feat: migrate leaderboard from REST to GraphQL

app/leaderboard/page.tsx

@@ -5,6 +5,7 @@ import { LeaderboardTable } from "@/components/leaderboard/leaderboard-table";
 import { LeaderboardFilters } from "@/components/leaderboard/leaderboard-filters";
 import { UserRankSidebar } from "@/components/leaderboard/user-rank-sidebar";
 import { LeaderboardFilters as FiltersType, ReputationTier } from "@/types/leaderboard";
+import { LeaderboardTimeframe } from "@/lib/graphql/generated";
 import { useState, useEffect } from "react";
 import { useRouter, useSearchParams } from "next/navigation";
 import { TIMEFRAMES, TIERS } from "@/components/leaderboard/leaderboard-filters";
@@ -22,7 +23,7 @@ export default function LeaderboardPage() {
 
     const initialTimeframe = TIMEFRAMES.some(t => t.value === rawTimeframe)
         ? (rawTimeframe as FiltersType["timeframe"])
-        : "ALL_TIME";
+        : LeaderboardTimeframe.AllTime;
 
     const initialTier = TIERS.some(t => t.value === rawTier)
         ? (rawTier as ReputationTier)
@@ -65,7 +66,7 @@ export default function LeaderboardPage() {
     // Sync debounced filters to URL
     useEffect(() => {
         const params = new URLSearchParams();
-        if (debouncedFilters.timeframe !== "ALL_TIME") params.set("timeframe", debouncedFilters.timeframe);
+        if (debouncedFilters.timeframe !== LeaderboardTimeframe.AllTime) params.set("timeframe", debouncedFilters.timeframe);
         if (debouncedFilters.tier) params.set("tier", debouncedFilters.tier);
         if (debouncedFilters.tags && debouncedFilters.tags.length > 0) {
             params.set("tags", debouncedFilters.tags.join(","));

components/leaderboard/leaderboard-filters.tsx

@@ -9,10 +9,9 @@ import {
     SelectValue,
 } from "@/components/ui/select";
 import {
-    LeaderboardFilters as FiltersType,
-    LeaderboardTimeframe,
-    ReputationTier
+    LeaderboardFilters as FiltersType
 } from "@/types/leaderboard";
+import { LeaderboardTimeframe, ReputationTier } from "@/lib/graphql/generated";
 import { FilterX } from "lucide-react";
 import { Badge } from "@/components/ui/badge";
 import {
@@ -38,17 +37,17 @@ interface LeaderboardFiltersProps {
 }
 
 export const TIMEFRAMES: { value: LeaderboardTimeframe; label: string }[] = [
-    { value: "ALL_TIME", label: "All Time" },
-    { value: "THIS_MONTH", label: "This Month" },
-    { value: "THIS_WEEK", label: "This Week" },
+    { value: LeaderboardTimeframe.AllTime, label: "All Time" },
+    { value: LeaderboardTimeframe.ThisMonth, label: "This Month" },
+    { value: LeaderboardTimeframe.ThisWeek, label: "This Week" },
 ];
 
 export const TIERS: { value: ReputationTier; label: string }[] = [
-    { value: "LEGEND", label: "Legend" },
-    { value: "EXPERT", label: "Expert" },
-    { value: "ESTABLISHED", label: "Established" },
-    { value: "CONTRIBUTOR", label: "Contributor" },
-    { value: "NEWCOMER", label: "Newcomer" },
+    { value: ReputationTier.Legend, label: "Legend" },
+    { value: ReputationTier.Expert, label: "Expert" },
+    { value: ReputationTier.Established, label: "Established" },
+    { value: ReputationTier.Contributor, label: "Contributor" },
+    { value: ReputationTier.Newcomer, label: "Newcomer" },
 ];
 
 // Mock available tags for filter - in real app could be passed as prop
@@ -72,13 +71,13 @@ export function LeaderboardFilters({ filters, onFilterChange }: LeaderboardFilte
 
     const clearFilters = () => {
         onFilterChange({
-            timeframe: "ALL_TIME",
+            timeframe: LeaderboardTimeframe.AllTime,
             tier: undefined,
             tags: [],
         });
     };
 
-    const hasActiveFilters = filters.timeframe !== "ALL_TIME" || filters.tier || (filters.tags?.length || 0) > 0;
+    const hasActiveFilters = filters.timeframe !== LeaderboardTimeframe.AllTime || filters.tier || (filters.tags?.length || 0) > 0;
 
     return (
         <div className="flex flex-wrap items-center gap-3 text-foreground">

components/leaderboard/mini-leaderboard.tsx

@@ -9,6 +9,7 @@ import { TierBadge } from "@/components/reputation/tier-badge";
 import { Trophy, ChevronRight, AlertCircle } from "lucide-react";
 import Link from "next/link";
 import { cn } from "@/lib/utils";
+import { LeaderboardContributor } from "@/lib/graphql/generated";
 
 interface MiniLeaderboardProps {
     className?: string;
@@ -61,7 +62,7 @@ export function MiniLeaderboard({
                     </div>
                 ) : (
                     <div className="flex flex-col">
-                        {contributors?.map((contributor, index) => (
+                        {contributors?.map((contributor: LeaderboardContributor, index: number) => (
                             <Link
                                 key={contributor.id}
                                 href={`/profile/${contributor.userId}`}

hooks/use-leaderboard.ts

@@ -1,6 +1,14 @@
 import { useQuery, useInfiniteQuery, useQueryClient } from '@tanstack/react-query';
-import { leaderboardApi } from '@/lib/api/leaderboard';
-import { LeaderboardFilters } from '@/types/leaderboard';
+import { fetcher } from '@/lib/graphql/client';
+import { 
+  LeaderboardQuery,
+  LeaderboardQueryVariables,
+  UserLeaderboardRankQuery,
+  UserLeaderboardRankQueryVariables,
+  TopContributorsQuery,
+  TopContributorsQueryVariables
+} from '@/lib/graphql/generated';
+import { LeaderboardFilters, LeaderboardResponse } from '@/types/leaderboard';
 
 export const LEADERBOARD_KEYS = {
     all: ['leaderboard'] as const,
@@ -13,9 +21,13 @@
 export const useLeaderboard = (filters: LeaderboardFilters, limit: number = 20) => {
     return useInfiniteQuery({
         queryKey: LEADERBOARD_KEYS.list(filters),
-        queryFn: ({ pageParam = 1 }) =>
-            leaderboardApi.fetchLeaderboard(filters, { page: pageParam, limit }),
-        getNextPageParam: (lastPage, allPages) => {
+        queryFn: ({ pageParam = 1 }) => {
+            return fetcher<LeaderboardQuery, LeaderboardQueryVariables>(
+                require('@/lib/graphql/generated').LeaderboardDocument,
+                { filters, pagination: { page: pageParam as number, limit } }
+            )().then(data => data.leaderboard);
+        },
+        getNextPageParam: (lastPage: LeaderboardResponse, allPages: LeaderboardResponse[]) => {
             // Optimization: Use simple math instead of iterating all entries
             if (allPages.length * limit < lastPage.totalCount) {
                 return allPages.length + 1;
@@ -30,15 +42,26 @@
 export const useUserRank = (userId?: string) => {
     return useQuery({
         queryKey: LEADERBOARD_KEYS.user(userId || ''),
-        queryFn: () => leaderboardApi.fetchUserRank(userId),
+        queryFn: () => {
+            if (!userId) return null;
+            return fetcher<UserLeaderboardRankQuery, UserLeaderboardRankQueryVariables>(
+                require('@/lib/graphql/generated').UserLeaderboardRankDocument,
+                { userId }
+            )().then(data => data.userLeaderboardRank);
+        },
         enabled: !!userId,
     });
 };
 
 export const useTopContributors = (count: number = 5) => {
     return useQuery({
         queryKey: LEADERBOARD_KEYS.top(count),
-        queryFn: () => leaderboardApi.fetchTopContributors(count),
+        queryFn: () => {
+            return fetcher<TopContributorsQuery, TopContributorsQueryVariables>(
+                require('@/lib/graphql/generated').TopContributorsDocument,
+                { count }
+            )().then(data => data.topContributors);
+        },
         staleTime: 1000 * 60 * 15, // 15 minutes
     });
 };
@@ -49,10 +72,15 @@
     return (filters: LeaderboardFilters, page: number, limit: number) => {
         queryClient.prefetchInfiniteQuery({
             queryKey: LEADERBOARD_KEYS.list(filters),
-            queryFn: ({ pageParam }) => leaderboardApi.fetchLeaderboard(filters, { page: pageParam as number, limit }),
+            queryFn: ({ pageParam }: { pageParam?: number }) => {
+                return fetcher<LeaderboardQuery, LeaderboardQueryVariables>(
+                    require('@/lib/graphql/generated').LeaderboardDocument,
+                    { filters, pagination: { page: pageParam as number, limit } }
+                )().then(data => data.leaderboard);
+            },
             initialPageParam: 1,
-            getNextPageParam: (lastPage, allPages) => {
-                const loadedCount = allPages.flatMap(p => p.entries).length;
+            getNextPageParam: (lastPage: LeaderboardResponse, allPages: LeaderboardResponse[]) => {
+                const loadedCount = allPages.flatMap((p: LeaderboardResponse) => p.entries).length;
                 if (loadedCount < lastPage.totalCount) {
                     return allPages.length + 1;
                 }