import 'package:flutter/foundation.dart';
import 'package:flutter/material.dart';
import 'package:go_router/go_router.dart';
import 'package:sentry_flutter/sentry_flutter.dart';

import '../utils/app_update_util.dart';
import '../viewmodels/admin_pin_view_model.dart';
import '../viewmodels/pin_lock_view_model.dart';
import '../viewmodels/remote_sync_view_model.dart';
import '../views/admin_screen_view.dart';
import '../views/bar/bar_screen_view.dart';
import '../views/dev_menu_view.dart';
import '../views/error_screen_view.dart';
import '../views/history_screen_view.dart';
import '../views/pin_lock_view.dart';
import '../views/product_form_view.dart';
import '../views/product_list_view.dart';
import '../views/registration_view.dart';
import '../views/settings_view.dart';
import '../views/update_progress_view.dart';

final RouteObserver<PageRoute> routeObserver = RouteObserver<PageRoute>();

String? _redirectApp({
  required PinLockViewModel pinLockViewModel,
  required AdminPinViewModel adminPinViewModel,
  required RemoteSyncViewModel remoteSyncViewModel,
  required GoRouterState state,
}) {
  if (!pinLockViewModel.hasLoaded ||
      !adminPinViewModel.hasLoaded ||
      !remoteSyncViewModel.hasLoaded) {
    return null;
  }

  final location = state.uri.path;
  final returnTo = _returnLocation(state);

  if (remoteSyncViewModel.isConfigured && location == '/register') {
    return '/admin';
  }

  final goingToLock = location == '/lock';
  final goingToAdminLock = location == '/admin/lock';
  final mustBeOnLock = _mustBeOnLock(pinLockViewModel);

  if (mustBeOnLock && !goingToLock) return _lockLocation('/lock', state);
  if (!mustBeOnLock && goingToLock) return returnTo ?? '/bar';

  final isAdminArea = _isAdminArea(location);
  final isDebugShortcutArea = _isDebugShortcutArea(location);

  if (isAdminArea &&
      !isDebugShortcutArea &&
      !goingToAdminLock &&
      !adminPinViewModel.isUnlocked) {
    return _lockLocation('/admin/lock', state);
  }

  if (goingToAdminLock && adminPinViewModel.isUnlocked) {
    return returnTo ?? '/admin';
  }

  return null;
}

/// Sends the user back where they were headed once the PIN is entered.
String _lockLocation(String lockPath, GoRouterState state) {
  return Uri(
    path: lockPath,
    queryParameters: {'from': state.uri.toString()},
  ).toString();
}

String? _returnLocation(GoRouterState state) {
  final from = state.uri.queryParameters['from'];
  if (from == null || !from.startsWith('/')) return null;

  final path = Uri.parse(from).path;
  if (path == '/lock' || path == '/admin/lock') return null;

  return from;
}

bool _mustBeOnLock(PinLockViewModel pinLockViewModel) {
  final needsPinSetup =
      !pinLockViewModel.isPinSet && pinLockViewModel.pinRequired;
  final isLocked =
      pinLockViewModel.isPinSet &&
      !pinLockViewModel.isUnlocked &&
      pinLockViewModel.pinRequired;

  return needsPinSetup || isLocked;
}

bool _isAdminArea(String location) {
  return location == '/admin' ||
      location.startsWith('/admin/') ||
      location == '/settings' ||
      location == '/dev' ||
      location == '/register' ||
      location == '/products' ||
      location.startsWith('/products/') ||
      location == '/history' ||
      location.startsWith('/history/');
}

bool _isDebugShortcutArea(String location) {
  if (!kDebugMode) return false;

  return location == '/products' ||
      location.startsWith('/products/') ||
      location == '/history' ||
      location.startsWith('/history/');
}

GoRouter createAppRouter({
  required PinLockViewModel pinLockViewModel,
  required AdminPinViewModel adminPinViewModel,
  required RemoteSyncViewModel remoteSyncViewModel,
}) {
  // go_router drops `extra` when it rebuilds a route from its location, e.g.
  // when the app returns from Android's installer, so keep the last update
  UpdateInfo? lastUpdate;

  return GoRouter(
    initialLocation: '/bar',
    observers: [routeObserver, SentryNavigatorObserver()],
    refreshListenable: Listenable.merge([
      pinLockViewModel,
      adminPinViewModel,
      remoteSyncViewModel,
    ]),
    redirect: (_, state) => _redirectApp(
      pinLockViewModel: pinLockViewModel,
      adminPinViewModel: adminPinViewModel,
      remoteSyncViewModel: remoteSyncViewModel,
      state: state,
    ),
    routes: [
      GoRoute(path: '/', redirect: (context, state) => '/bar'),

      GoRoute(
        path: '/register',
        builder: (context, state) => const RegistrationView(),
      ),

      GoRoute(
        path: '/lock',
        builder: (context, state) => PinEntryView(
          mode: pinLockViewModel.isPinSet
              ? PinEntryMode.unlock
              : PinEntryMode.create,
          onSuccess: () => context.go(_returnLocation(state) ?? '/bar'),
        ),
      ),

      GoRoute(path: '/bar', builder: (context, state) => const BarScreenView()),

      GoRoute(
        path: '/admin/lock',
        builder: (context, state) => PinEntryView(
          mode: adminPinViewModel.isPinSet
              ? PinEntryMode.unlock
              : PinEntryMode.create,
          isAdmin: true,
          onVerify: adminPinViewModel.verify,
          onSet: adminPinViewModel.setPin,
          error: () => adminPinViewModel.error,
          onSuccess: () => context.go(_returnLocation(state) ?? '/admin'),
          onClose: () => context.canPop() ? context.pop() : context.go('/bar'),
        ),
      ),

      GoRoute(
        path: '/admin',
        builder: (context, state) => const AdminScreenView(),
      ),

      GoRoute(
        path: '/products',
        builder: (context, state) => const ProductListView(),
        routes: [
          GoRoute(
            path: 'new',
            builder: (context, state) => const ProductFormView(),
          ),
          GoRoute(
            path: ':id/edit',
            builder: (context, state) {
              final productId = state.pathParameters['id']!;

              return ProductFormView(productId: productId);
            },
          ),
        ],
      ),
      GoRoute(
        path: '/history',
        builder: (context, state) => const HistoryScreenView(),
      ),

      GoRoute(
        path: '/settings',
        builder: (context, state) => const SettingsScreenView(),
      ),

      GoRoute(
        path: '/update-progress',
        redirect: (context, state) {
          if (state.extra case final UpdateInfo update) lastUpdate = update;
          return lastUpdate == null ? '/settings' : null;
        },
        builder: (context, state) {
          final update = lastUpdate!;
          final simulate = state.uri.queryParameters['simulate'] == 'true';
          final simulateError =
              state.uri.queryParameters['simulateError'] == 'true';
          return UpdateProgressView(
            update: update,
            simulate: simulate,
            simulateError: simulateError,
          );
        },
      ),

      GoRoute(path: '/dev', builder: (context, state) => const DevMenuView()),
      GoRoute(
        path: '/error',
        builder: (context, state) => const ErrorScreenView(),
      ),
    ],
  );
}