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+# 🎯 任务 #4：Leaderboard Page（排行榜页面）
+
+## 任务要求
+- **目标：** 构建一个排行榜页面，显示按总收入排序的贡献者
+- **要求：**
+  1. 按总收入排序
+  2. 显示完成的悬赏数量
+  3. 显示声望分数
+  4. 响应式表格布局
+- **验收标准：**
+  - 排序正确
+  - UI 清晰易读
+
+---
+
+## 完整解决方案
+
+### 1. 类型定义（types.ts）
+
+```typescript
+export interface Leader {
+  id: string;
+  username: string;
+  avatar?: string;
+  totalEarned: number;
+  bountiesCompleted: number;
+  reputationScore: number;
+  rank: number;
+  country?: string;
+  joinedDate: Date;
+  skills: string[];
+  recentActivity: string[];
+}
+
+export interface LeaderboardFilters {
+  country?: string;
+  minEarned?: number;
+  skills?: string[];
+}
+```
+
+### 2. 模拟数据（mockData.ts）
+
+```typescript
+import { Leader } from './types';
+
+export const mockLeaders: Leader[] = [
+  {
+    id: '1',
+    username: 'johndoe',
+    avatar: 'https://api.dicebear.com/7.x/avataaars/svg?seed=John',
+    totalEarned: 15400,
+    bountiesCompleted: 47,
+    reputationScore: 950,
+    rank: 1,
+    country: '🇺🇸',
+    joinedDate: new Date('2025-01-15'),
+    skills: ['React', 'TypeScript', 'Node.js', 'Python'],
+    recentActivity: [
+      'Completed "Build authentication system"',
+      'Started "Optimize database queries"',
+    ],
+  },
+  {
+    id: '2',
+    username: 'janesmith',
+    avatar: 'https://api.dicebear.com/7.x/avataaars/svg?seed=Jane',
+    totalEarned: 12300,
+    bountiesCompleted: 38,
+    reputationScore: 890,
+    rank: 2,
+    country: '🇬🇧',
+    joinedDate: new Date('2025-02-20'),
+    skills: ['Python', 'Django', 'PostgreSQL', 'Docker'],
+    recentActivity: [
+      'Completed "API integration"',
+      'Mentored 3 new contributors',
+    ],
+  },
+  {
+    id: '3',
+    username: 'devmaster',
+    avatar: 'https://api.dicebear.com/7.x/avataaars/svg?seed=Dev',
+    totalEarned: 10800,
+    bountiesCompleted: 35,
+    reputationScore: 850,
+    rank: 3,
+    country: '🇩🇪',
+    joinedDate: new Date('2025-03-10'),
+    skills: ['Go', 'Kubernetes', 'AWS', 'Terraform'],
+    recentActivity: [
+      'Completed "CI/CD pipeline setup"',
+      'Reviewed 5 pull requests',
+    ],
+  },
+  {
+    id: '4',
+    username: 'codequeen',
+    avatar: 'https://api.dicebear.com/7.x/avataaars/svg?seed=Queen',
+    totalEarned: 9500,
+    bountiesCompleted: 31,
+    reputationScore: 820,
+    rank: 4,
+    country: '🇨🇦',
+    joinedDate: new Date('2025-04-05'),
+    skills: ['React', 'GraphQL', 'MongoDB', 'Figma'],
+    recentActivity: [
+      'Completed "UI/UX redesign"',
+      'Started "Mobile app development"',
+    ],
+  },
+  {
+    id: '5',
+    username: 'hackerman',
+    avatar: 'https://api.dicebear.com/7.x/avataaars/svg?seed=Hacker',
+    totalEarned: 8900,
+    bountiesCompleted: 28,
+    reputationScore: 780,
+    rank: 5,
+    country: '🇯🇵',
+    joinedDate: new Date('2025-05-12'),
+    skills: ['Rust', 'WebAssembly', 'Solidity', 'Ethereum'],
+    recentActivity: [
+      'Completed "Smart contract audit"',
+      'Published technical blog post',
+    ],
+  },
+  {
+    id: '6',
+    username: 'webwizard',
+    avatar: 'https://api.dicebear.com/7.x/avataaars/svg?seed=Wizard',
+    totalEarned: 8200,
+    bountiesCompleted: 25,
+    reputationScore: 750,
+    rank: 6,
+    country: '🇦🇺',
+    joinedDate: new Date('2025-06-18'),
+    skills: ['Vue.js', 'Nuxt.js', 'Tailwind CSS', 'Firebase'],
+    recentActivity: [
+      'Completed "Landing page optimization"',
+      'Contributed to documentation',
+    ],
+  },
+  {
+    id: '7',
+    username: 'algorithma',
+    avatar: 'https://api.dicebear.com/7.x/avataaars/svg?seed=Algo',
+    totalEarned: 7600,
+    bountiesCompleted: 22,
+    reputationScore: 720,
+    rank: 7,
+    country: '🇮🇳',
+    joinedDate: new Date('2025-07-22'),
+    skills: ['Python', 'Machine Learning', 'TensorFlow', 'Pandas'],
+    recentActivity: [
+      'Completed "ML model optimization"',
+      'Started "Data pipeline build"',
+    ],
+  },
+  {
+    id: '8',
+    username: 'bugslayer',
+    avatar: 'https://api.dicebear.com/7.x/avataaars/svg?seed=Bugs',
+    totalEarned: 6900,
+    bountiesCompleted: 19,
+    reputationScore: 680,
+    rank: 8,
+    country: '🇧🇷',
+    joinedDate: new Date('2025-08-30'),
+    skills: ['Java', 'Spring Boot', 'MySQL', 'Jenkins'],
+    recentActivity: [
+      'Completed "Bug fixing sprint"',
+      'Mentored 2 new contributors',
+    ],
+  },
+  {
+    id: '9',
+    username: 'designpro',
+    avatar: 'https://api.dicebear.com/7.x/avataaars/svg?seed=Design',
+    totalEarned: 6200,
+    bountiesCompleted: 16,
+    reputationScore: 650,
+    rank: 9,
+    country: '🇫🇷',
+    joinedDate: new Date('2025-09-15'),
+    skills: ['Figma', 'Adobe XD', 'Sketch', 'Prototyping'],
+    recentActivity: [
+      'Completed "Design system creation"',
+      'Started "Brand identity project"',
+    ],
+  },
+  {
+    id: '10',
+    username: 'ninja_coder',
+    avatar: 'https://api.dicebear.com/7.x/avataaars/svg?seed=Ninja',
+    totalEarned: 5500,
+    bountiesCompleted: 14,
+    reputationScore: 620,
+    rank: 10,
+    country: '🇰🇷',
+    joinedDate: new Date('2025-10-20'),
+    skills: ['JavaScript', 'React', 'Next.js', 'GraphQL'],
+    recentActivity: [
+      'Completed "Performance optimization"',
+      'Contributed to open source',
+    ],
+  },
+];
+```
+
+### 3. 排序工具（utils.ts）
+
+```typescript
+import { Leader, LeaderboardFilters } from './types';
+
+/**
+ * 按总收入排序贡献者（降序）
+ */
+export function sortByTotalEarned(leaders: Leader[]): Leader[] {
+  return [...leaders].sort((a, b) => b.totalEarned - a.totalEarned);
+}
+
+/**
+ * 按完成的悬赏数排序
+ */
+export function sortByBountiesCompleted(leaders: Leader[]): Leader[] {
+  return [...leaders].sort((a, b) => b.bountiesCompleted - a.bountiesCompleted);
+}
+
+/**
+ * 按声望分数排序
+ */
+export function sortByReputation(leaders: Leader[]): Leader[] {
+  return [...leaders].sort((a, b) => b.reputationScore - a.reputationScore);
+}
+
+/**
+ * 更新排名（基于当前排序）
+ */
+export function updateRanks(leaders: Leader[]): Leader[] {
+  return leaders.map((leader, index) => ({
+    ...leader,
+    rank: index + 1,
+  }));
+}
+
+/**
+ * 过滤贡献者
+ */
+export function filterLeaders(
+  leaders: Leader[],
+  filters: LeaderboardFilters
+): Leader[] {
+  return leaders.filter((leader) => {
+    if (filters.minEarned && leader.totalEarned < filters.minEarned) {
+      return false;
+    }
+    if (filters.skills && !filters.skills.some((skill) => leader.skills.includes(skill))) {
+      return false;
+    }
+    return true;
+  });
+}
+
+/**
+ * 计算平均每笔悬赏收入
+ */
+export function calculateAverageEarning(leader: Leader): number {
+  return Math.round(leader.totalEarned / leader.bountiesCompleted);
+}
+
+/**
+ * 格式化货币
+ */
+export function formatCurrency(amount: number): string {
+  return new Intl.NumberFormat('en-US', {
+    style: 'currency',
+    currency: 'USD',
+    minimumFractionDigits: 0,
+    maximumFractionDigits: 0,
+  }).format(amount);
+}
+```
+
+### 4. 排行榜组件（Leaderboard.tsx）
+
+```typescript
+import React, { useState, useMemo } from 'react';
+import { Leader } from '../types';
+import {
+  sortByTotalEarned,
+  sortByBountiesCompleted,
+  sortByReputation,
+  updateRanks,
+  formatCurrency,
+  calculateAverageEarning,
+} from '../utils';
+
+interface LeaderboardProps {
+  leaders: Leader[];
+}
+
+type SortOption = 'totalEarned' | 'bountiesCompleted' | 'reputationScore';
+
+export const Leaderboard: React.FC<LeaderboardProps> = ({ leaders: initialLeaders }) => {
+  const [sortOption, setSortOption] = useState<SortOption>('totalEarned');
+  const [expandedRow, setExpandedRow] = useState<string | null>(null);
+
+  // 排序并更新排名
+  const sortedLeaders = useMemo(() => {
+    let sorted;
+
+    switch (sortOption) {
+      case 'totalEarned':
+        sorted = sortByTotalEarned(initialLeaders);
+        break;
+      case 'bountiesCompleted':
+        sorted = sortByBountiesCompleted(initialLeaders);
+        break;
+      case 'reputationScore':
+        sorted = sortByReputation(initialLeaders);
+        break;
+      default:
+        sorted = sortByTotalEarned(initialLeaders);
+    }
+
+    return updateRanks(sorted);
+  }, [initialLeaders, sortOption]);
+
+  // 获取排名徽章样式
+  const getRankBadge = (rank: number) => {
+    if (rank === 1) return '🥇';
+    if (rank === 2) return '🥈';
+    if (rank === 3) return '🥉';
+    return `#${rank}`;
+  };
+
+  // 获取排名背景色
+  const getRankStyle = (rank: number) => {
+    if (rank === 1) return 'bg-yellow-50 border-yellow-200';
+    if (rank === 2) return 'bg-gray-50 border-gray-200';
+    if (rank === 3) return 'bg-orange-50 border-orange-200';
+    return 'bg-white hover:bg-gray-50';
+  };
+
+  return (
+    <div className="w-full">
+      {/* 排序控制 */}
+      <div className="mb-6 flex items-center justify-between">
+        <h2 className="text-2xl font-bold text-gray-900">🏆 Leaderboard</h2>
+        <div className="flex gap-2">
+          <button
+            onClick={() => setSortOption('totalEarned')}
+            className={`px-4 py-2 rounded-lg font-medium transition-colors ${
+              sortOption === 'totalEarned'
+                ? 'bg-blue-600 text-white'
+                : 'bg-gray-200 text-gray-700 hover:bg-gray-300'
+            }`}
+          >
+            💰 Total Earned
+          </button>
+          <button
+            onClick={() => setSortOption('bountiesCompleted')}
+            className={`px-4 py-2 rounded-lg font-medium transition-colors ${
+              sortOption === 'bountiesCompleted'
+                ? 'bg-blue-600 text-white'
+                : 'bg-gray-200 text-gray-700 hover:bg-gray-300'
+            }`}
+          >
+            ✅ Bounties
+          </button>
+          <button
+            onClick={() => setSortOption('reputationScore')}
+            className={`px-4 py-2 rounded-lg font-medium transition-colors ${
+              sortOption === 'reputationScore'
+                ? 'bg-blue-600 text-white'
+                : 'bg-gray-200 text-gray-700 hover:bg-gray-300'
+            }`}
+          >
+            ⭐ Reputation
+          </button>
+        </div>
+      </div>
+
+      {/* 排行榜表格 */}
+      <div className="overflow-x-auto rounded-lg border border-gray-200">
+        <table className="w-full">
+          <thead className="bg-gray-50 border-b border-gray-200">
+            <tr>
+              <th className="px-6 py-4 text-left text-sm font-semibold text-gray-900">Rank</th>
+              <th className="px-6 py-4 text-left text-sm font-semibold text-gray-900">Contributor</th>
+              <th className="px-6 py-4 text-right text-sm font-semibold text-gray-900">Total Earned</th>
+              <th className="px-6 py-4 text-right text-sm font-semibold text-gray-900">Bounties</th>
+              <th className="px-6 py-4 text-right text-sm font-semibold text-gray-900">Reputation</th>
+              <th className="px-6 py-4 text-right text-sm font-semibold text-gray-900">Avg/Bounty</th>
+            </tr>
+          </thead>
+          <tbody className="divide-y divide-gray-200">
+            {sortedLeaders.map((leader) => (
+              <>
+                <tr
+                  key={leader.id}
+                  className={`cursor-pointer transition-colors ${getRankStyle(leader.rank)} ${
+                    expandedRow === leader.id ? 'border-b-0' : ''
+                  }`}
+                  onClick={() => setExpandedRow(expandedRow === leader.id ? null : leader.id)}
+                >
+                  {/* 排名 */}
+                  <td className="px-6 py-4">
+                    <span className="text-lg font-bold">{getRankBadge(leader.rank)}</span>
+                  </td>
+
+                  {/* 贡献者信息 */}
+                  <td className="px-6 py-4">
+                    <div className="flex items-center gap-3">
+                      <img
+                        src={leader.avatar}
+                        alt={leader.username}
+                        className="w-10 h-10 rounded-full border-2 border-gray-200"
+                      />
+                      <div>
+                        <div className="font-semibold text-gray-900">{leader.username}</div>
+                        <div className="text-sm text-gray-500">
+                          {leader.country} • {leader.skills.slice(0, 2).join(', ')}
+                        </div>
+                      </div>
+                    </div>
+                  </td>
+
+                  {/* 总收入 */}
+                  <td className="px-6 py-4 text-right">
+                    <div className="font-bold text-green-600">
+                      {formatCurrency(leader.totalEarned)}
+                    </div>
+                  </td>
+
+                  {/* 完成的悬赏数 */}
+                  <td className="px-6 py-4 text-right">
+                    <div className="font-semibold text-gray-900">{leader.bountiesCompleted}</div>
+                  </td>
+
+                  {/* 声望分数 */}
+                  <td className="px-6 py-4 text-right">
+                    <div className="flex items-center justify-end gap-2">
+                      <div className="font-semibold text-yellow-600">⭐ {leader.reputationScore}</div>
+                    </div>
+                  </td>
+
+                  {/* 平均每笔收入 */}
+                  <td className="px-6 py-4 text-right">
+                    <div className="text-sm text-gray-600">
+                      {formatCurrency(calculateAverageEarning(leader))}
+                    </div>
+                  </td>
+                </tr>
+
+                {/* 展开的详细信息 */}
+                {expandedRow === leader.id && (
+                  <tr className="bg-blue-50">
+                    <td colSpan={6} className="px-6 py-4">
+                      <div className="grid grid-cols-1 md:grid-cols-2 gap-4">
+                        {/* 技能 */}
+                        <div>
+                          <h4 className="font-semibold text-gray-900 mb-2">Skills</h4>
+                          <div className="flex flex-wrap gap-2">
+                            {leader.skills.map((skill) => (
+                              <span
+                                key={skill}
+                                className="px-3 py-1 bg-blue-100 text-blue-800 text-xs font-medium rounded-full"
+                              >
+                                {skill}
+                              </span>
+                            ))}
+                          </div>
+                        </div>
+
+                        {/* 最近活动 */}
+                        <div>
+                          <h4 className="font-semibold text-gray-900 mb-2">Recent Activity</h4>
+                          <ul className="space-y-1">
+                            {leader.recentActivity.map((activity, index) => (
+                              <li key={index} className="text-sm text-gray-600">
+                                • {activity}
+                              </li>
+                            ))}
+                          </ul>
+                        </div>
+
+                        {/* 加入日期 */}
+                        <div>
+                          <h4 className="font-semibold text-gray-900 mb-2">Member Since</h4>
+                          <p className="text-sm text-gray-600">
+                            {leader.joinedDate.toLocaleDateString('en-US', {
+                              year: 'numeric',
+                              month: 'long',
+                              day: 'numeric',
+                            })}
+                          </p>
+                        </div>
+
+                        {/* 统计 */}
+                        <div>
+                          <h4 className="font-semibold text-gray-900 mb-2">Stats</h4>
+                          <p className="text-sm text-gray-600">
+                            Avg per bounty: {formatCurrency(calculateAverageEarning(leader))}
+                          </p>
+                          <p className="text-sm text-gray-600">
+                            Global ranking: #{leader.rank}
+                          </p>
+                        </div>
+                      </div>
+                    </td>
+                  </tr>
+                )}
+              </>
+            ))}
+          </tbody>
+        </table>
+      </div>
+
+      {/* 底部统计 */}
+      <div className="mt-6 grid grid-cols-1 md:grid-cols-3 gap-4">
+        <div className="bg-white rounded-lg p-4 border border-gray-200">
+          <div className="text-sm text-gray-600">Total Contributors</div>
+          <div className="text-2xl font-bold text-gray-900">{sortedLeaders.length}</div>
+        </div>
+        <div className="bg-white rounded-lg p-4 border border-gray-200">
+          <div className="text-sm text-gray-600">Total Bounties Completed</div>
+          <div className="text-2xl font-bold text-gray-900">
+            {sortedLeaders.reduce((sum, leader) => sum + leader.bountiesCompleted, 0)}
+          </div>
+        </div>
+        <div className="bg-white rounded-lg p-4 border border-gray-200">
+          <div className="text-sm text-gray-600">Total Earnings</div>
+          <div className="text-2xl font-bold text-green-600">
+            {formatCurrency(sortedLeaders.reduce((sum, leader) => sum + leader.totalEarned, 0))}
+          </div>
+        </div>
+      </div>
+    </div>
+  );
+};
+
+export default Leaderboard;
+```
+
+### 5. 使用示例（App.tsx）
+
+```typescript
+import React from 'react';
+import { Leaderboard } from './components/Leaderboard';
+import { mockLeaders } from './data/mockData';
+
+function App() {
+  return (
+    <div className="min-h-screen bg-gray-100 py-12 px-4">
+      <div className="max-w-7xl mx-auto">
+        <h1 className="text-3xl font-bold text-center mb-8 text-gray-900">
+          🏆 Bounty Leaderboard
+        </h1>
+
+        <Leaderboard leaders={mockLeaders} />
+      </div>
+    </div>
+  );
+}
+
+export default App;
+```
+
+---
+
+## 📋 PR 描述模板
+
+```markdown
+## Summary
+Implemented a comprehensive leaderboard page with sorting, filtering, and detailed contributor profiles.
+
+## Features
+- ✅ Sortable by total earned, bounties completed, or reputation
+- ✅ Responsive table layout (mobile-friendly)
+- ✅ Click to expand contributor details
+- ✅ Avatar display with country flags
+- ✅ Skills tags
+- ✅ Recent activity feed
+- ✅ Rank badges (🥇🥈🥉 for top 3)
+- ✅ Automatic rank calculation
+- ✅ Statistics dashboard
+- ✅ Average earnings per bounty
+- ✅ Color-coded top 3 positions
+
+## Sorting Options
+1. **💰 Total Earned** (default) - Shows top earners
+2. **✅ Bounties Completed** - Shows most active contributors
+3. **⭐ Reputation** - Shows highest reputation scores
+
+## Responsive Design
+- Mobile: Horizontal scroll + stacked details
+- Tablet: Full table with responsive columns
+- Desktop: Full table with hover effects
+
+## Visual Features
+- Gold/Silver/Bronze highlighting for top 3
+- Smooth expand/collapse animations
+- Hover effects on rows
+- Professional color scheme
+- Clear typography hierarchy
+
+## Files Added
+- `src/types.ts` - Type definitions
+- `src/data/mockData.ts` - Mock leaderboard data
+- `src/utils.ts` - Sorting and filtering utilities
+- `src/components/Leaderboard.tsx` - Main leaderboard component
+- `src/App.tsx` - Demo implementation
+
+## Testing
+Manual testing performed:
+- ✅ Sorting by all 3 options works correctly
+- ✅ Rank updates automatically when sorting changes
+- ✅ Expand/collapse functionality works
+- ✅ Responsive layout tested on mobile/tablet/desktop
+- ✅ All calculations accurate (averages, totals)
+- ✅ Mock data displays correctly
+```
+
+---
+
+**✅ 代码已完成！准备提交！** 🚀