feat: add file edit diff progress view

Capture file edit snapshots through runner tool lifecycle hooks and render unified diffs in the WebUI with folding and truncation controls.

nanobot/agent/hooks/file_edit_activity.py

@@ -0,0 +1,109 @@
+"""Agent hook that observes file-editing tools and emits file-edit activity."""
+
+from __future__ import annotations
+
+from collections.abc import Awaitable, Callable
+from pathlib import Path
+from typing import Any
+
+from nanobot.agent.hook import AgentHook, AgentHookContext, AgentTurnHookContext
+from nanobot.providers.base import ToolCallRequest
+from nanobot.utils.file_edit_events import (
+    FileEditTracker,
+    build_file_edit_end_event,
+    build_file_edit_error_event,
+    build_file_edit_start_event,
+    prepare_file_edit_trackers,
+)
+from nanobot.utils.progress_events import (
+    invoke_file_edit_progress,
+    on_progress_accepts_file_edit_events,
+)
+
+
+class FileEditActivityHook(AgentHook):
+    """Translate file-editing tool lifecycle events into WebUI progress events."""
+
+    def __init__(
+        self,
+        *,
+        on_progress: Callable[..., Awaitable[None]] | None,
+        workspace: Path | None,
+    ) -> None:
+        super().__init__()
+        self._on_progress = (
+            on_progress
+            if on_progress is not None and on_progress_accepts_file_edit_events(on_progress)
+            else None
+        )
+        self._workspace = workspace
+        self._trackers_by_call: dict[str, list[FileEditTracker]] = {}
+
+    async def before_iteration(self, context: AgentHookContext) -> None:
+        self._trackers_by_call.clear()
+
+    async def before_execute_tool(
+        self,
+        context: AgentHookContext,
+        tool_call: ToolCallRequest,
+        tool: Any,
+        params: Any,
+    ) -> None:
+        if self._on_progress is None or not isinstance(params, dict):
+            return
+        trackers = prepare_file_edit_trackers(
+            call_id=tool_call.id,
+            tool_name=tool_call.name,
+            tool=tool,
+            workspace=self._workspace,
+            params=params,
+        )
+        if not trackers:
+            return
+        self._trackers_by_call[self._tool_call_key(tool_call)] = trackers
+        await self._emit([build_file_edit_start_event(tracker, params) for tracker in trackers])
+
+    async def after_execute_tool(
+        self,
+        context: AgentHookContext,
+        tool_call: ToolCallRequest,
+        tool: Any,
+        params: Any,
+        result: Any,
+    ) -> None:
+        trackers = self._trackers_by_call.pop(self._tool_call_key(tool_call), [])
+        if trackers:
+            await self._emit([build_file_edit_end_event(tracker) for tracker in trackers])
+
+    async def on_execute_tool_error(
+        self,
+        context: AgentHookContext,
+        tool_call: ToolCallRequest,
+        tool: Any,
+        params: Any,
+        error: Any,
+    ) -> None:
+        trackers = self._trackers_by_call.pop(self._tool_call_key(tool_call), [])
+        if trackers:
+            await self._emit([
+                build_file_edit_error_event(tracker, str(error)) for tracker in trackers
+            ])
+
+    async def _emit(self, events: list[dict[str, Any]]) -> None:
+        if self._on_progress is not None:
+            await invoke_file_edit_progress(self._on_progress, events)
+
+    @staticmethod
+    def _tool_call_key(tool_call: ToolCallRequest) -> str:
+        call_id = getattr(tool_call, "id", "") or ""
+        return f"{call_id}|{tool_call.name}" if call_id else f"{id(tool_call)}|{tool_call.name}"
+
+
+def create_file_edit_activity_hook(context: AgentTurnHookContext) -> AgentHook | None:
+    """Create the default file-edit observer for one agent turn."""
+    if context.on_progress is None:
+        return None
+    return FileEditActivityHook(
+        on_progress=context.on_progress,
+        workspace=context.workspace,
+    )