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

import 'package:miler/views/helpers/constants/Colorconstants.dart';
import 'package:miler/views/helpers/constants/design_constants.dart';
import 'package:miler/views/helpers/constants/Font_constant.dart';
import 'package:miler/views/helpers/widgets/app_widgets.dart';

/// ─────────────────────────────────────────────────────────────────────────
/// REVIEW & PAY — the last screen before a shipment exists.
///
/// ```
///   verify parcel ──▶ shipment desk ──▶  [ REVIEW & PAY ]  ──▶ order created
///                                         everything on
///                                         one screen
/// ```
///
/// ── Why this replaced a review, a payment page and a confirm sheet ──
///
/// The rider used to close a logistics stop across four screens: the verify
/// page's own review, then the shipment desk, then a confirm sheet, then a
/// payment page. Three of those asked him to look at the same facts again, and
/// the one that took the money was the furthest from the one that priced it —
/// so the number he quoted the customer and the number he collected were two
/// screens apart with no way to see them together.
///
/// This is the single review: what is being shipped, where from, where to, what
/// it weighs, what it costs, and how the customer is paying — then one button
/// that says the amount out loud. **`Pay ₹150`**, not `Confirm`. A rider taking
/// cash on a doorstep should never have to remember what the total was.
///
/// ── The button is the commit ──
///
/// Pressing it does three things in the order the contract requires: records
/// the payment, then posts `pickup-complete`, which converts the booking into a
/// live consignment with a tracking number. Only then does the screen change.
/// If any of it fails the rider stays here with the reason — nothing is
/// reported as created that was not created.
/// ─────────────────────────────────────────────────────────────────────────

/// How the customer paid. The wire values the payment endpoint expects.
enum ShipmentPayMethod { cash, upi }

extension ShipmentPayMethodX on ShipmentPayMethod {
  String get label => switch (this) {
    ShipmentPayMethod.cash => 'Cash',
    ShipmentPayMethod.upi => 'UPI',
  };

  IconData get icon => switch (this) {
    ShipmentPayMethod.cash => LucideIcons.banknote,
    ShipmentPayMethod.upi => LucideIcons.qrCode,
  };

  /// Lower-case, matching what `UpdatePickupProvider.submitPayment` maps from.
  String get wireName => name;
}

class ShipmentReviewPage extends StatefulWidget {
  /// The stop being closed.
  final Map<String, dynamic> pickup;

  /// What the shipment desk captured — from, to, weight, zone, price.
  final Map<String, dynamic> shipment;

  /// Takes the money and creates the order. Returns null on success, or a
  /// message to show the rider when it could not be completed.
  ///
  /// Injected rather than called directly so this page stays a widget: the
  /// caller owns the provider, the geofence and the controller.
  final Future<String?> Function(ShipmentPayMethod method, double amount)
  onConfirm;

  /// Read once the order exists, for the receipt line.
  final String Function() trackingNo;

  const ShipmentReviewPage({
    super.key,
    required this.pickup,
    required this.shipment,
    required this.onConfirm,
    required this.trackingNo,
  });

  @override
  State<ShipmentReviewPage> createState() => _ShipmentReviewPageState();
}

class _ShipmentReviewPageState extends State<ShipmentReviewPage>
    with TickerProviderStateMixin {
  ShipmentPayMethod _method = ShipmentPayMethod.cash;
  bool _busy = false;
  bool _created = false;
  String? _error;

  // ── Built in initState, deliberately, not as `late final` ──
  //
  // A `late final` controller is only constructed on first read — and on a
  // review the rider abandons, the first read is `dispose()`. Creating a Ticker
  // there looks up `TickerMode` on an element that is already deactivated,
  // which throws while the tree is being torn down. Eager construction is the
  // only ordering that is correct for every exit from this screen.
  late final AnimationController _successController;
  late final Animation<double> _tickScale;
  late final Animation<double> _ringScale;
  late final Animation<double> _copyFade;

  @override
  void initState() {
    super.initState();
    _successController = AnimationController(
      vsync: this,
      duration: DesignConstants.motionCelebrate,
    );
    _tickScale = CurvedAnimation(
      parent: _successController,
      // Overshoots and settles — the shape of a stamp coming down, which is
      // what this moment is. A linear tick reads as a loading state that
      // stopped.
      curve: Curves.elasticOut,
    );
    _ringScale = CurvedAnimation(
      parent: _successController,
      curve: const Interval(0, 0.55, curve: Curves.easeOutCubic),
    );
    _copyFade = CurvedAnimation(
      parent: _successController,
      curve: const Interval(0.35, 1, curve: Curves.easeOut),
    );
  }

  @override
  void dispose() {
    _successController.dispose();
    super.dispose();
  }

  double get _amount {
    final v = widget.shipment['price'];
    if (v is num) return v.toDouble();
    return double.tryParse('${v ?? ''}') ?? 0;
  }

  String get _currency => (widget.shipment['currency'] ?? 'INR').toString();

  /// `₹150` — the figure on the button and in the summary, from one place so
  /// the two can never disagree.
  String get _amountLabel {
    final symbol = _currency == 'INR' ? '₹' : '$_currency ';
    return '$symbol${_amount.toStringAsFixed(0)}';
  }

  String _s(dynamic v) => (v ?? '').toString().trim();

  Map<String, dynamic> get _from =>
      (widget.shipment['from'] as Map?)?.cast<String, dynamic>() ?? {};
  Map<String, dynamic> get _to =>
      (widget.shipment['to'] as Map?)?.cast<String, dynamic>() ?? {};

  Future<void> _confirm() async {
    if (_busy) return;
    setState(() {
      _busy = true;
      _error = null;
    });

    final failure = await widget.onConfirm(_method, _amount);
    if (!mounted) return;

    if (failure != null) {
      // Stayed here on purpose. The order does not exist, and a success
      // animation over a failed create is the one thing this screen must never
      // do — the rider would ride off believing a shipment had been raised.
      setState(() {
        _busy = false;
        _error = failure;
      });
      return;
    }

    setState(() {
      _busy = false;
      _created = true;
    });
    _successController.forward();
  }

  @override
  Widget build(BuildContext context) {
    return PopScope(
      // Once the order exists, going back would offer to create it twice.
      canPop: !_created && !_busy,
      child: Scaffold(
        backgroundColor: ColorConstants.daylightSurface,
        appBar: _created ? null : milerPageBar('Review & pay'),
        body: SafeArea(child: _created ? _successView() : _reviewView()),
      ),
    );
  }

  // ── Review ─────────────────────────────────────────────────────────────

  Widget _reviewView() {
    return Column(
      children: [
        Expanded(
          child: SingleChildScrollView(
            physics: const BouncingScrollPhysics(),
            padding: EdgeInsets.fromLTRB(16.w, 12.h, 16.w, 24.h),
            child: Column(
              crossAxisAlignment: CrossAxisAlignment.start,
              children: [
                _routeCard(),
                SizedBox(height: 14.h),
                const SectionHeader(title: 'Shipment'),
                SizedBox(height: 8.h),
                _shipmentCard(),
                SizedBox(height: 14.h),
                const SectionHeader(title: 'Payment'),
                SizedBox(height: 8.h),
                _paymentCard(),
                if (_error != null) ...[
                  SizedBox(height: 14.h),
                  InfoBanner(
                    icon: LucideIcons.circleAlert,
                    text: _error!,
                    color: ColorConstants.errorRed,
                  ),
                ],
              ],
            ),
          ),
        ),
        _payBar(),
      ],
    );
  }

  /// From → to, drawn as a journey rather than two labelled fields.
  Widget _routeCard() {
    return AppCard(
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          _routeEnd(
            icon: LucideIcons.circleDot,
            color: ColorConstants.primary,
            label: 'FROM',
            address: _s(_from['address']),
            pincode: _s(_from['pincode']),
          ),
          // The connector. Reads as one journey, which two stacked address
          // blocks do not.
          Padding(
            padding: EdgeInsets.only(left: 9.w),
            child: SizedBox(
              height: 22.h,
              child: VerticalDivider(
                width: 2.w,
                thickness: 2,
                color: ColorConstants.borderSubtle,
              ),
            ),
          ),
          _routeEnd(
            icon: LucideIcons.mapPin,
            color: ColorConstants.acceptGreen,
            label: 'TO',
            address: _s(_to['address']),
            pincode: _s(_to['pincode']),
            city: _s(_to['city']),
          ),
        ],
      ),
    );
  }

  Widget _routeEnd({
    required IconData icon,
    required Color color,
    required String label,
    required String address,
    required String pincode,
    String city = '',
  }) {
    final tail = [
      if (city.isNotEmpty) city,
      if (pincode.isNotEmpty) pincode,
    ].join(' · ');

    return Row(
      crossAxisAlignment: CrossAxisAlignment.start,
      children: [
        Icon(icon, size: 18.sp, color: color),
        SizedBox(width: 10.w),
        Expanded(
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              Text(
                label,
                style: TextStyle(
                  fontSize: 10.5.sp,
                  fontWeight: FontWeight.w700,
                  letterSpacing: 0.6,
                  color: ColorConstants.secondaryText,
                  fontFamily: FontConstants.fontFamily,
                ),
              ),
              SizedBox(height: 2.h),
              Text(
                address.isEmpty ? 'Not captured' : address,
                style: TextStyle(
                  fontSize: 13.5.sp,
                  fontWeight: FontWeight.w600,
                  height: 1.3,
                  color: address.isEmpty
                      ? ColorConstants.secondaryText
                      : ColorConstants.slateText,
                  fontFamily: FontConstants.fontFamily,
                ),
              ),
              if (tail.isNotEmpty)
                Padding(
                  padding: EdgeInsets.only(top: 2.h),
                  child: Text(
                    tail,
                    style: TextStyle(
                      fontSize: 11.5.sp,
                      fontWeight: FontWeight.w500,
                      color: ColorConstants.secondaryText,
                      fontFamily: FontConstants.fontFamily,
                    ),
                  ),
                ),
            ],
          ),
        ),
      ],
    );
  }

  Widget _shipmentCard() {
    final weight = widget.shipment['weight'];
    final km = widget.shipment['approxkm'];

    return AppCard(
      child: Column(
        children: [
          _row('Weight', weight == null ? '—' : '$weight kg'),
          _divider(),
          _row('Category', _s(widget.shipment['category'])),
          _divider(),
          _row('Service', _s(widget.shipment['servicetype'])),
          if (_s(widget.shipment['zone']).isNotEmpty) ...[
            _divider(),
            _row('Zone', _s(widget.shipment['zone'])),
          ],
          if (km is num) ...[
            _divider(),
            _row(
              'Distance',
              '≈ ${km.toStringAsFixed(1)} km',
              // Said plainly: it is a straight line between two pins, and the
              // fare comes from the zone. Letting the rider assume otherwise is
              // how a customer gets told the wrong basis for a charge.
              note: 'straight line — the fare uses the zone',
            ),
          ],
        ],
      ),
    );
  }

  Widget _paymentCard() {
    return AppCard(
      child: Column(
        children: [
          Row(
            children: [
              for (final m in ShipmentPayMethod.values) ...[
                Expanded(child: _methodTile(m)),
                if (m != ShipmentPayMethod.values.last) SizedBox(width: 8.w),
              ],
            ],
          ),
          SizedBox(height: 14.h),
          Row(
            children: [
              Expanded(
                child: Text(
                  'Amount to collect',
                  style: TextStyle(
                    fontSize: 13.sp,
                    fontWeight: FontWeight.w600,
                    color: ColorConstants.slateText,
                    fontFamily: FontConstants.fontFamily,
                  ),
                ),
              ),
              Text(
                _amountLabel,
                style: TextStyle(
                  fontSize: 20.sp,
                  fontWeight: FontWeight.w800,
                  letterSpacing: -0.4,
                  color: ColorConstants.primary,
                  fontFamily: FontConstants.fontFamily,
                ),
              ),
            ],
          ),
        ],
      ),
    );
  }

  Widget _methodTile(ShipmentPayMethod m) {
    final selected = _method == m;
    return GestureDetector(
      onTap: _busy ? null : () => setState(() => _method = m),
      child: AnimatedContainer(
        duration: DesignConstants.motionState,
        padding: EdgeInsets.symmetric(vertical: 12.h),
        decoration: BoxDecoration(
          color: selected
              ? ColorConstants.primary.withValues(alpha: 0.08)
              : ColorConstants.daylightSurface,
          borderRadius: BorderRadius.circular(DesignConstants.radiusLg),
          border: Border.all(
            color: selected
                ? ColorConstants.primary
                : ColorConstants.borderSubtle,
            width: selected ? 1.6 : 1,
          ),
        ),
        child: Column(
          children: [
            Icon(
              m.icon,
              size: 20.sp,
              color: selected
                  ? ColorConstants.primary
                  : ColorConstants.secondaryText,
            ),
            SizedBox(height: 5.h),
            Text(
              m.label,
              style: TextStyle(
                fontSize: 12.5.sp,
                fontWeight: FontWeight.w700,
                color: selected
                    ? ColorConstants.primary
                    : ColorConstants.slateText,
                fontFamily: FontConstants.fontFamily,
              ),
            ),
          ],
        ),
      ),
    );
  }

  /// The commit. Names the amount, because that is the fact the rider is acting
  /// on and the one he will be asked for at the door.
  Widget _payBar() {
    return Container(
      padding: EdgeInsets.fromLTRB(16.w, 10.h, 16.w, 12.h),
      decoration: BoxDecoration(
        color: ColorConstants.pureSurface,
        border: Border(
          top: BorderSide(color: ColorConstants.borderSubtle, width: 1),
        ),
        boxShadow: DesignConstants.shadowSm,
      ),
      child: PrimaryButton(
        label: _amount > 0
            ? 'Pay $_amountLabel'
            // A prepaid or zero-rated shipment still has to be created; the
            // button says what it does rather than asking for money nobody owes.
            : 'Create order',
        loading: _busy,
        onPressed: _busy ? null : _confirm,
      ),
    );
  }

  Widget _row(String label, String value, {String? note}) {
    return Padding(
      padding: EdgeInsets.symmetric(vertical: 7.h),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          Row(
            children: [
              Expanded(
                child: Text(
                  label,
                  style: TextStyle(
                    fontSize: 12.5.sp,
                    fontWeight: FontWeight.w500,
                    color: ColorConstants.secondaryText,
                    fontFamily: FontConstants.fontFamily,
                  ),
                ),
              ),
              Text(
                value.isEmpty ? '—' : value,
                style: TextStyle(
                  fontSize: 13.sp,
                  fontWeight: FontWeight.w700,
                  color: ColorConstants.slateText,
                  fontFamily: FontConstants.fontFamily,
                ),
              ),
            ],
          ),
          if (note != null)
            Padding(
              padding: EdgeInsets.only(top: 2.h),
              child: Text(
                note,
                style: TextStyle(
                  fontSize: 10.5.sp,
                  fontWeight: FontWeight.w500,
                  color: ColorConstants.secondaryText,
                  fontFamily: FontConstants.fontFamily,
                ),
              ),
            ),
        ],
      ),
    );
  }

  Widget _divider() => Divider(height: 1.h, color: ColorConstants.borderSubtle);

  // ── Success ────────────────────────────────────────────────────────────
  //
  // One moment, three beats, staggered so they read as a sequence rather than
  // a screen that swapped: the ring opens, the tick stamps down inside it, and
  // the words arrive last. All of it drives off one controller, so the timing
  // cannot drift.

  Widget _successView() {
    final tracking = widget.trackingNo();

    return Padding(
      padding: EdgeInsets.symmetric(horizontal: 24.w),
      child: Column(
        mainAxisAlignment: MainAxisAlignment.center,
        children: [
          const Spacer(),
          AnimatedBuilder(
            animation: _successController,
            builder: (_, _) => SizedBox(
              width: 132.w,
              height: 132.w,
              child: Stack(
                alignment: Alignment.center,
                children: [
                  // The ring, which expands and fades — a single ripple, not a
                  // loop. A repeating pulse would keep asking for attention on
                  // a screen whose job is finished.
                  Transform.scale(
                    scale: 0.6 + (_ringScale.value * 0.55),
                    child: Opacity(
                      opacity: (1 - _ringScale.value).clamp(0.0, 1.0) * 0.35,
                      child: Container(
                        decoration: BoxDecoration(
                          shape: BoxShape.circle,
                          color: ColorConstants.acceptGreen,
                        ),
                      ),
                    ),
                  ),
                  Transform.scale(
                    scale: _tickScale.value.clamp(0.0, 1.2),
                    child: Container(
                      width: 92.w,
                      height: 92.w,
                      decoration: BoxDecoration(
                        shape: BoxShape.circle,
                        color: ColorConstants.acceptGreen,
                        boxShadow: [
                          BoxShadow(
                            color: ColorConstants.acceptGreen.withValues(
                              alpha: 0.28,
                            ),
                            blurRadius: 24,
                            offset: const Offset(0, 8),
                          ),
                        ],
                      ),
                      child: Icon(
                        LucideIcons.check,
                        size: 46.sp,
                        color: ColorConstants.onAccent,
                      ),
                    ),
                  ),
                ],
              ),
            ),
          ),
          SizedBox(height: 26.h),
          FadeTransition(
            opacity: _copyFade,
            child: Column(
              children: [
                Text(
                  'Your order has been created',
                  textAlign: TextAlign.center,
                  style: TextStyle(
                    fontSize: 19.sp,
                    fontWeight: FontWeight.w800,
                    letterSpacing: -0.4,
                    color: ColorConstants.slateText,
                    fontFamily: FontConstants.fontFamily,
                  ),
                ),
                SizedBox(height: 8.h),
                Text(
                  _amount > 0
                      ? '$_amountLabel collected by ${_method.label}'
                      : 'Shipment created',
                  textAlign: TextAlign.center,
                  style: TextStyle(
                    fontSize: 13.sp,
                    fontWeight: FontWeight.w500,
                    color: ColorConstants.secondaryText,
                    fontFamily: FontConstants.fontFamily,
                  ),
                ),
                // The receipt. Real data from `pickup-complete`, so a customer
                // asking "what's my tracking number?" gets an answer on the
                // doorstep instead of a phone call to the hub.
                if (tracking.isNotEmpty) ...[
                  SizedBox(height: 18.h),
                  Container(
                    padding: EdgeInsets.symmetric(
                      horizontal: 16.w,
                      vertical: 10.h,
                    ),
                    decoration: BoxDecoration(
                      color: ColorConstants.daylightSurface,
                      borderRadius: BorderRadius.circular(
                        DesignConstants.radiusFull,
                      ),
                      border: Border.all(color: ColorConstants.borderSubtle),
                    ),
                    child: Row(
                      mainAxisSize: MainAxisSize.min,
                      children: [
                        Icon(
                          LucideIcons.truck,
                          size: 15.sp,
                          color: ColorConstants.secondaryText,
                        ),
                        SizedBox(width: 8.w),
                        Text(
                          tracking,
                          style: TextStyle(
                            fontSize: 13.sp,
                            fontWeight: FontWeight.w700,
                            letterSpacing: 0.3,
                            color: ColorConstants.slateText,
                            fontFamily: FontConstants.fontFamily,
                          ),
                        ),
                      ],
                    ),
                  ),
                ],
              ],
            ),
          ),
          const Spacer(),
          FadeTransition(
            opacity: _copyFade,
            child: Padding(
              padding: EdgeInsets.only(bottom: 16.h),
              child: PrimaryButton(
                label: 'Done',
                onPressed: () => Navigator.of(context).pop(<String, dynamic>{
                  // The shape `map.dart` already reads, so the handoff screen,
                  // the compliance stamping and the next-stop list all keep
                  // working untouched.
                  'outcome': 'completed',
                  'isDelivery': false,
                  'paymentMethod': _method.label,
                  'amountCollected': _amount,
                }),
              ),
            ),
          ),
        ],
      ),
    );
  }
}