import 'dart:async';

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

import '../../core/theme/app_colors.dart';
import '../../core/theme/theme_controller.dart';
import '../../data/models/slot_assignment.dart';
import '../../data/models/slot_type.dart';
import '../apps/all_apps_screen.dart';
import '../apps/app_picker_sheet.dart';
import '../jellyfin/jellyfin_dashboard_screen.dart';
import '../jellyfin/jellyfin_playback_controller.dart';
import '../settings/settings_screen.dart';
import 'gps_speed_controller.dart';
import 'home_media_state.dart';
import 'launcher_controller.dart';
import 'obd_controller.dart';
import 'pinned_app_actions.dart';
import 'system_controller.dart';
import 'telemetry_settings_controller.dart';
import 'weather_controller.dart';
import '../settings/update_controller.dart';
import 'widgets/clock_block.dart';
import 'widgets/gps_speed_card.dart';
import 'widgets/home_hint.dart';
import 'widgets/night_mode_overlay.dart';
import 'widgets/obd_card.dart';
import 'widgets/shortcut_grid.dart';
import 'widgets/status_cluster.dart';
import 'widgets/volume_card.dart';

/// The only home page. No app bar, no dock, no pages: information, the main
/// volume control, and up to 16 configurable shortcuts.
class HomeScreen extends StatefulWidget {
  const HomeScreen({super.key});

  @override
  State<HomeScreen> createState() => _HomeScreenState();
}

class _HomeScreenState extends State<HomeScreen> {
  bool _nightMode = false;

  void _enterNightMode() {
    setState(() => _nightMode = true);
  }

  void _leaveNightMode() {
    setState(() => _nightMode = false);
  }

  @override
  Widget build(BuildContext context) {
    final colors = context.colors;
    final theme = Theme.of(context);
    final launcher = context.watch<LauncherController>();
    final system = context.watch<SystemController>();
    final appearance = context.watch<ThemeController>();
    final obd = context.watch<ObdController>();
    final gps = context.watch<GpsSpeedController>();
    final weather = context.watch<WeatherController>();
    final telemetrySettings = context.watch<TelemetrySettingsController>();
    final update = context.watch<UpdateController>();
    final jellyfinPlayback = context.watch<JellyfinPlaybackController>();
    final screen = MediaQuery.sizeOf(context);
    final compact = screen.height < 700 || screen.width < 1100;
    final horizontalPadding = compact ? 30.0 : 44.0;
    final denseHome = launcher.homeButtonCount > 8;
    final leftWidth = denseHome
        ? (screen.width * 0.31).clamp(300.0, 400.0)
        : (screen.width * 0.37).clamp(300.0, 440.0);
    final gap = compact ? 26.0 : 40.0;

    final obdTemperature = obd.ambientCelsius;
    final useObdTemperature =
        telemetrySettings.temperatureUseObd && obdTemperature != null;
    final temperature = !telemetrySettings.temperatureEnabled
        ? null
        : useObdTemperature
        ? obdTemperature
        : (weather.hasTemperature ? weather.temperatureCelsius : null);
    final temperatureText = temperature == null
        ? null
        : useObdTemperature
        ? 'Outside, ${temperature.round()}°C'
        : '${weather.locationName}, ${temperature.round()}°C';
    final temperatureAlert = temperature != null && temperature < 3;

    final showObdSpeed =
        telemetrySettings.speedEnabled &&
        telemetrySettings.speedUseObd &&
        obd.hasTelemetry;
    final showGpsSpeed =
        telemetrySettings.speedEnabled && !showObdSpeed && gps.hasSpeed;

    final jellyfinPlaying = jellyfinPlayback.playing;
    final systemMediaIsExternal = isExternalSystemMedia(system.media);
    final otherMusicPlaying = shouldShowMusicEqualizer(
      systemMusicPlaying: system.isMusicPlaying,
      jellyfinPlaying: jellyfinPlaying,
      systemMedia: system.media,
    );

    ShortcutSpec slotSpec(SlotType slot) {
      final assignment = launcher.assignmentFor(slot);
      final playing =
          slot == SlotType.music && otherMusicPlaying && assignment != null;

      return ShortcutSpec(
        title: slot.label,
        subtitle: assignment?.label ?? 'Select app',
        iconAsset: slot.iconAsset,
        showEqualizer: playing,
        assigned: assignment != null,
        onTap: () => _openSlot(context, slot),
        onLongPress: () => showAppPicker(context, slot),
        longPressHint: 'change the app',
      );
    }

    ShortcutSpec jellyfinSpec() {
      final album = jellyfinPlayback.nowPlayingAlbum;
      final artist = jellyfinPlayback.nowPlayingArtist;
      final subtitle = jellyfinPlayback.isActive && album != null
          ? (artist != null && artist.isNotEmpty ? '$artist — $album' : album)
          : 'Music library';
      return ShortcutSpec(
        title: 'Jellyfin',
        subtitle: subtitle,
        iconAsset: 'assets/icons/headphones.svg',
        assigned: true,
        showEqualizer: jellyfinPlaying,
        onTap: () => _openJellyfin(context),
      );
    }

    ShortcutSpec pinnedSpec(SlotAssignment pinned) {
      final app = launcher.appForAssignment(pinned);
      final customIcon = pinned.iconAsset;
      return ShortcutSpec(
        title: pinned.label.isEmpty ? pinned.packageName : pinned.label,
        subtitle: null,
        iconAsset: customIcon ?? 'assets/icons/app-window.svg',
        iconBytes: customIcon == null ? app?.icon : null,
        assigned: true,
        onTap: () => _openPinned(context, pinned),
        onLongPress: () => showPinnedAppMenu(context, pinned),
        longPressHint: 'open app options',
      );
    }

    final shortcuts = <ShortcutSpec>[
      for (final slot in SlotType.values)
        if (launcher.isSlotEnabled(slot))
          slot == SlotType.jellyfin ? jellyfinSpec() : slotSpec(slot),
      for (final pinned in launcher.pinnedApps) pinnedSpec(pinned),
      ShortcutSpec(
        title: 'All apps',
        subtitle: 'Installed apps',
        iconAsset: 'assets/icons/layout-grid.svg',
        assigned: true,
        onTap: () => _openAllApps(context),
      ),
    ];

    final otherSystemMusicPlaying =
        system.isMusicPlaying && systemMediaIsExternal;
    final jellyfinActive =
        jellyfinPlayback.isActive &&
        (jellyfinPlaying || !otherSystemMusicPlaying);
    final cardMedia = jellyfinActive
        ? jellyfinPlayback.mediaPlayback
        : system.media;
    final cardPlaying = jellyfinActive
        ? jellyfinPlaying
        : system.isMusicPlaying;

    return PopScope(
      canPop: false,
      child: Scaffold(
        backgroundColor: colors.canvas,
        body: Stack(
          children: [
            Positioned.fill(
              child: DecoratedBox(
                decoration: homeBackground(
                  colors,
                  Theme.of(context).brightness,
                ),
              ),
            ),
            if (!_nightMode)
              Positioned.fill(
                child: GestureDetector(
                  behavior: HitTestBehavior.translucent,
                  onLongPress: _enterNightMode,
                ),
              ),
            const _FirstRunLauncherTip(),
            Positioned(
              top: -190,
              right: -120,
              child: IgnorePointer(
                child: Container(
                  width: 560,
                  height: 560,
                  decoration: BoxDecoration(
                    shape: BoxShape.circle,
                    gradient: RadialGradient(
                      colors: [
                        colors.accent.withValues(
                          alpha: Theme.of(context).brightness == Brightness.dark
                              ? 0.16
                              : 0.10,
                        ),
                        colors.accent.withValues(alpha: 0),
                      ],
                    ),
                  ),
                ),
              ),
            ),
            SafeArea(
              minimum: EdgeInsets.fromLTRB(
                horizontalPadding,
                compact ? 18 : 24,
                horizontalPadding,
                compact ? 14 : 18,
              ),
              child: SizedBox.expand(
                child: Column(
                  crossAxisAlignment: CrossAxisAlignment.stretch,
                  children: [
                    Row(
                      crossAxisAlignment: CrossAxisAlignment.start,
                      children: [
                        ClockBlock(
                          compact: compact,
                          temperatureText: temperatureText,
                          temperatureAlert: temperatureAlert,
                        ),
                        const Spacer(),
                        StatusCluster(
                          status: system.status,
                          compact: compact,
                          showBattery: appearance.showBattery,
                          onOpenSettings: () => _openSettings(context),
                          showUpdateAvailable: update.updateAvailable,
                        ),
                      ],
                    ),
                    SizedBox(height: compact ? 16 : 24),
                    Expanded(
                      child: Row(
                        crossAxisAlignment: CrossAxisAlignment.stretch,
                        children: [
                          SizedBox(
                            width: leftWidth,
                            child: Column(
                              crossAxisAlignment: CrossAxisAlignment.stretch,
                              mainAxisAlignment: MainAxisAlignment.end,
                              children: [
                                if (showObdSpeed) ...[
                                  ObdCard(
                                    speedKmh: obd.speedKmh,
                                    throttlePercent: obd.throttlePercent,
                                    economyL100: obd.economyL100,
                                    compact: compact,
                                  ),
                                  SizedBox(height: compact ? 12 : 14),
                                ] else if (showGpsSpeed) ...[
                                  GpsSpeedCard(
                                    speedKmh: gps.speedKmh ?? 0,
                                    compact: compact,
                                  ),
                                  SizedBox(height: compact ? 12 : 14),
                                ],
                                VolumeCard(
                                  volume: system.volume,
                                  compact: compact,
                                  onSetVolume: system.setVolume,
                                  onToggleMute: system.toggleMute,
                                  isMusicPlaying: cardPlaying,
                                  onPlayPause: jellyfinActive
                                      ? () =>
                                            unawaited(jellyfinPlayback.toggle())
                                      : () => unawaited(_toggleMusic(context)),
                                  media: cardMedia,
                                  diagnostics: system.volumeDiagnostics,
                                  onToggleDiagnostics:
                                      system.toggleVolumeDiagnostics,
                                  unconfirmed: system.volumeUnconfirmed,
                                ),
                              ],
                            ),
                          ),
                          SizedBox(width: gap),
                          Expanded(
                            child: Column(
                              children: [
                                Expanded(
                                  child: ShortcutGrid(
                                    shortcuts: shortcuts,
                                    compact: compact,
                                  ),
                                ),
                                if (!compact &&
                                    launcher.firstLaunchAt != null) ...[
                                  const SizedBox(height: 4),
                                  HomeHint(
                                    firstLaunchAt: launcher.firstLaunchAt!,
                                    text: launcher.pinnedApps.isEmpty
                                        ? 'Hold a shortcut to change the app'
                                        : 'Hold a slot to change · hold an added app for options',
                                    style: theme.textTheme.bodySmall?.copyWith(
                                      color: colors.inkFaint,
                                    ),
                                  ),
                                ],
                              ],
                            ),
                          ),
                        ],
                      ),
                    ),
                  ],
                ),
              ),
            ),
            if (_nightMode)
              Positioned.fill(
                child: NightModeOverlay(onDismiss: _leaveNightMode),
              ),
          ],
        ),
      ),
    );
  }

  Future<void> _openPinned(
    BuildContext context,
    SlotAssignment assignment,
  ) async {
    final error = await context.read<LauncherController>().launchAssignment(
      assignment,
    );
    if (error != null && context.mounted) {
      _showMessage(context, error);
    }
  }

  Future<void> _toggleMusic(BuildContext context) async {
    final system = context.read<SystemController>();
    final launcher = context.read<LauncherController>();

    if (system.isMusicPlaying) {
      await system.pauseMusic();
      return;
    }

    // A media play key resumes a paused session. If nothing responds, open the
    // app assigned to the Music slot (or ask the user to choose one).
    final started = await system.playMusic();
    if (started || !context.mounted) return;

    final assignment = launcher.assignmentFor(SlotType.music);
    if (assignment == null) {
      await showAppPicker(context, SlotType.music);
      return;
    }
    final error = await launcher.launchSlot(SlotType.music);
    if (error != null && context.mounted) {
      _showMessage(context, error);
    }
  }

  Future<void> _openSlot(BuildContext context, SlotType slot) async {
    final launcher = context.read<LauncherController>();
    if (launcher.assignmentFor(slot) == null) {
      await showAppPicker(context, slot);
      return;
    }
    final error = await launcher.launchSlot(slot);
    if (error != null && context.mounted) {
      _showMessage(context, error);
    }
  }

  void _openSettings(BuildContext context) {
    final playback = context.read<JellyfinPlaybackController>();
    Navigator.of(context).push(
      MaterialPageRoute<void>(
        builder: (_) => SettingsScreen(playback: playback),
      ),
    );
  }

  void _openAllApps(BuildContext context) {
    Navigator.of(context)
        .push(MaterialPageRoute<void>(builder: (_) => const AllAppsScreen()));
  }

  void _openJellyfin(BuildContext context) {
    final playback = context.read<JellyfinPlaybackController>();
    final album = playback.isActive ? playback.currentAlbum : null;
    Navigator.of(context).push(
      MaterialPageRoute<void>(
        builder: (_) => JellyfinDashboardScreen(openAlbum: album),
      ),
    );
  }

  void _showMessage(BuildContext context, String message) {
    final messenger = ScaffoldMessenger.of(context);
    messenger.hideCurrentSnackBar();
    messenger.showSnackBar(SnackBar(content: Text(message)));
  }
}

class _FirstRunLauncherTip extends StatefulWidget {
  const _FirstRunLauncherTip();

  @override
  State<_FirstRunLauncherTip> createState() => _FirstRunLauncherTipState();
}

class _FirstRunLauncherTipState extends State<_FirstRunLauncherTip> {
  @override
  void initState() {
    super.initState();
    WidgetsBinding.instance.addPostFrameCallback((_) async {
      if (!mounted) return;
      final launcher = context.read<LauncherController>();
      if (launcher.homeRoleHintShown) return;
      await launcher.markHomeRoleHintShown();
      if (!mounted) return;
      final messenger = ScaffoldMessenger.of(context);
      messenger.hideCurrentSnackBar();
      messenger.showSnackBar(
        const SnackBar(
          content: Text(
            'You can set CarDash as your default launcher in Settings.',
          ),
          duration: Duration(seconds: 5),
        ),
      );
    });
  }

  @override
  Widget build(BuildContext context) => const SizedBox.shrink();
}