// The shell: one page at a time, chosen from a menu that swipes in from the left
// (or opens from each page's menu button). Main views first, then Tools, the rarely
// used ones (pirate-station-aide's pattern), then Settings.
//
// Dash, Signals and Captures stay alive while hidden, so a capture run survives a look
// at the dash; Camera and Link test are built only while shown (the camera holds a stream).

import 'package:flutter/material.dart';

import 'actions/orin_power.dart';
import 'link/boundary.dart';
import 'link/net.dart';
import 'pages/camera.dart';
import 'pages/checklist.dart';
import 'pages/dash.dart';
import 'pages/link_test.dart';
import 'pages/settings.dart';
import 'pages/signals.dart';
import 'shell_scope.dart';
import 'theme/palette.dart';
import 'widgets/link_status.dart';
import 'widgets/mock_banner.dart';

class AppShell extends StatefulWidget {
  const AppShell({
    super.key,
    required this.boundary,
    required this.usb,
    required this.linkTest,
    required this.themes,
  });
  final Boundary boundary;
  final UsbLink usb;
  final LinkTest linkTest;
  final Themes themes;

  @override
  State<AppShell> createState() => _AppShellState();
}

class _AppShellState extends State<AppShell> {
  final _scaffold = GlobalKey<ScaffoldState>();
  // Captures runs its own navigator (list → checklist), so the menu stays reachable
  // inside it and the run survives switching views.
  final _captures = GlobalKey<NavigatorState>();
  final Set<ShellView> _built = {shellView.value};

  void _go(ShellView v) {
    shellView.value = v;
    _scaffold.currentState?.closeDrawer();
  }

  Widget _page(ShellView v) {
    final b = widget.boundary;
    return switch (v) {
      ShellView.dash => DashPage(boundary: b, themes: widget.themes),
      ShellView.signals => SignalsPage(boundary: b, usb: widget.usb),
      ShellView.captures => Navigator(
        key: _captures,
        onGenerateRoute: (_) => MaterialPageRoute<void>(
          builder: (_) => ChecklistsPage(boundary: b),
        ),
      ),
      ShellView.camera => CamViewPage(host: Uri.parse(b.url).host),
      ShellView.linkTest => LinkTestPage(
        test: widget.linkTest,
        host: Uri.parse(b.url).host,
        restoreBinding: () => widget.usb.bindFor(Uri.parse(b.url)),
      ),
      ShellView.settings => SettingsPage(
        boundary: b,
        usb: widget.usb,
        themes: widget.themes,
      ),
    };
  }

  static const _kept = {ShellView.dash, ShellView.signals, ShellView.captures};

  @override
  Widget build(BuildContext context) {
    return ValueListenableBuilder(
      valueListenable: shellView,
      builder: (context, current, _) {
        _built.add(current);
        return PopScope(
          // Back: inside Captures first, then to the landing view, then out of the app.
          canPop:
              current == landingView &&
              !(_captures.currentState?.canPop() ?? false),
          onPopInvokedWithResult: (didPop, _) {
            if (didPop) return;
            if (current == ShellView.captures &&
                (_captures.currentState?.canPop() ?? false)) {
              _captures.currentState!.pop();
            } else {
              shellView.value = landingView;
            }
          },
          child: ShellScope(
            openMenu: () => _scaffold.currentState?.openDrawer(),
            child: Scaffold(
              key: _scaffold,
              drawerEdgeDragWidth: 32,
              drawer: _Menu(
                boundary: widget.boundary,
                current: current,
                go: _go,
                // From the shell's context: the drawer's is gone once it closes.
                power: () {
                  _scaffold.currentState?.closeDrawer();
                  orinPowerOptions(context, widget.boundary);
                },
              ),
              body: ListenableBuilder(
                listenable: widget.boundary,
                builder: (context, child) => Column(
                  crossAxisAlignment: CrossAxisAlignment.stretch,
                  children: [
                    if (widget.boundary.mock)
                      const SafeArea(bottom: false, child: MockBanner()),
                    // Pages draw their own top (app bars); keep every bottom clear of the system bar.
                    Expanded(child: SafeArea(top: false, child: child!)),
                  ],
                ),
                child: IndexedStack(
                  index: ShellView.values.indexOf(current),
                  children: [
                    for (final v in ShellView.values)
                      // Kept views, once built, stay built; the rest exist only while shown.
                      if ((_kept.contains(v) && _built.contains(v)) ||
                          v == current)
                        _page(v)
                      else
                        const SizedBox.shrink(),
                  ],
                ),
              ),
            ),
          ),
        );
      },
    );
  }
}

class _Menu extends StatelessWidget {
  const _Menu({
    required this.boundary,
    required this.current,
    required this.go,
    required this.power,
  });
  final Boundary boundary;
  final ShellView current;
  final void Function(ShellView) go;
  final VoidCallback power;

  @override
  Widget build(BuildContext context) {
    final p = AppTheme.of(context);
    Widget item(ShellView v, IconData icon, String label) => ListTile(
      leading: Icon(icon),
      title: Text(label),
      selected: v == current,
      selectedColor: p.accent,
      selectedTileColor: p.accent.withValues(alpha: 0.12),
      onTap: () => go(v),
    );
    Widget heading(String t) => Padding(
      padding: const EdgeInsets.fromLTRB(16, 16, 16, 4),
      child: Text(
        t,
        style: Theme.of(context).textTheme.labelLarge
            ?.copyWith(color: p.subdued),
      ),
    );
    return Drawer(
      backgroundColor: p.surface,
      child: SafeArea(
        child: ListenableBuilder(
          listenable: boundary,
          builder: (context, _) {
            final b = boundary;
            final host = b.hello?['host'] as String?;
            return ListView(
              children: [
                // The link, always: tapping it goes to Settings, where the address is.
                InkWell(
                  onTap: () => go(ShellView.settings),
                  child: Padding(
                    padding: const EdgeInsets.fromLTRB(16, 24, 16, 12),
                    child: Column(
                      crossAxisAlignment: CrossAxisAlignment.start,
                      children: [
                        Text(
                          'Yukart',
                          style: Theme.of(context).textTheme.headlineSmall,
                        ),
                        const SizedBox(height: 8),
                        LinkChip(boundary: b),
                        const SizedBox(height: 4),
                        Text(host ?? b.url, style: TextStyle(color: p.subdued)),
                      ],
                    ),
                  ),
                ),
                const Divider(),
                item(ShellView.dash, Icons.speed, 'Dash'),
                item(ShellView.signals, Icons.list_alt, 'Signals'),
                item(ShellView.captures, Icons.checklist, 'Captures'),
                const Divider(),
                heading('Tools'),
                item(ShellView.camera, Icons.videocam, 'Camera'),
                item(ShellView.linkTest, Icons.network_check, 'Link test'),
                ListTile(
                  leading: const Icon(Icons.power_settings_new),
                  title: const Text('Orin power options'),
                  subtitle:
                      b.state == LinkState.up && b.hello?['boot_id'] is String
                      ? null
                      : Text(
                          'needs the link up',
                          style: TextStyle(color: p.subdued),
                        ),
                  enabled:
                      b.state == LinkState.up && b.hello?['boot_id'] is String,
                  onTap: power,
                ),
                const Divider(),
                item(ShellView.settings, Icons.settings, 'Settings'),
              ],
            );
          },
        ),
      ),
    );
  }
}