the-mews/app/lib/presentation/reader/address_bar.dart

import 'package:flutter/foundation.dart'
    show defaultTargetPlatform, TargetPlatform;
import 'package:flutter/material.dart';
import 'package:signals/signals_flutter.dart' show SignalBuilder;

import '../../application/pages/mews_urls.dart';
import '../app.dart';

/// The single-field address bar. The left icon opens the hub and, on pointer
/// platforms, carries the back and forward buttons; the right icons reload,
/// subscribe (only when the page offers something to subscribe to) and
/// bookmark the current page.
class AddressBar extends StatefulWidget {
  const AddressBar({this.focusNode, super.key});

  /// The reader can ask for the field's focus from outside, for a keyboard
  /// shortcut. When null the bar owns its own node.
  final FocusNode? focusNode;

  @override
  State<AddressBar> createState() => _AddressBarState();
}

class _AddressBarState extends State<AddressBar> {
  final _controller = TextEditingController();
  late final FocusNode _focus = widget.focusNode ?? FocusNode();
  bool _focused = false;

  @override
  void initState() {
    super.initState();
    _focus.addListener(_onFocusChange);
  }

  void _onFocusChange() {
    if (_focus.hasFocus != _focused) {
      setState(() => _focused = _focus.hasFocus);
      if (_focused) {
        _controller.selection = TextSelection(
          baseOffset: 0,
          extentOffset: _controller.text.length,
        );
      }
    }
  }

  @override
  void dispose() {
    _focus.removeListener(_onFocusChange);
    // A focus node handed in from outside belongs to whoever handed it in.
    if (widget.focusNode == null) _focus.dispose();
    _controller.dispose();
    super.dispose();
  }

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

    return SignalBuilder(
      builder: (context) {
        final page = deps.browser.currentPage.value;
        final url = page?.url;
        if (url != null && !_focused) {
          _controller.text = url;
        }

        // Touch devices navigate with swipes; desktops get buttons.
        final hasButtons = switch (defaultTargetPlatform) {
          TargetPlatform.linux ||
          TargetPlatform.windows ||
          TargetPlatform.macOS => true,
          _ => false,
        };

        // Only pages with dated entry links or an Atom feed can be subscribed
        // to (mews spec, section 6).
        final canSubscribe =
            page != null &&
            !MewsUrls.isInternal(page.url) &&
            (page.atomFeedHref != null || page.entries.isNotEmpty);
        final canBookmark = page != null && !MewsUrls.isInternal(page.url);

        // One button, two layouts: on pointer platforms it sits beside the
        // back and forward buttons.
        final hubButton = IconButton(
          icon: const Icon(Icons.menu),
          tooltip: strings.t('reader-open-hub'),
          onPressed: () => deps.browser.open(MewsUrls.hub),
        );

        return Padding(
          padding: const EdgeInsets.fromLTRB(8, 8, 8, 4),
          // The label is for screen readers only: the placeholder is what a
          // sighted reader sees, and a visible labelText would repeat it.
          child: Semantics(
            label: strings.t('reader-address-label'),
            textField: true,
            child: TextField(
              controller: _controller,
              focusNode: _focus,
              autofocus: false,
              keyboardType: TextInputType.url,
              textInputAction: TextInputAction.go,
              autocorrect: false,
              enableSuggestions: false,
              onSubmitted: (value) {
                _focus.unfocus();
                deps.browser.open(value);
              },
              decoration: InputDecoration(
                hintText: strings.t('reader-address-placeholder'),
                isDense: true,
                border: const OutlineInputBorder(),
                prefixIcon: hasButtons
                    ? Row(
                        mainAxisSize: MainAxisSize.min,
                        children: [
                          hubButton,
                          IconButton(
                            icon: const Icon(Icons.arrow_back),
                            tooltip: strings.t('reader-back'),
                            onPressed: deps.browser.canGoBack
                                ? deps.browser.back
                                : null,
                          ),
                          IconButton(
                            icon: const Icon(Icons.arrow_forward),
                            tooltip: strings.t('reader-forward'),
                            onPressed: deps.browser.canGoForward
                                ? deps.browser.forward
                                : null,
                          ),
                        ],
                      )
                    : hubButton,
                prefixIconConstraints: hasButtons
                    ? const BoxConstraints(minWidth: 138, minHeight: 48)
                    : null,
                suffixIcon: Row(
                  mainAxisSize: MainAxisSize.min,
                  children: [
                    IconButton(
                      icon: const Icon(Icons.refresh),
                      tooltip: strings.t('reader-reload'),
                      onPressed: () => deps.browser.reload(),
                    ),
                    if (canSubscribe)
                      IconButton(
                        icon: Icon(
                          deps.subscriptions.isSubscribed(page.url)
                              ? Icons.notifications_active
                              : Icons.notifications_outlined,
                        ),
                        tooltip: deps.subscriptions.isSubscribed(page.url)
                            ? strings.t('reader-unsubscribe')
                            : strings.t('reader-subscribe'),
                        onPressed: () => deps.subscriptions.toggle(page),
                      ),
                    if (canBookmark)
                      IconButton(
                        icon: Icon(
                          deps.bookmarks.isBookmarked(page.url)
                              ? Icons.star
                              : Icons.star_border,
                        ),
                        tooltip: deps.bookmarks.isBookmarked(page.url)
                            ? strings.t('reader-bookmark-remove')
                            : strings.t('reader-bookmark-add'),
                        onPressed: () =>
                            deps.bookmarks.toggle(page.url, page.title),
                      ),
                  ],
                ),
              ),
            ),
          ),
        );
      },
    );
  }
}