cake_wallet/lib/src/screens/base_page.dart

import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';
import 'package:cake_wallet/src/widgets/nav_bar.dart';
import 'package:provider/provider.dart';
import 'package:cake_wallet/themes.dart';
import 'package:cake_wallet/theme_changer.dart';

enum AppBarStyle { regular, withShadow }

abstract class BasePage extends StatelessWidget {
  String get title => null;
  bool get isModalBackButton => false;
  Color get backgroundColor => Colors.white;
  bool get resizeToAvoidBottomPadding => true;
  AppBarStyle get appBarStyle => AppBarStyle.regular;

  final _backArrowImage = Image.asset('assets/images/back_arrow.png');
  final _backArrowImageDarkTheme =
      Image.asset('assets/images/back_arrow_dark_theme.png');
  final _closeButtonImage = Image.asset('assets/images/close_button.png');
  final _closeButtonImageDarkTheme =
      Image.asset('assets/images/close_button_dark_theme.png');

  void onClose(BuildContext context) => Navigator.of(context).pop();

  Widget leading(BuildContext context) {
    if (ModalRoute.of(context).isFirst) {
      return null;
    }

    final _themeChanger = Provider.of<ThemeChanger>(context);
    Image _closeButton, _backButton;

    if (_themeChanger.getTheme() == Themes.darkTheme) {
      _backButton = _backArrowImageDarkTheme;
      _closeButton = _closeButtonImageDarkTheme;
    } else {
      _backButton = _backArrowImage;
      _closeButton = _closeButtonImage;
    }

    return SizedBox(
      height: 37,
      width: isModalBackButton ? 37 : 20,
      child: ButtonTheme(
        minWidth: double.minPositive,
        child: FlatButton(
            highlightColor: Colors.transparent,
            splashColor: Colors.transparent,
            padding: EdgeInsets.all(0),
            onPressed: () => onClose(context),
            child: isModalBackButton ? _closeButton : _backButton),
      ),
    );
  }

  Widget middle(BuildContext context) {
    return title == null
        ? null
        : Text(
            title,
            style: TextStyle(
                fontSize: 16.0,
                fontWeight: FontWeight.w600,
                color: Theme.of(context).primaryTextTheme.title.color),
          );
  }

  Widget trailing(BuildContext context) => null;

  Widget floatingActionButton(BuildContext context) => null;

  ObstructingPreferredSizeWidget appBar(BuildContext context) {
    final _themeChanger = Provider.of<ThemeChanger>(context);
    final _isDarkTheme = _themeChanger.getTheme() == Themes.darkTheme;

    switch (appBarStyle) {
      case AppBarStyle.regular:
        return NavBar(
            context: context,
            leading: leading(context),
            middle: middle(context),
            trailing: trailing(context),
            backgroundColor: _isDarkTheme
                ? Theme.of(context).backgroundColor
                : backgroundColor);

      case AppBarStyle.withShadow:
        return NavBar.withShadow(
            context: context,
            leading: leading(context),
            middle: middle(context),
            trailing: trailing(context),
            backgroundColor: _isDarkTheme
                ? Theme.of(context).backgroundColor
                : backgroundColor);

      default:
        return NavBar(
            context: context,
            leading: leading(context),
            middle: middle(context),
            trailing: trailing(context),
            backgroundColor: _isDarkTheme
                ? Theme.of(context).backgroundColor
                : backgroundColor);
    }
  }

  Widget body(BuildContext context);

  @override
  Widget build(BuildContext context) {
    final _themeChanger = Provider.of<ThemeChanger>(context);
    final _isDarkTheme = _themeChanger.getTheme() == Themes.darkTheme;

    return Scaffold(
        backgroundColor:
            _isDarkTheme ? Theme.of(context).backgroundColor : backgroundColor,
        resizeToAvoidBottomPadding: resizeToAvoidBottomPadding,
        appBar: appBar(context),
        body: SafeArea(child: body(context)),
        floatingActionButton: floatingActionButton(context));
  }
}