE | G_PARAM_EXPLICIT_NOTIFY | G_PARAM_STATIC_STRINGS);
+
+  g_object_class_install_properties (object_class, N_PROPS, properties);
+}
+
+static void
+gcal_agenda_view_item_init (GcalAgendaViewItem *self)
+{
+}
+
+/*
+ * Public API
+ */
+
+/**
+ * gcal_agenda_view_item_new:
+ *
+ * Creates a new #GcalAgendaViewItem
+ *
+ * Returns: (transfer full): a #GcalAgendaViewItem
+ */
+GcalAgendaViewItem *
+gcal_agenda_view_item_new (void)
+{
+  GcalAgendaViewItem *item = g_object_new (GCAL_TYPE_AGENDA_VIEW_ITEM, NULL);
+
+  return item;
+}
+
+/**
+ * gcal_agenda_view_item_get_event:
+ * @self: a #GcalAgendaViewItem
+ *
+ * Gets the event the item presents in the agenda view.
+ *
+ * Returns (nullable) (transfer none): the #GcalEvent being presented.
+ */
+GcalEvent *
+gcal_agenda_view_item_get_event (GcalAgendaViewItem *self)
+{
+  g_assert (GCAL_IS_AGENDA_VIEW_ITEM (self));
+
+  return self->event;
+}
+
+/**
+ * gcal_agenda_view_item_set_event:
+ * @self: a #GcalAgendaViewItem
+ * @event (nullable) (transfer none): the #GcalEvent to present
+ *
+ * Sets the event the item will present in the agenda view.
+ */
+void
+gcal_agenda_view_item_set_event (GcalAgendaViewItem *self,
+                                 GcalEvent          *event)
+{
+  g_return_if_fail (GCAL_IS_AGENDA_VIEW_ITEM (self));
+  g_return_if_fail (event == NULL || GCAL_IS_EVENT (event));
+
+  if (g_set_object (&self->event, event))
+    g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_EVENT]);
+}
+
+/**
+ * gcal_agenda_view_item_get_event_widget:
+ * @self: a #GcalAgendaViewItem
+ *
+ * Gets the event widget representing the item in the agenda view.
+ *
+ * Returns (nullable) (transfer none): the #GcalEventWidget presenting the @event.
+ */
+
+GcalEventWidget *
+gcal_agenda_view_item_get_event_widget (GcalAgendaViewItem *self)
+{
+  g_return_val_if_fail (GCAL_IS_AGENDA_VIEW_ITEM (self), NULL);
+
+  return self->event_widget;
+}
+
+/**
+ * gcal_agenda_view_item_set_event_widget:
+ * @self: a #GcalAgendaViewItem
+ * @widget: (nullable) (transfer none): the #GcalEventWidget presenting the @event.
+ *
+ * Sets the event widget representing the item in the agenda view.
+ */
+void
+gcal_agenda_view_item_set_event_widget (GcalAgendaViewItem *self,
+                                        GcalEventWidget    *event_widget)
+{
+  g_return_if_fail (GCAL_IS_AGENDA_VIEW_ITEM (self));
+  g_return_if_fail (event_widget == NULL || GCAL_IS_EVENT_WIDGET (event_widget));
+
+  if (g_set_object (&self->event_widget, event_widget))
+    g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_EVENT_WIDGET]);
+}

src/gui/views/gcal-agenda-view-item.h

@@ -0,0 +1,42 @@
+/*
+ * gcal-agenda-view-item.h
+ *
+ * Copyright 2026 Zelda Ahmed <zoeyahmed10@proton.me>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ */
+
+#pragma once
+
+#include "gcal-event.h"
+#include "gcal-event-widget.h"
+
+#include <glib-object.h>
+
+G_BEGIN_DECLS
+
+#define GCAL_TYPE_AGENDA_VIEW_ITEM (gcal_agenda_view_item_get_type())
+G_DECLARE_FINAL_TYPE (GcalAgendaViewItem, gcal_agenda_view_item, GCAL, AGENDA_VIEW_ITEM, GObject)
+
+GcalAgendaViewItem *gcal_agenda_view_item_new              (void);
+GcalEvent          *gcal_agenda_view_item_get_event        (GcalAgendaViewItem *self);
+void                gcal_agenda_view_item_set_event        (GcalAgendaViewItem *self,
+                                                            GcalEvent          *event);
+GcalEventWidget    *gcal_agenda_view_item_get_event_widget (GcalAgendaViewItem *self);
+void                gcal_agenda_view_item_set_event_widget (GcalAgendaViewItem *self,
+                                                            GcalEventWidget    *widget);
+
+G_END_DECLS

src/gui/views/gcal-agenda-view.c

@@ -21,6 +21,7 @@
 #include "gcal-agenda-view.h"
 #include "gcal-agenda-view-day.h"
 #include "gcal-agenda-view-day-row.h"
+#include "gcal-agenda-view-item.h"
 #include "gcal-debug.h"
 #include "gcal-enums.h"
 #include "gcal-event-widget.h"
@@ -422,6 +423,7 @@ gcal_agenda_view_class_init (GcalAgendaViewClass *klass)
   GObjectClass *object_class = G_OBJECT_CLASS (klass);
   GtkWidgetClass *widget_class = GTK_WIDGET_CLASS (klass);
 
+  g_type_ensure (GCAL_TYPE_AGENDA_VIEW_ITEM);
   g_type_ensure (GCAL_TYPE_AGENDA_VIEW_DAY_ROW);
 
   object_class->dispose = gcal_agenda_view_dispose;

src/gui/views/meson.build

@@ -32,6 +32,7 @@ sources += files(
   'gcal-agenda-view.c',
   'gcal-agenda-view-day.c',
   'gcal-agenda-view-day-row.c',
+  'gcal-agenda-view-item.c',
   'gcal-month-cell.c',
   'gcal-month-popover.c',
   'gcal-month-view.c',