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';

/// "Pemilihan harga" — tier list scoped to the currently-selected mode.
/// A chat|call mode toggle at the top rebuilds the list and resets the
/// selection. Bottom CTA carries the picked tier into `/payment/method`.
class DurationPickScreen extends ConsumerWidget {
  const DurationPickScreen({super.key});

  List<PriceTier> _tiersForMode(PricingData pricing, PaymentMode mode) {
    return mode == PaymentMode.call ? pricing.callTiers : pricing.chatTiers;
  }

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

    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('/payment/method-pick');
            }
          },
        ),
        title: const Text(
          'pilih durasi',
          style: TextStyle(
            fontFamily: HaloTokens.fontDisplay,
            fontSize: 18,
            fontWeight: FontWeight.w700,
            color: HaloTokens.brandDark,
          ),
        ),
        centerTitle: false,
      ),
      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) => _Body(
          pricing: pricing,
          mode: draft.mode,
          selectedDurationId: draft.durationId,
          tiers: _tiersForMode(pricing, draft.mode),
        ),
      ),
    );
  }
}

class _Body extends ConsumerWidget {
  final PricingData pricing;
  final PaymentMode mode;
  final String? selectedDurationId;
  final List<PriceTier> tiers;

  const _Body({
    required this.pricing,
    required this.mode,
    required this.selectedDurationId,
    required this.tiers,
  });

  void _onModeToggle(WidgetRef ref, PaymentMode next) {
    if (next == mode) return;
    ref.read(paymentDraftNotifierProvider.notifier).setMode(next);
  }

  void _onTierTap(WidgetRef ref, PriceTier tier) {
    ref.read(paymentDraftNotifierProvider.notifier).setTier(
          durationId: tier.id ?? tier.durationMinutes.toString(),
          durationMinutes: tier.durationMinutes,
          priceIDR: tier.price,
        );
  }

  void _onPay(BuildContext context) {
    context.push('/payment/method');
  }

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final selectedTier = tiers.firstWhere(
      (t) => (t.id ?? t.durationMinutes.toString()) == selectedDurationId,
      orElse: () => const PriceTier(durationMinutes: 0, price: 0, label: ''),
    );
    final hasSelection = selectedTier.durationMinutes > 0;
    final ctaLabel = hasSelection
        ? '${mode == PaymentMode.call ? '📞' : '💬'} bayar ${formatRupiah(selectedTier.price)}'
        : 'pilih durasi dulu';

    return Column(
      children: [
        Padding(
          padding: const EdgeInsets.fromLTRB(
            HaloSpacing.s24,
            HaloSpacing.s8,
            HaloSpacing.s24,
            HaloSpacing.s8,
          ),
          child: _ModeToggle(mode: mode, onChanged: (m) => _onModeToggle(ref, m)),
        ),
        Expanded(
          child: tiers.isEmpty
              ? const _EmptyState()
              : ListView.separated(
                  padding: const EdgeInsets.fromLTRB(
                    HaloSpacing.s24,
                    HaloSpacing.s12,
                    HaloSpacing.s24,
                    HaloSpacing.s24,
                  ),
                  itemCount: tiers.length,
                  separatorBuilder: (_, __) => const SizedBox(height: HaloSpacing.s8),
                  itemBuilder: (context, i) {
                    final tier = tiers[i];
                    final id = tier.id ?? tier.durationMinutes.toString();
                    final selected = id == selectedDurationId;
                    return _TierCard(
                      tier: tier,
                      selected: selected,
                      onTap: () => _onTierTap(ref, tier),
                    );
                  },
                ),
        ),
        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: HaloButton(
            label: ctaLabel,
            size: HaloButtonSize.lg,
            fullWidth: true,
            onPressed: hasSelection ? () => _onPay(context) : null,
          ),
        ),
      ],
    );
  }
}

class _ModeToggle extends StatelessWidget {
  final PaymentMode mode;
  final ValueChanged<PaymentMode> onChanged;

  const _ModeToggle({required this.mode, required this.onChanged});

  @override
  Widget build(BuildContext context) {
    return Container(
      padding: const EdgeInsets.all(4),
      decoration: const BoxDecoration(
        color: HaloTokens.brandSofter,
        borderRadius: HaloRadius.pill,
      ),
      child: Row(
        children: [
          Expanded(child: _Pill(label: 'chat', selected: mode == PaymentMode.chat, onTap: () => onChanged(PaymentMode.chat))),
          Expanded(child: _Pill(label: 'call', selected: mode == PaymentMode.call, onTap: () => onChanged(PaymentMode.call))),
        ],
      ),
    );
  }
}

class _Pill extends StatelessWidget {
  final String label;
  final bool selected;
  final VoidCallback onTap;
  const _Pill({required this.label, required this.selected, required this.onTap});

  @override
  Widget build(BuildContext context) {
    return Material(
      color: selected ? HaloTokens.surface : Colors.transparent,
      borderRadius: HaloRadius.pill,
      child: InkWell(
        borderRadius: HaloRadius.pill,
        onTap: onTap,
        child: Container(
          padding: const EdgeInsets.symmetric(vertical: HaloSpacing.s8),
          alignment: Alignment.center,
          child: Text(
            label,
            style: TextStyle(
              fontFamily: HaloTokens.fontBody,
              fontSize: 13.5,
              fontWeight: FontWeight.w600,
              color: selected ? HaloTokens.brandDark : HaloTokens.inkSoft,
            ),
          ),
        ),
      ),
    );
  }
}

class _TierCard extends StatelessWidget {
  final PriceTier tier;
  final bool selected;
  final VoidCallback onTap;

  const _TierCard({required this.tier, required this.selected, required this.onTap});

  @override
  Widget build(BuildContext context) {
    return Material(
      color: selected ? HaloTokens.brandSofter : HaloTokens.surface,
      borderRadius: HaloRadius.lg,
      child: InkWell(
        borderRadius: HaloRadius.lg,
        onTap: onTap,
        child: AnimatedContainer(
          duration: HaloMotion.fast,
          padding: const EdgeInsets.all(HaloSpacing.s16),
          decoration: BoxDecoration(
            border: Border.all(
              color: selected ? HaloTokens.brand : HaloTokens.border,
              width: selected ? 2 : 1,
            ),
            borderRadius: HaloRadius.lg,
          ),
          child: Row(
            children: [
              Container(
                width: 44,
                height: 44,
                decoration: const BoxDecoration(
                  color: HaloTokens.surface,
                  borderRadius: HaloRadius.md,
                ),
                alignment: Alignment.center,
                child: Text(
                  '${tier.durationMinutes}',
                  style: const TextStyle(
                    fontFamily: HaloTokens.fontDisplay,
                    fontSize: 16,
                    fontWeight: FontWeight.w700,
                    color: HaloTokens.brandDark,
                  ),
                ),
              ),
              const SizedBox(width: HaloSpacing.s12),
              Expanded(
                child: Column(
                  crossAxisAlignment: CrossAxisAlignment.start,
                  children: [
                    Row(
                      children: [
                        Text(
                          '${tier.durationMinutes} menit',
                          style: const TextStyle(
                            fontSize: 15,
                            fontWeight: FontWeight.w600,
                            color: HaloTokens.ink,
                          ),
                        ),
                        if (tier.tag != null) ...[
                          const SizedBox(width: HaloSpacing.s8),
                          Container(
                            padding: const EdgeInsets.symmetric(
                              horizontal: HaloSpacing.s8,
                              vertical: 2,
                            ),
                            decoration: const BoxDecoration(
                              color: HaloTokens.mint,
                              borderRadius: HaloRadius.pill,
                            ),
                            child: Text(
                              tier.tag!,
                              style: const TextStyle(
                                fontSize: 9,
                                fontWeight: FontWeight.w700,
                                color: Color(0xFF1F4D34),
                                letterSpacing: 0.4,
                              ),
                            ),
                          ),
                        ],
                      ],
                    ),
                  ],
                ),
              ),
              Text(
                formatRupiah(tier.price),
                style: const TextStyle(
                  fontFamily: HaloTokens.fontDisplay,
                  fontSize: 16,
                  fontWeight: FontWeight.w700,
                  color: HaloTokens.brandDark,
                ),
              ),
            ],
          ),
        ),
      ),
    );
  }
}

class _EmptyState extends StatelessWidget {
  const _EmptyState();
  @override
  Widget build(BuildContext context) {
    return const Center(
      child: Padding(
        padding: EdgeInsets.all(HaloSpacing.s24),
        child: Text(
          'Belum ada paket untuk mode ini.',
          style: TextStyle(color: HaloTokens.inkSoft),
        ),
      ),
    );
  }
}