// lib/features/gamification/services/gamification_service.dart
//
// Stub service using the real API contract from TechDocs v2.
// All methods currently return mock data.
// TODO: replace each mock block with a real ApiClient call once
//       the backend endpoints are live on uat.eventifyplus.com.

import 'dart:math';
import '../models/gamification_models.dart';

class GamificationService {
  // ---------------------------------------------------------------------------
  // User Gamification Profile
  // TODO: replace with ApiClient.get(ApiEndpoints.gamificationProfile)
  // ---------------------------------------------------------------------------
  Future<UserGamificationProfile> getProfile() async {
    await Future.delayed(const Duration(milliseconds: 400));
    return const UserGamificationProfile(
      userId: 'mock-user-001',
      lifetimeEp: 320,
      currentEp: 70,
      currentRp: 45,
      tier: ContributorTier.SILVER,
    );
  }

  // ---------------------------------------------------------------------------
  // Leaderboard
  // district: 'Overall Kerala' | 'Thiruvananthapuram' | 'Kollam' | ...
  // timePeriod: 'all_time' | 'this_month'
  // TODO: replace with ApiClient.get(ApiEndpoints.leaderboard, params: {'district': district, 'period': timePeriod})
  // ---------------------------------------------------------------------------
  Future<List<LeaderboardEntry>> getLeaderboard({
    required String district,
    required String timePeriod,
  }) async {
    await Future.delayed(const Duration(milliseconds: 500));

    // Realistic mock names per district
    final names = [
      'Annette Black', 'Jerome Bell', 'Theresa Webb', 'Courtney Henry',
      'Cameron Williamson', 'Dianne Russell', 'Wade Warren', 'Albert Flores',
      'Kristin Watson', 'Guy Hawkins',
    ];

    final rng = Random(district.hashCode ^ timePeriod.hashCode);
    final baseEp = timePeriod == 'this_month' ? 800 : 4500;

    final entries = List.generate(10, (i) {
      final ep = baseEp - (i * (timePeriod == 'this_month' ? 55 : 280)) + rng.nextInt(30);
      return LeaderboardEntry(
        rank: i + 1,
        username: names[i],
        lifetimeEp: ep,
        tier: tierFromEp(ep),
        eventsCount: 149 - i * 12,
        isCurrentUser: i == 7, // mock: current user is rank 8
      );
    });

    return entries;
  }

  // ---------------------------------------------------------------------------
  // Redeem Shop Items
  // TODO: replace with ApiClient.get(ApiEndpoints.shopItems)
  // ---------------------------------------------------------------------------
  Future<List<ShopItem>> getShopItems() async {
    await Future.delayed(const Duration(milliseconds: 400));
    return const [
      ShopItem(
        id: 'item-001',
        name: 'Amazon ₹500 Voucher',
        description: 'Redeem for any purchase on Amazon India.',
        rpCost: 50,
        stockQuantity: 20,
      ),
      ShopItem(
        id: 'item-002',
        name: 'Swiggy ₹200 Voucher',
        description: 'Free food delivery credit on Swiggy.',
        rpCost: 20,
        stockQuantity: 35,
      ),
      ShopItem(
        id: 'item-003',
        name: 'Eventify Pro — 1 Month',
        description: 'Premium access to Eventify.Plus features.',
        rpCost: 30,
        stockQuantity: 100,
      ),
      ShopItem(
        id: 'item-004',
        name: 'Zomato ₹150 Voucher',
        description: 'Discount on your next Zomato order.',
        rpCost: 15,
        stockQuantity: 50,
      ),
      ShopItem(
        id: 'item-005',
        name: 'BookMyShow ₹300 Voucher',
        description: 'Movie & event ticket credit on BookMyShow.',
        rpCost: 30,
        stockQuantity: 15,
      ),
      ShopItem(
        id: 'item-006',
        name: 'Exclusive Badge',
        description: 'Rare "Pioneer" badge for your profile.',
        rpCost: 5,
        stockQuantity: 0, // out of stock
      ),
    ];
  }

  // ---------------------------------------------------------------------------
  // Redeem an item
  // TODO: replace with ApiClient.post(ApiEndpoints.shopRedeem, body: {'item_id': itemId})
  // ---------------------------------------------------------------------------
  Future<RedemptionRecord> redeemItem(String itemId) async {
    await Future.delayed(const Duration(milliseconds: 600));
    // Generate a fake voucher code
    final code = 'EVT-${itemId.toUpperCase().replaceAll('-', '').substring(0, 4)}-${Random().nextInt(9000) + 1000}';
    return RedemptionRecord(
      id: 'redemption-${DateTime.now().millisecondsSinceEpoch}',
      itemId: itemId,
      rpSpent: 0, // provider will look up cost
      voucherCode: code,
      timestamp: DateTime.now(),
    );
  }

  // ---------------------------------------------------------------------------
  // Submit Contribution
  // TODO: replace with ApiClient.post(ApiEndpoints.contributeSubmit, body: data)
  // ---------------------------------------------------------------------------
  Future<void> submitContribution(Map<String, dynamic> data) async {
    await Future.delayed(const Duration(milliseconds: 800));
    // Mock always succeeds
  }

  // ---------------------------------------------------------------------------
  // Achievements
  // ---------------------------------------------------------------------------
  Future<List<AchievementBadge>> getAchievements() async {
    await Future.delayed(const Duration(milliseconds: 300));
    return const [
      AchievementBadge(
        id: 'badge-01', title: 'First Submission',
        description: 'Submitted your first event.',
        iconName: 'edit', isUnlocked: true, progress: 1.0,
      ),
      AchievementBadge(
        id: 'badge-02', title: 'Silver Streak',
        description: 'Reached Silver tier.',
        iconName: 'star', isUnlocked: true, progress: 1.0,
      ),
      AchievementBadge(
        id: 'badge-03', title: 'Gold Rush',
        description: 'Reach Gold tier (500 EP).',
        iconName: 'emoji_events', isUnlocked: false, progress: 0.64,
      ),
      AchievementBadge(
        id: 'badge-04', title: 'Top 10',
        description: 'Appear in the district leaderboard top 10.',
        iconName: 'leaderboard', isUnlocked: false, progress: 0.5,
      ),
      AchievementBadge(
        id: 'badge-05', title: 'Image Pro',
        description: 'Submit 10 events with 3+ images.',
        iconName: 'photo_library', isUnlocked: false, progress: 0.3,
      ),
      AchievementBadge(
        id: 'badge-06', title: 'Pioneer',
        description: 'One of the first 100 contributors.',
        iconName: 'verified', isUnlocked: true, progress: 1.0,
      ),
    ];
  }
}