import 'package:flutter/material.dart';

import '../../core/models/email.dart';
import '../app_state.dart';

/// 文件夹树（一个账户）
class FolderTree extends StatelessWidget {
  final int accountId;
  final List<MailFolder> folders;
  final String? selected;
  final ValueChanged<String> onSelect;

  const FolderTree({
    super.key,
    required this.accountId,
    required this.folders,
    required this.selected,
    required this.onSelect,
  });

  @override
  Widget build(BuildContext context) {
    // 排序: INBOX 最前, 然后按类型
    final sorted = [...folders]..sort((a, b) {
        final ra = _rank(a);
        final rb = _rank(b);
        if (ra != rb) return ra.compareTo(rb);
        return a.name.toLowerCase().compareTo(b.name.toLowerCase());
      });

    return ListView.builder(
      padding: const EdgeInsets.symmetric(vertical: 4),
      itemCount: sorted.length,
      itemBuilder: (context, i) {
        final f = sorted[i];
        final unread = AppState.instance.unreadByFolder[accountId]?[f.name] ?? 0;
        final isSel = f.name == selected;
        return _FolderTile(
          folder: f,
          unread: unread,
          selected: isSel,
          onTap: () => onSelect(f.name),
        );
      },
    );
  }

  int _rank(MailFolder f) {
    switch (f.kind) {
      case 'inbox':
        return 0;
      case 'starred':
        return 1;
      case 'sent':
        return 2;
      case 'drafts':
        return 3;
      case 'junk':
        return 4;
      case 'trash':
        return 5;
      default:
        return 6;
    }
  }
}

class _FolderTile extends StatelessWidget {
  final MailFolder folder;
  final int unread;
  final bool selected;
  final VoidCallback onTap;

  const _FolderTile({
    required this.folder,
    required this.unread,
    required this.selected,
    required this.onTap,
  });

  @override
  Widget build(BuildContext context) {
    final scheme = Theme.of(context).colorScheme;
    final icon = _iconFor(folder);
    final label = _labelFor(folder);

    return Material(
      color: selected ? scheme.primaryContainer.withValues(alpha: 0.6) : Colors.transparent,
      borderRadius: BorderRadius.circular(8),
      child: InkWell(
        borderRadius: BorderRadius.circular(8),
        onTap: onTap,
        child: Padding(
          padding: const EdgeInsets.symmetric(horizontal: 10, vertical: 7),
          child: Row(
            children: [
              Icon(icon, size: 17, color: selected ? scheme.primary : scheme.onSurfaceVariant),
              const SizedBox(width: 8),
              Expanded(
                child: Text(
                  label,
                  overflow: TextOverflow.ellipsis,
                  style: TextStyle(
                    fontSize: 13.5,
                    fontWeight: selected ? FontWeight.w600 : FontWeight.w400,
                    color: selected ? scheme.primary : scheme.onSurface,
                  ),
                ),
              ),
              if (unread > 0)
                Container(
                  padding: const EdgeInsets.symmetric(horizontal: 7, vertical: 2),
                  decoration: BoxDecoration(
                    color: scheme.primary,
                    borderRadius: BorderRadius.circular(10),
                  ),
                  child: Text(
                    unread > 999 ? '999+' : '$unread',
                    style: TextStyle(fontSize: 11, color: scheme.onPrimary),
                  ),
                ),
            ],
          ),
        ),
      ),
    );
  }

  IconData _iconFor(MailFolder f) {
    switch (f.kind) {
      case 'inbox':
        return Icons.inbox_outlined;
      case 'starred':
        return Icons.star_outline;
      case 'sent':
        return Icons.send_outlined;
      case 'drafts':
        return Icons.edit_outlined;
      case 'junk':
        return Icons.report_gmailerrorred_outlined;
      case 'trash':
        return Icons.delete_outline;
      default:
        return Icons.folder_outlined;
    }
  }

  String _labelFor(MailFolder f) {
    // 取路径最后一段
    final parts = f.name.split(f.delim);
    final last = parts.last;
    switch (last.toUpperCase()) {
      case 'INBOX':
        return '收件箱';
      case 'SENT':
      case 'SENT ITEMS':
      case '已发送':
        return '已发送';
      case 'DRAFTS':
      case '草稿':
      case '草稿箱':
        return '草稿箱';
      case 'TRASH':
      case 'DELETED ITEMS':
      case '已删除':
        return '已删除';
      case 'SPAM':
      case 'JUNK':
      case '垃圾邮件':
        return '垃圾邮件';
      case 'STARRED':
      case '星标':
        return '星标邮件';
      default:
        return last;
    }
  }
}