import 'dart:async';

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

import '../../core/app_clock.dart';
import '../../core/theme/app_colors.dart';
import '../../core/theme/theme_controller.dart';
import '../../core/widgets/app_icon.dart';
import '../../core/widgets/surface_card.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 '../settings/settings_screen.dart';
import 'launcher_controller.dart';
import 'system_controller.dart';
import 'widgets/clock_block.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 StatelessWidget {
  const HomeScreen({super.key});

  @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 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 showHomeBanner = launcher.defaultHomeKnown && !launcher.isDefaultHome;

    ShortcutSpec slotSpec(SlotType slot) {
      final assignment = launcher.assignmentFor(slot);
      final app = assignment == null
          ? null
          : launcher.appForAssignment(assignment);
      final playing =
          slot == SlotType.music && system.isMusicPlaying && assignment != null;
      final nonSystemIcon = app != null && !app.isSystemApp ? app.icon : null;

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

    ShortcutSpec pinnedSpec(SlotAssignment pinned) {
      final app = launcher.appForAssignment(pinned);
      final useRealIcon = app != null && !app.isSystemApp;
      return ShortcutSpec(
        title: pinned.label.isEmpty ? pinned.packageName : pinned.label,
        subtitle: null,
        iconAsset: 'assets/icons/app-window.svg',
        iconBytes: useRealIcon ? app.icon : null,
        assigned: true,
        onTap: () => _openPinned(context, pinned),
        onLongPress: () => _removePinned(context, pinned),
        longPressHint: 'remove from Home',
      );
    }

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

    return PopScope(
      canPop: false,
      child: Scaffold(
        backgroundColor: colors.canvas,
        body: Stack(
          children: [
            Positioned.fill(
              child: DecoratedBox(
                decoration: homeBackground(
                  colors,
                  Theme.of(context).brightness,
                ),
              ),
            ),
            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),
                        const Spacer(),
                        StatusCluster(
                          status: system.status,
                          compact: compact,
                          showBattery: appearance.showBattery,
                        ),
                      ],
                    ),
                    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 (showHomeBanner) ...[
                                  _HomeRoleBanner(
                                    launcher: launcher,
                                    onSetUp: () => _requestHome(context),
                                  ),
                                  const SizedBox(height: 14),
                                ],
                                VolumeCard(
                                  volume: system.volume,
                                  compact: compact,
                                  onSetVolume: system.setVolume,
                                  onToggleMute: system.toggleMute,
                                ),
                              ],
                            ),
                          ),
                          SizedBox(width: gap),
                          Expanded(
                            child: Column(
                              children: [
                                Expanded(
                                  child: ShortcutGrid(
                                    shortcuts: shortcuts,
                                    compact: compact,
                                  ),
                                ),
                                if (!compact) ...[
                                  const SizedBox(height: 4),
                                  _HomeHint(
                                    text: launcher.pinnedApps.isEmpty
                                        ? 'Hold a shortcut to change the app'
                                        : 'Hold a slot to change · hold an added app to remove',
                                    style: theme.textTheme.bodySmall?.copyWith(
                                      color: colors.inkFaint,
                                    ),
                                  ),
                                ],
                              ],
                            ),
                          ),
                        ],
                      ),
                    ),
                  ],
                ),
              ),
            ),
          ],
        ),
      ),
    );
  }

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

  void _removePinned(BuildContext context, SlotAssignment assignment) {
    unawaited(context.read<LauncherController>().removePinnedApp(assignment));
    _showMessage(
      context,
      '${assignment.label.isEmpty ? 'App' : assignment.label} removed from Home',
    );
  }

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

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

  Future<void> _requestHome(BuildContext context) async {
    final launcher = context.read<LauncherController>();
    final launched = await launcher.requestDefaultHome();
    if (!launched && context.mounted) {
      _showMessage(context, 'Could not open the home app settings.');
    }
  }

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

class _HomeRoleBanner extends StatelessWidget {
  const _HomeRoleBanner({required this.launcher, required this.onSetUp});

  final LauncherController launcher;
  final VoidCallback onSetUp;

  @override
  Widget build(BuildContext context) {
    final colors = context.colors;
    final theme = Theme.of(context);

    return SurfaceCard(
      padding: const EdgeInsets.fromLTRB(18, 16, 18, 16),
      radius: 24,
      color: colors.accentSoft.withValues(alpha: 0.62),
      borderColor: colors.accent.withValues(alpha: 0.18),
      showShadow: false,
      child: Row(
        children: [
          Container(
            width: 38,
            height: 38,
            decoration: BoxDecoration(
              color: colors.accent.withValues(alpha: 0.14),
              borderRadius: BorderRadius.circular(13),
            ),
            alignment: Alignment.center,
            child: AppIcon(
              'assets/icons/smartphone.svg',
              size: 18,
              color: colors.accent,
            ),
          ),
          const SizedBox(width: 13),
          Expanded(
            child: Column(
              crossAxisAlignment: CrossAxisAlignment.start,
              children: [
                Text(
                  'Make CarDash your home app',
                  style: theme.textTheme.titleSmall,
                ),
                const SizedBox(height: 2),
                Text(
                  'Open it with the Home button.',
                  style: theme.textTheme.bodySmall?.copyWith(
                    color: colors.inkMuted,
                  ),
                ),
              ],
            ),
          ),
          TextButton(
            onPressed: onSetUp,
            style: TextButton.styleFrom(
              foregroundColor: colors.accent,
              textStyle: theme.textTheme.labelLarge,
            ),
            child: const Text('Set up'),
          ),
        ],
      ),
    );
  }
}

class _HomeHint extends StatefulWidget {
  const _HomeHint({required this.text, this.style});

  final String text;
  final TextStyle? style;

  @override
  State<_HomeHint> createState() => _HomeHintState();
}

class _HomeHintState extends State<_HomeHint> {
  Timer? _timer;
  bool _visible = true;

  @override
  void initState() {
    super.initState();
    final elapsed = DateTime.now().difference(AppClock.startedAt);
    final remaining = const Duration(minutes: 2) - elapsed;
    if (remaining <= Duration.zero) {
      _visible = false;
    } else {
      _timer = Timer(remaining, () {
        if (mounted) setState(() => _visible = false);
      });
    }
  }

  @override
  void dispose() {
    _timer?.cancel();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return AnimatedSwitcher(
      duration: const Duration(milliseconds: 350),
      switchInCurve: Curves.easeOut,
      switchOutCurve: Curves.easeIn,
      child: _visible
          ? Text(
              widget.text,
              key: const ValueKey('home-hint'),
              textAlign: TextAlign.center,
              style: widget.style,
            )
          : const SizedBox.shrink(key: ValueKey('home-hint-gone')),
    );
  }
}