fix(input): parse default mouse reports

src/raw_input.rs

@@ -784,6 +784,9 @@ fn extract_one_event(buffer: &[u8]) -> Option<(RawInputEvent, usize)> {
 
     if buffer[0] == ESC {
         let seq_len = complete_escape_sequence_len(buffer)?;
+        if let Some(mouse) = parse_default_mouse(&buffer[..seq_len]) {
+            return Some((RawInputEvent::Mouse(mouse), seq_len));
+        }
         let seq = std::str::from_utf8(&buffer[..seq_len]).ok()?;
 
         if let Some((kind, color)) = parse_default_color_response(seq) {
@@ -980,6 +983,13 @@ fn complete_escape_sequence_len(buffer: &[u8]) -> Option<usize> {
         }
     }
 
+    if buffer.len() >= 7
+        && buffer.starts_with(b"\x1b\x1b[M")
+        && parse_default_mouse(&buffer[1..7]).is_some()
+    {
+        return Some(1);
+    }
+
     if buffer.starts_with(b"\x1b\x1b") {
         return complete_escape_sequence_len(&buffer[1..]).map(|len| len + 1);
     }
@@ -988,6 +998,9 @@ fn complete_escape_sequence_len(buffer: &[u8]) -> Option<usize> {
         if buffer.starts_with(b"\x1b[<") {
             return find_csi_final(buffer, b"Mm");
         }
+        if buffer.starts_with(b"\x1b[M") {
+            return (buffer.len() >= 6).then_some(6);
+        }
         return find_csi_final(
             buffer,
             b"@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_`abcdefghijklmnopqrstuvwxyz{|}~",
@@ -1166,6 +1179,23 @@ fn find_subsequence(haystack: &[u8], needle: &[u8]) -> Option<usize> {
         .position(|window| window == needle)
 }
 
+fn parse_default_mouse(sequence: &[u8]) -> Option<MouseEvent> {
+    let &[ESC, b'[', b'M', encoded_cb, encoded_column, encoded_row] = sequence else {
+        return None;
+    };
+    let cb = encoded_cb.checked_sub(32)?;
+    let column = u16::from(encoded_column).checked_sub(33)?;
+    let row = u16::from(encoded_row).checked_sub(33)?;
+    let (kind, modifiers) = parse_mouse_cb(cb)?;
+
+    Some(MouseEvent {
+        kind,
+        column,
+        row,
+        modifiers,
+    })
+}
+
 fn parse_sgr_mouse(sequence: &str) -> Option<MouseEvent> {
     let body = sequence.strip_prefix("\x1b[<")?;
     let final_char = body.chars().last()?;
@@ -1361,6 +1391,17 @@ mod tests {
         assert_eq!(mouse.modifiers, KeyModifiers::empty());
     }
 
+    #[test]
+    fn parses_default_mouse_encoding() {
+        let events = parse_raw_input_bytes_sync(b"\x1b[MCN1");
+        let [RawInputEvent::Mouse(mouse)] = events.as_slice() else {
+            panic!("expected one mouse event");
+        };
+        assert_eq!(mouse.kind, MouseEventKind::Moved);
+        assert_eq!((mouse.column, mouse.row), (45, 16));
+        assert_eq!(mouse.modifiers, KeyModifiers::empty());
+    }
+
     #[test]
     fn parses_extended_button_drag_as_mouse_motion() {
         for input in [
@@ -1916,6 +1957,28 @@ mod tests {
         }
     }
 
+    #[test]
+    fn lone_escape_then_default_mouse_report_emits_both_events() {
+        let mut framer = RawInputFramer::default();
+
+        assert!(framer.push(b"\x1b").is_empty());
+        let events = framer.push(b"\x1b[MCN1");
+
+        assert_eq!(events.len(), 2);
+        let mut events = events.into_iter();
+        assert_raw_key(events.next().unwrap(), KeyCode::Esc, KeyModifiers::empty());
+        assert!(matches!(
+            events.next().unwrap(),
+            RawInputEvent::Mouse(MouseEvent {
+                kind: MouseEventKind::Moved,
+                column: 45,
+                row: 16,
+                ..
+            })
+        ));
+        assert!(framer.flush_timeout().is_empty());
+    }
+
     #[test]
     fn legacy_doubled_escape_alt_arrow_remains_one_event() {
         let mut framer = RawInputFramer::default();