/**
 * GET /api/leaderboard - Get top users by points
 */

import { NextRequest, NextResponse } from 'next/server';
import { getCurrentUser } from '@/app/lib/auth';
import { getAllUsers, getUserBalance, getUserCompletedTasks, getUserBadges } from '@/app/lib/db/store';
import { LeaderboardResponse, LeaderboardEntry, ApiResponse } from '@/app/lib/types';

export async function GET(request: NextRequest) {
  try {
    // Get current user (optional - for user rank)
    const currentUser = getCurrentUser(request);

    // Get all users
    const users = getAllUsers();

    // Build leaderboard entries
    const entries: LeaderboardEntry[] = users
      .map(user => ({
        userId: user.id,
        userName: user.name,
        points: getUserBalance(user.id),
        tasksCompleted: getUserCompletedTasks(user.id).length,
        badgesEarned: getUserBadges(user.id).length,
        rank: 0 // Will be set after sorting
      }))
      .sort((a, b) => {
        // Sort by points descending, then by tasks completed
        if (b.points !== a.points) {
          return b.points - a.points;
        }
        return b.tasksCompleted - a.tasksCompleted;
      })
      .map((entry, index) => ({
        ...entry,
        rank: index + 1
      }));

    // Get top 100 entries
    const topEntries = entries.slice(0, 100);

    // Find current user's rank
    let userRank: LeaderboardEntry | undefined;
    if (currentUser) {
      userRank = entries.find(entry => entry.userId === currentUser.id);
    }

    const response: LeaderboardResponse = {
      entries: topEntries,
      userRank
    };

    return NextResponse.json<ApiResponse<LeaderboardResponse>>(
      {
        success: true,
        data: response
      },
      { status: 200 }
    );
  } catch (error) {
    console.error('Get leaderboard error:', error);
    return NextResponse.json<ApiResponse>(
      {
        success: false,
        error: 'Internal server error'
      },
      { status: 500 }
    );
  }
}