feat: implement ai doubt bookmark and favorites feature

app/(dashboard)/ai-tutor/page.tsx

@@ -60,6 +60,7 @@ import NextLink from "next/link"
 import { LoginGateModal } from "@/components/login-gate-modal"
 import { CreditsExhaustedModal } from "@/components/credits-exhausted-modal"
 import { MarkdownRenderer } from "@/components/markdown-renderer"
+import { BookmarkButton } from "@/components/bookmarks/BookmarkButton"
 
 interface ResourceLink {
   title: string
@@ -1143,9 +1144,14 @@ function AITutorContent() {
             >
               <div className="mx-auto max-w-4xl space-y-4 md:space-y-6">
                 <div ref={messagesTopRef} />
-                {messages.map((message) => {
+                {messages.map((message, messageIndex) => {
                   const feedback = messageFeedback[message.id]
                   const hasSources = message.role === "assistant" && (message.sources?.length || 0) > 0
+
+                  const precedingUserMessage = [...messages.slice(0, messageIndex)].reverse().find((m) => m.role === "user")
+                  const userQuestion = precedingUserMessage?.content || "AI Tutor Doubt"
+                  const currentSession = chatSessions.find((s) => s.id === activeSessionId)
+                  const subjectTopic = currentSession?.title || "AI Tutor"
 
                   return (
                     <div
@@ -1274,6 +1280,13 @@ function AITutorContent() {
                                   )}
                                 </Button>
 
+                                <BookmarkButton
+                                  question={userQuestion}
+                                  answer={message.content}
+                                  subject={subjectTopic}
+                                  tags={["AI Tutor"]}
+                                />
+
                                 <Button
                                   variant="ghost"
                                   size="icon"

app/(dashboard)/bookmarks/page.tsx

@@ -0,0 +1,28 @@
+import type { Metadata } from "next"
+import { BookmarkList } from "@/components/bookmarks/BookmarkList"
+import { Bookmark } from "lucide-react"
+
+export const metadata: Metadata = {
+  title: "Bookmarks",
+  description: "Revisit and organize your bookmarked AI Tutor responses.",
+}
+
+export default function BookmarksPage() {
+  return (
+    <div className="flex-1 space-y-6 p-4 md:p-8 max-w-7xl mx-auto">
+      <div className="flex items-center gap-3">
+        <div className="flex h-12 w-12 items-center justify-center rounded-2xl bg-primary/10">
+          <Bookmark className="h-6 w-6 text-primary" />
+        </div>
+        <div>
+          <h1 className="text-2xl font-bold tracking-tight text-foreground md:text-3xl">Saved Bookmarks</h1>
+          <p className="text-sm text-muted-foreground md:text-base">
+            Your personal knowledge library of bookmarked AI responses.
+          </p>
+        </div>
+      </div>
+
+      <BookmarkList />
+    </div>
+  )
+}

app/api/ai/chat/route.ts

@@ -1,3 +1,4 @@
+
 export const dynamic = "force-dynamic";
 
 import { NextRequest, NextResponse } from "next/server";
@@ -97,19 +98,19 @@ export async function POST(req: NextRequest) {
 
     const aiResponse = attachments.length
       ? await analyzeAttachmentsWithGemini({
-          message:
-            cleanMessage ||
-            "Please review the uploaded file and help me understand it.",
-          attachments,
-          webContext,
-        })
+        message:
+          cleanMessage ||
+          "Please review the uploaded file and help me understand it.",
+        attachments,
+        webContext,
+      })
       : await generateAIResponse(
-          cleanMessage || "Please help me with the uploaded study material.",
-          {
-            mode,
-            webContext,
-          },
-        );
+        cleanMessage || "Please help me with the uploaded study material.",
+        {
+          mode,
+          webContext,
+        },
+      );
 
     const finalReply = formatReplyWithSources(aiResponse, sources);
 

app/api/bookmarks/[id]/route.ts

@@ -0,0 +1,26 @@
+import { NextResponse } from "next/server"
+import { getUser } from "@/lib/auth-server"
+import { deleteBookmark } from "@/lib/bookmarks-db"
+
+export const dynamic = "force-dynamic"
+
+export async function DELETE(
+  _req: Request,
+  context: { params: Promise<{ id: string }> }
+) {
+  try {
+    const user = await getUser()
+    if (!user) {
+      return NextResponse.json({ error: "Unauthorized" }, { status: 401 })
+    }
+
+    const { id } = await context.params
+    await deleteBookmark(user.id, id)
+
+    return NextResponse.json({ success: true })
+  } catch (err) {
+    console.error("[api/bookmarks/[id]] DELETE Error:", err)
+    const msg = err instanceof Error ? err.message : "Failed to delete bookmark"
+    return NextResponse.json({ error: msg }, { status: 500 })
+  }
+}

app/api/bookmarks/route.ts

@@ -0,0 +1,64 @@
+import { NextResponse, NextRequest } from "next/server"
+import { getUser } from "@/lib/auth-server"
+import { getBookmarks, createBookmark } from "@/lib/bookmarks-db"
+import { z } from "zod"
+
+export const dynamic = "force-dynamic"
+
+const createBookmarkSchema = z.object({
+  question: z.string().min(1, "Question is required"),
+  answer: z.string().min(1, "Answer is required"),
+  subject: z.string().nullable().optional(),
+  tags: z.array(z.string()).default([]),
+})
+
+export async function GET(req: NextRequest) {
+  try {
+    const user = await getUser()
+    if (!user) {
+      return NextResponse.json({ error: "Unauthorized" }, { status: 401 })
+    }
+
+    const { searchParams } = new URL(req.url)
+    const search = searchParams.get("search") || undefined
+    const tag = searchParams.get("tag") || undefined
+
+    const bookmarks = await getBookmarks(user.id, { search, tag })
+    return NextResponse.json({ success: true, data: bookmarks })
+  } catch (err) {
+    console.error("[api/bookmarks] GET Error:", err)
+    const msg = err instanceof Error ? err.message : "Failed to load bookmarks"
+    return NextResponse.json({ error: msg }, { status: 500 })
+  }
+}
+
+export async function POST(req: Request) {
+  try {
+    const user = await getUser()
+    if (!user) {
+      return NextResponse.json({ error: "Unauthorized" }, { status: 401 })
+    }
+
+    const body = await req.json().catch(() => ({}))
+    const result = createBookmarkSchema.safeParse(body)
+
+    if (!result.success) {
+      const errorMsg = result.error.errors.map((e) => e.message).join(", ")
+      return NextResponse.json({ error: errorMsg }, { status: 400 })
+    }
+
+    const bookmark = await createBookmark(user.id, result.data)
+    return NextResponse.json({ success: true, data: bookmark }, { status: 201 })
+  } catch (err) {
+    console.error("[api/bookmarks] POST Error:", err)
+    const code = (err as { code?: string })?.code
+    if (code === "DUPLICATE_BOOKMARK") {
+      return NextResponse.json(
+        { error: "This response is already bookmarked", code: "DUPLICATE_BOOKMARK" },
+        { status: 409 }
+      )
+    }
+    const msg = err instanceof Error ? err.message : "Failed to save bookmark"
+    return NextResponse.json({ error: msg }, { status: 500 })
+  }
+}

components/bookmarks/BookmarkButton.tsx

@@ -0,0 +1,109 @@
+"use client"
+
+import { useState } from "react"
+import { Button } from "@/components/ui/button"
+import { Bookmark, BookmarkCheck, Loader2 } from "lucide-react"
+import { useToast } from "@/hooks/use-toast"
+import { cn } from "@/lib/utils"
+
+interface BookmarkButtonProps {
+  question: string
+  answer: string
+  subject?: string | null
+  tags?: string[]
+  className?: string
+}
+
+export function BookmarkButton({
+  question,
+  answer,
+  subject,
+  tags = [],
+  className,
+}: BookmarkButtonProps) {
+  const [isBookmarked, setIsBookmarked] = useState(false)
+  const [isSaving, setIsSaving] = useState(false)
+  const { toast } = useToast()
+
+  const handleBookmark = async (e: React.MouseEvent) => {
+    e.stopPropagation()
+    if (isSaving || isBookmarked) return
+
+    setIsSaving(true)
+    try {
+      const response = await fetch("/api/bookmarks", {
+        method: "POST",
+        headers: {
+          "Content-Type": "application/json",
+        },
+        body: JSON.stringify({
+          question,
+          answer,
+          subject: subject || "AI Tutor",
+          tags,
+        }),
+      })
+
+      const data = await response.json()
+
+      if (response.status === 401) {
+        toast({
+          title: "Sign in required",
+          description: "You must be signed in to bookmark AI Tutor responses.",
+          variant: "destructive",
+        })
+        return
+      }
+
+      if (response.status === 409 || data.code === "DUPLICATE_BOOKMARK") {
+        setIsBookmarked(true)
+        toast({
+          title: "Already bookmarked",
+          description: "This response is already saved in your bookmarks.",
+        })
+        return
+      }
+
+      if (!response.ok) {
+        throw new Error(data.error || "Failed to save bookmark")
+      }
+
+      setIsBookmarked(true)
+      toast({
+        title: "Bookmark saved",
+        description: "AI response has been bookmarked successfully.",
+      })
+    } catch (error) {
+      toast({
+        variant: "destructive",
+        title: "Error saving bookmark",
+        description: error instanceof Error ? error.message : "Something went wrong.",
+      })
+    } finally {
+      setIsSaving(false)
+    }
+  }
+
+  return (
+    <Button
+      variant="ghost"
+      size="icon"
+      className={cn(
+        "h-7 w-7 text-muted-foreground hover:text-foreground transition-colors duration-200",
+        isBookmarked && "text-primary hover:text-primary",
+        className
+      )}
+      onClick={handleBookmark}
+      disabled={isSaving}
+      title={isBookmarked ? "Bookmarked" : "Bookmark this answer"}
+    >
+      {isSaving ? (
+        <Loader2 className="h-3.5 w-3.5 animate-spin" />
+      ) : isBookmarked ? (
+        <BookmarkCheck className="h-3.5 w-3.5" />
+      ) : (
+        <Bookmark className="h-3.5 w-3.5" />
+      )}
+    </Button>
+  )
+}