import 'package:flutter/material.dart';
import 'package:flutter_map/flutter_map.dart';

import '../../data/map_config.dart';
import '../tokens.dart';

/// Turns the configured tile provider ([DmMapConfig]) into a flutter_map layer.
///
/// The one bridge between map configuration and map rendering: no widget in
/// this app knows a tile URL, a subdomain list or an API key, and changing
/// provider never reaches a screen.
class DmMapTiles {
  DmMapTiles._();

  /// What shows through before a tile paints, or when one never arrives.
  static const ground = Color(0xFFF0EDE9);

  static DmMapConfig get config => DmMapConfig.instance;

  static TileLayer layer(
    BuildContext context, {
    DmMapStyle style = DmMapStyle.streets,
  }) {
    final map = config;
    return TileLayer(
      urlTemplate: map.urlFor(style),
      subdomains: map.subdomains,
      // Identifies the app to the provider so our traffic is attributable and
      // can be rate-limited or allow-listed properly.
      userAgentPackageName: DmMapConfig.packageName,
      tileProvider: NetworkTileProvider(
        headers: {'User-Agent': map.userAgent},
        // A failed tile is a cosmetic event — the ground colour covers it.
        silenceExceptions: true,
      ),
      retinaMode: map.retina && RetinaMode.isHighDensity(context),
      maxNativeZoom: map.maxNativeZoom,
      // Defaults, stated so they are not "tuned" upward later: the app fetches
      // only the tiles it is about to draw plus the standard render margin.
      // Bulk prefetching or scraping a provider's tiles is out of bounds.
      keepBuffer: 2,
      panBuffer: 1,
      tileDisplay: const TileDisplay.fadeIn(
        duration: Duration(milliseconds: 160),
      ),
      // Offline, or under `flutter test`, tiles simply never arrive.
      errorTileCallback: (_, _, _) {},
    );
  }
}

/// The credit line the tile licence requires. Small, quiet, and on every map —
/// its text comes from the provider, so it stays correct after a swap.
class DmMapAttribution extends StatelessWidget {
  const DmMapAttribution({super.key, this.dark = false});

  /// Slightly stronger contrast for maps with busy cartography behind it.
  final bool dark;

  @override
  Widget build(BuildContext context) {
    return IgnorePointer(
      child: Container(
        padding: const EdgeInsets.symmetric(horizontal: 7, vertical: 3),
        decoration: BoxDecoration(
          color: DmColors.surface.withValues(alpha: dark ? 0.92 : 0.82),
          borderRadius: DmRadius.all(DmRadius.pill),
        ),
        child: Text(
          DmMapTiles.config.attribution,
          style: DmText.small.copyWith(fontSize: 9.5, color: DmColors.ink3),
        ),
      ),
    );
  }
}