import 'dart:async';

import 'package:flutter/foundation.dart';
import 'package:flutter/material.dart';
import 'package:flutter/services.dart';

import 'data/app_config.dart';

import 'state/app_scope.dart';
import 'state/app_state.dart';
import 'ui/screens/auth/login_screen.dart';
import 'ui/screens/shell_screen.dart';
import 'ui/screens/splash_screen.dart';
import 'ui/tokens.dart';

void main() {
  WidgetsFlutterBinding.ensureInitialized();

  // What this build is, in the log, on every launch.
  //
  // Not a debugging leftover: the offline build and the auto-login build look
  // identical to the real one from the outside, and the whole reason the first
  // mock was deleted was that nobody could tell which mode a handset was in.
  // The Account screen says it too, but a build that cannot get past the login
  // screen cannot show you the Account screen — which is exactly the session
  // where you most need to know. Release builds print nothing.
  if (!kReleaseMode) debugPrint('[BUILD] ${AppConfig.describe}');

  // Draw behind the system bars — expected on Android 15+ and the reason the
  // screens manage their own SafeArea insets.
  SystemChrome.setEnabledSystemUIMode(SystemUiMode.edgeToEdge);
  SystemChrome.setPreferredOrientations([
    DeviceOrientation.portraitUp,
    DeviceOrientation.portraitDown,
  ]);

  runApp(const DoormileApp());
}

/// Doormile — customer app.
///
/// Book pickup → Track → Delivered.
///
/// `lib/data/doormile_api.dart` is the service surface, and it has exactly one
/// implementation: the live customer API. Nothing on screen is invented.
class DoormileApp extends StatefulWidget {
  const DoormileApp({super.key, this.initialState});

  /// Injectable for tests.
  final AppState? initialState;

  @override
  State<DoormileApp> createState() => _DoormileAppState();
}

class _DoormileAppState extends State<DoormileApp> {
  late final AppState _state = widget.initialState ?? AppState();

  @override
  void initState() {
    super.initState();
    // A returning customer's session outlives the process: the refresh token is
    // good for 60 days. Look for it before deciding which screen to open.
    unawaited(_state.restoreSession());
  }

  @override
  void dispose() {
    _state.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return AppScope(
      state: _state,
      child: MaterialApp(
        title: 'Doormile',
        debugShowCheckedModeBanner: false,
        theme: buildDoormileTheme(),
        home: const _Launch(),
        // No text-scale clamp: components adapt instead. Rows grow, important
        // text wraps, and ellipsis is reserved for secondary information.
        builder: (context, child) {
          return AnnotatedRegion<SystemUiOverlayStyle>(
            value: const SystemUiOverlayStyle(
              statusBarColor: Colors.transparent,
              statusBarIconBrightness: Brightness.dark,
              statusBarBrightness: Brightness.light,
              systemNavigationBarColor: Colors.transparent,
              systemNavigationBarIconBrightness: Brightness.dark,
            ),
            child: child ?? const SizedBox.shrink(),
          );
        },
      ),
    );
  }
}

ThemeData buildDoormileTheme() {
  const scheme = ColorScheme.light(
    primary: DmColors.brand,
    onPrimary: Colors.white,
    secondary: DmColors.brand,
    onSecondary: Colors.white,
    surface: DmColors.surface,
    onSurface: DmColors.ink,
    error: DmColors.danger,
  );

  return ThemeData(
    useMaterial3: true,
    fontFamily: 'Switzer',
    colorScheme: scheme,
    scaffoldBackgroundColor: DmColors.bg,
    splashFactory: InkSparkle.splashFactory,
    highlightColor: const Color(0x0A17110F),
    textSelectionTheme: const TextSelectionThemeData(
      cursorColor: DmColors.brand,
      selectionColor: Color(0x338F0F06),
      selectionHandleColor: DmColors.brand,
    ),
    textTheme: const TextTheme().apply(
      bodyColor: DmColors.ink,
      displayColor: DmColors.ink,
    ),
    dividerTheme: const DividerThemeData(
      color: DmColors.hairline,
      thickness: 1,
      space: 1,
    ),
    pageTransitionsTheme: const PageTransitionsTheme(
      builders: {
        TargetPlatform.android: _DmPageTransitions(),
        TargetPlatform.iOS: _DmPageTransitions(),
        TargetPlatform.macOS: _DmPageTransitions(),
        TargetPlatform.windows: _DmPageTransitions(),
        TargetPlatform.linux: _DmPageTransitions(),
      },
    ),
  );
}

/// Navigation, as a vertical axis.
///
/// ── What was wrong with the old one ──
///
/// It was horizontal. A push slid the incoming page 14% in from the right and
/// nudged the page behind it left; going back ran that in reverse, so the
/// screen the customer was leaving slid off to the **right**. Two things are
/// wrong with that here.
///
/// The first is that it is the system back gesture's direction. On Android the
/// predictive-back swipe and on iOS the edge swipe both drag horizontally, so a
/// page that also leaves horizontally under a button press reads as a gesture
/// the customer did not make.
///
/// The second is what these pages *are*. Every push in this app is a layer over
/// the one before it — the booking form over Home, the map pin over the form,
/// tracking over an order. A layer arrives from below and falls away below; it
/// does not slide in from beside the thing it is covering.
///
/// ── What it is ──
///
/// The incoming page rises from the bottom edge and covers the screen. The page
/// it covers stays exactly where it is and dims, because it has not moved — it
/// has been covered, and pretending otherwise was the horizontal version's
/// parallax trick solving a problem a full-travel cover does not have.
///
/// Going back, the top page falls straight down off the bottom and the page
/// underneath comes back up to full strength. Top to bottom, out of the way.
///
/// The travel is the full height rather than a token 14%, which is what makes
/// the direction legible at all: a page that moves 55 points and fades has no
/// direction a customer can name. The timing lives on [DmPageRoute] — 420ms in,
/// 340ms back. Going back is always quicker than going forward, because the
/// customer already knows what is behind them.
class _DmPageTransitions extends PageTransitionsBuilder {
  const _DmPageTransitions();

  @override
  Widget buildTransitions<T>(
    PageRoute<T> route,
    BuildContext context,
    Animation<double> animation,
    Animation<double> secondaryAnimation,
    Widget child,
  ) {
    final enter = CurvedAnimation(
      parent: animation,
      curve: DmMotion.enter,
      // Flipped on the way back: the emphasised decelerate leaves quickly and
      // settles slowly, and a page falling away wants the same shape read from
      // the other end — off the bottom edge decisively, not trailing.
      reverseCurve: DmMotion.enter.flipped,
    );
    final exit = CurvedAnimation(
      parent: secondaryAnimation,
      curve: DmMotion.enter,
      reverseCurve: DmMotion.enter.flipped,
    );

    return FadeTransition(
      // This page, being covered by the one above it. Not to nothing: at 0.5
      // the page behind is still legibly itself, which is what tells the
      // customer the thing on top is a layer and not a new place.
      opacity: Tween(begin: 1.0, end: 0.5).animate(exit),
      child: SlideTransition(
        position: Tween(
          begin: const Offset(0, 1),
          end: Offset.zero,
        ).animate(enter),
        child: child,
      ),
    );
  }
}

/// What the app opens on.
///
/// Three states, and the middle one is the reason this widget exists: until the
/// stored session has been looked for we do not yet know whether this customer
/// is signed in, and showing them a login form that vanishes a moment later is
/// worse than showing them nothing.
///
/// That middle state used to be a blank canvas — correct, and a hole where the
/// app's first impression goes. It is [SplashScreen] now, which owns both the
/// wait and its own minimum, and tells this widget when it is finished. The
/// native window background carries the same mark from process start, so the
/// handover into Flutter is invisible.
class _Launch extends StatefulWidget {
  const _Launch();

  @override
  State<_Launch> createState() => _LaunchState();
}

class _LaunchState extends State<_Launch> {
  bool _splashDone = false;

  @override
  Widget build(BuildContext context) {
    final app = AppScope.of(context);

    if (!_splashDone) {
      return SplashScreen(
        ready: !app.restoringSession,
        onDone: () => setState(() => _splashDone = true),
      );
    }
    return app.isSignedIn ? const ShellScreen() : const LoginScreen();
  }
}