import 'package:flutter/material.dart';
import 'package:lucide_icons_flutter/lucide_icons.dart';
import 'package:flutter_map/flutter_map.dart';
import 'package:latlong2/latlong.dart';

import '../../data/location_service.dart';
import '../../data/map_config.dart';
import '../../data/models.dart';
import '../tokens.dart';
import 'map_tiles.dart';

/// A real map of the journey: pickup and destination joined by the transit
/// path, with the Miler's live position when there is one.
///
/// Read-only by design — it summarises a booking, and a non-interactive map
/// never steals a scroll gesture from the list it sits in.
class DmRouteMap extends StatefulWidget {
  const DmRouteMap({
    super.key,
    this.height = 190,
    this.pickup,
    this.destination,
    this.progress = 0,
    this.showMiler = false,
    this.pickupLabel,
    this.destinationLabel,
    this.badge,
    this.overlay,
    this.radius = DmRadius.lg,
  });

  final double height;

  /// Where the Miler collects. Without coordinates the map falls back to the
  /// service-area centre rather than showing an empty ocean.
  final Place? pickup;

  /// The destination hub. Null draws pickup only — which is exactly right
  /// before a district has been chosen.
  final Place? destination;

  /// How far along the route the Miler is, 0..1.
  final double progress;
  final bool showMiler;

  final String? pickupLabel;
  final String? destinationLabel;

  /// Pill shown top-left, e.g. "En route · 1.4 km away".
  final Widget? badge;

  /// Anything centred over the map, e.g. the "searching" state.
  final Widget? overlay;

  final double radius;

  @override
  State<DmRouteMap> createState() => _DmRouteMapState();
}

class _DmRouteMapState extends State<DmRouteMap>
    with TickerProviderStateMixin {
  late final AnimationController _pulse = AnimationController(
    vsync: this,
    duration: const Duration(milliseconds: 2000),
  )..repeat();

  late final AnimationController _draw = AnimationController(
    vsync: this,
    duration: const Duration(milliseconds: 900),
  )..forward();

  @override
  void dispose() {
    _pulse.dispose();
    _draw.dispose();
    super.dispose();
  }

  LatLng? get _from => widget.pickup != null && widget.pickup!.hasLocation
      ? LatLng(widget.pickup!.lat!, widget.pickup!.lng!)
      : null;

  LatLng? get _to =>
      widget.destination != null && widget.destination!.hasLocation
      ? LatLng(widget.destination!.lat!, widget.destination!.lng!)
      : null;

  /// A gentle arc rather than a ruler-straight line — it reads as a journey,
  /// and it separates the two ends when they are nearly aligned.
  List<LatLng> _arc(LatLng a, LatLng b) {
    final dLat = b.latitude - a.latitude;
    final dLng = b.longitude - a.longitude;
    // Perpendicular offset, proportional to the span.
    final bowLat = -dLng * 0.12;
    final bowLng = dLat * 0.12;
    final control = LatLng(
      (a.latitude + b.latitude) / 2 + bowLat,
      (a.longitude + b.longitude) / 2 + bowLng,
    );

    return [
      for (var i = 0; i <= 48; i++)
        _quadratic(a, control, b, i / 48),
    ];
  }

  static LatLng _quadratic(LatLng a, LatLng c, LatLng b, double t) {
    final u = 1 - t;
    return LatLng(
      u * u * a.latitude + 2 * u * t * c.latitude + t * t * b.latitude,
      u * u * a.longitude + 2 * u * t * c.longitude + t * t * b.longitude,
    );
  }

  @override
  Widget build(BuildContext context) {
    final from = _from;
    final to = _to;
    final route = (from != null && to != null) ? _arc(from, to) : null;

    return ClipRRect(
      borderRadius: DmRadius.all(widget.radius),
      child: SizedBox(
        height: widget.height,
        child: ColoredBox(
          color: DmMapTiles.ground,
          child: Stack(
            children: [
              Positioned.fill(
                child: _map(context, from: from, to: to, route: route),
              ),
              if (widget.badge != null)
                Positioned(
                  top: 12,
                  left: 12,
                  // Held to half the map's width so it cannot run under the
                  // attribution chip opposite it, whatever the badge says.
                  child: ConstrainedBox(
                    constraints: BoxConstraints(
                      maxWidth: MediaQuery.sizeOf(context).width * 0.5,
                    ),
                    child: widget.badge!,
                  ),
                ),
              if (widget.pickupLabel != null)
                Positioned(
                  left: 12,
                  bottom: 12,
                  child: _MapLabel(
                    icon: LucideIcons.circleDot,
                    color: DmColors.ink,
                    label: widget.pickupLabel!,
                  ),
                ),
              if (widget.destinationLabel != null)
                Positioned(
                  right: 12,
                  bottom: 12,
                  child: _MapLabel(
                    icon: LucideIcons.mapPin,
                    color: DmColors.brand,
                    label: widget.destinationLabel!,
                  ),
                ),
              // Attribution is required on every map, so it sits top-right,
              // clear of the badge (top-left) and the labels (bottom).
              const Positioned(top: 10, right: 10, child: DmMapAttribution()),
              if (widget.overlay != null) Center(child: widget.overlay!),
            ],
          ),
        ),
      ),
    );
  }

  Widget _map(
    BuildContext context, {
    required LatLng? from,
    required LatLng? to,
    required List<LatLng>? route,
  }) {
    final centre =
        from ??
        to ??
        const LatLng(
          LocationService.fallbackLat,
          LocationService.fallbackLng,
        );

    // The map itself is built once. Only the layers that animate sit inside an
    // AnimatedBuilder, so a pulsing Miler never re-creates the camera.
    return FlutterMap(
      options: MapOptions(
        initialCenter: centre,
        initialZoom: to == null ? 13.5 : 11,
        initialCameraFit: route == null
            ? null
            : CameraFit.coordinates(
                coordinates: route,
                padding: const EdgeInsets.fromLTRB(46, 34, 46, 52),
                maxZoom: 14,
              ),
        backgroundColor: DmMapTiles.ground,
        interactionOptions: const InteractionOptions(
          flags: InteractiveFlag.none,
        ),
      ),
      children: [
        // The quieter basemap: this map is a summary, the route is the subject.
        DmMapTiles.layer(context, style: DmMapStyle.muted),

        if (route != null)
          AnimatedBuilder(
            animation: _draw,
            builder: (context, _) {
              final drawn = Curves.easeOutCubic.transform(_draw.value);
              final upto = (route.length * drawn).ceil().clamp(2, route.length);
              return PolylineLayer(
                polylines: [
                  Polyline(
                    points: route.sublist(0, upto),
                    color: DmColors.brand,
                    strokeWidth: 4,
                    borderColor: Colors.white,
                    borderStrokeWidth: 3,
                  ),
                ],
              );
            },
          ),

        AnimatedBuilder(
          animation: widget.showMiler
              ? Listenable.merge([_pulse, _draw])
              : _draw,
          builder: (context, _) {
            final drawn = Curves.easeOutCubic.transform(_draw.value);
            return MarkerLayer(
              markers: [
                if (from != null)
                  Marker(
                    point: from,
                    width: 26,
                    height: 26,
                    child: const _OriginDot(),
                  ),
                if (to != null)
                  Marker(
                    point: to,
                    width: 34,
                    height: 40,
                    alignment: Alignment.topCenter,
                    child: const _DestinationPin(),
                  ),
                if (widget.showMiler && route != null)
                  Marker(
                    point: route[(
                      (route.length - 1) *
                          widget.progress.clamp(0.02, 0.98) *
                          drawn
                    ).round()],
                    width: 58,
                    height: 58,
                    child: _MilerDot(pulse: _pulse.value),
                  ),
              ],
            );
          },
        ),
      ],
    );
  }
}

class _OriginDot extends StatelessWidget {
  const _OriginDot();

  @override
  Widget build(BuildContext context) {
    return Center(
      child: Container(
        width: 18,
        height: 18,
        decoration: BoxDecoration(
          color: Colors.white,
          shape: BoxShape.circle,
          border: Border.all(color: DmColors.ink, width: 3.5),
          boxShadow: DmShadow.float,
        ),
      ),
    );
  }
}

class _DestinationPin extends StatelessWidget {
  const _DestinationPin();

  @override
  Widget build(BuildContext context) {
    return const Stack(
      alignment: Alignment.topCenter,
      children: [
        Icon(
          LucideIcons.mapPin,
          size: 34,
          color: DmColors.brand,
          shadows: [
            Shadow(color: Color(0x338F0F06), blurRadius: 8, offset: Offset(0, 4)),
          ],
        ),
        Positioned(
          top: 9,
          child: CircleAvatar(radius: 4, backgroundColor: Colors.white),
        ),
      ],
    );
  }
}

/// The Miler's live position. The expanding ring is what makes it read as live.
class _MilerDot extends StatelessWidget {
  const _MilerDot({required this.pulse});

  final double pulse;

  @override
  Widget build(BuildContext context) {
    return Center(
      child: Stack(
        alignment: Alignment.center,
        children: [
          Container(
            width: 24 + pulse * 30,
            height: 24 + pulse * 30,
            decoration: BoxDecoration(
              shape: BoxShape.circle,
              color: DmColors.brand.withValues(alpha: (1 - pulse) * 0.22),
            ),
          ),
          Container(
            width: 26,
            height: 26,
            decoration: BoxDecoration(
              color: Colors.white,
              shape: BoxShape.circle,
              boxShadow: DmShadow.float,
            ),
            child: const Icon(
              LucideIcons.bike,
              size: 15,
              color: DmColors.brand,
            ),
          ),
        ],
      ),
    );
  }
}

class _MapLabel extends StatelessWidget {
  const _MapLabel({required this.icon, required this.color, required this.label});

  final IconData icon;
  final Color color;
  final String label;

  @override
  Widget build(BuildContext context) {
    return Container(
      constraints: const BoxConstraints(maxWidth: 168),
      padding: const EdgeInsets.fromLTRB(9, 6, 12, 6),
      decoration: BoxDecoration(
        color: DmColors.surface,
        border: Border.all(color: DmColors.border),
        borderRadius: DmRadius.all(6),
        boxShadow: DmShadow.float,
      ),
      child: Row(
        mainAxisSize: MainAxisSize.min,
        children: [
          Icon(icon, size: 14, color: color),
          const SizedBox(width: 6),
          Flexible(
            child: Text(
              label,
              maxLines: 1,
              overflow: TextOverflow.ellipsis,
              style: DmText.label.copyWith(fontSize: 12),
            ),
          ),
        ],
      ),
    );
  }
}