feat(tui): search a room's log and members, and a conversation

A busy room's log scrolls past and its member list runs to a thousand
names, with nothing to narrow either. In a room / now filters the log
to lines mentioning the text and u filters the member list, the same
way the room list and the results filter: type, Enter keeps it, Esc
clears it before it leaves the room. The inbox takes / over the open
conversation. The member keys, b and m among them, act on the narrowed
list, and the titles say what is filtered and how many made it.

soulseek-rs/src/ui/main_tui/rooms.rs

@@ -1,6 +1,6 @@
 use super::MainTui;
 use super::input::{jumped, list_jump, scroll_log};
-use crate::models::RoomsView;
+use crate::models::{ChatFilter, RoomsView};
 use ratatui::crossterm::event::{KeyCode, KeyEvent, KeyModifiers};
 
 impl MainTui {
@@ -30,6 +30,14 @@ impl MainTui {
             self.handle_room_filter_input(key);
             return;
         }
+        // So does typing a filter over the log or the member list; the
+        // other keys still move around.
+        if self.state.rooms.view == RoomsView::Chat
+            && self.state.rooms.filtering.is_some()
+            && self.handle_chat_filter_input(key)
+        {
+            return;
+        }
 
         match self.state.rooms.view {
             RoomsView::List => self.handle_rooms_list_input(key),
@@ -113,11 +121,24 @@ impl MainTui {
         if key.modifiers.contains(KeyModifiers::CONTROL) {
             return;
         }
+        let filtered = !self.state.rooms.log_filter.is_empty()
+            || !self.state.rooms.user_filter.is_empty();
         match key.code {
             KeyCode::Char('q') => self.state.show_rooms = false,
+            // Esc peels back one level: the filters first, then the list.
+            KeyCode::Esc if filtered => {
+                self.state.rooms.set_log_filter(String::new());
+                self.state.rooms.set_user_filter(String::new());
+            }
             KeyCode::Esc | KeyCode::Char('l') => {
                 self.state.rooms.view = RoomsView::List;
             }
+            KeyCode::Char('/') => {
+                self.state.rooms.filtering = Some(ChatFilter::Log);
+            }
+            KeyCode::Char('u') => {
+                self.state.rooms.filtering = Some(ChatFilter::Users);
+            }
             KeyCode::Tab => self.state.rooms.next_tab(),
             KeyCode::BackTab => self.state.rooms.prev_tab(),
             KeyCode::Char('x') => self.leave_active_room(),
@@ -137,6 +158,42 @@ impl MainTui {
         }
     }
 
+    /// The keys that edit whichever filter is being typed, the log's or the
+    /// member list's. Says whether `key` was one of them.
+    fn handle_chat_filter_input(&mut self, key: KeyEvent) -> bool {
+        let rooms = &mut self.state.rooms;
+        let over_log = rooms.filtering == Some(ChatFilter::Log);
+        let current = if over_log {
+            rooms.log_filter.clone()
+        } else {
+            rooms.user_filter.clone()
+        };
+        let next = match key.code {
+            KeyCode::Esc => String::new(),
+            KeyCode::Enter => current,
+            KeyCode::Char(c) => {
+                let mut next = current;
+                next.push(c);
+                next
+            }
+            KeyCode::Backspace => {
+                let mut next = current;
+                next.pop();
+                next
+            }
+            _ => return false,
+        };
+        if matches!(key.code, KeyCode::Esc | KeyCode::Enter) {
+            rooms.filtering = None;
+        }
+        if over_log {
+            rooms.set_log_filter(next);
+        } else {
+            rooms.set_user_filter(next);
+        }
+        true
+    }
+
     /// Browse the shares of the member highlighted in the active room. Closes
     /// the rooms popup so the browse tree is the sole overlay.
     fn browse_selected_room_user(&mut self) {