import 'dart:async';
import 'dart:developer' as developer;
import 'dart:ui' as ui;

import 'package:audio_service/audio_service.dart';
import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:google_mobile_ads/google_mobile_ads.dart';
import 'package:shared_preferences/shared_preferences.dart';
import 'app.dart';
import 'estado/estado_entitlement.dart';
import 'servicios/arranque_audio.dart';
import 'servicios/musica_local_auto.dart';
import 'servicios/navegacion_auto.dart';
import 'servicios/servicio_audio.dart';
import 'servicios/servicio_audio_session.dart';
import 'servicios/servicio_compras.dart';
import 'servicios/servicio_consentimiento.dart';
import 'servicios/servicio_ecualizador.dart';
import 'servicios/servicio_presets_personalizados.dart';
import 'tema/pluriwave_tokens.dart';

const _anchoMinimoLandscape = 600.0;

/// Branded monochrome status-bar icon, replacing the default full-color
/// launcher silhouette fallback.
const androidNotificationIconResource = 'drawable/ic_stat_pluriwave';

/// S5-R8: media notification accent uses the brand color, not the M3
/// default purple. Top-level const so tests can assert it.
const configuracionAudioService = AudioServiceConfig(
  androidNotificationChannelId: 'es.freetimelab.pluriwave.audio',
  androidNotificationChannelName: 'PluriWave Radio',
  // Paired with `androidStopForegroundOnPause: false` below, and required to
  // be: the plugin asserts `androidNotificationOngoing` implies
  // `androidStopForegroundOnPause`. Nothing is lost by turning it off —
  // while the service is in the foreground the OS forces the notification to
  // be ongoing anyway, which is now the whole time playback is alive.
  androidNotificationOngoing: false,
  // The service stays in the FOREGROUND while paused.
  //
  // With `true`, a pause called `stopForeground(...)`, and a service that is
  // not in the foreground is a service Android may kill at will. In the car
  // that is exactly what happened: an interruption paused playback, the
  // service dropped out of the foreground, Android reclaimed it, and
  // PluriWave disappeared from the Android Auto pane — another media app
  // took the slot. Ducking (see `ServicioAudioSession.configurar`) removes
  // most pauses, but a real pause must not be a death sentence either.
  //
  // The plugin's own doc for this flag says it outright: «while in this
  // lower priority state, the operating system will also be able to kill
  // your service at any time to reclaim resources».
  //
  // Cost of `false`: the notification is not swipe-dismissible while paused,
  // only after Stop. That is how every serious media app behaves, and Stop
  // still tears everything down.
  androidStopForegroundOnPause: false,
  notificationColor: PluriWaveTokens.brand,
  androidNotificationIcon: androidNotificationIconResource,
);

Future<void> main() async {
  WidgetsFlutterBinding.ensureInitialized();

  // Android Auto browse source: registered FIRST, before any await at all.
  // It depends on nothing, and everything below it is a potential place to
  // get stuck — so nothing may sit between engine start and this line.
  //
  // Reported: with Android Auto connected, the car screen sometimes came up
  // black and the app then opened WHITE on the phone until it was
  // force-killed. `AudioServiceActivity.provideFlutterEngine` returns the
  // engine from `AudioServicePlugin.getFlutterEngine`, which CREATES the
  // engine and runs `main()` headlessly the first time — with no Activity —
  // when the car binds the MediaBrowserService before the app is opened.
  // `_aplicarPoliticaOrientacion` used to be the first `await` here, and
  // `SystemChrome.setPreferredOrientations` travels the `flutter/platform`
  // channel, whose handler (`PlatformPlugin`) is installed by the Activity.
  // Headless there is nobody to answer it, so `main()` died or hung on line
  // one: the browse source below was never registered (`getChildren` had no
  // source -> black car screen) and `runApp` was never reached. Opening the
  // app then REUSED that same cached, already-dead engine -> white screen,
  // and only a force-kill (which disposes the engine) recovered it.
  final fuenteAuto = FuenteEmisorasAutoLocal();
  registrarFuenteNavegacion(fuenteAuto);

  // Local music registers HERE, above every await, alongside the station
  // source — not after `SharedPreferences.getInstance()` where it used to
  // sit.
  //
  // Regression this fixes, self-inflicted by the reordering above: the root
  // menu decides whether to offer "Música Local" with
  // `fuenteLocal != null && await fuenteLocal.estadoCarpeta() != noConfigurada`.
  // Moving ONLY the station source above the awaits meant the car could get
  // a root response in the window before this line ran, find a null source,
  // and be told there is no local music — and Android Auto caches the browse
  // root, so it stayed missing for the whole session. Before the reorder
  // both registrations sat together after the await, so the window did not
  // exist.
  //
  // `FuenteMusicaLocalAutoImpl` needs no prefs to be CONSTRUCTED: it
  // resolves them lazily per call (`_resolverPrefs`, falling back to
  // `getInstance()`), the same convention `ServicioAlarmas` uses. So there
  // was never a reason for it to wait on that await.
  registrarFuenteMusicaLocal(FuenteMusicaLocalAutoImpl());

  // Cosmetic, and deliberately NOT awaited: a display preference must never
  // gate `runApp`. `OrientacionResponsiveApp.didChangeDependencies` applies
  // it again as soon as a real view exists, which is the only moment it can
  // actually take effect anyway.
  unawaited(aplicarPoliticaOrientacion());

  // iap-freemium-unlock: neither SDK init call blocks `runApp` — a purchase
  // stream subscription and an ad-SDK warm-up are both safe to finish late
  // (mirrors `aplicarPoliticaOrientacion`'s "cosmetic, never gates startup"
  // rule immediately above).
  //
  // FIX 4 (code review): the Mobile Ads SDK is only initialized AFTER the
  // GDPR/UMP consent flow resolves that ads may actually be requested
  // (`ConsentInformation.canRequestAds()`) — serving personalized ads to
  // EEA/UK users with no CMP violates Google's EU User Consent Policy.
  // Premium users never even reach the consent form (`resolverConsentimientoAnuncios`
  // short-circuits for them — they get zero ads regardless). This whole
  // chain is deliberately `unawaited`: consent/ads are exactly as
  // "cosmetic, never gates startup" as `aplicarPoliticaOrientacion` above,
  // and any failure inside it degrades to "no ads", never a crash or a
  // blocked UI.
  unawaited(
    esPremiumPersistido()
        .then(
          (premium) => resolverConsentimientoAnuncios(
            esPremium: premium,
            consentimiento: ServicioConsentimientoUmp(),
          ),
        )
        .then((puedeSolicitarAnuncios) async {
          if (puedeSolicitarAnuncios) {
            await MobileAds.instance.initialize();
          }
        }),
  );
  final compras = ServicioComprasPlayBilling();

  // S3-R4: single SharedPreferences instance resolved once at startup and
  // injected into every state/service below.
  final prefs = await SharedPreferences.getInstance();

  // User-saved EQ presets for the car's Ecualizador folder, same
  // injectable-prefs DI convention and same pre-init placement as the two
  // registrations above (neither depends on the AudioHandler). Passed as a
  // read function, not the service, so the folder re-reads on every browse:
  // a preset saved on the phone appears in the car without an app restart.
  final presetsPersonalizados = ServicioPresetsPersonalizados(prefs: prefs);
  registrarFuentePresetsPersonalizados(presetsPersonalizados.listar);

  // eq-estado-unico items A/B: the handler's own link to the equalizer's
  // persisted on/off flag. `ServicioEcualizador` needs nothing but the
  // `prefs` instance resolved just above — no widget tree, no Provider — so
  // it is available on EVERY engine, including the headless one Android Auto
  // starts. Before this, the persisted value only reached the handler
  // through `EstadoEcualizador.cargarPersistido()`, which that engine never
  // runs: the handler played with the equalizer forced on while disk and the
  // phone UI both said off, and a toggle made in the car was lost on
  // restart. Passed as two narrow function ports, mirroring the
  // read-function convention used for the preset folder right above.
  final ecualizador = ServicioEcualizador(prefs: prefs);

  // Silent-error channel (fix/notificacion-media): `AudioService.asyncError`
  // had ZERO subscribers app-wide, and a `PublishSubject` with no listeners
  // drops what it is given — so every exception `audio_service` catches
  // internally was discarded without a trace, which is exactly why the
  // "media notification disappeared" report came with no evidence attached.
  // Subscribed BEFORE `AudioService.init` below (the getter only touches a
  // static subject, so it needs no initialisation) so nothing reported
  // during the MediaBrowser handshake is missed, and placed here rather than
  // in `conectarHandler` so ONE subscription covers both the on-time and the
  // degraded/timeout startup paths.
  final subErroresAudio = observarErroresAudio(
    AudioService.asyncError,
    registrar: registrarErrorAudioService,
  );

  // Design "Timeout without re-init": AudioService.init is started exactly
  // ONCE here and `handlerFuturo` is the only future ever awaited for it —
  // the plugin caches state internally, so a double-configure call is
  // unsafe and must never happen, even on the degraded/timeout path below.
  final handlerFuturo = AudioService.init(
    builder: () => PluriWaveAudioHandler(),
    config: configuracionAudioService,
  );

  // S3-R1: audio focus — phone calls / transient losses pause or duck the
  // radio; headphones unplugged pauses it. Shared by both the on-time and
  // degraded/late-completion paths below.
  void conectarHandler(PluriWaveAudioHandler handler) {
    registrarHandler(
      handler,
      leerEqActivoPersistido: ecualizador.leerActivo,
      guardarEqActivoPersistido: ecualizador.guardarActivo,
    );
    // The handler is the only thing this app ever tears down
    // (`onTaskRemoved`), so the asyncError subscription's `cancel` travels
    // with it and can never leak — same "register from main.dart" convention
    // as `registrarHandler` itself.
    registrarLimpiezaArranque(subErroresAudio.cancel);
    final sesionAudio = ServicioAudioSession(objetivo: handler);
    unawaited(sesionAudio.configurar());
  }

  Widget construirApp() => OrientacionResponsiveApp(
    child: PluriWaveApp(prefs: prefs, fuenteAuto: fuenteAuto, compras: compras),
  );

  final resultado = await esperarArranqueAudio(handlerFuturo);
  switch (resultado) {
    case ArranqueAudioListo<PluriWaveAudioHandler>(:final handler):
      // Handshake finished in time — exactly today's startup path.
      conectarHandler(handler);
      runApp(construirApp());
    case ArranqueAudioPendiente<PluriWaveAudioHandler>(
      handlerFuturo: final futuroPendiente,
    ):
      // Handshake still hung after the timeout: run the app anyway with a
      // minimal loading bootstrap that keeps awaiting the SAME
      // `futuroPendiente` — identical to the outer `handlerFuturo`, per
      // esperarArranqueAudio's contract (never a second AudioService.init
      // call) — and wires the handler + swaps to the real app once it
      // eventually resolves.
      runApp(
        ArranqueAudioApp<PluriWaveAudioHandler>(
          handlerFuturo: futuroPendiente,
          alListo: conectarHandler,
          construirApp: (_) => construirApp(),
        ),
      );
  }
}

/// Which orientations a display [anchoLogico] dp wide may use: phones stay
/// portrait, tablets get everything. Pure, so the policy is testable without
/// a platform channel.
@visibleForTesting
List<DeviceOrientation> orientacionesPara(double anchoLogico) =>
    anchoLogico < _anchoMinimoLandscape
        ? const [DeviceOrientation.portraitUp]
        : DeviceOrientation.values;

/// Applies [orientacionesPara] to the active display.
///
/// NEVER throws and never blocks a caller that matters. This runs on the
/// headless engine Android Auto starts (see `main`), where the
/// `flutter/platform` channel has no handler because there is no Activity to
/// install `PlatformPlugin` — so the call can fail with a
/// `MissingPluginException` or simply never be answered. Before this guard
/// that outcome killed `main()` outright, taking the Android Auto browse
/// registration and `runApp` with it.
///
/// [aplicar] is injectable so the swallow-everything contract is testable
/// without a real platform channel.
@visibleForTesting
Future<void> aplicarPoliticaOrientacion({
  ui.Display? display,
  Future<void> Function(List<DeviceOrientation>)? aplicar,
}) async {
  try {
    final vista =
        WidgetsBinding.instance.platformDispatcher.views.isNotEmpty
            ? WidgetsBinding.instance.platformDispatcher.views.first
            : null;
    final displayActivo = display ?? vista?.display;
    if (displayActivo == null) return;

    final anchoLogico =
        displayActivo.size.width / displayActivo.devicePixelRatio;
    await (aplicar ?? SystemChrome.setPreferredOrientations)(
      orientacionesPara(anchoLogico),
    );
  } catch (e) {
    // Deliberately broad: a cosmetic preference is never worth a failed
    // startup, and headless is exactly where this fails.
    developer.log(
      '[PluriWave] no se pudo aplicar la política de orientación: $e',
      name: 'Arranque',
      level: 900,
    );
  }
}

/// Whether the Android Auto browse tree must be invalidated right now
/// (fix/android-auto-musica-local, item 4 — CORRECTED trigger).
///
/// The trigger used to be `View.maybeOf(context) != null` inside
/// `didChangeDependencies`, latched once, on the premise that «a View means
/// there is an Activity». That premise is FALSE: `runApp` unconditionally
/// wraps the tree in a `View` built from
/// `platformDispatcher.implicitView` and throws a `StateError` when there is
/// none (`flutter/lib/src/widgets/binding.dart`, `wrapWithDefaultView`). So
/// on the headless `audio_service` engine — which demonstrably reaches
/// `runApp`, see [aplicarPoliticaOrientacion] — the View is ALREADY there at
/// the first `didChangeDependencies`. The one-shot latch was spent at the
/// exact moment it could accomplish nothing (`_childrenSubjects` still
/// empty, so `notificarHijosCambiaron` is a silent no-op) and could never
/// fire again, because `didChangeDependencies` does not re-run when an
/// Activity later attaches to that same cached engine.
///
/// Two conditions replace it, both required:
///
/// * [estado] is [AppLifecycleState.resumed] — the only state that genuinely
///   means «an Activity is attached and in the foreground». It reaches Dart
///   exclusively through `SystemChannels.lifecycle` (or
///   `PlatformDispatcher.initialLifecycleState`, which buffers the same
///   messages), and on Android only `LifecycleChannel.appIsResumed()` sends
///   it, driven by the Activity's own `onResume`.
///   `AudioServicePlugin.getFlutterEngine` builds its engine from the
///   APPLICATION context and runs the Dart entrypoint immediately, with no
///   Activity and no `FlutterActivityAndFragmentDelegate`, so nothing sends
///   it on the headless engine.
/// * [hayCocheSuscrito] — a head unit has actually subscribed to at least
///   one browse id (`hayCocheSuscritoAlArbol`). This is what makes the latch
///   worth spending, and it is also the belt to `resumed`'s braces: even if
///   a lifecycle event did somehow arrive during a headless cold start,
///   nothing has subscribed yet, so the latch survives for the moment an
///   Activity really does attach.
///
/// [yaInvalidado] keeps it one-shot: an app foregrounded twenty times must
/// not send twenty `notifyChildrenChanged` storms to the car.
///
/// Pure, so the whole policy is testable without an engine.
@visibleForTesting
bool debeInvalidarArbolAutoAlReanudar({
  required AppLifecycleState estado,
  required bool hayCocheSuscrito,
  required bool yaInvalidado,
}) =>
    !yaInvalidado && hayCocheSuscrito && estado == AppLifecycleState.resumed;

/// Root wrapper that keeps the orientation policy applied and owns the
/// Android Auto browse-tree recovery hook.
///
/// Public only so a test can mount it and drive real lifecycle events
/// through [debeInvalidarArbolAutoAlReanudar]'s call site — the previous
/// trigger shipped broken precisely because nothing could reach it.
@visibleForTesting
class OrientacionResponsiveApp extends StatefulWidget {
  const OrientacionResponsiveApp({super.key, required this.child});

  final Widget child;

  @override
  State<OrientacionResponsiveApp> createState() =>
      _OrientacionResponsiveAppState();
}

class _OrientacionResponsiveAppState extends State<OrientacionResponsiveApp>
    with WidgetsBindingObserver {
  ui.Display? _display;

  /// fix/android-auto-musica-local, item 4: la invalidación del árbol del
  /// coche se dispara UNA sola vez. Ver
  /// [debeInvalidarArbolAutoAlReanudar].
  bool _arbolAutoInvalidado = false;

  @override
  void initState() {
    super.initState();
    WidgetsBinding.instance.addObserver(this);
  }

  @override
  void didChangeDependencies() {
    super.didChangeDependencies();
    _display = View.maybeOf(context)?.display;
    unawaited(aplicarPoliticaOrientacion(display: _display));
  }

  /// `resumed` es lo único que significa de verdad «ya hay Activity
  /// adjunta», y con ella el handler nativo de `pluriwave/file_actions` que
  /// `MainActivity.configureFlutterEngine` instala. Si el coche había
  /// navegado la raíz ANTES (arranque headless), la cacheó sin poder
  /// resolver la música local; Android Auto no vuelve a preguntar por su
  /// cuenta, así que se lo decimos aquí. Ver
  /// [debeInvalidarArbolAutoAlReanudar] para las tres condiciones.
  @override
  void didChangeAppLifecycleState(AppLifecycleState state) {
    super.didChangeAppLifecycleState(state);
    if (!debeInvalidarArbolAutoAlReanudar(
      estado: state,
      hayCocheSuscrito: hayCocheSuscritoAlArbol(),
      yaInvalidado: _arbolAutoInvalidado,
    )) {
      return;
    }
    _arbolAutoInvalidado = true;
    invalidarArbolAuto();
  }

  @override
  void didChangeMetrics() {
    unawaited(aplicarPoliticaOrientacion(display: _display));
  }

  @override
  void dispose() {
    WidgetsBinding.instance.removeObserver(this);
    super.dispose();
  }

  @override
  Widget build(BuildContext context) => widget.child;
}