Make incidents diff resilient and send sample if empty

handlers/system.py

@@ -397,69 +397,91 @@ async def incidents_summary(msg: Message):
 async def incidents_diff(msg: Message):
     if not is_admin_msg(msg):
         return
-    parts = msg.text.split()
-    hours = 24
-    reset = False
-    if len(parts) >= 2:
-        if parts[1].lower() in {"reset", "clear"}:
-            reset = True
-        else:
-            try:
-                hours = max(1, int(parts[1]))
-            except ValueError:
-                hours = 24
-    if reset:
-        runtime_state.set_state("incidents_diff_last_ts", None)
-        await msg.answer("📣 Diff marker reset. Next run will show all within window.", reply_markup=system_logs_audit_kb)
-        return
-    last_iso = runtime_state.get("incidents_diff_last_ts")
-    last_dt = None
-    if isinstance(last_iso, str):
-        try:
-            last_dt = datetime.fromisoformat(last_iso)
-        except Exception:
-            last_dt = None
-    rows = read_raw(cfg, hours=hours, limit=5000, include_old=True)
-
-    def collect(from_dt):
-        fresh: list[tuple[datetime, str]] = []
-        for dt, line in rows:
-            if from_dt and dt <= from_dt:
-                continue
-            fresh.append((dt, line))
-        return fresh
-
-    fresh = collect(last_dt)
-    # auto-reset if marker is ahead of all rows
-    if not fresh and last_dt and rows and last_dt >= rows[-1][0]:
-        last_dt = None
-        runtime_state.set_state("incidents_diff_last_ts", None)
-        fresh = collect(None)
-
-    if not fresh:
-        note = f"since {last_dt.astimezone().strftime('%Y-%m-%d %H:%M')}" if last_dt else "for the period"
-        if rows:
-            sample = rows[-50:]
-            body = "\n".join(f"{dt.astimezone().strftime('%m-%d %H:%M')}  {line}" for dt, line in sample)
-            await msg.answer(
-                f"📣 No new incidents {note} (window {hours}h).\nRecent sample:\n```\n{body}\n```",
-                reply_markup=system_logs_audit_kb,
-                parse_mode="Markdown",
-            )
-        else:
-            await msg.answer(f"📣 No new incidents {note} (window {hours}h)", reply_markup=system_logs_audit_kb)
-        return
-    fresh.sort(key=lambda x: x[0])
-    body = "\n".join(f"{dt.astimezone().strftime('%m-%d %H:%M')}  {line}" for dt, line in fresh[-200:])
-    await msg.answer(
-        f"📣 New incidents (since last mark, window {hours}h): {len(fresh)}\n```\n{body}\n```",
-        reply_markup=system_logs_audit_kb,
-        parse_mode="Markdown",
-    )
     try:
-        runtime_state.set_state("incidents_diff_last_ts", fresh[-1][0].isoformat())
+        parts = msg.text.split()
-    except Exception:
+        hours = 24
-        pass
+        reset = False
+        if len(parts) >= 2:
+            if parts[1].lower() in {"reset", "clear"}:
+                reset = True
+            else:
+                try:
+                    hours = max(1, int(parts[1]))
+                except ValueError:
+                    hours = 24
+        if reset:
+            runtime_state.set_state("incidents_diff_last_ts", None)
+            await msg.answer(
+                "📣 Diff marker reset. Next run will show all within window.",
+                reply_markup=system_logs_audit_kb,
+            )
+            return
+
+        last_iso = runtime_state.get("incidents_diff_last_ts")
+        last_dt = None
+        if isinstance(last_iso, str):
+            try:
+                last_dt = datetime.fromisoformat(last_iso)
+            except Exception:
+                last_dt = None
+        rows = read_raw(cfg, hours=hours, limit=5000, include_old=True)
+
+        def collect(from_dt):
+            fresh: list[tuple[datetime, str]] = []
+            for dt, line in rows:
+                if from_dt and dt <= from_dt:
+                    continue
+                fresh.append((dt, line))
+            return fresh
+
+        fresh = collect(last_dt)
+        # auto-reset if marker is ahead of all rows
+        if not fresh and last_dt and rows and last_dt >= rows[-1][0]:
+            last_dt = None
+            runtime_state.set_state("incidents_diff_last_ts", None)
+            fresh = collect(None)
+
+        def fmt_lines(items: list[tuple[datetime, str]], limit_chars: int = 3500) -> str:
+            buf = []
+            total_len = 0
+            for dt, line in items:
+                entry = f"{dt.astimezone().strftime('%m-%d %H:%M')}  {line}"
+                if total_len + len(entry) + 1 > limit_chars:
+                    break
+                buf.append(entry)
+                total_len += len(entry) + 1
+            return "\n".join(buf)
+
+        if not fresh:
+            note = f"since {last_dt.astimezone().strftime('%Y-%m-%d %H:%M')}" if last_dt else "for the period"
+            if rows:
+                sample = rows[-50:][::-1]  # newest first
+                body = fmt_lines(sample)
+                await msg.answer(
+                    f"📣 No new incidents {note} (window {hours}h).\nRecent sample:\n```\n{body}\n```",
+                    reply_markup=system_logs_audit_kb,
+                    parse_mode="Markdown",
+                )
+            else:
+                await msg.answer(
+                    f"📣 No new incidents {note} (window {hours}h)",
+                    reply_markup=system_logs_audit_kb,
+                )
+            return
+
+        fresh.sort(key=lambda x: x[0], reverse=True)
+        body = fmt_lines(fresh)
+        await msg.answer(
+            f"📣 New incidents (since last mark, window {hours}h): {len(fresh)}\n```\n{body}\n```",
+            reply_markup=system_logs_audit_kb,
+            parse_mode="Markdown",
+        )
+        try:
+            runtime_state.set_state("incidents_diff_last_ts", fresh[0][0].isoformat())
+        except Exception:
+            pass
+    except Exception as e:
+        await msg.answer(f"⚠️ Diff error: {type(e).__name__}: {e}", reply_markup=system_logs_audit_kb)
 
 
 @dp.message(F.text.startswith("/alerts_heatmap"))