import 'package:flutter/material.dart';
import 'package:flutter_animate/flutter_animate.dart';
import 'package:provider/provider.dart';
import 'package:shimmer/shimmer.dart' as shimmer;

import '../estado/estado_busqueda.dart';
import '../estado/estado_radio.dart';
import '../l10n/gen/app_localizations.dart';
import '../modelos/emisora.dart';
import '../widgets/pluri_glass_surface.dart';
import '../widgets/pluri_icon.dart';
import '../widgets/pluri_layout.dart';
import '../widgets/pluri_premium_widgets.dart';
import 'package:pluriwave/widgets/tarjeta_emisora.dart';

import 'reproducir_minimizado.dart';

/// Pantalla principal: emisoras populares y por género.
class PantallaInicio extends StatefulWidget {
  const PantallaInicio({super.key});

  @override
  State<PantallaInicio> createState() => _PantallaInicioState();
}

class _PantallaInicioState extends State<PantallaInicio> {
  static const _generos = [
    'pop',
    'rock',
    'jazz',
    'classical',
    'electronic',
    'news',
    'talk',
    'hip-hop',
    'country',
    'metal',
    'reggae',
    'latin',
  ];
  String? _generoSeleccionado;

  @override
  Widget build(BuildContext context) {
    // S4-R5: no root watch on EstadoRadio. Every field is consumed through
    // context.select over identity-memoized getters, so audio buffer events
    // (which notify EstadoRadio) no longer rebuild this screen.
    final theme = Theme.of(context);
    final l10n = AppLocalizations.of(context);
    final error = context.select<EstadoRadio, String?>((e) => e.error);

    return RefreshIndicator(
      onRefresh: () => context.read<EstadoRadio>().cargarPopulares(),
      child: CustomScrollView(
        slivers: [
          SliverToBoxAdapter(child: _heroHeader(context, l10n)),
          SliverToBoxAdapter(child: _seccionCercanas(context, theme, l10n)),
          SliverToBoxAdapter(child: _seccionTendencias(context, theme, l10n)),
          SliverToBoxAdapter(child: _chipGeneros(context, theme, l10n)),
          if (error != null)
            SliverToBoxAdapter(
              child: _errorBanner(context, error, theme, l10n),
            ),
          SliverPadding(
            padding: const EdgeInsets.fromLTRB(
              PluriLayout.horizontal,
              0,
              PluriLayout.horizontal,
              PluriLayout.bottomChromeInset,
            ),
            sliver: _gridEmisoras(context, l10n),
          ),
        ],
      ),
    );
  }

  Widget _heroHeader(BuildContext context, AppLocalizations l10n) {
    final totalEmisoras = context.select<EstadoRadio, int>(
      (e) => e.emisorasInicio.length,
    );
    return PluriScreenHeader(
      title: l10n.appTitle,
      subtitle: l10n.homeScreenSubtitle,
      glyph: PluriIconGlyph.home,
      primaryActionLabel: l10n.exploreStations,
      onPrimaryAction: () => context.read<EstadoRadio>().cargarPopulares(),
      trailing: Column(
        crossAxisAlignment: CrossAxisAlignment.end,
        children: [
          PluriStatusPill(
            icon: Icons.public_rounded,
            label: l10n.stationsCount(totalEmisoras),
            accent: Theme.of(context).colorScheme.secondary,
          ),
          const SizedBox(height: 8),
          PluriStatusPill(icon: Icons.hd_rounded, label: l10n.qualityHd),
        ],
      ),
    );
  }

  Widget _seccionCercanas(
    BuildContext context,
    ThemeData theme,
    AppLocalizations l10n,
  ) {
    // Nearby stations live in EstadoBusqueda (S4-R3).
    final busqueda = context.watch<EstadoBusqueda>();
    final pais = busqueda.paisCercanoDetectado;
    return Padding(
      padding: const EdgeInsets.fromLTRB(
        PluriLayout.horizontal,
        8,
        PluriLayout.horizontal,
        0,
      ),
      child: PluriGlassSurface(
        padding: const EdgeInsets.all(12),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            Row(
              children: [
                Expanded(
                  child: Text(
                    pais == null ? l10n.nearYou : l10n.nearYouInCountry(pais),
                    style: theme.textTheme.titleMedium?.copyWith(
                      fontWeight: FontWeight.w900,
                    ),
                  ),
                ),
                TextButton.icon(
                  onPressed:
                      busqueda.cargandoCercanas
                          ? null
                          : busqueda.cargarEmisorasCercanas,
                  icon:
                      busqueda.cargandoCercanas
                          ? const SizedBox(
                            width: 16,
                            height: 16,
                            child: CircularProgressIndicator(strokeWidth: 2),
                          )
                          : const Icon(Icons.my_location_rounded, size: 18),
                  label: Text(l10n.detectAction),
                ),
              ],
            ),
            if (busqueda.errorCercanas != null)
              Text(
                busqueda.errorCercanas!,
                style: theme.textTheme.bodySmall?.copyWith(
                  color: theme.colorScheme.error,
                ),
              ),
            if (busqueda.cercanas.isNotEmpty) ...[
              const SizedBox(height: 8),
              SizedBox(
                height: 76,
                child: ListView.separated(
                  scrollDirection: Axis.horizontal,
                  itemCount: busqueda.cercanas.length,
                  separatorBuilder: (_, __) => const SizedBox(width: 8),
                  itemBuilder: (context, i) {
                    final emisora = busqueda.cercanas[i];
                    return SizedBox(
                      width: 260,
                      child: TarjetaEmisora(
                        emisora: emisora,
                        esCompacta: true,
                        onTap: () => reproducirMinimizado(context, emisora),
                      ),
                    );
                  },
                ),
              ),
            ],
          ],
        ),
      ),
    );
  }

  Widget _seccionTendencias(
    BuildContext context,
    ThemeData theme,
    AppLocalizations l10n,
  ) {
    final cargando = context.select<EstadoRadio, bool>(
      (e) => e.cargandoPopulares,
    );
    final tendencias = context.select<EstadoRadio, List<Emisora>>(
      (e) => e.tendencias,
    );
    return Padding(
      padding: const EdgeInsets.fromLTRB(
        PluriLayout.horizontal,
        8,
        PluriLayout.horizontal,
        0,
      ),
      child: PluriGlassSurface(
        padding: const EdgeInsets.all(12),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            Text(l10n.liveRadar, style: theme.textTheme.titleMedium),
            const SizedBox(height: 8),
            SizedBox(
              height: 56,
              child:
                  cargando
                      ? ListView.separated(
                        scrollDirection: Axis.horizontal,
                        itemCount: 5,
                        separatorBuilder: (_, __) => const SizedBox(width: 8),
                        itemBuilder: (_, __) => _ChipShimmer(theme: theme),
                      )
                      : ListView.separated(
                        scrollDirection: Axis.horizontal,
                        itemCount: tendencias.length,
                        separatorBuilder: (_, __) => const SizedBox(width: 8),
                        itemBuilder: (context, i) {
                          final e = tendencias[i];
                          return ActionChip(
                            avatar: const Icon(
                              Icons.graphic_eq_rounded,
                              size: 18,
                            ),
                            label: Text(e.nombre, maxLines: 1),
                            onPressed: () => reproducirMinimizado(context, e),
                          ).animate().fadeIn(delay: (i * 50).ms);
                        },
                      ),
            ),
          ],
        ),
      ),
    );
  }

  Widget _chipGeneros(
    BuildContext context,
    ThemeData theme,
    AppLocalizations l10n,
  ) {
    return Padding(
      padding: const EdgeInsets.fromLTRB(
        PluriLayout.horizontal,
        16,
        PluriLayout.horizontal,
        8,
      ),
      child: PluriGlassSurface(
        padding: const EdgeInsets.all(12),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            Text(l10n.genresTitle, style: theme.textTheme.titleMedium),
            const SizedBox(height: 8),
            Wrap(
              spacing: 8,
              runSpacing: 4,
              children:
                  _generos.map((g) {
                    final seleccionado = _generoSeleccionado == g;
                    return FilterChip(
                      label: Text(_genreName(l10n, g)),
                      selected: seleccionado,
                      onSelected: (_) {
                        setState(() {
                          _generoSeleccionado = seleccionado ? null : g;
                        });
                        if (!seleccionado) {
                          context.read<EstadoBusqueda>().buscar(tag: g);
                        } else {
                          context.read<EstadoRadio>().cargarPopulares();
                        }
                      },
                    );
                  }).toList(),
            ),
          ],
        ),
      ),
    );
  }

  Widget _errorBanner(
    BuildContext context,
    String error,
    ThemeData theme,
    AppLocalizations l10n,
  ) {
    return Padding(
      padding: const EdgeInsets.all(16),
      child: PluriGlassSurface(
        padding: const EdgeInsets.all(12),
        child: Row(
          children: [
            Icon(Icons.wifi_off, color: theme.colorScheme.error),
            const SizedBox(width: 8),
            Expanded(child: Text(error)),
            TextButton(
              onPressed: () => context.read<EstadoRadio>().cargarPopulares(),
              child: Text(l10n.retryAction),
            ),
          ],
        ),
      ),
    );
  }

  Widget _gridEmisoras(BuildContext context, AppLocalizations l10n) {
    final porGenero = _generoSeleccionado != null;
    final emisoras =
        porGenero
            ? context.select<EstadoBusqueda, List<Emisora>>((b) => b.resultados)
            : context.select<EstadoRadio, List<Emisora>>(
              (e) => e.emisorasInicio,
            );
    final cargando =
        context.select<EstadoRadio, bool>((e) => e.cargandoPopulares) ||
        (porGenero && context.select<EstadoBusqueda, bool>((b) => b.cargando));

    if (cargando) {
      return SliverGrid(
        delegate: SliverChildBuilderDelegate(
          (_, __) => const TarjetaEmisoraShimmer(),
          childCount: 12,
        ),
        gridDelegate: const SliverGridDelegateWithFixedCrossAxisCount(
          crossAxisCount: 2,
          childAspectRatio: 0.78,
          crossAxisSpacing: 12,
          mainAxisSpacing: 12,
        ),
      );
    }

    if (emisoras.isEmpty) {
      return SliverFillRemaining(
        child: PluriEmptyState(
          glyph: PluriIconGlyph.home,
          title: l10n.noStationsAvailable,
          subtitle: l10n.noStationsAvailableSubtitle,
        ),
      );
    }

    return SliverGrid(
      delegate: SliverChildBuilderDelegate(
        (context, i) => TarjetaEmisora(
          emisora: emisoras[i],
          onTap: () => reproducirMinimizado(context, emisoras[i]),
        ).animate().fadeIn(delay: (i * 30).ms).slideY(begin: 0.1),
        childCount: emisoras.length,
      ),
      gridDelegate: const SliverGridDelegateWithFixedCrossAxisCount(
        crossAxisCount: 2,
        childAspectRatio: 0.78,
        crossAxisSpacing: 12,
        mainAxisSpacing: 12,
      ),
    );
  }
}

String _genreName(AppLocalizations l10n, String tag) => switch (tag) {
  'pop' => l10n.genrePop,
  'rock' => l10n.genreRock,
  'jazz' => l10n.genreJazz,
  'classical' => l10n.genreClassical,
  'electronic' => l10n.genreElectronic,
  'news' => l10n.genreNews,
  'talk' => l10n.genreTalk,
  'hip-hop' => l10n.genreHipHop,
  'country' => l10n.genreCountry,
  'metal' => l10n.genreMetal,
  'reggae' => l10n.genreReggae,
  'latin' => l10n.genreLatin,
  _ => tag,
};

class _ChipShimmer extends StatelessWidget {
  final ThemeData theme;
  const _ChipShimmer({required this.theme});

  @override
  Widget build(BuildContext context) {
    return shimmer.Shimmer.fromColors(
      baseColor: theme.colorScheme.surfaceContainerHighest,
      highlightColor: theme.colorScheme.surface,
      child: Container(
        width: 120,
        height: 56,
        decoration: BoxDecoration(
          color: theme.colorScheme.surfaceContainerHighest,
          borderRadius: BorderRadius.circular(20),
        ),
      ),
    );
  }
}