[evolution] I#1306 - Calendar: Drag&drop events in Week/Month views

[Milan Crha <mcrha src gnome org>]

commit a1d8ad393cc81e762afc24ad02fb3a2d87406419
Author: Milan Crha <mcrha redhat com>
Date:   Thu Jun 9 17:56:37 2022 +0200

    I#1306 - Calendar: Drag&drop events in Week/Month views
    
    Closes https://gitlab.gnome.org/GNOME/evolution/-/issues/1306

 src/calendar/gui/e-week-view.c | 170 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 170 insertions(+)
---
diff --git a/src/calendar/gui/e-week-view.c b/src/calendar/gui/e-week-view.c
index 8398941ac7..a26276ba0f 100644
--- a/src/calendar/gui/e-week-view.c
+++ b/src/calendar/gui/e-week-view.c
@@ -69,6 +69,10 @@
  * we get from the server. */
 #define E_WEEK_VIEW_LAYOUT_TIMEOUT     100
 
+static         GtkTargetEntry target_table[] = {
+       { (gchar *) "application/x-e-calendar-event", 0, 0 }
+};
+
 struct _EWeekViewPrivate {
        /* The first day shown in the view. */
        GDate first_day_shown;
@@ -103,6 +107,9 @@ struct _EWeekViewPrivate {
        gboolean days_left_to_right;
 
        gchar *today_background_color;
+
+       gint drag_event_num;
+       gint drag_from_day;
 };
 
 typedef struct {
@@ -1682,6 +1689,101 @@ e_week_view_query_tooltip_cb (GtkWidget *widget,
        return TRUE;
 }
 
+static void
+e_week_view_drag_end_cb (GtkWidget *widget,
+                        GdkDragContext *context,
+                        gpointer user_data)
+{
+       EWeekView *self = user_data;
+
+       self->pressed_event_num = -1;
+       self->drag_event_x = -1;
+       self->drag_event_y = -1;
+       self->priv->drag_event_num = -1;
+       self->priv->drag_from_day = -1;
+}
+
+static gboolean
+e_week_view_drag_motion_cb (GtkWidget *widget,
+                           GdkDragContext *context,
+                           gint x,
+                           gint y,
+                           guint time,
+                           gpointer user_data)
+{
+       EWeekView *self = user_data;
+       gint day;
+       gboolean can_drop;
+
+       day = e_week_view_convert_position_to_day (self, x, y);
+       can_drop = day > -1 && day < G_N_ELEMENTS (self->day_starts) &&
+               self->priv->drag_event_num > -1 &&
+               self->priv->drag_from_day != day;
+
+       gdk_drag_status (context,
+               can_drop ? gdk_drag_context_get_selected_action (context) : 0, time);
+
+       return TRUE;
+}
+
+static gboolean
+e_week_view_drag_drop_cb (GtkWidget *widget,
+                         GdkDragContext *context,
+                         gint x,
+                         gint y,
+                         guint time,
+                         gpointer user_data)
+{
+       EWeekView *self = user_data;
+       gint day;
+       gboolean can_drop;
+
+       day = e_week_view_convert_position_to_day (self, x, y);
+       can_drop = day > -1 && day < G_N_ELEMENTS (self->day_starts) &&
+               self->priv->drag_event_num > -1 &&
+               self->priv->drag_from_day != day;
+
+       if (can_drop) {
+               time_t day_start = self->day_starts[day];
+               time_t from_start = self->day_starts[self->priv->drag_from_day];
+               gint diff_days = (day_start - from_start) / (60 * 60 * 24);
+
+               if (diff_days != 0 && is_array_index_in_bounds (self->events, self->priv->drag_event_num)) {
+                       EWeekViewEvent *event;
+
+                       event = &g_array_index (self->events, EWeekViewEvent, self->priv->drag_event_num);
+
+                       if (is_comp_data_valid (event)) {
+                               ECalClient *client;
+                               ECalComponent *comp;
+
+                               client = g_object_ref (event->comp_data->client);
+                               comp = e_cal_component_new_from_icalcomponent (i_cal_component_clone 
(event->comp_data->icalcomp));
+
+                               if (comp) {
+                                       ECalModel *model = e_calendar_view_get_model (E_CALENDAR_VIEW (self));
+                                       GtkWidget *toplevel;
+                                       GtkWindow *parent;
+                                       gboolean is_move;
+
+                                       toplevel = gtk_widget_get_toplevel (widget);
+                                       parent = GTK_IS_WINDOW (toplevel) ? GTK_WINDOW (toplevel) : NULL;
+                                       is_move = gdk_drag_context_get_selected_action (context) == 
GDK_ACTION_MOVE;
+
+                                       cal_comp_util_move_component_by_days (parent, model, client, comp, 
diff_days, is_move);
+                               }
+
+                               g_clear_object (&comp);
+                               g_clear_object (&client);
+                       }
+               }
+       }
+
+       gtk_drag_finish (context, can_drop, FALSE, time);
+
+       return FALSE;
+}
+
 static void
 e_week_view_class_init (EWeekViewClass *class)
 {
@@ -1845,6 +1947,8 @@ e_week_view_init (EWeekView *week_view)
 
        week_view->pressed_event_num = -1;
        week_view->editing_event_num = -1;
+       week_view->priv->drag_event_num = -1;
+       week_view->priv->drag_from_day = -1;
 
        week_view->last_edited_comp_string = NULL;
 
@@ -1924,6 +2028,20 @@ e_week_view_init (EWeekView *week_view)
        g_signal_connect_object (
                week_view->main_canvas, "query-tooltip",
                G_CALLBACK (e_week_view_query_tooltip_cb), week_view, 0);
+       g_signal_connect_object (
+               week_view->main_canvas, "drag-end",
+               G_CALLBACK (e_week_view_drag_end_cb), week_view, 0);
+       g_signal_connect_object (
+               week_view->main_canvas, "drag-motion",
+               G_CALLBACK (e_week_view_drag_motion_cb), week_view, 0);
+       g_signal_connect_object (
+               week_view->main_canvas, "drag-drop",
+               G_CALLBACK (e_week_view_drag_drop_cb), week_view, 0);
+
+       gtk_drag_dest_set (
+               week_view->main_canvas, GTK_DEST_DEFAULT_ALL,
+               target_table, G_N_ELEMENTS (target_table),
+               GDK_ACTION_COPY | GDK_ACTION_MOVE);
 
        /* Create the buttons to jump to each days. */
        pixbuf = gdk_pixbuf_new_from_xpm_data ((const gchar **) jump_xpm);
@@ -3372,6 +3490,8 @@ e_week_view_free_events (EWeekView *week_view)
        week_view->editing_event_num = -1;
        week_view->editing_span_num = -1;
        week_view->popup_event_num = -1;
+       week_view->priv->drag_event_num = -1;
+       week_view->priv->drag_from_day = -1;
 
        for (event_num = 0; event_num < week_view->events->len; event_num++) {
                event = &g_array_index (week_view->events, EWeekViewEvent,
@@ -3642,6 +3762,47 @@ e_week_view_reshape_events (EWeekView *week_view)
        }
 }
 
+static void
+e_week_view_maybe_start_event_drag_on_motion (EWeekView *week_view,
+                                             GdkEvent *gdk_event,
+                                             gint event_num)
+{
+       EWeekViewEvent *pevent;
+       gdouble event_x_root = 0;
+       gdouble event_y_root = 0;
+
+       g_return_if_fail (E_IS_WEEK_VIEW (week_view));
+       g_return_if_fail (gdk_event != NULL);
+
+       if (!gdk_event_get_root_coords (gdk_event, &event_x_root, &event_y_root))
+               return;
+
+       pevent = e_week_view_get_event (week_view, -1, event_num);
+       if (!pevent)
+               return;
+
+       if (week_view->pressed_event_num != -1 &&
+           week_view->pressed_event_num == event_num &&
+           week_view->priv->drag_event_num == -1 &&
+           week_view->drag_event_x != -1 &&
+           week_view->drag_event_y != -1 &&
+           gtk_drag_check_threshold (GTK_WIDGET (week_view), week_view->drag_event_x, 
week_view->drag_event_y, event_x_root, event_y_root) &&
+           !e_client_is_readonly (E_CLIENT (pevent->comp_data->client))) {
+               GtkTargetList *target_list;
+
+               week_view->priv->drag_event_num = event_num;
+               week_view->priv->drag_from_day = e_week_view_convert_position_to_day (week_view, 
week_view->drag_event_x, week_view->drag_event_y);
+
+               target_list = gtk_target_list_new (
+                       target_table, G_N_ELEMENTS (target_table));
+               gtk_drag_begin_with_coordinates (
+                       week_view->main_canvas, target_list,
+                       GDK_ACTION_COPY | GDK_ACTION_MOVE,
+                       1, gdk_event, event_x_root, event_y_root);
+               gtk_target_list_unref (target_list);
+       }
+}
+
 static gboolean
 background_item_event_cb (GnomeCanvasItem *item,
                          GdkEvent *event,
@@ -3674,6 +3835,7 @@ background_item_event_cb (GnomeCanvasItem *item,
                        pevent->x = ((GdkEventMotion *) event)->x_root;
                        pevent->y = ((GdkEventMotion *) event)->y_root;
 
+                       e_week_view_maybe_start_event_drag_on_motion (view, event, event_num);
                        return TRUE;
                case GDK_LEAVE_NOTIFY:
                case GDK_KEY_PRESS:
@@ -4341,6 +4503,8 @@ e_week_view_on_text_item_event (GnomeCanvasItem *item,
                                        span_num,
                                        NULL);
                                week_view->pressed_event_num = -1;
+                               week_view->drag_event_x = -1;
+                               week_view->drag_event_y = -1;
                        }
 
                        /* Stop the signal last or we will also stop any
@@ -4349,6 +4513,8 @@ e_week_view_on_text_item_event (GnomeCanvasItem *item,
                        return TRUE;
                }
                week_view->pressed_event_num = -1;
+               week_view->drag_event_x = -1;
+               week_view->drag_event_y = -1;
                break;
        case GDK_ENTER_NOTIFY:
        {
@@ -4381,6 +4547,10 @@ e_week_view_on_text_item_event (GnomeCanvasItem *item,
 
                pevent->x = (gint) event_x_root;
                pevent->y = (gint) event_y_root;
+
+               if (!E_TEXT (item)->editing)
+                       e_week_view_maybe_start_event_drag_on_motion (week_view, gdk_event, nevent);
+
                return TRUE;
        case GDK_FOCUS_CHANGE:
                if (gdk_event->focus_change.in) {