import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';

import '../../models/org_node.dart';
import '../../services/org_service.dart';
import '../../utils/session_org_scope.dart';

/// 组织架构树页：递归树展示、颜色编码、新增/删除/详情。
class OrgTreePage extends ConsumerStatefulWidget {
  const OrgTreePage({super.key});

  @override
  ConsumerState<OrgTreePage> createState() => _OrgTreePageState();
}

class _OrgTreePageState extends ConsumerState<OrgTreePage> {
  final OrgService _orgService = OrgService();

  List<OrgNode> _tree = [];
  bool _loading = false;
  String? _error;
  OrgNode? _selectedNode;

  /// 受限账号（带 orgId 的渠道/代理商等）仅有只读查看权限，隐藏新增/删除等写操作入口。
  bool get _canEdit => !SessionOrgScope.instance.enabled;

  @override
  void initState() {
    super.initState();
    _loadTree();
  }

  Future<void> _loadTree() async {
    setState(() {
      _loading = true;
      _error = null;
    });
    try {
      final tree = await _orgService.getOrgTree();
      if (!mounted) return;
      setState(() {
        _tree = tree;
        _loading = false;
      });
    } catch (e) {
      if (!mounted) return;
      setState(() {
        _error = '$e';
        _loading = false;
      });
    }
  }

  Future<void> _deleteNode(OrgNode node) async {
    final confirmed = await showDialog<bool>(
      context: context,
      builder: (ctx) => AlertDialog(
        title: const Text('删除组织'),
        content: Text('确定要删除「${node.name}」吗？子节点也会一并删除。'),
        actions: [
          TextButton(
            onPressed: () => Navigator.pop(ctx, false),
            child: const Text('取消'),
          ),
          TextButton(
            onPressed: () => Navigator.pop(ctx, true),
            style: TextButton.styleFrom(foregroundColor: Colors.red),
            child: const Text('删除'),
          ),
        ],
      ),
    );
    if (confirmed != true) return;

    try {
      await _orgService.deleteOrg(node.id);
      if (!mounted) return;
      ScaffoldMessenger.of(context).showSnackBar(
        const SnackBar(content: Text('组织已删除')),
      );
      _loadTree();
    } catch (e) {
      if (!mounted) return;
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(content: Text('删除失败：$e')),
      );
    }
  }

  void _showAddSheet({OrgNode? parent}) {
    showModalBottomSheet(
          useSafeArea: true,
      context: context,
      isScrollControlled: true,
      builder: (ctx) => _OrgFormSheet(
        orgService: _orgService,
        parentId: parent?.id,
        parentName: parent?.name,
        onSaved: () {
          Navigator.pop(ctx);
          _loadTree();
        },
      ),
    );
  }

  void _showDetailSheet(OrgNode node) {
    showModalBottomSheet(
          useSafeArea: true,
      context: context,
      isScrollControlled: true,
      builder: (ctx) => _OrgDetailSheet(
        node: node,
        canEdit: _canEdit,
        onAddChild: () {
          Navigator.pop(ctx);
          _showAddSheet(parent: node);
        },
        onDelete: () {
          Navigator.pop(ctx);
          _deleteNode(node);
        },
      ),
    );
  }

  @override
  Widget build(BuildContext context) {
    final canEdit = _canEdit;
    return Scaffold(
      appBar: AppBar(automaticallyImplyLeading: false, title: const Text('组织架构')),
      body: _buildBody(),
      floatingActionButton: canEdit
          ? FloatingActionButton(
              onPressed: () => _showAddSheet(parent: _selectedNode),
              child: const Icon(Icons.add),
            )
          : null,
    );
  }

  Widget _buildBody() {
    final canEdit = _canEdit;
    if (_loading) {
      return const Center(child: CircularProgressIndicator());
    }
    if (_error != null) {
      return Center(
        child: Column(
          mainAxisSize: MainAxisSize.min,
          children: [
            Text('加载失败：$_error'),
            const SizedBox(height: 8),
            FilledButton.tonal(
              onPressed: _loadTree,
              child: const Text('重试'),
            ),
          ],
        ),
      );
    }
    if (_tree.isEmpty) {
      return Center(
        child: Column(
          mainAxisSize: MainAxisSize.min,
          children: [
            Icon(Icons.account_tree_outlined,
                size: 64, color: Theme.of(context).colorScheme.outline),
            const SizedBox(height: 16),
            const Text('暂无组织数据'),
            const SizedBox(height: 8),
            if (canEdit) const Text('点击 + 添加组织'),
          ],
        ),
      );
    }
    return RefreshIndicator(
      onRefresh: _loadTree,
      child: ListView(
        padding: const EdgeInsets.symmetric(vertical: 8),
        physics: const AlwaysScrollableScrollPhysics(),
        children: _tree.map((node) => _buildTreeNode(node, 0)).toList(),
      ),
    );
  }

  Widget _buildTreeNode(OrgNode node, int depth) {
    final hasChildren = node.children.isNotEmpty;
    final typeInfo = _orgTypeInfo(node.type);
    final canEdit = _canEdit;

    if (hasChildren) {
      return ExpansionTile(
        key: ValueKey('org-${node.id}'),
        leading: _typeDot(typeInfo.color),
        title: _nodeTitle(node, typeInfo),
        subtitle: Text('${node.children.length} 个子节点',
            style: const TextStyle(fontSize: 12)),
        children: [
          ...node.children.map((child) => _buildTreeNode(child, depth + 1)),
          if (canEdit)
            Padding(
              padding: const EdgeInsets.only(left: 56, top: 4, bottom: 4),
              child: Align(
                alignment: Alignment.centerLeft,
                child: TextButton.icon(
                  onPressed: () => _showAddSheet(parent: node),
                  icon: const Icon(Icons.add, size: 18),
                  label: const Text('添加子节点'),
                ),
              ),
            ),
        ],
      );
    }

    return ListTile(
      key: ValueKey('org-${node.id}'),
      leading: _typeDot(typeInfo.color),
      title: _nodeTitle(node, typeInfo),
      onLongPress: () => _selectNode(node),
      onTap: () => _showDetailSheet(node),
      trailing: PopupMenuButton<String>(
        onSelected: (value) {
          if (value == 'add') {
            _showAddSheet(parent: node);
          } else if (value == 'detail') {
            _showDetailSheet(node);
          } else if (value == 'delete') {
            _deleteNode(node);
          }
        },
        itemBuilder: (ctx) => [
          if (canEdit)
            const PopupMenuItem(value: 'add', child: Text('添加子节点')),
          const PopupMenuItem(value: 'detail', child: Text('查看详情')),
          if (canEdit)
            const PopupMenuItem(value: 'delete', child: Text('删除')),
        ],
      ),
    );
  }

  void _selectNode(OrgNode node) {
    setState(() => _selectedNode = node);
    ScaffoldMessenger.of(context).showSnackBar(
      SnackBar(content: Text('已选择「${node.name}」为父节点，点击 + 添加子组织')),
    );
  }

  Widget _nodeTitle(OrgNode node, _TypeInfo info) {
    return Row(
      children: [
        Expanded(
          child: Text(
            node.name,
            style: TextStyle(fontWeight: FontWeight.w600),
          ),
        ),
        const SizedBox(width: 8),
        Container(
          padding: const EdgeInsets.symmetric(horizontal: 8, vertical: 2),
          decoration: BoxDecoration(
            color: info.color.withOpacity(0.15),
            borderRadius: BorderRadius.circular(999),
            border: Border.all(color: info.color.withOpacity(0.6)),
          ),
          child: Text(
            info.label,
            style: TextStyle(
              color: info.color,
              fontSize: 11,
              fontWeight: FontWeight.w600,
            ),
          ),
        ),
      ],
    );
  }

  Widget _typeDot(Color color) {
    return Container(
      width: 12,
      height: 12,
      decoration: BoxDecoration(
        color: color,
        shape: BoxShape.circle,
      ),
    );
  }

  _TypeInfo _orgTypeInfo(int type) {
    switch (type) {
      case 0:
        return const _TypeInfo('平台', Colors.purple);
      case 1:
        return const _TypeInfo('渠道', Color(0xFF0B6397)); // 语义信息蓝
      case 2:
        return const _TypeInfo('代理商', Colors.orange);
      case 3:
        return const _TypeInfo('门店', Colors.green);
      case 4:
        return const _TypeInfo('设备分组', Colors.grey);
      default:
        return const _TypeInfo('未知', Colors.grey);
    }
  }
}

class _TypeInfo {
  const _TypeInfo(this.label, this.color);
  final String label;
  final Color color;
}

/// 组织详情底部弹窗。
class _OrgDetailSheet extends StatelessWidget {
  const _OrgDetailSheet({
    required this.node,
    required this.onAddChild,
    required this.onDelete,
    this.canEdit = true,
  });

  final OrgNode node;
  final VoidCallback onAddChild;
  final VoidCallback onDelete;
  final bool canEdit;

  @override
  Widget build(BuildContext context) {
    final theme = Theme.of(context);
    return SingleChildScrollView(
      padding: EdgeInsets.only(
        bottom: MediaQuery.of(context).viewInsets.bottom,
      ),
      child: Container(
        padding: const EdgeInsets.all(20),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          mainAxisSize: MainAxisSize.min,
          children: [
            Text(
              node.name,
              style: theme.textTheme.titleLarge
                  ?.copyWith(fontWeight: FontWeight.bold),
            ),
            const Divider(height: 24),
            _row(theme, '节点ID', node.id),
            _row(theme, '父级ID', node.parentId),
            _row(theme, '地址', node.address),
            _row(theme, '联系电话', node.contactPhone),
            _row(theme, '激活码', node.activationCode),
            const SizedBox(height: 20),
            if (canEdit)
              Row(
                children: [
                  Expanded(
                    child: FilledButton.tonal(
                      onPressed: onAddChild,
                      child: const Text('添加子节点'),
                    ),
                  ),
                  const SizedBox(width: 12),
                  Expanded(
                    child: OutlinedButton(
                      onPressed: onDelete,
                      style: OutlinedButton.styleFrom(
                        foregroundColor: Colors.red,
                      ),
                      child: const Text('删除'),
                    ),
                  ),
                ],
              ),
          ],
        ),
      ),
    );
  }

  Widget _row(ThemeData theme, String label, String value) {
    return Padding(
      padding: const EdgeInsets.symmetric(vertical: 6),
      child: Row(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          SizedBox(
            width: 80,
            child: Text(
              label,
              style: theme.textTheme.bodyMedium
                  ?.copyWith(color: theme.colorScheme.onSurfaceVariant),
            ),
          ),
          Expanded(
            child: Text(value.isEmpty ? '—' : value),
          ),
        ],
      ),
    );
  }
}

/// 新增组织表单。
class _OrgFormSheet extends StatefulWidget {
  const _OrgFormSheet({
    required this.orgService,
    this.parentId,
    this.parentName,
    required this.onSaved,
  });

  final OrgService orgService;
  final String? parentId;
  final String? parentName;
  final VoidCallback onSaved;

  @override
  State<_OrgFormSheet> createState() => _OrgFormSheetState();
}

class _OrgFormSheetState extends State<_OrgFormSheet> {
  final _formKey = GlobalKey<FormState>();
  final _nameController = TextEditingController();
  int _type = 1;
  bool _saving = false;

  static const _typeOptions = [
    _TypeOption(0, '平台'),
    _TypeOption(1, '渠道'),
    _TypeOption(2, '代理商'),
    _TypeOption(3, '门店'),
    _TypeOption(4, '设备分组'),
  ];

  @override
  void dispose() {
    _nameController.dispose();
    super.dispose();
  }

  Future<void> _save() async {
    if (!_formKey.currentState!.validate()) return;
    setState(() => _saving = true);
    try {
      final data = <String, dynamic>{
        'name': _nameController.text.trim(),
        'type': _type,
        'parentId': widget.parentId ?? '',
      };
      await widget.orgService.saveOrUpdateOrg(data);
      if (!mounted) return;
      ScaffoldMessenger.of(context).showSnackBar(
        const SnackBar(content: Text('组织已创建')),
      );
      widget.onSaved();
    } catch (e) {
      if (!mounted) return;
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(content: Text('保存失败：$e')),
      );
    } finally {
      if (mounted) setState(() => _saving = false);
    }
  }

  @override
  Widget build(BuildContext context) {
    return SingleChildScrollView(
      padding: EdgeInsets.only(
        bottom: MediaQuery.of(context).viewInsets.bottom,
      ),
      child: Container(
        padding: const EdgeInsets.all(20),
        child: Form(
          key: _formKey,
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            mainAxisSize: MainAxisSize.min,
            children: [
              Text(
                '新增组织',
                style: Theme.of(context)
                    .textTheme
                    .titleLarge
                    ?.copyWith(fontWeight: FontWeight.bold),
              ),
              if (widget.parentName != null) ...[
                const SizedBox(height: 8),
                Text(
                  '父级组织：${widget.parentName}',
                  style: TextStyle(
                    color: Theme.of(context).colorScheme.onSurfaceVariant,
                    fontSize: 13,
                  ),
                ),
              ],
              const SizedBox(height: 20),
              TextFormField(
                controller: _nameController,
                decoration: const InputDecoration(
                  labelText: '组织名称',
                  border: OutlineInputBorder(),
                  prefixIcon: Icon(Icons.label),
                ),
                validator: (v) =>
                    v == null || v.trim().isEmpty ? '请输入组织名称' : null,
              ),
              const SizedBox(height: 12),
              DropdownButtonFormField<int>(
                value: _type,
                decoration: const InputDecoration(
                  labelText: '组织类型',
                  border: OutlineInputBorder(),
                  prefixIcon: Icon(Icons.category),
                ),
                items: _typeOptions
                    .map((opt) => DropdownMenuItem(
                          value: opt.type,
                          child: Text(opt.label),
                        ))
                    .toList(),
                onChanged: (v) {
                  if (v != null) setState(() => _type = v);
                },
              ),
              const SizedBox(height: 24),
              SizedBox(
                width: double.infinity,
                child: FilledButton(
                  onPressed: _saving ? null : _save,
                  child: _saving
                      ? const SizedBox(
                          height: 20,
                          width: 20,
                          child: CircularProgressIndicator(strokeWidth: 2),
                        )
                      : const Text('创建'),
                ),
              ),
            ],
          ),
        ),
      ),
    );
  }
}

class _TypeOption {
  const _TypeOption(this.type, this.label);
  final int type;
  final String label;
}