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

/// Extension-only pricing sheet — Phase 4 Stage 6 layout.
///
/// Used solely for in-session extension requests; the initial pairing flow
/// goes through `/payment` instead. Free-trial is never offered for extensions.
///
/// Mirrors the Stage 3 duration-pick screen: chat/call toggle on top,
/// 5-option tier list below, single CTA at the bottom. The `perpanjang`
/// behavior is unchanged from Phase 3.7 — submit calls
/// [SessionClosure.requestExtension], which runs the payment-session
/// create+confirm and then the extend POST.
class PricingBottomSheet extends ConsumerStatefulWidget {
  /// Required — the in-progress chat session id this extension targets.
  final String extensionSessionId;

  /// Optional — fired when the customer chooses the "cukup, akhiri sesi"
  /// ghost CTA. The sheet pops itself before invoking the callback so the
  /// downstream confirm-end popup chain can stack on a clean route.
  final VoidCallback? onEndSession;

  const PricingBottomSheet({
    super.key,
    required this.extensionSessionId,
    this.onEndSession,
  });

  /// Show for session extension (from chat screen).
  static Future<void> showForExtension(
    BuildContext context, {
    required String sessionId,
    VoidCallback? onEndSession,
  }) {
    return showModalBottomSheet(
      context: context,
      isScrollControlled: true,
      backgroundColor: HaloTokens.surface,
      // Material 3 auto-injects a drag-handle widget above the sheet when
      // the theme has one configured. We render our own pill inside
      // `_Body` to control its exact tint/size — explicitly disable the
      // auto one so the user doesn't see two stacked horizontal lines.
      showDragHandle: false,
      shape: const RoundedRectangleBorder(
        borderRadius: BorderRadius.only(
          topLeft: Radius.circular(24),
          topRight: Radius.circular(24),
        ),
      ),
      builder: (_) => PricingBottomSheet(
        extensionSessionId: sessionId,
        onEndSession: onEndSession,
      ),
    );
  }

  @override
  ConsumerState<PricingBottomSheet> createState() => _PricingBottomSheetState();
}

class _PricingBottomSheetState extends ConsumerState<PricingBottomSheet> {
  PaymentMode _mode = PaymentMode.chat;
  String? _selectedDurationId;

  List<PriceTier> _tiersForMode(PricingData pricing) {
    // Phase 4 — chat/call tier groups. Falls back to legacy `tiers` when the
    // backend hasn't been cut over yet (so the sheet still works locally
    // against an old backend).
    if (_mode == PaymentMode.call) {
      return pricing.callTiers.isNotEmpty ? pricing.callTiers : pricing.tiers;
    }
    return pricing.chatTiers.isNotEmpty ? pricing.chatTiers : pricing.tiers;
  }

  void _onTierTap(PriceTier tier) {
    setState(() {
      _selectedDurationId = tier.id ?? tier.durationMinutes.toString();
    });
  }

  void _onConfirm(PriceTier tier) {
    Navigator.of(context).pop();
    ref.read(sessionClosureProvider.notifier).requestExtension(
          widget.extensionSessionId,
          durationMinutes: tier.durationMinutes,
          price: tier.price,
        );
  }

  void _onEndSession() {
    Navigator.of(context).pop();
    widget.onEndSession?.call();
  }

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

    return DraggableScrollableSheet(
      initialChildSize: 0.65,
      minChildSize: 0.5,
      maxChildSize: 0.92,
      expand: false,
      builder: (_, scrollController) {
        return SafeArea(
          top: false,
          child: pricingAsync.when(
            loading: () => const SizedBox(
              height: 240,
              child: Center(child: CircularProgressIndicator()),
            ),
            error: (_, __) => const SizedBox(
              height: 240,
              child: Center(child: Text('Gagal memuat harga. Coba lagi.')),
            ),
            data: (pricing) => _Body(
              pricing: pricing,
              mode: _mode,
              selectedDurationId: _selectedDurationId,
              tiers: _tiersForMode(pricing),
              scrollController: scrollController,
              onModeChanged: (m) => setState(() {
                _mode = m;
                _selectedDurationId = null;
              }),
              onTierTap: _onTierTap,
              onConfirm: _onConfirm,
              onEndSession: widget.onEndSession != null ? _onEndSession : null,
            ),
          ),
        );
      },
    );
  }
}

class _Body extends StatelessWidget {
  final PricingData pricing;
  final PaymentMode mode;
  final String? selectedDurationId;
  final List<PriceTier> tiers;
  final ScrollController scrollController;
  final ValueChanged<PaymentMode> onModeChanged;
  final ValueChanged<PriceTier> onTierTap;
  final ValueChanged<PriceTier> onConfirm;
  final VoidCallback? onEndSession;

  const _Body({
    required this.pricing,
    required this.mode,
    required this.selectedDurationId,
    required this.tiers,
    required this.scrollController,
    required this.onModeChanged,
    required this.onTierTap,
    required this.onConfirm,
    required this.onEndSession,
  });

  @override
  Widget build(BuildContext context) {
    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 ? '📞' : '💬'} perpanjang ${formatRupiah(selectedTier.price)}'
        : 'pilih durasi dulu';

    return Column(
      children: [
        const SizedBox(height: HaloSpacing.s8),
        Container(
          width: 40,
          height: 4,
          decoration: const BoxDecoration(
            color: HaloTokens.border,
            borderRadius: HaloRadius.pill,
          ),
        ),
        const SizedBox(height: HaloSpacing.s12),
        const Text(
          'waktu curhat habis',
          style: TextStyle(
            fontFamily: HaloTokens.fontDisplay,
            fontSize: 18,
            fontWeight: FontWeight.w700,
            color: HaloTokens.brandDark,
          ),
        ),
        const SizedBox(height: HaloSpacing.s4),
        const Text(
          'mau tambah waktu?',
          style: TextStyle(
            fontFamily: HaloTokens.fontBody,
            fontSize: 13,
            color: HaloTokens.inkSoft,
          ),
        ),
        const SizedBox(height: HaloSpacing.s16),
        Padding(
          padding: const EdgeInsets.symmetric(horizontal: HaloSpacing.s24),
          child: _ModeToggle(mode: mode, onChanged: onModeChanged),
        ),
        const SizedBox(height: HaloSpacing.s12),
        Expanded(
          child: tiers.isEmpty
              ? const _EmptyState()
              : ListView.separated(
                  controller: scrollController,
                  padding: const EdgeInsets.fromLTRB(
                    HaloSpacing.s24,
                    HaloSpacing.s4,
                    HaloSpacing.s24,
                    HaloSpacing.s16,
                  ),
                  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(tier),
                    );
                  },
                ),
        ),
        Padding(
          // No top border here — the drag handle is the only top "divider"
          // the figma shows. A second border above the action bar reads as a
          // duplicate line stacked under the list separator visuals.
          padding: const EdgeInsets.fromLTRB(
            HaloSpacing.s24,
            HaloSpacing.s12,
            HaloSpacing.s24,
            HaloSpacing.s16,
          ),
          child: Column(
            mainAxisSize: MainAxisSize.min,
            children: [
              HaloButton(
                label: ctaLabel,
                size: HaloButtonSize.lg,
                fullWidth: true,
                onPressed: hasSelection ? () => onConfirm(selectedTier) : null,
              ),
              if (onEndSession != null) ...[
                const SizedBox(height: HaloSpacing.s8),
                HaloButton(
                  label: 'cukup, akhiri sesi',
                  variant: HaloButtonVariant.ghost,
                  fullWidth: true,
                  onPressed: onEndSession,
                ),
              ],
            ],
          ),
        ),
      ],
    );
  }
}

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(
                  '${tier.durationMinutes}',
                  style: const TextStyle(
                    fontFamily: HaloTokens.fontDisplay,
                    fontSize: 16,
                    fontWeight: FontWeight.w700,
                    color: HaloTokens.brandDark,
                  ),
                ),
              ),
              const SizedBox(width: HaloSpacing.s12),
              Expanded(
                child: Row(
                  children: [
                    Text(
                      '${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),
        ),
      ),
    );
  }
}