feat: reset tmux window indexes

src/hqt/tmux/runner.py

@@ -116,6 +116,15 @@ class WindowInfo:
     last_activity: int
 
 
+@dataclass(frozen=True)
+class WindowIndex:
+    """Stable tmux window identity plus its current numeric index."""
+
+    window_id: str
+    index: int
+    name: str
+
+
 class TmuxRunner:
     """Low-level async tmux command wrapper. All operations target windows within a single session."""
 
@@ -231,6 +240,103 @@ class TmuxRunner:
             flags.extend(["-e", f"{key}={value}"])
         return flags
 
+    async def _list_window_indexes(self) -> list[WindowIndex] | None:
+        """Return window ids, indexes, and names for this tmux session.
+
+        None means tmux failed or returned malformed data; an empty list means
+        the session listed successfully but has no windows.
+        """
+        rc, stdout, err = await self._exec(
+            "list-windows",
+            "-t",
+            self.session_name,
+            "-F",
+            "#{window_id}\t#{window_index}\t#{window_name}",
+        )
+        if rc != 0:
+            log.error("list-windows failed for %s: %s", self.session_name, err)
+            return None
+
+        windows: list[WindowIndex] = []
+        for line in stdout.splitlines():
+            if not line.strip():
+                continue
+            parts = line.split("\t", 2)
+            if len(parts) != 3:
+                log.error("Malformed list-windows row: %r", line)
+                return None
+            window_id, index_text, name = parts
+            try:
+                index = int(index_text)
+            except ValueError:
+                log.error("Malformed window index in row: %r", line)
+                return None
+            windows.append(WindowIndex(window_id=window_id, index=index, name=name))
+        return windows
+
+    async def _move_window_id_to_index(self, window_id: str, index: int) -> bool:
+        rc, _, err = await self._exec(
+            "move-window",
+            "-s",
+            window_id,
+            "-t",
+            f"{self.session_name}:{index}",
+        )
+        if rc != 0:
+            log.error("move-window failed for %s -> %s: %s", window_id, index, err)
+            return False
+        return True
+
+    async def reset_window_indexes(self, home_window: str) -> bool:
+        """Compact tmux window indexes while keeping the home window at 0.
+
+        The operation changes tmux indexes only. It preserves window names,
+        panes, processes, hqt database rows, and harness session ids.
+        """
+        windows = await self._list_window_indexes()
+        if windows is None:
+            return False
+
+        home = next((window for window in windows if window.name == home_window), None)
+        if home is None:
+            log.error(
+                "Home window %r not found in session %s",
+                home_window,
+                self.session_name,
+            )
+            return False
+
+        non_home = sorted(
+            (window for window in windows if window.window_id != home.window_id),
+            key=lambda window: window.index,
+        )
+        desired: list[tuple[WindowIndex, int]] = [(home, 0)]
+        desired.extend(
+            (window, index) for index, window in enumerate(non_home, start=1)
+        )
+
+        if all(window.index == target_index for window, target_index in desired):
+            return True
+
+        # Move every window out of the target range before placing final indexes.
+        # This avoids move-window failures when a destination index is occupied.
+        temp_start = max(window.index for window in windows) + len(windows)
+        for offset, window in enumerate(
+            sorted(windows, key=lambda item: item.index),
+            start=1,
+        ):
+            if not await self._move_window_id_to_index(
+                window.window_id,
+                temp_start + offset,
+            ):
+                return False
+
+        for window, target_index in desired:
+            if not await self._move_window_id_to_index(window.window_id, target_index):
+                return False
+
+        return True
+
     async def new_window(
         self,
         window_name: str,