Support writing quote tweets with attached images

src/async/ComposeJob.vala

@@ -125,7 +125,12 @@ class ComposeJob : GLib.Object {
       Cb.MiniTweet mt = quoted_tweet.retweeted_tweet ?? quoted_tweet.source_tweet;
       var quoted_url = "https://twitter.com/%s/status/%s".printf (mt.author.screen_name,
                                                                   mt.id.to_string ());
-      call.add_param ("attachment_url", quoted_url);
+
+      if (media_ids == null || media_ids.length == 0) {
+        call.add_param ("attachment_url", quoted_url);
+      } else {
+        this.text += " " + quoted_url;
+      }
     }
 
     call.add_param ("status", this.text);

src/util/TweetUtils.vala

@@ -160,16 +160,20 @@ namespace TweetUtils {
    * Calculates the length of a tweet.
    *
    * @param text The text to calculate the length for
+   * @param add_url Whether to add a Twitter URL to the calculation
    *
    * @return The length of the tweet, taking Twitter's rules for
    *         tweet length into account.
    */
-  public int calc_tweet_length (string text, int media_count = 0) {
+  public int calc_tweet_length (string text, bool add_url = false) {
     int length = 0;
 
+    if (add_url)
+      length += 1 + Twitter.short_url_length_https;
+
     /* trailing & laeding whitespace don't count unless there's other text */
     if (text.strip ().length == 0) {
-      return 0;
+      return length;
     }
 
     unichar c;

src/window/ComposeTweetWindow.vala

@@ -142,6 +142,8 @@ class ComposeTweetWindow : Gtk.ApplicationWindow {
 
       if (this.compose_image_manager.n_images == 0)
         this.compose_image_manager.hide ();
+
+      this.recalc_tweet_length();
     });
 
     this.add_accel_group (ag);
@@ -161,10 +163,16 @@ class ComposeTweetWindow : Gtk.ApplicationWindow {
     tweet_text.buffer.get_bounds (out start, out end);
     string text = tweet_text.buffer.get_text (start, end, true);
 
-    int length = TweetUtils.calc_tweet_length (text);
+    bool add_url = false;
+    //We can only add an image or a quoted URL as an attachment, so if we
+    //have both then the quoted tweet must become an inline URL
+    if (compose_image_manager.n_images > 0 && mode == Mode.QUOTE)
+      add_url = true;
+
+    int length = TweetUtils.calc_tweet_length (text, add_url);
 
     length_label.label = (Cb.Tweet.MAX_LENGTH - length).to_string ();
-    if (length > 0 && length <= Cb.Tweet.MAX_LENGTH)
+    if ((length > 0 && length <= Cb.Tweet.MAX_LENGTH) || (compose_image_manager.n_images > 0 && length == 0))
       send_button.sensitive = true;
     else
       send_button.sensitive = false;
@@ -295,6 +303,7 @@ class ComposeTweetWindow : Gtk.ApplicationWindow {
         }
       }
       filechooser.destroy ();
+      this.recalc_tweet_length();
     });
 
     var filter = new Gtk.FileFilter ();