web: better progress bar

web/src/state.rs

@@ -332,6 +332,8 @@ pub fn update(msg: Msg, model: &mut Model, orders: &mut impl Orders<Msg>) {
                 selected_threads,
             };
             orders.send_msg(Msg::UpdateServerVersion(data.version));
+            // Generate signal so progress bar is reset
+            orders.send_msg(Msg::WindowScrolled);
         }
 
         Msg::ShowThreadRequest { thread_id } => {
@@ -382,6 +384,8 @@ pub fn update(msg: Msg, model: &mut Model, orders: &mut impl Orders<Msg>) {
                 }
             }
             orders.send_msg(Msg::UpdateServerVersion(data.version));
+            // Generate signal so progress bar is reset
+            orders.send_msg(Msg::WindowScrolled);
         }
         Msg::ShowThreadResult(bad) => {
             error!("show_thread_query error: {bad:#?}");
@@ -511,9 +515,29 @@ pub fn update(msg: Msg, model: &mut Model, orders: &mut impl Orders<Msg>) {
                     .value_of();
 
                 let r = el.get_bounding_client_rect();
-                let end = r.height() - ih;
+                if r.height() < ih {
+                    // The whole content fits in the window, no scrollbar
+                    orders.send_msg(Msg::SetProgress(0.));
+                    return;
+                }
+                let end: f64 = r.height() - ih;
+                if end < 0. {
+                    orders.send_msg(Msg::SetProgress(0.));
+                    return;
+                }
+                // Flip Y, normally it's 0-point when the top of the content hits the top of the
+                // screen and goes negative from there.
                 let y = -r.y();
-                orders.send_msg(Msg::SetProgress((y / end).max(0.)));
+                let ratio: f64 = (y / end).max(0.);
+                debug!(
+                    "WindowScrolled ih {ih} end {end} ratio {ratio:.02} {}x{} @ {},{}",
+                    r.width(),
+                    r.height(),
+                    r.x(),
+                    r.y()
+                );
+
+                orders.send_msg(Msg::SetProgress(ratio));
             } else {
                 orders.send_msg(Msg::SetProgress(0.));
             }