import 'package:flutter/material.dart';

import '../models/session.dart';
import '../theme/app_theme.dart';

/// Side drawer showing session list with reordering, unread badges, and controls.
class SessionDrawer extends StatelessWidget {
  final List<Session> sessions;
  final String? activeSessionId;
  final Map<String, int> unreadCounts;
  final void Function(Session session) onSelect;
  final void Function(Session session) onRemove;
  final void Function(Session session, String newName) onRename;
  final void Function(int oldIndex, int newIndex) onReorder;
  final VoidCallback onNewSession;
  final VoidCallback onRefresh;

  const SessionDrawer({
    super.key,
    required this.sessions,
    required this.activeSessionId,
    required this.unreadCounts,
    required this.onSelect,
    required this.onRemove,
    required this.onRename,
    required this.onReorder,
    required this.onNewSession,
    required this.onRefresh,
  });

  @override
  Widget build(BuildContext context) {
    final isDark = Theme.of(context).brightness == Brightness.dark;

    return Drawer(
      child: SafeArea(
        child: Column(
          children: [
            // Header
            Padding(
              padding:
                  const EdgeInsets.symmetric(horizontal: 16, vertical: 12),
              child: Row(
                mainAxisAlignment: MainAxisAlignment.spaceBetween,
                children: [
                  Text(
                    'Sessions',
                    style: Theme.of(context).textTheme.titleLarge,
                  ),
                  IconButton(
                    icon: const Icon(Icons.refresh, size: 22),
                    onPressed: onRefresh,
                    tooltip: 'Refresh sessions',
                  ),
                ],
              ),
            ),
            const Divider(height: 1),
            // Session list
            Expanded(
              child: sessions.isEmpty
                  ? const Center(
                      child: Text(
                        'No sessions',
                        style: TextStyle(color: AppColors.darkTextTertiary),
                      ),
                    )
                  : ReorderableListView.builder(
                      itemCount: sessions.length,
                      onReorder: onReorder,
                      buildDefaultDragHandles: false,
                      itemBuilder: (context, index) {
                        final session = sessions[index];
                        final isActive = session.id == activeSessionId;
                        final unread = unreadCounts[session.id] ?? 0;

                        return Dismissible(
                          key: ValueKey(session.id),
                          direction: DismissDirection.endToStart,
                          background: Container(
                            color: AppColors.error,
                            alignment: Alignment.centerRight,
                            padding: const EdgeInsets.only(right: 16),
                            child: const Icon(Icons.delete,
                                color: Colors.white),
                          ),
                          confirmDismiss: (_) async {
                            return await showDialog<bool>(
                              context: context,
                              builder: (ctx) => AlertDialog(
                                title: const Text('Remove session?'),
                                content: Text(
                                    'Remove "${session.name}" from the list?'),
                                actions: [
                                  TextButton(
                                    onPressed: () =>
                                        Navigator.pop(ctx, false),
                                    child: const Text('Cancel'),
                                  ),
                                  TextButton(
                                    onPressed: () =>
                                        Navigator.pop(ctx, true),
                                    child: const Text('Remove',
                                        style: TextStyle(
                                            color: AppColors.error)),
                                  ),
                                ],
                              ),
                            );
                          },
                          onDismissed: (_) => onRemove(session),
                          child: ListTile(
                            key: ValueKey('tile_${session.id}'),
                            leading: Text(
                              session.icon,
                              style: const TextStyle(fontSize: 20),
                            ),
                            title: GestureDetector(
                              onDoubleTap: () =>
                                  _showRenameDialog(context, session),
                              child: Text(
                                session.name,
                                style: TextStyle(
                                  fontWeight: isActive
                                      ? FontWeight.bold
                                      : FontWeight.normal,
                                  color: isActive ? AppColors.accent : null,
                                ),
                                maxLines: 1,
                                overflow: TextOverflow.ellipsis,
                              ),
                            ),
                            trailing: Row(
                              mainAxisSize: MainAxisSize.min,
                              children: [
                                if (unread > 0)
                                  Container(
                                    padding: const EdgeInsets.symmetric(
                                        horizontal: 6, vertical: 2),
                                    decoration: BoxDecoration(
                                      color: AppColors.unreadBadge,
                                      borderRadius:
                                          BorderRadius.circular(10),
                                    ),
                                    child: Text(
                                      '$unread',
                                      style: const TextStyle(
                                        color: Colors.white,
                                        fontSize: 11,
                                        fontWeight: FontWeight.bold,
                                      ),
                                    ),
                                  ),
                                const SizedBox(width: 4),
                                ReorderableDragStartListener(
                                  index: index,
                                  child: Icon(
                                    Icons.drag_handle,
                                    color: isDark
                                        ? AppColors.darkTextTertiary
                                        : Colors.grey.shade400,
                                    size: 20,
                                  ),
                                ),
                              ],
                            ),
                            selected: isActive,
                            selectedTileColor: isDark
                                ? Colors.white.withAlpha(10)
                                : Colors.blue.withAlpha(15),
                            onTap: () {
                              onSelect(session);
                              Navigator.pop(context);
                            },
                          ),
                        );
                      },
                    ),
            ),
            // New session button
            const Divider(height: 1),
            Padding(
              padding: const EdgeInsets.all(12),
              child: SizedBox(
                width: double.infinity,
                child: ElevatedButton.icon(
                  onPressed: onNewSession,
                  icon: const Icon(Icons.add, size: 20),
                  label: const Text('New Session'),
                  style: ElevatedButton.styleFrom(
                    backgroundColor: AppColors.accent,
                    foregroundColor: Colors.white,
                  ),
                ),
              ),
            ),
          ],
        ),
      ),
    );
  }

  void _showRenameDialog(BuildContext context, Session session) {
    final controller = TextEditingController(text: session.name);
    showDialog(
      context: context,
      builder: (ctx) => AlertDialog(
        title: const Text('Rename session'),
        content: TextField(
          controller: controller,
          autofocus: true,
          decoration: const InputDecoration(hintText: 'Session name'),
          onSubmitted: (value) {
            if (value.isNotEmpty) {
              onRename(session, value);
            }
            Navigator.pop(ctx);
          },
        ),
        actions: [
          TextButton(
            onPressed: () => Navigator.pop(ctx),
            child: const Text('Cancel'),
          ),
          TextButton(
            onPressed: () {
              if (controller.text.isNotEmpty) {
                onRename(session, controller.text);
              }
              Navigator.pop(ctx);
            },
            child: const Text('Save'),
          ),
        ],
      ),
    ).then((_) => controller.dispose());
  }
}