Tighten typing and input validation across study pages

src/app/(protected)/[classSlug]/flashcards/page.tsx

@@ -27,6 +27,7 @@ import {
   useSortable,
 } from "@dnd-kit/sortable";
 import { CSS } from "@dnd-kit/utilities";
+import type { ReorderItem } from "@/types/study";
 
 interface DeckItem {
   id: string;
@@ -65,7 +66,14 @@ function getProgressLabel(deck: DeckItem) {
   return `${current}/${total}, ${modeLabel} · ${correctCount} ✓`;
 }
 
-function SortableDeckCard({ deck, onEdit, onDelete, classSlug }: any) {
+interface SortableDeckCardProps {
+  deck: DeckItem;
+  onEdit: (deck: DeckItem) => void;
+  onDelete: (deck: DeckItem) => void;
+  classSlug: string;
+}
+
+function SortableDeckCard({ deck, onEdit, onDelete, classSlug }: SortableDeckCardProps) {
   const { attributes, listeners, setNodeRef, transform, transition, isDragging } = useSortable({ id: deck.id });
   const style = {
     transform: CSS.Transform.toString(transform),
@@ -314,8 +322,6 @@ export default function FlashcardsPage() {
     if (!activeDeck) return;
 
     let targetGroupId: string | null = null;
-    let targetIndex = 0;
-
     const overContainerId = over.data.current?.sortable?.containerId;
     if (overContainerId) {
        targetGroupId = overContainerId === "uncategorized" ? null : overContainerId;
@@ -344,7 +350,7 @@ export default function FlashcardsPage() {
         }
 
         const affectedGroups = new Set([activeDeck.groupId, targetGroupId]);
-        const updates: any[] = [];
+        const updates: ReorderItem[] = [];
         
         affectedGroups.forEach(gId => {
            const gItems = newItems.filter(d => d.groupId === gId);

src/app/(protected)/[classSlug]/quizzes/page.tsx

@@ -27,6 +27,7 @@ import {
   useSortable,
 } from "@dnd-kit/sortable";
 import { CSS } from "@dnd-kit/utilities";
+import type { ReorderItem } from "@/types/study";
 
 interface QuizItem {
   id: string;
@@ -51,7 +52,14 @@ interface MaterialGroup {
 
 const cache: Record<string, { quizzes: QuizItem[]; groups: MaterialGroup[] }> = {};
 
-function SortableQuizCard({ quiz, onEdit, onDelete, classSlug }: any) {
+interface SortableQuizCardProps {
+  quiz: QuizItem;
+  onEdit: (quiz: QuizItem) => void;
+  onDelete: (quiz: QuizItem) => void;
+  classSlug: string;
+}
+
+function SortableQuizCard({ quiz, onEdit, onDelete, classSlug }: SortableQuizCardProps) {
   const { attributes, listeners, setNodeRef, transform, transition, isDragging } = useSortable({ id: quiz.id });
   const style = {
     transform: CSS.Transform.toString(transform),
@@ -312,8 +320,6 @@ export default function QuizzesPage() {
     if (!activeQuiz) return;
 
     let targetGroupId: string | null = null;
-    let targetIndex = 0;
-
     // Check if over a group container directly
     const overContainerId = over.data.current?.sortable?.containerId;
     if (overContainerId) {
@@ -345,7 +351,7 @@ export default function QuizzesPage() {
 
         // Re-calculate sortOrder for the affected groups to persist
         const affectedGroups = new Set([activeQuiz.groupId, targetGroupId]);
-        const updates: any[] = [];
+        const updates: ReorderItem[] = [];
         
         affectedGroups.forEach(gId => {
            const gItems = newItems.filter(q => q.groupId === gId);

src/app/api/decks/reorder/route.ts

@@ -1,19 +1,20 @@
 import { NextRequest, NextResponse } from "next/server";
 import { prisma } from "@/lib/db";
+import { reorderRequestSchema } from "@/lib/validation/reorderSchemas";
 
 export async function PATCH(request: NextRequest) {
   try {
-    const body = await request.json();
+    const parsed = reorderRequestSchema.safeParse(await request.json());
-    const { items } = body;
+    if (!parsed.success) {
-
-    if (!Array.isArray(items)) {
       return NextResponse.json({ error: "Invalid input" }, { status: 400 });
     }
 
+    const { items } = parsed.data;
+
     // items should be an array of { id, sortOrder, groupId }
     // Using a transaction to perform all updates
     await prisma.$transaction(
-      items.map((item: any) =>
+      items.map((item) =>
         prisma.deck.update({
           where: { id: item.id },
           data: {

src/app/api/material-groups/[id]/route.ts

@@ -1,5 +1,6 @@
 import { NextRequest, NextResponse } from "next/server";
 import { prisma } from "@/lib/db";
+import type { Prisma } from "@/generated/prisma/client";
 
 export async function PATCH(
   request: NextRequest,
@@ -10,7 +11,7 @@ export async function PATCH(
     const body = await request.json();
     const { name, sortOrder } = body;
 
-    const updateData: any = {};
+    const updateData: Prisma.MaterialGroupUpdateInput = {};
     if (name !== undefined) updateData.name = name;
     if (sortOrder !== undefined) updateData.sortOrder = sortOrder;
 

src/app/api/material-groups/route.ts

@@ -1,5 +1,6 @@
 import { NextRequest, NextResponse } from "next/server";
 import { prisma } from "@/lib/db";
+import type { Prisma } from "@/generated/prisma/client";
 
 export async function GET(request: NextRequest) {
   const { searchParams } = new URL(request.url);
@@ -14,7 +15,7 @@ export async function GET(request: NextRequest) {
     return NextResponse.json({ error: "Invalid type" }, { status: 400 });
   }
 
-  const whereClause: any = { classId };
+  const whereClause: Prisma.MaterialGroupWhereInput = { classId };
   if (type) {
     whereClause.type = type;
   }

src/app/api/quizzes/reorder/route.ts

@@ -1,19 +1,20 @@
 import { NextRequest, NextResponse } from "next/server";
 import { prisma } from "@/lib/db";
+import { reorderRequestSchema } from "@/lib/validation/reorderSchemas";
 
 export async function PATCH(request: NextRequest) {
   try {
-    const body = await request.json();
+    const parsed = reorderRequestSchema.safeParse(await request.json());
-    const { items } = body;
+    if (!parsed.success) {
-
-    if (!Array.isArray(items)) {
       return NextResponse.json({ error: "Invalid input" }, { status: 400 });
     }
 
+    const { items } = parsed.data;
+
     // items should be an array of { id, sortOrder, groupId }
     // Using a transaction to perform all updates
     await prisma.$transaction(
-      items.map((item: any) =>
+      items.map((item) =>
         prisma.quizSet.update({
           where: { id: item.id },
           data: {

src/app/shared/[classSlug]/[type]/[token]/SharedGroupViewer.tsx

@@ -4,8 +4,9 @@ import { useState, useEffect } from "react";
 
 import Link from "next/link";
 import { usePathname, useRouter } from "next/navigation";
+import type { SharedGroupData } from "@/types/study";
 
-export function SharedGroupViewer({ data }: { data: any }) {
+export function SharedGroupViewer({ data }: { data: SharedGroupData }) {
   const pathname = usePathname();
   const router = useRouter();
   
@@ -18,7 +19,7 @@ export function SharedGroupViewer({ data }: { data: any }) {
     if (typeof window === 'undefined') return;
     
     const newProgress: Record<string, { currentIndex: number, total: number }> = {};
-    items.forEach((item: any) => {
+    items.forEach((item) => {
       const key = data.type === "DECK" ? `flashcard_progress_${item.id}` : `quiz_progress_${item.id}`;
       const saved = localStorage.getItem(key);
       if (saved) {
@@ -71,7 +72,7 @@ export function SharedGroupViewer({ data }: { data: any }) {
       </div>
 
       <div className="grid grid-cols-1 md:grid-cols-2 gap-4">
-        {items.map((item: any) => (
+        {items.map((item) => (
           <div
             key={item.id}
             className="group flex flex-col bg-bg-surface border border-border-light rounded-xl shadow-[var(--shadow-card)] hover:shadow-[var(--shadow-card-hover)] hover:border-primary/20 transition-all duration-300"

src/app/shared/[classSlug]/[type]/[token]/SharedViewer.tsx

@@ -6,10 +6,11 @@ import { usePathname } from "next/navigation";
 import { FlashcardViewer } from "@/components/flashcards/FlashcardViewer";
 import { QuizViewer } from "@/components/quizzes/QuizViewer";
 import { CardList } from "@/components/flashcards/CardList";
+import type { SharedStudyItem } from "@/types/study";
 
 interface SharedViewerProps {
-  type: string;
+  type: "flashcards" | "quizzes";
-  data: any;
+  data: SharedStudyItem;
   groupMode?: boolean;
 }
 
@@ -36,7 +37,7 @@ export function SharedViewer({ type, data, groupMode = false }: SharedViewerProp
 
   const [showTopics, setShowTopics] = useState(false);
   const categories = type === "quizzes" && data.questions
-    ? Array.from(new Set(data.questions.map((q: any) => q.category.toUpperCase()))).join(" · ")
+    ? Array.from(new Set(data.questions.map((q) => q.category.toUpperCase()))).join(" · ")
     : "";
 
   return (
@@ -137,18 +138,20 @@ export function SharedViewer({ type, data, groupMode = false }: SharedViewerProp
         view === "study" ? (
           <FlashcardViewer 
             key={restartKey} 
-            cards={data.cards} 
+            cards={data.cards ?? []}
             deckId={data.id} 
             isShared={true} 
           />
         ) : (
-          <CardList cards={data.cards} />
+          <CardList cards={data.cards ?? []} />
         )
       ) : (
         <QuizViewer
           key={restartKey}
           quiz={{
-            ...data,
+            id: data.id,
+            name: data.name,
+            questions: data.questions ?? [],
             progress: [], // Start fresh since it's shared
           }}
           retakeIds={null}

src/app/shared/[classSlug]/[type]/[token]/page.tsx

@@ -4,6 +4,9 @@ import { ThemeToggle } from "@/components/ui/ThemeToggle";
 import Link from "next/link";
 import { SharedViewer } from "./SharedViewer";
 import { SharedGroupViewer } from "./SharedGroupViewer";
+import type { SharedGroupData, SharedStudyItem } from "@/types/study";
+
+type SharedContentType = "flashcards" | "quizzes";
 
 interface SharedPageProps {
   params: Promise<{
@@ -48,17 +51,17 @@ export default async function SharedPage(props: SharedPageProps & { searchParams
     notFound();
   }
   
-  let targetData: any = null;
+  let targetData: SharedStudyItem | SharedGroupData | null = null;
-  let targetType = type;
+  let targetType: SharedContentType = type === "flashcards" ? "flashcards" : "quizzes";
   
   if (type === "groups" && link.group) {
     if (itemId) {
       // Find the specific item inside the group
       if (link.group.type === "DECK") {
-        targetData = link.group.decks.find(d => d.id === itemId);
+        targetData = link.group.decks.find(d => d.id === itemId) ?? null;
         targetType = "flashcards";
       } else {
-        targetData = link.group.quizSets.find(q => q.id === itemId);
+        targetData = link.group.quizSets.find(q => q.id === itemId) ?? null;
         targetType = "quizzes";
       }
       if (!targetData) notFound();
@@ -69,6 +72,8 @@ export default async function SharedPage(props: SharedPageProps & { searchParams
     targetData = type === "flashcards" ? link.deck : link.quizSet;
   }
 
+  if (!targetData) notFound();
+
   return (
     <div className="min-h-screen bg-bg-base flex flex-col">
       {/* Read-only Header */}
@@ -105,11 +110,11 @@ export default async function SharedPage(props: SharedPageProps & { searchParams
       <main className="flex-1 overflow-y-auto">
         <div className="mx-auto max-w-5xl px-4 py-6 sm:px-6 sm:py-8 lg:px-8">
           {type === "groups" && !itemId ? (
-            <SharedGroupViewer data={targetData} />
+            <SharedGroupViewer data={targetData as SharedGroupData} />
           ) : (
             <SharedViewer 
               type={targetType} 
-              data={targetData}
+              data={targetData as SharedStudyItem}
               groupMode={type === "groups"}
             />
           )}

src/components/import/CreateTab.tsx

@@ -74,8 +74,8 @@ export function CreateTab({ classId, onCreated }: CreateTabProps) {
       }
 
       onCreated();
-    } catch (err: any) {
+    } catch (err: unknown) {
-      setError(err.message);
+      setError(err instanceof Error ? err.message : "Failed to create deck");
     } finally {
       setSaving(false);
     }

src/components/quizzes/AttemptHistory.tsx

@@ -2,15 +2,16 @@
 
 import { useState } from "react";
 import { QuizResults } from "./QuizResults";
+import type { QuizAttempt, QuizSummary } from "@/types/study";
 
 interface AttemptHistoryProps {
-  quiz: any;
+  quiz: QuizSummary;
-  attempts: any[];
+  attempts: QuizAttempt[];
   onRetake: (missedIds: string[]) => void;
 }
 
 export function AttemptHistory({ quiz, attempts, onRetake }: AttemptHistoryProps) {
-  const [selectedAttempt, setSelectedAttempt] = useState<any | null>(null);
+  const [selectedAttempt, setSelectedAttempt] = useState<QuizAttempt | null>(null);
 
   if (selectedAttempt) {
     return (

src/components/quizzes/CategoryBreakdown.tsx

@@ -2,20 +2,20 @@
 
 import { Fragment } from "react";
 import { scoreQuestion } from "@/lib/scoring";
+import type { QuizSummary } from "@/types/study";
 
 interface CategoryBreakdownProps {
-  quiz: any;
+  quiz: QuizSummary;
-  attempt: any;
   answeredIds: string[];
   answers: Record<string, string[]>;
 }
 
-export function CategoryBreakdown({ quiz, attempt, answeredIds, answers }: CategoryBreakdownProps) {
+export function CategoryBreakdown({ quiz, answeredIds, answers }: CategoryBreakdownProps) {
   // Aggregate stats per category
   const stats: Record<string, { earned: number; possible: number }> = {};
   
   answeredIds.forEach((qId) => {
-    const q = quiz.questions.find((x: any) => x.id === qId);
+    const q = quiz.questions.find((x) => x.id === qId);
     if (!q) return;
     
     const cat = q.category.trim().toLowerCase();
@@ -23,7 +23,11 @@ export function CategoryBreakdown({ quiz, attempt, answeredIds, answers }: Categ
       stats[cat] = { earned: 0, possible: 0 };
     }
     
-    const formattedQ = { id: q.id, type: q.type, options: q.options };
+    const formattedQ = {
+      id: q.id,
+      type: q.type as "MULTIPLE_CHOICE" | "SATA",
+      options: q.options,
+    };
     const points = scoreQuestion(formattedQ, answers[q.id] || []);
     
     stats[cat].earned += points;

src/components/quizzes/QuizResults.tsx

@@ -4,14 +4,21 @@ import ReactMarkdown from "react-markdown";
 import remarkGfm from "remark-gfm";
 import { CategoryBreakdown } from "./CategoryBreakdown";
 import { scoreQuestion } from "@/lib/scoring";
+import type { QuizAttempt, QuizQuestion, QuizSummary } from "@/types/study";
 
 interface QuizResultsProps {
-  quiz: any; // QuizData
+  quiz: QuizSummary;
-  attempt: any; // QuizAttempt
+  attempt: QuizAttempt;
   onRetake: (missedIds: string[]) => void;
   onClose?: () => void;
 }
 
+interface ReviewItem {
+  question: QuizQuestion;
+  score: number;
+  selections: string[];
+}
+
 export function QuizResults({ quiz, attempt, onRetake, onClose }: QuizResultsProps) {
   let answers: Record<string, string[]> = {};
   try {
@@ -19,16 +26,16 @@ export function QuizResults({ quiz, attempt, onRetake, onClose }: QuizResultsPro
   } catch {}
 
   // Determine non-full-credit questions for review list
-  const reviewItems: any[] = [];
+  const reviewItems: ReviewItem[] = [];
   const missedIds: string[] = [];
 
   const answeredIds = Object.keys(answers);
-  const questionsToReview = quiz.questions.filter((q: any) => answeredIds.includes(q.id));
+  const questionsToReview = quiz.questions.filter((q) => answeredIds.includes(q.id));
 
-  questionsToReview.forEach((q: any) => {
+  questionsToReview.forEach((q) => {
     const formattedQ = {
       id: q.id,
-      type: q.type,
+      type: q.type as "MULTIPLE_CHOICE" | "SATA",
       options: q.options,
     };
     const score = scoreQuestion(formattedQ, answers[q.id] || []);
@@ -92,7 +99,7 @@ export function QuizResults({ quiz, attempt, onRetake, onClose }: QuizResultsPro
 
           <button
             onClick={() => {
-              const allIds = quiz.questions.map((q: any) => q.id).sort(() => Math.random() - 0.5);
+              const allIds = quiz.questions.map((q) => q.id).sort(() => Math.random() - 0.5);
               onRetake(allIds);
             }}
             className="px-6 py-2.5 rounded-lg border border-primary text-primary font-medium hover:bg-primary/5 transition-all duration-200 cursor-pointer"
@@ -105,7 +112,7 @@ export function QuizResults({ quiz, attempt, onRetake, onClose }: QuizResultsPro
       {/* Category Breakdown */}
       <div className="bg-bg-surface rounded-2xl border border-border-light shadow-[var(--shadow-card)] p-6 md:p-8">
         <h3 className="text-lg font-bold text-text-heading mb-6">Category Breakdown</h3>
-        <CategoryBreakdown quiz={quiz} attempt={attempt} answeredIds={answeredIds} answers={answers} />
+        <CategoryBreakdown quiz={quiz} answeredIds={answeredIds} answers={answers} />
       </div>
 
       {/* Review List */}
@@ -113,7 +120,7 @@ export function QuizResults({ quiz, attempt, onRetake, onClose }: QuizResultsPro
         <div className="space-y-6">
           <h3 className="text-xl font-bold text-text-heading px-2">Areas for Review</h3>
           
-          {reviewItems.map((item, idx) => {
+          {reviewItems.map((item) => {
             const q = item.question;
             const sels = item.selections;
             return (
@@ -128,7 +135,7 @@ export function QuizResults({ quiz, attempt, onRetake, onClose }: QuizResultsPro
                   </div>
                   
                   <div className="space-y-2 mb-6">
-                    {q.options.map((opt: any) => {
+                    {q.options.map((opt) => {
                       const isSelected = sels.includes(opt.id);
                       let stateClass = "cursor-default opacity-80";
                       let icon = null;

src/components/quizzes/QuizViewer.tsx

@@ -6,6 +6,7 @@ import remarkGfm from "remark-gfm";
 import { scoreQuestion } from "@/lib/scoring";
 import { QuizResults } from "./QuizResults";
 import { recordStudyActivity } from "@/lib/activityClient";
+import type { QuizAttempt } from "@/types/study";
 
 interface Option {
   id: string;
@@ -48,7 +49,7 @@ export function QuizViewer({ quiz, retakeIds, isShared = false, onFinished }: Qu
   const [shuffledOptions, setShuffledOptions] = useState<Record<string, Option[]>>({});
   
   const [loading, setLoading] = useState(true);
-  const [resultsData, setResultsData] = useState<any | null>(null);
+  const [resultsData, setResultsData] = useState<QuizAttempt | null>(null);
   const [toastMessage, setToastMessage] = useState<string | null>(null);
 
   // Auto-hide toast

src/lib/validation/reorderSchemas.ts

@@ -0,0 +1,11 @@
+import { z } from "zod";
+
+const reorderItemSchema = z.object({
+  id: z.string().min(1),
+  sortOrder: z.number().int(),
+  groupId: z.string().nullable(),
+});
+
+export const reorderRequestSchema = z.object({
+  items: z.array(reorderItemSchema),
+});

src/types/study.ts

@@ -0,0 +1,65 @@
+export interface ReorderItem {
+  id: string;
+  sortOrder: number;
+  groupId: string | null;
+}
+
+export interface QuizOption {
+  id: string;
+  text: string;
+  isCorrect: boolean;
+}
+
+export interface QuizQuestion {
+  id: string;
+  type: string;
+  prompt: string;
+  rationale: string;
+  category: string;
+  options: QuizOption[];
+}
+
+export interface QuizSummary {
+  id: string;
+  name: string;
+  questions: QuizQuestion[];
+}
+
+export interface QuizAttempt {
+  id: string;
+  score: number;
+  maxScore: number;
+  answersJson: string;
+  isPartialRetake: boolean;
+  completedAt: string;
+}
+
+export interface SharedClass {
+  slug: string;
+  name: string;
+}
+
+export interface SharedCard {
+  id: string;
+  front: string;
+  back: string;
+  sortOrder?: number;
+}
+
+export interface SharedStudyItem {
+  id: string;
+  name: string;
+  description: string | null;
+  class: SharedClass;
+  cards?: SharedCard[];
+  questions?: QuizQuestion[];
+}
+
+export interface SharedGroupData {
+  id: string;
+  name: string;
+  type: string;
+  class: SharedClass;
+  decks: SharedStudyItem[];
+  quizSets: SharedStudyItem[];
+}