ai_english/client/lib/shared/widgets/custom_app_bar.dart

import 'package:flutter/material.dart';

/// 自定义应用栏
class CustomAppBar extends StatelessWidget implements PreferredSizeWidget {
  final String title;
  final List<Widget>? actions;
  final Widget? leading;
  final bool centerTitle;
  final Color? backgroundColor;
  final Color? foregroundColor;
  final double elevation;
  final bool automaticallyImplyLeading;
  final PreferredSizeWidget? bottom;
  final VoidCallback? onBackPressed;

  const CustomAppBar({
    super.key,
    required this.title,
    this.actions,
    this.leading,
    this.centerTitle = true,
    this.backgroundColor,
    this.foregroundColor,
    this.elevation = 0,
    this.automaticallyImplyLeading = true,
    this.bottom,
    this.onBackPressed,
  });

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);
    
    return AppBar(
      title: Text(
        title,
        style: theme.textTheme.titleLarge?.copyWith(
          fontWeight: FontWeight.w600,
          color: foregroundColor ?? theme.colorScheme.onSurface,
        ),
      ),
      centerTitle: centerTitle,
      backgroundColor: backgroundColor ?? theme.colorScheme.surface,
      foregroundColor: foregroundColor ?? theme.colorScheme.onSurface,
      elevation: elevation,
      automaticallyImplyLeading: automaticallyImplyLeading,
      leading: leading ?? (onBackPressed != null 
        ? IconButton(
            icon: const Icon(Icons.arrow_back_ios),
            onPressed: onBackPressed,
          )
        : null),
      actions: actions,
      bottom: bottom,
      surfaceTintColor: Colors.transparent,
    );
  }

  @override
  Size get preferredSize => Size.fromHeight(
    kToolbarHeight + (bottom?.preferredSize.height ?? 0.0),
  );
}

/// 带搜索功能的应用栏
class SearchAppBar extends StatefulWidget implements PreferredSizeWidget {
  final String title;
  final String hintText;
  final ValueChanged<String>? onSearchChanged;
  final VoidCallback? onSearchSubmitted;
  final List<Widget>? actions;
  final bool automaticallyImplyLeading;
  final VoidCallback? onBackPressed;

  const SearchAppBar({
    super.key,
    required this.title,
    this.hintText = '搜索...',
    this.onSearchChanged,
    this.onSearchSubmitted,
    this.actions,
    this.automaticallyImplyLeading = true,
    this.onBackPressed,
  });

  @override
  State<SearchAppBar> createState() => _SearchAppBarState();

  @override
  Size get preferredSize => const Size.fromHeight(kToolbarHeight);
}

class _SearchAppBarState extends State<SearchAppBar> {
  bool _isSearching = false;
  final TextEditingController _searchController = TextEditingController();
  final FocusNode _searchFocusNode = FocusNode();

  @override
  void dispose() {
    _searchController.dispose();
    _searchFocusNode.dispose();
    super.dispose();
  }

  void _startSearch() {
    setState(() {
      _isSearching = true;
    });
    _searchFocusNode.requestFocus();
  }

  void _stopSearch() {
    setState(() {
      _isSearching = false;
      _searchController.clear();
    });
    _searchFocusNode.unfocus();
    widget.onSearchChanged?.call('');
  }

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);
    
    return AppBar(
      title: _isSearching
          ? TextField(
              controller: _searchController,
              focusNode: _searchFocusNode,
              decoration: InputDecoration(
                hintText: widget.hintText,
                border: InputBorder.none,
                hintStyle: theme.textTheme.bodyLarge?.copyWith(
                  color: theme.colorScheme.onSurface.withOpacity(0.6),
                ),
              ),
              style: theme.textTheme.bodyLarge,
              onChanged: widget.onSearchChanged,
              onSubmitted: (_) => widget.onSearchSubmitted?.call(),
            )
          : Text(
              widget.title,
              style: theme.textTheme.titleLarge?.copyWith(
                fontWeight: FontWeight.w600,
              ),
            ),
      centerTitle: !_isSearching,
      backgroundColor: theme.colorScheme.surface,
      foregroundColor: theme.colorScheme.onSurface,
      elevation: 0,
      automaticallyImplyLeading: widget.automaticallyImplyLeading && !_isSearching,
      leading: _isSearching
          ? IconButton(
              icon: const Icon(Icons.arrow_back),
              onPressed: _stopSearch,
            )
          : (widget.onBackPressed != null
              ? IconButton(
                  icon: const Icon(Icons.arrow_back_ios),
                  onPressed: widget.onBackPressed,
                )
              : null),
      actions: _isSearching
          ? [
              IconButton(
                icon: const Icon(Icons.clear),
                onPressed: () {
                  _searchController.clear();
                  widget.onSearchChanged?.call('');
                },
              ),
            ]
          : [
              IconButton(
                icon: const Icon(Icons.search),
                onPressed: _startSearch,
              ),
              ...?widget.actions,
            ],
      surfaceTintColor: Colors.transparent,
    );
  }
}

/// 带标签页的应用栏
class TabAppBar extends StatelessWidget implements PreferredSizeWidget {
  final String title;
  final List<Tab> tabs;
  final TabController? controller;
  final List<Widget>? actions;
  final bool automaticallyImplyLeading;
  final VoidCallback? onBackPressed;

  const TabAppBar({
    super.key,
    required this.title,
    required this.tabs,
    this.controller,
    this.actions,
    this.automaticallyImplyLeading = true,
    this.onBackPressed,
  });

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);
    
    return AppBar(
      title: Text(
        title,
        style: theme.textTheme.titleLarge?.copyWith(
          fontWeight: FontWeight.w600,
        ),
      ),
      centerTitle: true,
      backgroundColor: theme.colorScheme.surface,
      foregroundColor: theme.colorScheme.onSurface,
      elevation: 0,
      automaticallyImplyLeading: automaticallyImplyLeading,
      leading: onBackPressed != null
          ? IconButton(
              icon: const Icon(Icons.arrow_back_ios),
              onPressed: onBackPressed,
            )
          : null,
      actions: actions,
      bottom: TabBar(
        controller: controller,
        tabs: tabs,
        labelColor: theme.colorScheme.primary,
        unselectedLabelColor: theme.colorScheme.onSurface.withOpacity(0.6),
        indicatorColor: theme.colorScheme.primary,
        indicatorWeight: 2,
        labelStyle: theme.textTheme.titleSmall?.copyWith(
          fontWeight: FontWeight.w600,
        ),
        unselectedLabelStyle: theme.textTheme.titleSmall,
      ),
      surfaceTintColor: Colors.transparent,
    );
  }

  @override
  Size get preferredSize => const Size.fromHeight(kToolbarHeight + kTextTabBarHeight);
}