/**
 * POST /api/referrals/claim - Claim referral bonus
 */

import { NextRequest, NextResponse } from 'next/server';
import { requireAuth } from '@/app/lib/auth';
import { createReferral, findUser, getUserReferrals } from '@/app/lib/db/store';
import { awardReferralBonus } from '@/app/lib/points';
import { checkAndAwardBadges } from '@/app/lib/badges';
import { ApiResponse } from '@/app/lib/types';

interface ClaimReferralRequest {
  referralCode: string;
}

const REFERRAL_BONUS = 50; // Points awarded for referrals

export async function POST(request: NextRequest) {
  try {
    // Authenticate user
    const user = requireAuth(request);

    // Parse request body
    const body: ClaimReferralRequest = await request.json();
    const { referralCode } = body;

    if (!referralCode) {
      return NextResponse.json<ApiResponse>(
        {
          success: false,
          error: 'Referral code is required'
        },
        { status: 400 }
      );
    }

    // Decode referral code to get referrer user ID
    let referrerId: string;
    try {
      referrerId = Buffer.from(referralCode, 'base64').toString('utf-8');
    } catch (error) {
      return NextResponse.json<ApiResponse>(
        {
          success: false,
          error: 'Invalid referral code'
        },
        { status: 400 }
      );
    }

    // Check if referrer exists
    const referrer = findUser(referrerId);
    if (!referrer) {
      return NextResponse.json<ApiResponse>(
        {
          success: false,
          error: 'Referrer not found'
        },
        { status: 404 }
      );
    }

    // Prevent self-referral
    if (referrerId === user.id) {
      return NextResponse.json<ApiResponse>(
        {
          success: false,
          error: 'You cannot refer yourself'
        },
        { status: 400 }
      );
    }

    // Check if user was already referred
    const allReferrals = getUserReferrals(referrerId);
    const alreadyReferred = allReferrals.some(ref => ref.referredId === user.id);

    if (alreadyReferred) {
      return NextResponse.json<ApiResponse>(
        {
          success: false,
          error: 'Referral bonus already claimed'
        },
        { status: 409 }
      );
    }

    // Create referral record
    const referral = createReferral(referrerId, user.id, REFERRAL_BONUS);

    // Award points to referrer
    awardReferralBonus(referrerId, referral.id, REFERRAL_BONUS);

    // Award smaller bonus to referred user
    const referredBonus = Math.floor(REFERRAL_BONUS / 2); // 25 points
    awardReferralBonus(user.id, referral.id, referredBonus);

    // Check and award badges for both users
    const referrerBadges = checkAndAwardBadges(referrerId);
    const referredBadges = checkAndAwardBadges(user.id);

    return NextResponse.json<ApiResponse>(
      {
        success: true,
        data: {
          referral,
          referrerBonus: REFERRAL_BONUS,
          referredBonus,
          referrerName: referrer.name
        },
        message: `Referral claimed! You earned ${referredBonus} points, and ${referrer.name} earned ${REFERRAL_BONUS} points${
          referredBadges.length > 0 ? `. You also earned ${referredBadges.length} new badge(s)!` : ''
        }`
      },
      { status: 201 }
    );
  } catch (error) {
    if (error instanceof Error && error.message === 'Unauthorized') {
      return NextResponse.json<ApiResponse>(
        {
          success: false,
          error: 'Unauthorized'
        },
        { status: 401 }
      );
    }

    console.error('Claim referral error:', error);
    return NextResponse.json<ApiResponse>(
      {
        success: false,
        error: 'Internal server error'
      },
      { status: 500 }
    );
  }
}