packages/flutter/lib/src/material/user_accounts_drawer_header.dart

// Copyright 2015 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

import 'package:flutter/foundation.dart';
import 'package:flutter/widgets.dart';

import 'colors.dart';
import 'debug.dart';
import 'drawer_header.dart';
import 'icons.dart';
import 'ink_well.dart';
import 'theme.dart';

class _AccountPictures extends StatelessWidget {
  const _AccountPictures({
    Key key,
    this.currentAccountPicture,
    this.otherAccountsPictures,
  }) : super(key: key);

  final Widget currentAccountPicture;
  final List<Widget> otherAccountsPictures;

  @override
  Widget build(BuildContext context) {
    return new Stack(
      children: <Widget>[
        new PositionedDirectional(
          top: 0.0,
          end: 0.0,
          child: new Row(
            children: (otherAccountsPictures ?? <Widget>[]).take(3).map((Widget picture) {
              return new Container(
                margin: const EdgeInsetsDirectional.only(start: 16.0),
                width: 40.0,
                height: 40.0,
                child: picture
              );
            }).toList(),
          ),
        ),
        new Positioned(
          top: 0.0,
          child: new SizedBox(
            width: 72.0,
            height: 72.0,
            child: currentAccountPicture
          ),
        ),
      ],
    );
  }
}

class _AccountDetails extends StatelessWidget {
  const _AccountDetails({
    Key key,
    @required this.accountName,
    @required this.accountEmail,
    this.onTap,
    this.isOpen,
  }) : super(key: key);

  final Widget accountName;
  final Widget accountEmail;
  final VoidCallback onTap;
  final bool isOpen;

  Widget addDropdownIcon(Widget line) {
    final Widget icon = new Expanded(
      child: new Align(
        alignment: AlignmentDirectional.centerEnd,
        child: new Icon(
          isOpen ? Icons.arrow_drop_up : Icons.arrow_drop_down,
          color: Colors.white
        ),
      ),
    );
    return new Row(
      crossAxisAlignment: CrossAxisAlignment.center,
      children: line == null ? <Widget>[icon] : <Widget>[line, icon],
    );
  }

  @override
  Widget build(BuildContext context) {
    final ThemeData theme = Theme.of(context);
    Widget accountNameLine = accountName == null ? null : new DefaultTextStyle(
      style: theme.primaryTextTheme.body2,
      child: accountName,
    );
    Widget accountEmailLine = accountEmail == null ? null : new DefaultTextStyle(
      style: theme.primaryTextTheme.body1,
      child: accountEmail,
    );
    if (onTap != null) {
      if (accountEmailLine != null)
        accountEmailLine = addDropdownIcon(accountEmailLine);
      else
        accountNameLine = addDropdownIcon(accountNameLine);
    }

    Widget accountDetails;
    if (accountEmailLine != null || accountNameLine != null) {
      accountDetails = new Padding(
        padding: const EdgeInsets.symmetric(vertical: 8.0),
        child: new Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          mainAxisAlignment: MainAxisAlignment.spaceEvenly,
          children: (accountEmailLine != null && accountNameLine != null)
            ? <Widget>[accountNameLine, accountEmailLine]
            : <Widget>[accountNameLine ?? accountEmailLine]
        ),
      );
    }

    if (onTap != null)
      accountDetails = new InkWell(onTap: onTap, child: accountDetails);

    return new SizedBox(
      height: 56.0,
      child: accountDetails,
    );
  }
}

/// A material design [Drawer] header that identifies the app's user.
///
/// Requires one of its ancestors to be a [Material] widget.
///
/// See also:
///
///  * [DrawerHeader], for a drawer header that doesn't show user accounts
///  * <https://material.google.com/patterns/navigation-drawer.html>
class UserAccountsDrawerHeader extends StatefulWidget {
  /// Creates a material design drawer header.
  ///
  /// Requires one of its ancestors to be a [Material] widget.
  const UserAccountsDrawerHeader({
    Key key,
    this.decoration,
    this.margin: const EdgeInsets.only(bottom: 8.0),
    this.currentAccountPicture,
    this.otherAccountsPictures,
    @required this.accountName,
    @required this.accountEmail,
    this.onDetailsPressed
  }) : super(key: key);

  /// The header's background. If decoration is null then a [BoxDecoration]
  /// with its background color set to the current theme's primaryColor is used.
  final Decoration decoration;

  /// The margin around the drawer header.
  final EdgeInsetsGeometry margin;

  /// A widget placed in the upper-left corner that represents the current
  /// user's account. Normally a [CircleAvatar].
  final Widget currentAccountPicture;

  /// A list of widgets that represent the current user's other accounts.
  /// Up to three of these widgets will be arranged in a row in the header's
  /// upper-right corner. Normally a list of [CircleAvatar] widgets.
  final List<Widget> otherAccountsPictures;

  /// A widget that represents the user's current account name. It is
  /// displayed on the left, below the [currentAccountPicture].
  final Widget accountName;

  /// A widget that represents the email address of the user's current account.
  /// It is displayed on the left, below the [accountName].
  final Widget accountEmail;

  /// A callback that is called when the horizontal area which contains the
  /// [accountName] and [accountEmail] is tapped.
  final VoidCallback onDetailsPressed;

  @override
  _UserAccountsDrawerHeaderState createState() => new _UserAccountsDrawerHeaderState();
}

class _UserAccountsDrawerHeaderState extends State<UserAccountsDrawerHeader> {
  bool _isOpen = false;

  void _handleDetailsPressed() {
    setState(() {
      _isOpen = !_isOpen;
    });
    widget.onDetailsPressed();
  }

  @override
  Widget build(BuildContext context) {
    assert(debugCheckHasMaterial(context));
    return new DrawerHeader(
      decoration: widget.decoration ?? new BoxDecoration(
        color: Theme.of(context).primaryColor,
      ),
      margin: widget.margin,
      child: new Column(
        crossAxisAlignment: CrossAxisAlignment.stretch,
        children: <Widget>[
          new Expanded(
            child: new _AccountPictures(
              currentAccountPicture: widget.currentAccountPicture,
              otherAccountsPictures: widget.otherAccountsPictures,
            )
          ),
          new _AccountDetails(
            accountName: widget.accountName,
            accountEmail: widget.accountEmail,
            isOpen: _isOpen,
            onTap: widget.onDetailsPressed == null ? null : _handleDetailsPressed,
          ),
        ],
      ),
    );
  }
}