import 'package:flutter/material.dart';

import '../l10n/gen/app_localizations.dart';
import '../tema/pluriwave_theme.dart';
import 'pluri_icon.dart';

/// Shared station-art fallback (feedback-pruebas issue 6).
///
/// Before this widget existed, `TarjetaEmisora` had the only good fallback —
/// a deterministic pick from 4 bundled illustrations (`_fallbackArtFor`),
/// with a gradient + player glyph as a last resort if the asset itself ever
/// fails to decode. Every OTHER surface that can render a station without
/// artwork (`FilaEmisoraPlana`'s flat rows, the Escuchar hero, the "Tus
/// emisoras" grid cell, the mini player, the full player) had its own,
/// separate, much poorer copy: a flat `primaryContainer`-coloured square
/// with a bare `radio_rounded` icon. This widget is the ONE shared
/// implementation every one of those call sites now uses instead.
///
/// The selection formula is pinned EXACTLY as `TarjetaEmisora` originally
/// had it (`seed.codeUnits.fold<int>(0, (a, b) => a + b) % 4`, asset order
/// aurora/cosmic/pulse/nova) — `lib/servicios/navegacion_auto.dart` (a
/// protected, empty-diff file) independently mirrors this SAME formula for
/// Android Auto's own drawable-resource rotation
/// (`test/servicios/navegacion_auto_test.dart`'s `indiceArtePara`/
/// `artUriPara` tests assert it inline, not by importing this widget) —
/// changing the order or the modulo here would silently desync the two
/// without either test suite noticing until an actual device compared them
/// side by side.
class PluriStationArtFallback extends StatelessWidget {
  const PluriStationArtFallback({
    super.key,
    required this.seed,
    this.iconSize = 22,
  });

  /// Typically the station's `uuid` — the seed that deterministically picks
  /// one of the 4 bundled arts below.
  final String seed;

  /// Size of the centred player glyph drawn over the art.
  final double iconSize;

  static const _arts = [
    'assets/images/station_art_aurora.png',
    'assets/images/station_art_cosmic.png',
    'assets/images/station_art_pulse.png',
    'assets/images/station_art_nova.png',
  ];

  /// Exposed so other call sites (and tests) can assert which asset a given
  /// seed resolves to without needing to render the widget.
  static String artFor(String seed) {
    final index = seed.codeUnits.fold<int>(0, (a, b) => a + b) % _arts.length;
    return _arts[index];
  }

  @override
  Widget build(BuildContext context) {
    return Stack(
      fit: StackFit.expand,
      children: [
        Image.asset(
          artFor(seed),
          fit: BoxFit.cover,
          errorBuilder:
              (_, __, ___) => DecoratedBox(
                decoration: BoxDecoration(
                  gradient: LinearGradient(
                    begin: Alignment.topLeft,
                    end: Alignment.bottomRight,
                    colors: [
                      context.pluriTokens.deepViolet,
                      context.pluriTokens.electricMagenta.withValues(
                        alpha: 0.8,
                      ),
                    ],
                  ),
                ),
              ),
        ),
        Center(
          child: PluriIcon(
            glyph: PluriIconGlyph.player,
            variant: PluriIconVariant.activeGlow,
            size: iconSize,
            semanticLabel: AppLocalizations.of(context).stationIconLabel,
          ),
        ),
      ],
    );
  }
}