import 'package:flutter/material.dart';
import 'package:provider/provider.dart';
import 'package:superport/screens/common/theme_shadcn.dart';
import 'package:superport/utils/constants.dart';
import 'package:superport/utils/validators.dart';
import 'package:flutter/services.dart';
import 'package:superport/screens/user/controllers/user_form_controller.dart';
import 'package:superport/models/user_model.dart';

// 사용자 등록/수정 화면 (UI만 담당, 상태/로직 분리)
class UserFormScreen extends StatefulWidget {
  final int? userId;
  const UserFormScreen({super.key, this.userId});

  @override
  State<UserFormScreen> createState() => _UserFormScreenState();
}

class _UserFormScreenState extends State<UserFormScreen> {
  final TextEditingController _passwordController = TextEditingController();
  final TextEditingController _confirmPasswordController = TextEditingController();
  bool _showPassword = false;
  bool _showConfirmPassword = false;

  @override
  void dispose() {
    _passwordController.dispose();
    _confirmPasswordController.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return ChangeNotifierProvider(
      create: (_) => UserFormController(
        userId: widget.userId,
      ),
      child: Consumer<UserFormController>(
        builder: (context, controller, child) {
          return Scaffold(
            appBar: AppBar(
              title: Text(controller.isEditMode ? '사용자 수정' : '사용자 등록'),
            ),
            body: controller.isLoading
                ? const Center(child: CircularProgressIndicator())
                : Padding(
                    padding: const EdgeInsets.all(16.0),
                    child: Form(
                      key: controller.formKey,
                      child: SingleChildScrollView(
                        child: Column(
                          crossAxisAlignment: CrossAxisAlignment.start,
                          children: [
                            // 이름 (*필수)
                            _buildTextField(
                              label: '이름 *',
                              initialValue: controller.name,
                              hintText: '사용자 이름을 입력하세요',
                              validator: (value) => validateRequired(value, '이름'),
                              onSaved: (value) => controller.name = value!,
                            ),
                            
                            // 사용자명 (신규 등록 시만)
                            if (!controller.isEditMode) ...[                              
                              _buildTextField(
                                label: '사용자명 *',
                                initialValue: controller.username,
                                hintText: '로그인에 사용할 사용자명 (3자 이상)',
                                validator: (value) {
                                  if (value == null || value.isEmpty) {
                                    return '사용자명을 입력해주세요';
                                  }
                                  if (value.length < 3) {
                                    return '사용자명은 3자 이상이어야 합니다';
                                  }
                                  if (controller.isUsernameAvailable == false) {
                                    return '이미 사용 중인 사용자명입니다';
                                  }
                                  return null;
                                },
                                onChanged: (value) {
                                  controller.username = value;
                                  controller.checkUsernameAvailability(value);
                                },
                                onSaved: (value) => controller.username = value!,
                                suffixIcon: controller.isCheckingUsername
                                    ? const SizedBox(
                                        width: 20,
                                        height: 20,
                                        child: Padding(
                                          padding: EdgeInsets.all(12.0),
                                          child: CircularProgressIndicator(
                                            strokeWidth: 2,
                                          ),
                                        ),
                                      )
                                    : controller.isUsernameAvailable != null
                                        ? Icon(
                                            controller.isUsernameAvailable!
                                                ? Icons.check_circle
                                                : Icons.cancel,
                                            color: controller.isUsernameAvailable!
                                                ? Colors.green
                                                : Colors.red,
                                          )
                                        : null,
                              ),
                              
                              // 비밀번호 (*필수)
                              _buildPasswordField(
                                label: '비밀번호 *',
                                controller: _passwordController,
                                hintText: '비밀번호를 입력하세요 (6자 이상)',
                                obscureText: !_showPassword,
                                onToggleVisibility: () {
                                  setState(() {
                                    _showPassword = !_showPassword;
                                  });
                                },
                                validator: (value) {
                                  if (value == null || value.isEmpty) {
                                    return '비밀번호를 입력해주세요';
                                  }
                                  if (value.length < 6) {
                                    return '비밀번호는 6자 이상이어야 합니다';
                                  }
                                  return null;
                                },
                                onSaved: (value) => controller.password = value!,
                              ),
                              
                              // 비밀번호 확인
                              _buildPasswordField(
                                label: '비밀번호 확인',
                                controller: _confirmPasswordController,
                                hintText: '비밀번호를 다시 입력하세요',
                                obscureText: !_showConfirmPassword,
                                onToggleVisibility: () {
                                  setState(() {
                                    _showConfirmPassword = !_showConfirmPassword;
                                  });
                                },
                                validator: (value) {
                                  if (value == null || value.isEmpty) {
                                    return '비밀번호를 다시 입력해주세요';
                                  }
                                  if (value != _passwordController.text) {
                                    return '비밀번호가 일치하지 않습니다';
                                  }
                                  return null;
                                },
                              ),
                            ],
                            
                            // 수정 모드에서 비밀번호 변경 (선택사항)
                            if (controller.isEditMode) ...[                              
                              ExpansionTile(
                                title: const Text('비밀번호 변경'),
                                children: [
                                  _buildPasswordField(
                                    label: '새 비밀번호',
                                    controller: _passwordController,
                                    hintText: '변경할 경우만 입력하세요',
                                    obscureText: !_showPassword,
                                    onToggleVisibility: () {
                                      setState(() {
                                        _showPassword = !_showPassword;
                                      });
                                    },
                                    validator: (value) {
                                      if (value != null && value.isNotEmpty && value.length < 6) {
                                        return '비밀번호는 6자 이상이어야 합니다';
                                      }
                                      return null;
                                    },
                                    onSaved: (value) => controller.password = value ?? '',
                                  ),
                                  
                                  _buildPasswordField(
                                    label: '새 비밀번호 확인',
                                    controller: _confirmPasswordController,
                                    hintText: '비밀번호를 다시 입력하세요',
                                    obscureText: !_showConfirmPassword,
                                    onToggleVisibility: () {
                                      setState(() {
                                        _showConfirmPassword = !_showConfirmPassword;
                                      });
                                    },
                                    validator: (value) {
                                      if (_passwordController.text.isNotEmpty && value != _passwordController.text) {
                                        return '비밀번호가 일치하지 않습니다';
                                      }
                                      return null;
                                    },
                                  ),
                                ],
                              ),
                            ],
                            
                            
                            // 이메일 (*필수)
                            _buildTextField(
                              label: '이메일 *',
                              initialValue: controller.email,
                              hintText: '이메일을 입력하세요',
                              keyboardType: TextInputType.emailAddress,
                              validator: (value) {
                                if (value == null || value.isEmpty) {
                                  return '이메일을 입력해주세요';
                                }
                                return validateEmail(value);
                              },
                              onSaved: (value) => controller.email = value!,
                            ),
                            
                            // 전화번호 (선택)
                            _buildPhoneNumberSection(controller),
                            
                            // 권한 (*필수)
                            _buildRoleDropdown(controller),
                            const SizedBox(height: 24),
                            // 오류 메시지 표시
                            if (controller.error != null)
                              Container(
                                padding: const EdgeInsets.all(12),
                                margin: const EdgeInsets.only(bottom: 16),
                                decoration: BoxDecoration(
                                  color: Colors.red.shade50,
                                  borderRadius: BorderRadius.circular(8),
                                  border: Border.all(color: Colors.red.shade200),
                                ),
                                child: Row(
                                  children: [
                                    Icon(Icons.error_outline, color: Colors.red.shade700),
                                    const SizedBox(width: 8),
                                    Expanded(
                                      child: Text(
                                        controller.error!,
                                        style: TextStyle(color: Colors.red.shade700),
                                      ),
                                    ),
                                  ],
                                ),
                              ),
                            // 저장 버튼
                            SizedBox(
                              width: double.infinity,
                              child: ElevatedButton(
                                onPressed: controller.isLoading
                                    ? null
                                    : () => _onSaveUser(controller),
                                style: ElevatedButton.styleFrom(
                                  backgroundColor: ShadcnTheme.primary,
                                  foregroundColor: Colors.white,
                                ),
                                child: Padding(
                                  padding: const EdgeInsets.all(12.0),
                                  child: controller.isLoading
                                      ? const SizedBox(
                                          height: 20,
                                          width: 20,
                                          child: CircularProgressIndicator(
                                            strokeWidth: 2,
                                            valueColor: AlwaysStoppedAnimation<Color>(Colors.white),
                                          ),
                                        )
                                      : Text(
                                          controller.isEditMode ? '수정하기' : '등록하기',
                                          style: const TextStyle(fontSize: 16),
                                        ),
                                ),
                              ),
                            ),
                          ],
                        ),
                      ),
                    ),
                  ),
          );
        },
      ),
    );
  }

  // 이름/직급/이메일 등 공통 텍스트 필드 위젯
  Widget _buildTextField({
    required String label,
    required String initialValue,
    required String hintText,
    TextInputType? keyboardType,
    List<TextInputFormatter>? inputFormatters,
    String? Function(String?)? validator,
    void Function(String?)? onSaved,
    void Function(String)? onChanged,
    Widget? suffixIcon,
  }) {
    return Padding(
      padding: const EdgeInsets.only(bottom: 16.0),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          Text(label, style: const TextStyle(fontWeight: FontWeight.bold)),
          const SizedBox(height: 4),
          TextFormField(
            initialValue: initialValue,
            decoration: InputDecoration(
              hintText: hintText,
              suffixIcon: suffixIcon,
            ),
            keyboardType: keyboardType,
            inputFormatters: inputFormatters,
            validator: validator,
            onSaved: onSaved,
            onChanged: onChanged,
          ),
        ],
      ),
    );
  }

  // 비밀번호 필드 위젯
  Widget _buildPasswordField({
    required String label,
    required TextEditingController controller,
    required String hintText,
    required bool obscureText,
    required VoidCallback onToggleVisibility,
    String? Function(String?)? validator,
    void Function(String?)? onSaved,
  }) {
    return Padding(
      padding: const EdgeInsets.only(bottom: 16.0),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          Text(label, style: const TextStyle(fontWeight: FontWeight.bold)),
          const SizedBox(height: 4),
          TextFormField(
            controller: controller,
            obscureText: obscureText,
            decoration: InputDecoration(
              hintText: hintText,
              suffixIcon: IconButton(
                icon: Icon(
                  obscureText ? Icons.visibility : Icons.visibility_off,
                ),
                onPressed: onToggleVisibility,
              ),
            ),
            validator: validator,
            onSaved: onSaved,
          ),
        ],
      ),
    );
  }
  
  // 전화번호 입력 섹션 (드롭다운 + 텍스트 필드)
  Widget _buildPhoneNumberSection(UserFormController controller) {
    return Padding(
      padding: const EdgeInsets.only(bottom: 16.0),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          const Text('전화번호', style: TextStyle(fontWeight: FontWeight.bold)),
          const SizedBox(height: 4),
          Row(
            children: [
              // 접두사 드롭다운 (010, 02, 031 등)
              Container(
                padding: const EdgeInsets.symmetric(horizontal: 12),
                decoration: BoxDecoration(
                  border: Border.all(color: Colors.grey),
                  borderRadius: BorderRadius.circular(4),
                ),
                child: DropdownButton<String>(
                  value: controller.phonePrefix,
                  items: controller.phonePrefixes.map((prefix) {
                    return DropdownMenuItem(
                      value: prefix,
                      child: Text(prefix),
                    );
                  }).toList(),
                  onChanged: (value) {
                    if (value != null) {
                      controller.updatePhonePrefix(value);
                    }
                  },
                  underline: Container(), // 밑줄 제거
                ),
              ),
              const SizedBox(width: 8),
              const Text('-', style: TextStyle(fontSize: 16)),
              const SizedBox(width: 8),
              // 전화번호 입력 (7-8자리)
              Expanded(
                child: TextFormField(
                  initialValue: controller.phoneNumber,
                  decoration: const InputDecoration(
                    hintText: '1234567 또는 12345678',
                    border: OutlineInputBorder(),
                  ),
                  keyboardType: TextInputType.phone,
                  inputFormatters: [
                    FilteringTextInputFormatter.digitsOnly,
                    LengthLimitingTextInputFormatter(8),
                  ],
                  validator: (value) {
                    if (value != null && value.isNotEmpty) {
                      if (value.length < 7 || value.length > 8) {
                        return '전화번호는 7-8자리 숫자를 입력해주세요';
                      }
                    }
                    return null;
                  },
                  onChanged: (value) {
                    controller.updatePhoneNumber(value);
                  },
                  onSaved: (value) {
                    if (value != null) {
                      controller.updatePhoneNumber(value);
                    }
                  },
                ),
              ),
            ],
          ),
          if (controller.combinedPhoneNumber.isNotEmpty)
            Padding(
              padding: const EdgeInsets.only(top: 4),
              child: Text(
                '전화번호: ${controller.combinedPhoneNumber}',
                style: TextStyle(
                  fontSize: 12,
                  color: Colors.grey[600],
                ),
              ),
            ),
        ],
      ),
    );
  }

  // 권한 드롭다운 (새 UserRole 시스템)
  Widget _buildRoleDropdown(UserFormController controller) {
    return Padding(
      padding: const EdgeInsets.only(bottom: 16.0),
      child: Column(
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          const Text('권한 *', style: TextStyle(fontWeight: FontWeight.bold)),
          const SizedBox(height: 4),
          DropdownButtonFormField<UserRole>(
            value: controller.role,
            decoration: const InputDecoration(
              hintText: '권한을 선택하세요',
              border: OutlineInputBorder(),
            ),
            items: UserRole.values.map((role) {
              return DropdownMenuItem<UserRole>(
                value: role,
                child: Text(role.displayName),
              );
            }).toList(),
            onChanged: (value) {
              if (value != null) {
                controller.role = value;
              }
            },
            validator: (value) {
              if (value == null) {
                return '권한을 선택해주세요';
              }
              return null;
            },
          ),
          const SizedBox(height: 4),
          Text(
            '권한 설명:\n'
            '• 관리자: 전체 시스템 관리 및 모든 기능 접근\n'
            '• 매니저: 중간 관리 기능 및 승인 권한\n'
            '• 직원: 기본 사용 기능만 접근 가능',
            style: TextStyle(
              fontSize: 12,
              color: Colors.grey[600],
            ),
          ),
        ],
      ),
    );
  }

  // 저장 버튼 클릭 시 사용자 저장
  void _onSaveUser(UserFormController controller) async {
    await controller.saveUser((error) {
      if (error != null) {
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(
            content: Text(error),
            backgroundColor: Colors.red,
          ),
        );
      } else {
        ScaffoldMessenger.of(context).showSnackBar(
          SnackBar(
            content: Text(controller.isEditMode ? '사용자 정보가 수정되었습니다' : '사용자가 등록되었습니다'),
            backgroundColor: Colors.green,
          ),
        );
        Navigator.pop(context, true);
      }
    });
  }
}