feat(ui,window): add accurate unread indicators and history paging support

- Track unread message indicators and paging state in the window component
- Clear and restore unread markers correctly when navigating between conversations
- Suppress buffer updates and message printing while viewing history to prevent
  unwanted scroll jumps and viewport lock

Also includes minor code-style, whitespace, and comment cleanups as well as
updated documentation for metrics and buffer handling.

src/ui/titlebar.c

@@ -268,7 +268,11 @@ _show_scrolled(ProfWin* current)
         wattroff(win, bracket_attrs);
 
         wattron(win, scrolled_attrs);
-        wprintw(win, "SCROLLED");
+        if (current->layout->unread_msg == 0) {
+            wprintw(win, "SCROLLED");
+        } else {
+            wprintw(win, "SCROLLED, NEW MESSAGES");
+        }
         wattroff(win, scrolled_attrs);
 
         wattron(win, bracket_attrs);

src/ui/win_types.h

@@ -120,6 +120,7 @@ typedef struct prof_layout_t
     ProfBuff buffer;
     int y_pos;
     int paged;
+    int unread_msg;
 } ProfLayout;
 
 typedef struct prof_layout_simple_t

src/ui/window.c

@@ -103,6 +103,7 @@ _win_create_simple_layout(void)
     layout->base.buffer = buffer_create();
     layout->base.y_pos = 0;
     layout->base.paged = 0;
+    layout->base.unread_msg = 0;
     scrollok(layout->base.win, TRUE);
 
     return &layout->base;
@@ -120,6 +121,7 @@ _win_create_split_layout(void)
     layout->base.buffer = buffer_create();
     layout->base.y_pos = 0;
     layout->base.paged = 0;
+    layout->base.unread_msg = 0;
     scrollok(layout->base.win, TRUE);
     layout->subwin = NULL;
     layout->sub_y_pos = 0;
@@ -197,6 +199,7 @@ win_create_muc(const char* const roomjid)
     layout->base.buffer = buffer_create();
     layout->base.y_pos = 0;
     layout->base.paged = 0;
+    layout->base.unread_msg = 0;
     scrollok(layout->base.win, TRUE);
     new_win->window.layout = (ProfLayout*)layout;
 
@@ -698,9 +701,11 @@ void
 win_page_down(ProfWin* window, int scroll_size)
 {
     int total_rows = getcury(window->layout->win);
+    int total_rows_with_unread = total_rows + window->layout->unread_msg;
     int* page_start = &(window->layout->y_pos);
     int page_space = getmaxy(stdscr) - 4;
     int page_start_initial = *page_start;
+
     if (scroll_size == 0)
         scroll_size = page_space;
     win_scroll_state_t* scroll_state = &window->scroll_state;
@@ -709,7 +714,11 @@ win_page_down(ProfWin* window, int scroll_size)
     *page_start += scroll_size;
 
     // Scrolled down after reaching the bottom of the page
-    if ((*page_start > total_rows - page_space || (*page_start == page_space && *page_start >= total_rows)) && window->type == WIN_CHAT) {
+    gboolean past_bottom = *page_start > total_rows_with_unread - page_space;
+    gboolean at_page_space_and_past_unread = (*page_start == page_space && *page_start >= total_rows_with_unread);
+    gboolean is_chat = window->type == WIN_CHAT;
+
+    if ((past_bottom || at_page_space_and_past_unread) && is_chat) {
         int bf_size = buffer_size(window->layout->buffer);
         if (bf_size > 0 && *scroll_state != WIN_SCROLL_REACHED_BOTTOM) {
             // How many lines are left until end of the screen
@@ -743,13 +752,16 @@ win_page_down(ProfWin* window, int scroll_size)
     window->layout->paged = 1;
 
     // update only if position has changed
-    if (page_start_initial != *page_start) {
+    if ((page_start_initial != *page_start) || window->layout->unread_msg) {
         win_update_virtual(window);
     }
 
-    // switch off page if last line and space line visible
-    if (total_rows - *page_start == page_space) {
+    /* Switch off page if no messages left to read.
+     * TODO: update buffer end handling to check messages just after last entry.
+     */
+    if (*scroll_state == WIN_SCROLL_REACHED_BOTTOM) {
         window->layout->paged = 0;
+        window->layout->unread_msg = 0;
     }
 }
 
@@ -810,6 +822,7 @@ win_clear(ProfWin* window)
     int* page_start = &(window->layout->y_pos);
     *page_start = y;
     window->layout->paged = 1;
+    window->layout->unread_msg = 0;
     win_update_virtual(window);
 }
 
@@ -914,6 +927,7 @@ void
 win_move_to_end(ProfWin* window)
 {
     window->layout->paged = 0;
+    window->layout->unread_msg = 0;
 
     int rows = getmaxy(stdscr);
     int y = getcury(window->layout->win);
@@ -1696,6 +1710,13 @@ win_newline(ProfWin* window)
 static void
 _win_printf(ProfWin* window, const char* show_char, int pad_indent, GDateTime* timestamp, int flags, theme_item_t theme_item, const char* const display_from, const char* const from_jid, const char* const message_id, const char* const message, ...)
 {
+
+    /* Prevent printing and buffer update when user is viewing message history [SCROLLING]*/
+    if (window->layout->paged && wins_is_current(window)) {
+        window->layout->unread_msg++;
+        return;
+    }
+
     if (timestamp == NULL) {
         timestamp = g_date_time_new_now_local();
     } else {