import 'package:flutter/material.dart';
import 'package:lucide_icons_flutter/lucide_icons.dart';

import '../../data/models.dart';
import '../../state/app_scope.dart';
import '../format.dart';
import '../tokens.dart';
import '../widgets/buttons.dart';
import '../widgets/cards.dart';
import '../widgets/chrome.dart';
import '../widgets/misc.dart';
import '../widgets/route_rail.dart';
import 'booking/booking_routes.dart';
import 'booking/send_screen.dart';
import 'shell_screen.dart';
import 'sheets/place_search_sheet.dart';
import 'tracking_screen.dart';

/// Home — one question, one dominant action, and whatever is live right now.
/// Nothing else competes; history belongs to the Orders tab.
class HomeScreen extends StatelessWidget {
  const HomeScreen({super.key});

  @override
  Widget build(BuildContext context) {
    final app = AppScope.of(context);
    final active = app.activeBookings.isEmpty ? null : app.activeBookings.first;
    final firstRun = app.orders.isEmpty;

    // The pickup point is already confirmed on this screen, so booking starts
    // at the destination — two taps from here to a reserved slot.
    void startBooking() {
      AppScope.read(context).startBooking();
      Navigator.of(context).push(
        bookingRoute<void>(BookingRoutes.send, (_) => const SendScreen()),
      );
    }

    return Column(
      crossAxisAlignment: CrossAxisAlignment.stretch,
      children: [
        DmBrandHeader(
          eyebrow: 'Welcome, ${_firstName(app.customer?.name)}',
          title: firstRun ? 'Send your first parcel' : 'Send a parcel',
          action: InkResponse(
            onTap: () => ShellScreen.of(context)?.goToTab(2),
            radius: 26,
            child: DmAvatar(initials: initialsOf(app.customer?.name), onBrand: true),
          ),
          // The address is the one fact every booking starts from, so it sits
          // in the header as a live value the customer can change in place —
          // not as the first question of the flow.
          child: DmHeaderTrack(
            leading: const DmLiveDot(size: 6, color: Colors.white),
            trailing: const Icon(
              LucideIcons.chevronDown,
              size: 16,
              color: DmColors.onBrand3,
            ),
            onTap: () async {
              final place = await showPlaceSearchSheet(context);
              if (place != null && context.mounted) app.setPickup(place);
            },
            child: Text(
              app.pickup?.title ?? 'Set a pickup address',
              maxLines: 1,
              overflow: TextOverflow.ellipsis,
              style: DmText.cardTitle.copyWith(color: Colors.white),
            ),
          ),
        ),
        Expanded(
          child: RefreshIndicator(
            color: DmColors.brand,
            backgroundColor: DmColors.surface,
            onRefresh: () async {
              await Future.wait([app.detectPickupLocation(), app.refreshOrders()]);
            },
            child: ListView(
              physics: const AlwaysScrollableScrollPhysics(),
              padding: const EdgeInsets.fromLTRB(DmSpace.pad, 16, DmSpace.pad, 28),
              children: [
                _BookCta(onTap: startBooking),
                if (active != null) ...[
                  const DmMicroHead('Happening now'),
                  _ActiveCard(booking: active),
                ],
                if (firstRun) const _HowItWorks(),
              ],
            ),
          ),
        ),
      ],
    );
  }

  static String _firstName(String? name) {
    final first = (name ?? '').trim().split(RegExp(r'\s+')).first;
    return first.isEmpty ? 'there' : first;
  }
}

/// The screen's one action, as a filled crimson card.
///
/// It was a 68pt bar reading BOOK in tracked capitals — a word with no object,
/// which on first run told a new customer nothing about what the app does. The
/// card says what will happen ("a Miler collects from your door in a window you
/// choose") and puts the action inside it, so the promise and the button are
/// one object rather than a shout followed by an explanation elsewhere.
class _BookCta extends StatelessWidget {
  const _BookCta({required this.onTap});

  final VoidCallback onTap;

  @override
  Widget build(BuildContext context) {
    return DmCard(
      tone: DmCardTone.fill,
      children: [
        DmCardCell(
          padding: const EdgeInsets.fromLTRB(16, 16, 16, 16),
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              Text(
                'Book a pickup',
                style: DmText.heading.copyWith(fontSize: 19, color: Colors.white),
              ),
              const SizedBox(height: 4),
              Text(
                'A Miler collects from your door in a window you choose.',
                style: DmText.small.copyWith(color: DmColors.onBrand2),
              ),
              const SizedBox(height: 14),
              // White on crimson: inside a filled card the primary action has
              // to invert, or it disappears into its own background.
              _WhiteButton(label: 'Start booking', onTap: onTap),
            ],
          ),
        ),
      ],
    );
  }
}

class _WhiteButton extends StatefulWidget {
  const _WhiteButton({required this.label, required this.onTap});

  final String label;
  final VoidCallback onTap;

  @override
  State<_WhiteButton> createState() => _WhiteButtonState();
}

class _WhiteButtonState extends State<_WhiteButton> {
  bool _down = false;

  @override
  Widget build(BuildContext context) {
    return Semantics(
      button: true,
      label: widget.label,
      child: GestureDetector(
        behavior: HitTestBehavior.opaque,
        onTapDown: (_) => setState(() => _down = true),
        onTapUp: (_) => setState(() => _down = false),
        onTapCancel: () => setState(() => _down = false),
        onTap: widget.onTap,
        child: AnimatedContainer(
          duration: DmMotion.fast,
          curve: DmMotion.ease,
          // A minimum, not a height: at large accessibility text the label
          // needs the extra line, and a fixed 46 would clip it.
          constraints: const BoxConstraints(minHeight: 46),
          padding: const EdgeInsets.symmetric(horizontal: 14, vertical: 10),
          decoration: BoxDecoration(
            color: _down ? DmColors.brandSoft : Colors.white,
            borderRadius: DmRadius.all(DmRadius.sm),
          ),
          child: Row(
            mainAxisAlignment: MainAxisAlignment.center,
            children: [
              Flexible(
                child: Text(
                  widget.label,
                  textAlign: TextAlign.center,
                  style: DmText.button.copyWith(fontSize: 15, color: DmColors.brand),
                ),
              ),
              const SizedBox(width: 9),
              const Icon(LucideIcons.arrowRight, size: 18, color: DmColors.brand),
            ],
          ),
        ),
      ),
    );
  }
}

/// Shown on first run only: three numbered rows that match the booking flow
/// exactly, so the first send has no surprises in it.
class _HowItWorks extends StatelessWidget {
  const _HowItWorks();

  static const _steps = [
    ('Tell us where it goes', 'City, address and recipient'),
    ('Pick a two-hour window', 'With live Miler availability'),
    ('Hand it over and track', 'Door to hub to doorstep, with proof'),
  ];

  @override
  Widget build(BuildContext context) {
    return Column(
      crossAxisAlignment: CrossAxisAlignment.stretch,
      children: [
        const DmMicroHead('How it works'),
        DmCard(
          children: [
            for (var i = 0; i < _steps.length; i++)
              DmCardRow(
                leading: DmTile(label: '${i + 1}', tone: DmTileTone.brand),
                title: _steps[i].$1,
                subtitle: _steps[i].$2,
              ),
          ],
        ),
      ],
    );
  }
}

class _ActiveCard extends StatelessWidget {
  const _ActiveCard({required this.booking});

  final Booking booking;

  @override
  Widget build(BuildContext context) {
    final app = AppScope.read(context);
    final slot = app.slotById(booking.slotId);
    final beforeHandover = booking.stage.index <= JourneyStage.pickedUp.index;
    final windowLabel = slot == null
        ? 'Pickup scheduled'
        : '${slot.day} · ${slot.window}';

    final courierLine = switch (booking.stage) {
      JourneyStage.booked => 'Matching the nearest Miler',
      JourneyStage.assigned when booking.miler != null =>
        '${booking.miler!.name} will collect your parcel',
      JourneyStage.onTheWay when booking.miler != null =>
        '${booking.miler!.name} is on route'
            '${booking.milerDistanceKm == null ? '' : ' · ${booking.milerDistanceKm} km away'}',
      JourneyStage.arrived when booking.miler != null =>
        '${booking.miler!.name} is at your door',
      _ =>
        booking.isMultiDestination
            ? 'To ${booking.destinations.length} destinations'
            : 'To ${booking.destination.label}',
    };

    return DmCard(
      onTap: () {
        app.openTracking(booking.reference);
        Navigator.of(context).push(
          bookingRoute<void>(BookingRoutes.tracking, (_) => const TrackingScreen()),
        );
      },
      children: [
        DmCardCell(
          background: DmColors.brandSoft,
          padding: const EdgeInsets.fromLTRB(14, 11, 14, 11),
          child: Row(
            children: [
              Flexible(child: DmPill(booking.stage.milestoneLabel)),
              const SizedBox(width: 10),
              Expanded(
                child: Text(
                  booking.displayId,
                  textAlign: TextAlign.right,
                  maxLines: 1,
                  overflow: TextOverflow.ellipsis,
                  style: DmText.mono,
                ),
              ),
            ],
          ),
        ),
        DmCardCell(
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              DmRouteRail(
                compact: true,
                pickup: booking.pickup.title,
                drop: booking.isMultiDestination
                    ? '${booking.destinations.length} destinations'
                    : booking.destination.label,
              ),
              const SizedBox(height: 12),
              Text(courierLine, style: DmText.small),
            ],
          ),
        ),
        DmCardCell(
          padding: const EdgeInsets.fromLTRB(16, 12, 10, 12),
          child: Row(
            children: [
              Icon(
                beforeHandover ? LucideIcons.clock : LucideIcons.truck,
                size: 15,
                color: DmColors.ink3,
              ),
              const SizedBox(width: 10),
              Expanded(
                child: Text(
                  beforeHandover ? windowLabel : 'On its way',
                  style: DmText.small,
                  maxLines: 1,
                  overflow: TextOverflow.ellipsis,
                ),
              ),
              DmTextAction(
                label: 'Track',
                icon: LucideIcons.arrowRight,
                onPressed: () {
                  app.openTracking(booking.reference);
                  Navigator.of(context).push(
                    bookingRoute<void>(
                      BookingRoutes.tracking,
                      (_) => const TrackingScreen(),
                    ),
                  );
                },
              ),
            ],
          ),
        ),
      ],
    );
  }
}