lunasea/lib/core/ui/appbar.dart

import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:lunasea/core.dart';

enum _APPBAR_TYPE {
  DEFAULT,
  EMPTY,
  DROPDOWN,
}

class LunaAppBar extends StatefulWidget implements PreferredSizeWidget {
  static const APPBAR_HEIGHT = kToolbarHeight;

  final _APPBAR_TYPE type;
  final String title;
  final List<Widget> actions;
  final PreferredSizeWidget bottom;
  final bool hideLeading;
  final bool useDrawer;
  final Widget child;
  final double height;
  final List<String> profiles;
  final PageController pageController;
  final List<ScrollController> scrollControllers;

  @override
  Size get preferredSize {
    double _size = (height ?? APPBAR_HEIGHT);
    if (bottom != null) _size += bottom.preferredSize.height;
    return Size.fromHeight(_size);
  }

  const LunaAppBar._internal({
    @required this.type,
    @required this.useDrawer,
    this.title,
    this.actions,
    this.bottom,
    this.child,
    this.height,
    this.profiles,
    this.pageController,
    this.scrollControllers,
    this.hideLeading = false,
  });

  /// Create a new [AppBar] widget pre-styled for LunaSea.
  ///
  /// Will register an onTap gesture for the AppBar if:
  /// - [state] is supplied, and will call [scrollBackList] on the state controller.
  /// - [pageController] and [scrollControllers] are supplied, will register a listener on the page controller and scroll back the respective scroll controller.
  ///
  /// Passing in all 3 will result in state.scrollBackList taking precedence.
  factory LunaAppBar({
    @required String title,
    List<Widget> actions,
    PreferredSizeWidget bottom,
    bool useDrawer = false,
    bool hideLeading = false,
    PageController pageController,
    List<ScrollController> scrollControllers,
  }) {
    assert(title != null);
    if (pageController != null)
      assert(scrollControllers != null,
          'pageController is defined, scrollControllers should as well.');
    return LunaAppBar._internal(
      title: title,
      actions: actions,
      bottom: bottom,
      useDrawer: useDrawer,
      pageController: pageController,
      scrollControllers: scrollControllers,
      hideLeading: hideLeading,
      type: _APPBAR_TYPE.DEFAULT,
    );
  }

  /// Create a new, empty [LunaAppBar] which can be used to attach to a [Scaffold] in a [PageView] that is already wrapped in an [AppBar].
  ///
  /// Example usages would be a [PageView] but a single page needs an [AppBar] bottom widget.
  ///
  /// The default padding is for a [LunaTextInputBar].
  factory LunaAppBar.empty({
    @required Widget child,
    @required double height,
    EdgeInsets padding = LunaTextInputBar.appBarMargin,
    Alignment alignment = Alignment.topCenter,
  }) {
    assert(child != null);
    assert(height != null);
    return LunaAppBar._internal(
      child: Container(
        child: child,
        height: height,
        padding: padding,
        alignment: alignment,
      ),
      height: height,
      useDrawer: false,
      type: _APPBAR_TYPE.EMPTY,
    );
  }

  /// Create a [lunaAppBar] with the title widget having a dropdown to switch to the supplied list of profiles.
  ///
  /// Will register an onTap gesture for the AppBar if:
  /// - [state] is supplied, and will call [scrollBackList] on the state controller.
  /// - [pageController] and [scrollControllers] are supplied, will register a listener on the page controller and scroll back the respective scroll controller.
  ///
  /// Passing in all 3 will result in state.scrollBackList taking precedence.
  factory LunaAppBar.dropdown({
    @required String title,
    @required List<String> profiles,
    bool useDrawer = true,
    bool hideLeading = false,
    List<Widget> actions,
    PageController pageController,
    List<ScrollController> scrollControllers,
  }) {
    assert(title != null);
    assert(profiles != null);
    if (pageController != null)
      assert(scrollControllers != null,
          'if pageController is defined, scrollControllers should as well.');
    if (profiles == null || profiles.length < 2)
      return LunaAppBar._internal(
        title: title,
        actions: actions,
        useDrawer: useDrawer,
        hideLeading: hideLeading,
        pageController: pageController,
        scrollControllers: scrollControllers,
        type: _APPBAR_TYPE.DEFAULT,
      );
    return LunaAppBar._internal(
      title: title,
      profiles: profiles,
      actions: actions,
      useDrawer: useDrawer,
      hideLeading: hideLeading,
      pageController: pageController,
      scrollControllers: scrollControllers,
      type: _APPBAR_TYPE.DROPDOWN,
    );
  }

  @override
  State<StatefulWidget> createState() => _State();
}

class _State extends State<LunaAppBar> {
  int _index;

  @override
  void initState() {
    _index = widget.pageController?.initialPage ?? 0;
    widget.pageController?.addListener(_pageControllerListener);
    super.initState();
  }

  @override
  void dispose() {
    widget.pageController?.removeListener(_pageControllerListener);
    super.dispose();
  }

  void _pageControllerListener() {
    if ((widget.pageController?.page?.round() ?? _index) == _index) return;
    _index = widget.pageController.page.round();
  }

  void _onTap() {
    try {
      if ((widget.scrollControllers?.isNotEmpty ?? false) &&
          ((widget.scrollControllers.length - 1) >= _index) &&
          (widget.scrollControllers[_index] != null)) {
        widget.scrollControllers[_index]?.lunaAnimateToStart();
      }
    } catch (error, stack) {
      LunaLogger().error(
          'Failed to scroll back: Index: $_index, ScrollControllers: ${widget.scrollControllers?.length ?? 0}',
          error,
          stack);
    }
  }

  @override
  Widget build(BuildContext context) {
    Widget child;
    switch (widget.type) {
      case _APPBAR_TYPE.DEFAULT:
        child = _default(context);
        break;
      case _APPBAR_TYPE.EMPTY:
        child = _empty(context);
        break;
      case _APPBAR_TYPE.DROPDOWN:
        child = _dropdown(context);
        break;
      default:
        throw Exception('Unknown AppBar type.');
    }
    return GestureDetector(
      child: child,
      onTap: _onTap,
    );
  }

  Widget _sharedLeading(BuildContext context) {
    if (widget.hideLeading ?? false) return null;
    if (widget.useDrawer)
      return IconButton(
        icon: const Icon(Icons.menu_rounded),
        onPressed: () async {
          HapticFeedback.lightImpact();
          if (Scaffold.of(context).hasDrawer) {
            Scaffold.of(context).openDrawer();
            FocusManager.instance.primaryFocus?.unfocus();
          }
        },
      );
    return InkWell(
      child: const Center(
        child: Icon(Icons.arrow_back_ios_rounded),
      ),
      onTap: () async {
        HapticFeedback.lightImpact();
        Navigator.of(context).lunaSafetyPop();
      },
      onLongPress: () async {
        HapticFeedback.heavyImpact();
        Navigator.of(context).lunaPopToFirst();
      },
      borderRadius: BorderRadius.circular(28.0),
    );
  }

  Widget _default(BuildContext context) {
    return AppBar(
      title: Text(
        widget.title ?? '',
        overflow: TextOverflow.fade,
        style: const TextStyle(fontSize: LunaUI.FONT_SIZE_APP_BAR),
      ),
      leading: _sharedLeading(context),
      automaticallyImplyLeading: !(widget.hideLeading ?? false),
      centerTitle: false,
      elevation: 0,
      actions: widget.actions,
      bottom: widget.bottom,
    );
  }

  Widget _empty(BuildContext context) {
    return AppBar(
      automaticallyImplyLeading: false,
      toolbarHeight: widget.height,
      leadingWidth: 0.0,
      elevation: 0.0,
      titleSpacing: 0.0,
      title: widget.child,
    );
  }

  Widget _dropdown(BuildContext context) {
    return AppBar(
      title: LunaPopupMenuButton<String>(
        tooltip: 'Change Profiles',
        child: Wrap(
          direction: Axis.horizontal,
          crossAxisAlignment: WrapCrossAlignment.center,
          children: [
            Text(
              widget.title,
              style: const TextStyle(fontSize: LunaUI.FONT_SIZE_HEADER),
            ),
            const Icon(Icons.arrow_drop_down),
          ],
        ),
        onSelected: (result) {
          HapticFeedback.selectionClick();
          LunaProfile().safelyChangeProfiles(result);
        },
        itemBuilder: (context) {
          return <PopupMenuEntry<String>>[
            for (String profile in widget.profiles)
              PopupMenuItem<String>(
                value: profile,
                child: Text(
                  profile,
                  style: TextStyle(
                    fontSize: LunaUI.FONT_SIZE_SUBTITLE,
                    color:
                        (LunaDatabaseValue.ENABLED_PROFILE.data ?? 'default') ==
                                profile
                            ? LunaColours.accent
                            : Colors.white,
                  ),
                ),
              )
          ];
        },
      ),
      leading: _sharedLeading(context),
      centerTitle: false,
      elevation: 0,
      actions: widget.actions,
    );
  }
}