feat: clear chat history manually, auto-expire old history after 90 days

Manual: DELETE /api/v1/ai/chat-history (scoped by recipeId or scope=general,
matching GET's scoping) plus a trash-icon button + confirm dialog in both
chat panels' headers.

Automatic: new internal cron endpoint (chat-cleanup), same shared-secret
pattern as the existing leftover-reminders/weekly-digest crons, deletes
any chat_messages older than 90 days. Wired into cron/crontab (daily,
03:00 UTC) and the Dockerfile's cron stage.

Verified locally: cleared a real conversation through the actual UI and
confirmed it didn't come back on reopen (not just cleared client-side);
inserted a 100-day-old and a 5-day-old message directly, called the cron
endpoint with the real shared-secret check, confirmed only the old one
was deleted and the recent one survived; confirmed the endpoint 401s with
no/wrong secret.

Dockerfile

@@ -76,5 +76,6 @@ RUN apk add --no-cache curl
 COPY cron/crontab /etc/crontabs/root
 COPY cron/run-digest.sh /usr/local/bin/run-digest.sh
 COPY cron/run-leftover-reminders.sh /usr/local/bin/run-leftover-reminders.sh
-RUN chmod +x /usr/local/bin/run-digest.sh /usr/local/bin/run-leftover-reminders.sh
+COPY cron/run-chat-cleanup.sh /usr/local/bin/run-chat-cleanup.sh
+RUN chmod +x /usr/local/bin/run-digest.sh /usr/local/bin/run-leftover-reminders.sh /usr/local/bin/run-chat-cleanup.sh
 CMD ["crond", "-f", "-l", "2"]

apps/web/app/api/internal/cron/chat-cleanup/route.ts

@@ -0,0 +1,39 @@
+import { NextRequest, NextResponse } from "next/server";
+import crypto from "node:crypto";
+import { db, chatMessages, lt } from "@epicure/db";
+
+// Internal cron endpoint — triggered daily by a cron container (see
+// compose.prod.yml / cron/crontab). Not part of the public API surface;
+// protected by a shared secret rather than user auth.
+//
+// AI chat history (both the per-recipe chat and the general cooking
+// assistant) has no size cap and no per-user retention setting — this just
+// deletes anything past a fixed retention window so the table doesn't grow
+// unbounded.
+
+const RETENTION_DAYS = 90;
+
+function isAuthorized(req: NextRequest): boolean {
+  const secret = process.env["CRON_SECRET"];
+  if (!secret) return false;
+
+  const header = req.headers.get("authorization");
+  if (!header?.startsWith("Bearer ")) return false;
+  const provided = header.slice("Bearer ".length);
+
+  const a = Buffer.from(provided);
+  const b = Buffer.from(secret);
+  if (a.length !== b.length) return false;
+  return crypto.timingSafeEqual(a, b);
+}
+
+export async function POST(req: NextRequest) {
+  if (!isAuthorized(req)) {
+    return NextResponse.json({ error: "Unauthorized" }, { status: 401 });
+  }
+
+  const cutoff = new Date(Date.now() - RETENTION_DAYS * 24 * 60 * 60 * 1000);
+  const deleted = await db.delete(chatMessages).where(lt(chatMessages.createdAt, cutoff)).returning({ id: chatMessages.id });
+
+  return NextResponse.json({ ok: true, deleted: deleted.length });
+}

apps/web/app/api/v1/ai/chat-history/route.ts

@@ -51,3 +51,33 @@ export async function GET(req: NextRequest) {
     })),
   });
 }
+
+const DeleteSchema = z.object({
+  recipeId: z.string().uuid().optional(),
+  scope: z.enum(["general"]).optional(),
+});
+
+// No `q` here on purpose — clearing is "this whole conversation" (or
+// everything), not "every message matching a search term".
+export async function DELETE(req: NextRequest) {
+  const { session, response } = await requireSession();
+  if (response) return response;
+
+  const { searchParams } = new URL(req.url);
+  const parsed = DeleteSchema.safeParse({
+    recipeId: searchParams.get("recipeId") ?? undefined,
+    scope: searchParams.get("scope") ?? undefined,
+  });
+  if (!parsed.success) {
+    return NextResponse.json({ error: "Validation error" }, { status: 400 });
+  }
+  const { recipeId, scope } = parsed.data;
+
+  const conditions = [eq(chatMessages.userId, session!.user.id)];
+  if (recipeId) conditions.push(eq(chatMessages.recipeId, recipeId));
+  else if (scope === "general") conditions.push(isNull(chatMessages.recipeId));
+
+  await db.delete(chatMessages).where(and(...conditions));
+
+  return NextResponse.json({ ok: true });
+}

apps/web/components/recipe/clear-chat-history-button.tsx

@@ -0,0 +1,83 @@
+"use client";
+
+import { useState } from "react";
+import { useTranslations } from "next-intl";
+import { Trash2 } from "lucide-react";
+import { toast } from "sonner";
+import {
+  AlertDialog,
+  AlertDialogAction,
+  AlertDialogCancel,
+  AlertDialogContent,
+  AlertDialogDescription,
+  AlertDialogFooter,
+  AlertDialogHeader,
+  AlertDialogTitle,
+} from "@/components/ui/alert-dialog";
+
+export function ClearChatHistoryButton({
+  recipeId,
+  disabled,
+  onCleared,
+}: {
+  recipeId?: string;
+  disabled?: boolean;
+  onCleared: () => void;
+}) {
+  const t = useTranslations("chatHistory");
+  const [confirmOpen, setConfirmOpen] = useState(false);
+  const [clearing, setClearing] = useState(false);
+
+  async function handleClear() {
+    setClearing(true);
+    try {
+      const params = new URLSearchParams();
+      if (recipeId) params.set("recipeId", recipeId);
+      else params.set("scope", "general");
+      const res = await fetch(`/api/v1/ai/chat-history?${params.toString()}`, { method: "DELETE" });
+      if (!res.ok) {
+        toast.error(t("clearFailed"));
+        return;
+      }
+      onCleared();
+      toast.success(t("cleared"));
+    } catch {
+      toast.error(t("clearFailed"));
+    } finally {
+      setClearing(false);
+      setConfirmOpen(false);
+    }
+  }
+
+  return (
+    <>
+      <button
+        type="button"
+        onClick={() => setConfirmOpen(true)}
+        disabled={disabled || clearing}
+        className="p-1.5 rounded-md hover:bg-muted transition-colors text-muted-foreground disabled:opacity-40"
+        aria-label={t("clearAriaLabel")}
+      >
+        <Trash2 className="h-4 w-4" />
+      </button>
+
+      <AlertDialog open={confirmOpen} onOpenChange={setConfirmOpen}>
+        <AlertDialogContent>
+          <AlertDialogHeader>
+            <AlertDialogTitle>{t("clearConfirmTitle")}</AlertDialogTitle>
+            <AlertDialogDescription>{t("clearConfirmDescription")}</AlertDialogDescription>
+          </AlertDialogHeader>
+          <AlertDialogFooter>
+            <AlertDialogCancel>{t("clearCancel")}</AlertDialogCancel>
+            <AlertDialogAction
+              onClick={() => { void handleClear(); }}
+              className="bg-destructive text-destructive-foreground hover:bg-destructive/90"
+            >
+              {t("clearConfirm")}
+            </AlertDialogAction>
+          </AlertDialogFooter>
+        </AlertDialogContent>
+      </AlertDialog>
+    </>
+  );
+}

apps/web/components/recipe/cooking-assistant-panel.tsx

@@ -9,6 +9,7 @@ import { MessageCircle, Send, Bot, User } from "lucide-react";
 import ReactMarkdown from "react-markdown";
 import { cn } from "@/lib/utils";
 import { ChatHistorySearch } from "./chat-history-search";
+import { ClearChatHistoryButton } from "./clear-chat-history-button";
 
 type Message = {
   role: "user" | "assistant";
@@ -103,7 +104,10 @@ export function CookingAssistantPanel() {
                 <Bot className="h-4 w-4 text-primary" />
                 {t("title")}
               </SheetTitle>
+              <div className="flex items-center gap-0.5">
                 <ChatHistorySearch />
+                <ClearChatHistoryButton disabled={messages.length === 0} onCleared={() => setMessages([])} />
+              </div>
             </div>
             <p className="text-xs text-muted-foreground text-left">{t("subtitle")}</p>
           </SheetHeader>

apps/web/components/recipe/recipe-chat-panel.tsx

@@ -9,6 +9,7 @@ import { MessageCircle, Send, Bot, User } from "lucide-react";
 import ReactMarkdown from "react-markdown";
 import { cn } from "@/lib/utils";
 import { ChatHistorySearch } from "./chat-history-search";
+import { ClearChatHistoryButton } from "./clear-chat-history-button";
 
 type Message = {
   role: "user" | "assistant";
@@ -105,7 +106,10 @@ export function RecipeChatPanel({ recipeId, recipeTitle }: Props) {
                 <Bot className="h-4 w-4 text-primary" />
                 {t("title")}
               </SheetTitle>
+              <div className="flex items-center gap-0.5">
                 <ChatHistorySearch recipeId={recipeId} />
+                <ClearChatHistoryButton recipeId={recipeId} disabled={messages.length === 0} onCleared={() => setMessages([])} />
+              </div>
             </div>
             <p className="text-xs text-muted-foreground text-left">{recipeTitle}</p>
           </SheetHeader>

apps/web/messages/en.json

@@ -393,7 +393,14 @@
     "searchPlaceholder": "Search past questions…",
     "searching": "Searching…",
     "noResults": "No matching messages",
-    "close": "Close"
+    "close": "Close",
+    "clearAriaLabel": "Clear chat history",
+    "clearConfirmTitle": "Clear this conversation?",
+    "clearConfirmDescription": "This deletes the saved history for this chat. This can't be undone.",
+    "clearCancel": "Cancel",
+    "clearConfirm": "Clear history",
+    "cleared": "Chat history cleared",
+    "clearFailed": "Failed to clear chat history"
   },
   "cookingChat": {
     "sorry": "Sorry, I couldn't answer that.",

apps/web/messages/fr.json

@@ -393,7 +393,14 @@
     "searchPlaceholder": "Rechercher une question passée…",
     "searching": "Recherche…",
     "noResults": "Aucun message correspondant",
-    "close": "Fermer"
+    "close": "Fermer",
+    "clearAriaLabel": "Effacer l'historique",
+    "clearConfirmTitle": "Effacer cette conversation ?",
+    "clearConfirmDescription": "Cela supprime l'historique enregistré de cette conversation. Cette action est irréversible.",
+    "clearCancel": "Annuler",
+    "clearConfirm": "Effacer l'historique",
+    "cleared": "Historique effacé",
+    "clearFailed": "Échec de l'effacement de l'historique"
   },
   "cookingChat": {
     "sorry": "Désolé, je n'ai pas pu répondre à cela.",

cron/crontab

@@ -3,3 +3,6 @@
 
 # Leftover-expiry reminders — daily at 09:00 UTC.
 0 9 * * * /usr/local/bin/run-leftover-reminders.sh >> /proc/1/fd/1 2>> /proc/1/fd/2
+
+# AI chat history cleanup (90-day retention) — daily at 03:00 UTC.
+0 3 * * * /usr/local/bin/run-chat-cleanup.sh >> /proc/1/fd/1 2>> /proc/1/fd/2

cron/run-chat-cleanup.sh

@@ -0,0 +1,17 @@
+#!/bin/sh
+# Triggers deletion of AI chat history older than the retention window on the
+# `web` service. Run on a schedule by busybox crond (see cron/crontab). Fails
+# loudly (non-zero exit, stderr) but crond just tries again tomorrow — no
+# retry loop here on purpose, keep this script trivial.
+set -eu
+
+: "${WEB_INTERNAL_URL:=http://web:3000}"
+
+if [ -z "${CRON_SECRET:-}" ]; then
+  echo "run-chat-cleanup: CRON_SECRET is not set, refusing to call the endpoint" >&2
+  exit 1
+fi
+
+curl -fsS -X POST \
+  -H "Authorization: Bearer ${CRON_SECRET}" \
+  "${WEB_INTERNAL_URL}/api/internal/cron/chat-cleanup"