import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:go_router/go_router.dart';
import '../../../core/chat/chat_opening_provider.dart';
import '../../../core/constants.dart';
import '../../../core/theme/halo_tokens.dart';
import '../../../core/theme/widgets/halo_button.dart';
import '../state/payment_draft_provider.dart';

/// S6 first-session discount paywall.
///
/// Renders only when `chat-pricing.first_session_discount.eligible == true`.
/// Layout: struck-through gimmick price next to a prominent actual price,
/// "untuk N menit ngobrol" subtitle, and a primary CTA that seeds the payment
/// draft and routes to `/payment/method`.
class DiscountPaywallScreen extends ConsumerWidget {
  const DiscountPaywallScreen({super.key});

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final pricingAsync = ref.watch(chatPricingProvider);

    return Scaffold(
      backgroundColor: HaloTokens.bg,
      appBar: AppBar(
        backgroundColor: HaloTokens.bg,
        elevation: 0,
        leading: IconButton(
          icon: const Icon(Icons.chevron_left, color: HaloTokens.brandDark),
          onPressed: () {
            if (context.canPop()) {
              context.pop();
            } else {
              context.go('/home');
            }
          },
        ),
      ),
      body: pricingAsync.when(
        loading: () => const Center(child: CircularProgressIndicator()),
        error: (_, __) => const Center(
          child: Padding(
            padding: EdgeInsets.all(HaloSpacing.s24),
            child: Text(
              'Gagal memuat harga. Coba lagi.',
              textAlign: TextAlign.center,
            ),
          ),
        ),
        data: (pricing) {
          final discount = pricing.firstSessionDiscount;
          if (discount == null || !discount.eligible) {
            // Defensive: route guard normally prevents this. If we got here
            // anyway (stale state), kick over to method-pick.
            WidgetsBinding.instance.addPostFrameCallback((_) {
              if (!context.mounted) return;
              context.go('/payment/method-pick');
            });
            return const SizedBox.shrink();
          }
          return _Body(discount: discount);
        },
      ),
    );
  }
}

class _Body extends ConsumerWidget {
  final FirstSessionDiscount discount;
  const _Body({required this.discount});

  void _onMulai(BuildContext context, WidgetRef ref) {
    ref.read(paymentDraftNotifierProvider.notifier).setDiscountPlan(
          durationMinutes: discount.durationMinutes,
          priceIDR: discount.actualPriceIDR,
        );
    context.push('/payment/method');
  }

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final showModeToggle = discount.modes.length > 1;
    final actual = formatRupiah(discount.actualPriceIDR);
    final gimmick = formatRupiah(discount.gimmickPriceIDR);

    return Column(
      children: [
        Expanded(
          child: SingleChildScrollView(
            padding: const EdgeInsets.fromLTRB(
              HaloSpacing.s24,
              HaloSpacing.s8,
              HaloSpacing.s24,
              HaloSpacing.s16,
            ),
            child: Column(
              crossAxisAlignment: CrossAxisAlignment.start,
              children: [
                if (showModeToggle) const _ModeToggleHidden(),
                const Text(
                  '🌷',
                  style: TextStyle(fontSize: 38),
                ),
                const SizedBox(height: HaloSpacing.s12),
                Text(
                  'biar yakin yang mau cerita,\nbestie cuma minta $actual',
                  style: const TextStyle(
                    fontFamily: HaloTokens.fontDisplay,
                    fontSize: 26,
                    fontWeight: FontWeight.w700,
                    color: HaloTokens.brandDark,
                    height: 1.2,
                    letterSpacing: -0.5,
                  ),
                ),
                const SizedBox(height: HaloSpacing.s16),
                const Text(
                  'bukan biaya — anggap aja seperti senyum hangat di awal pertemuan, biar bestie tau kamu beneran mau ngobrol.',
                  style: TextStyle(
                    fontSize: 14,
                    color: HaloTokens.inkSoft,
                    height: 1.55,
                  ),
                ),
                const SizedBox(height: HaloSpacing.s20),
                _PriceCard(
                  actual: actual,
                  gimmick: gimmick,
                  durationMinutes: discount.durationMinutes,
                ),
                const SizedBox(height: HaloSpacing.s12),
                const Center(
                  child: Text(
                    'sesi-sesi berikutnya pakai harga normal, sesuai durasi yang kamu pilih.',
                    textAlign: TextAlign.center,
                    style: TextStyle(
                      fontSize: 12,
                      color: HaloTokens.inkMuted,
                      height: 1.5,
                    ),
                  ),
                ),
              ],
            ),
          ),
        ),
        Container(
          padding: const EdgeInsets.fromLTRB(
            HaloSpacing.s24,
            HaloSpacing.s12,
            HaloSpacing.s24,
            HaloSpacing.s32,
          ),
          decoration: const BoxDecoration(
            color: HaloTokens.bg,
            border: Border(top: BorderSide(color: HaloTokens.border)),
          ),
          child: Column(
            children: [
              HaloButton(
                label: 'mulai · $actual',
                size: HaloButtonSize.lg,
                fullWidth: true,
                onPressed: () => _onMulai(context, ref),
              ),
              const SizedBox(height: HaloSpacing.s8),
              const Text(
                'QRIS · GoPay · OVO · DANA · ShopeePay',
                style: TextStyle(fontSize: 11, color: HaloTokens.inkMuted),
              ),
            ],
          ),
        ),
      ],
    );
  }
}

class _PriceCard extends StatelessWidget {
  final String actual;
  final String gimmick;
  final int durationMinutes;

  const _PriceCard({
    required this.actual,
    required this.gimmick,
    required this.durationMinutes,
  });

  @override
  Widget build(BuildContext context) {
    return Container(
      padding: const EdgeInsets.all(HaloSpacing.s20),
      decoration: BoxDecoration(
        gradient: const LinearGradient(
          begin: Alignment.topLeft,
          end: Alignment.bottomRight,
          colors: [HaloTokens.brandSofter, HaloTokens.surface],
        ),
        borderRadius: HaloRadius.xl,
        border: Border.all(color: HaloTokens.brandSoft),
      ),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          Row(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              Expanded(
                child: Column(
                  crossAxisAlignment: CrossAxisAlignment.start,
                  children: [
                    const Text(
                      'SESI PERTAMA',
                      style: TextStyle(
                        fontSize: 11,
                        color: HaloTokens.inkSoft,
                        fontWeight: FontWeight.w500,
                        letterSpacing: 0.6,
                      ),
                    ),
                    const SizedBox(height: HaloSpacing.s4),
                    Row(
                      crossAxisAlignment: CrossAxisAlignment.end,
                      children: [
                        Text(
                          actual,
                          style: const TextStyle(
                            fontFamily: HaloTokens.fontDisplay,
                            fontSize: 36,
                            fontWeight: FontWeight.w700,
                            color: HaloTokens.brandDark,
                            height: 1,
                            letterSpacing: -1,
                          ),
                        ),
                        const SizedBox(width: HaloSpacing.s8),
                        Padding(
                          padding: const EdgeInsets.only(bottom: 4),
                          child: Text(
                            gimmick,
                            style: const TextStyle(
                              fontSize: 14,
                              color: HaloTokens.inkMuted,
                              decoration: TextDecoration.lineThrough,
                            ),
                          ),
                        ),
                      ],
                    ),
                    const SizedBox(height: HaloSpacing.s4),
                    Text(
                      'untuk $durationMinutes menit ngobrol',
                      style: const TextStyle(
                        fontSize: 13,
                        color: HaloTokens.inkSoft,
                      ),
                    ),
                  ],
                ),
              ),
              Container(
                padding: const EdgeInsets.symmetric(
                  horizontal: HaloSpacing.s12,
                  vertical: 6,
                ),
                decoration: const BoxDecoration(
                  color: HaloTokens.mint,
                  borderRadius: HaloRadius.pill,
                ),
                child: const Text(
                  'HANYA SEKALI',
                  style: TextStyle(
                    fontSize: 10,
                    fontWeight: FontWeight.w700,
                    color: Color(0xFF1F4D34),
                    letterSpacing: 0.6,
                  ),
                ),
              ),
            ],
          ),
          const Padding(
            padding: EdgeInsets.symmetric(vertical: HaloSpacing.s16),
            child: Divider(height: 1, color: HaloTokens.border),
          ),
          ..._features.map((row) => Padding(
                padding: const EdgeInsets.only(bottom: HaloSpacing.s8),
                child: Row(
                  children: [
                    Text(row.$1, style: const TextStyle(fontSize: 14)),
                    const SizedBox(width: HaloSpacing.s8),
                    Expanded(
                      child: Text(
                        row.$2,
                        style: const TextStyle(
                          fontSize: 13,
                          color: HaloTokens.ink,
                        ),
                      ),
                    ),
                  ],
                ),
              )),
        ],
      ),
    );
  }

  static const List<(String, String)> _features = [
    ('🤍', 'menit private sama bestie kamu'),
    ('👤', 'manusia nyata, bukan AI'),
    ('🛡️', 'gak cocok? sesi gratis tanpa tanya'),
  ];
}

/// Placeholder for the chat|call mode toggle on the discount screen. Default
/// config is chat-only (`modes = ['chat']`) so we never render anything yet —
/// kept as a marker so the spot is reserved when ops eventually flips
/// `first_session_discount_modes` to `['chat', 'call']`.
class _ModeToggleHidden extends StatelessWidget {
  const _ModeToggleHidden();
  @override
  Widget build(BuildContext context) => const SizedBox.shrink();
}