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

import '../../../../core/errors/failure.dart';
import '../../../../core/utils/validators.dart';
import '../../../../shared/models/user_management_models.dart';
import '../../../../shared/widgets/app_button.dart';
import '../../../../shared/widgets/app_dropdown.dart';
import '../../../../shared/widgets/app_loading_view.dart';
import '../../../../shared/widgets/app_searchable_dropdown.dart';
import '../../../../shared/widgets/app_searchable_multi_select_dropdown.dart';
import '../../../../shared/widgets/app_text_field.dart';
import '../../../../shared/widgets/error_view.dart';
import '../../../../shared/widgets/app_side_panel.dart';
import '../../../master_data/presentation/widgets/master_quick_add.dart';
import '../providers/add_user_form_provider.dart';
import '../../../../shared/widgets/app_toast.dart';

class AddUserPanel extends ConsumerStatefulWidget {
  const AddUserPanel({super.key, this.userId});

  final String? userId;

  bool get isEditing => userId != null;

  @override
  ConsumerState<AddUserPanel> createState() => _AddUserPanelState();
}

class _AddUserPanelState extends ConsumerState<AddUserPanel> {
  final _formKey = GlobalKey<FormState>();
  final _nameController = TextEditingController();
  final _employeeCodeController = TextEditingController();
  final _emailController = TextEditingController();
  final _mobileController = TextEditingController();
  final _passwordController = TextEditingController();
  List<String> _selectedRoleIds = [];
  String _selectedStatus = 'Active';
  String? _selectedDepartmentId;
  String? _selectedPlantId;
  String? _selectedDesignationId;
  String? _selectedReportingToId;
  bool _prefilled = false;
  bool _obscurePassword = true;

  static const _statusOptions = [
    AppDropdownOption(value: 'Active', label: 'Active'),
    AppDropdownOption(value: 'Inactive', label: 'Inactive'),
    AppDropdownOption(value: 'Locked', label: 'Locked'),
  ];

  @override
  void dispose() {
    _nameController.dispose();
    _employeeCodeController.dispose();
    _emailController.dispose();
    _mobileController.dispose();
    _passwordController.dispose();
    super.dispose();
  }

  String _statusToApi(String label) => switch (label) {
        'Active' => 'active',
        'Inactive' => 'inactive',
        'Locked' => 'locked',
        _ => 'active',
      };

  String _statusFromApi(String status) => switch (status.toLowerCase()) {
        'active' => 'Active',
        'inactive' => 'Inactive',
        'locked' => 'Locked',
        _ => 'Active',
      };

  void _prefillFromUser(ManagedUserModel user) {
    if (_prefilled) return;
    _prefilled = true;
    _nameController.text = user.fullName;
    _employeeCodeController.text = user.employeeCode;
    _emailController.text = user.email;
    _mobileController.text = user.mobile;
    _selectedRoleIds = user.effectiveRoleIds;
    _selectedDepartmentId = user.departmentId;
    _selectedDesignationId = user.designationId;
    _selectedPlantId = user.plantId;
    _selectedReportingToId = user.reportingTo;
    _selectedStatus = _statusLabelFromUser(user);
  }

  String _statusLabelFromUser(ManagedUserModel user) {
    final normalized = user.status.trim().toLowerCase();
    if (normalized.isNotEmpty && normalized != 'active') {
      return _statusFromApi(user.status);
    }
    if (!user.isActive) return 'Inactive';
    return _statusFromApi(user.status);
  }

  List<AppDropdownOption<String>> _toOptions(List<FilterOptionModel> items) {
    return items
        .map((item) => AppDropdownOption(value: item.id, label: item.name))
        .toList();
  }

  Future<void> _save() async {
    if (!_formKey.currentState!.validate()) return;

    final roleIds = _selectedRoleIds
        .map((id) => int.tryParse(id))
        .whereType<int>()
        .toList();
    if (roleIds.isEmpty) {
      showAppToastFromSnackBar(context, 
        const SnackBar(content: Text('Please select at least one role')),
      );
      return;
    }

    final notifier = ref.read(addUserFormProvider(widget.userId).notifier);
    final bool success;

    if (widget.isEditing) {
      success = await notifier.submitUpdate(
        widget.userId!,
        UpdateUserRequest(
          employeeCode: _employeeCodeController.text.trim(),
          fullName: _nameController.text.trim(),
          email: _emailController.text.trim(),
          password: _passwordController.text.isEmpty ? null : _passwordController.text,
          mobile: _mobileController.text.trim().isEmpty
              ? null
              : _mobileController.text.trim(),
          roleId: roleIds.first,
          roleIds: roleIds,
          departmentId: int.tryParse(_selectedDepartmentId ?? ''),
          designationId: int.tryParse(_selectedDesignationId ?? ''),
          plantId: int.tryParse(_selectedPlantId ?? ''),
          reportingTo: int.tryParse(_selectedReportingToId ?? ''),
          status: _statusToApi(_selectedStatus),
          isActive: _selectedStatus == 'Active',
        ),
      );
    } else {
      success = await notifier.submitCreate(
        CreateUserRequest(
          employeeCode: _employeeCodeController.text.trim(),
          fullName: _nameController.text.trim(),
          email: _emailController.text.trim(),
          password: _passwordController.text,
          mobile: _mobileController.text.trim().isEmpty
              ? null
              : _mobileController.text.trim(),
          roleId: roleIds.first,
          roleIds: roleIds,
          departmentId: int.tryParse(_selectedDepartmentId ?? ''),
          designationId: int.tryParse(_selectedDesignationId ?? ''),
          plantId: int.tryParse(_selectedPlantId ?? ''),
          reportingTo: int.tryParse(_selectedReportingToId ?? ''),
          status: _statusToApi(_selectedStatus),
          isActive: _selectedStatus == 'Active',
        ),
      );
    }

    if (!mounted) return;

    if (success) {
      Navigator.of(context, rootNavigator: true).pop(true);
      return;
    }

    final error = ref.read(addUserFormProvider(widget.userId)).valueOrNull?.errorMessage;
    showAppToastFromSnackBar(context, 
      SnackBar(
        content: Text(
          error ?? (widget.isEditing ? 'Failed to update user' : 'Failed to create user'),
        ),
      ),
    );
  }

  Widget _buildDropdown({
    required String label,
    required String? value,
    required List<FilterOptionModel> options,
    required ValueChanged<String?> onChanged,
    String? hint,
    bool required = false,
    String? masterId,
    Map<String, dynamic>? initialValues,
  }) {
    final fieldLabel = required ? '$label *' : label;
    final fieldHint = hint ?? 'Select ${label.toLowerCase()}';
    final fieldEnabled = options.isNotEmpty || masterId != null;
    final validator =
        required ? (String? v) => v == null ? 'Please select $label' : null : null;

    if (masterId == null) {
      return AppSearchableDropdown<String>(
        label: fieldLabel,
        value: value,
        hint: fieldHint,
        searchHint: 'Search $label...',
        enabled: fieldEnabled,
        options: _toOptions(options),
        onChanged: onChanged,
        validator: validator,
      );
    }

    return MasterQuickAddDropdown<String>(
      masterId: masterId,
      label: fieldLabel,
      value: value,
      hint: fieldHint,
      searchHint: 'Search $label...',
      enabled: fieldEnabled,
      options: _toOptions(options),
      initialValues: initialValues,
      refreshLookups: () =>
          ref.invalidate(addUserFormProvider(widget.userId)),
      parseCreatedId: (id) => id,
      onChanged: onChanged,
      validator: validator,
    );
  }

  @override
  Widget build(BuildContext context) {
    final formAsync = ref.watch(addUserFormProvider(widget.userId));
    final isSubmitting = formAsync.valueOrNull?.isSubmitting ?? false;

    return SidePanelScaffold(
      title: widget.isEditing ? 'Edit User' : 'Add User',
      footer: Row(
        mainAxisAlignment: MainAxisAlignment.end,
        children: [
          OutlinedButton(
            onPressed: isSubmitting
                ? null
                : () => Navigator.of(context, rootNavigator: true).pop(),
            child: const Text('Cancel'),
          ),
          const SizedBox(width: 12),
          AppButton(
            label: widget.isEditing ? 'Update User' : 'Save User',
            expand: false,
            icon: Icons.check,
            isLoading: isSubmitting,
            onPressed: isSubmitting ? null : _save,
          ),
        ],
      ),
      child: formAsync.when(
        loading: () => AppLoadingView(
          message: widget.isEditing ? 'Loading user...' : 'Loading form options...',
        ),
        error: (error, _) => ErrorView.fromFailure(
          error is Failure ? error : Failure.unknown(message: error.toString()),
          onRetry: () => ref.invalidate(addUserFormProvider(widget.userId)),
        ),
        data: (formState) {
          if (formState.editingUser != null) {
            _prefillFromUser(formState.editingUser!);
          }

          return Form(
            key: _formKey,
            child: Column(
              crossAxisAlignment: CrossAxisAlignment.stretch,
              children: [
                SidePanelFormRow(
                  left: AppTextField(
                    controller: _nameController,
                    label: 'Full Name *',
                    hint: 'e.g. Ravi Kumar',
                    validator: (v) => Validators.required(v, fieldName: 'Name'),
                  ),
                  right: AppTextField(
                    controller: _employeeCodeController,
                    label: 'Employee Code *',
                    hint: 'e.g. EMP002',
                    validator: (v) =>
                        Validators.required(v, fieldName: 'Employee Code'),
                  ),
                ),
                SidePanelFormRow(
                  left: AppTextField(
                    controller: _emailController,
                    label: 'Email *',
                    hint: 'ravi@company.com',
                    keyboardType: TextInputType.emailAddress,
                    validator: Validators.email,
                  ),
                  right: AppTextField(
                    controller: _mobileController,
                    label: 'Mobile',
                    hint: '9XXXXXXXXX',
                    keyboardType: TextInputType.phone,
                    validator: Validators.optionalMobile,
                    inputFormatters: Validators.mobileInput,
                  ),
                ),
                const SizedBox(height: 12),
                SidePanelSection(
                  title: 'ROLE & ACCESS',
                  children: [
                    SidePanelFormRow(
                      left: AppSearchableMultiSelectDropdown<String>(
                        label: 'Role *',
                        values: _selectedRoleIds,
                        hint: formState.roles.isEmpty
                            ? 'No roles available'
                            : 'Select roles',
                        searchHint: 'Search role...',
                        enabled: formState.roles.isNotEmpty,
                        options: _toOptions(formState.roles),
                        onChanged: (ids) =>
                            setState(() => _selectedRoleIds = ids),
                        validator: (ids) =>
                            ids == null || ids.isEmpty
                                ? 'Please select at least one role'
                                : null,
                      ),
                      right: AppSearchableDropdown<String>(
                        label: 'Status',
                        value: _selectedStatus,
                        options: _statusOptions,
                        searchHint: 'Search status...',
                        onChanged: (v) =>
                            setState(() => _selectedStatus = v ?? 'Active'),
                      ),
                    ),
                  ],
                ),
                SidePanelSection(
                  title: 'ORGANISATION',
                  children: [
                    SidePanelFormRow(
                      left: _buildDropdown(
                        label: 'Department',
                        value: _selectedDepartmentId,
                        options: formState.departments,
                        masterId: 'departments',
                        onChanged: (v) =>
                            setState(() => _selectedDepartmentId = v),
                      ),
                      right: _buildDropdown(
                        label: 'Designation',
                        value: _selectedDesignationId,
                        options: formState.designations,
                        masterId: 'designations',
                        onChanged: (v) =>
                            setState(() => _selectedDesignationId = v),
                      ),
                    ),
                    SidePanelFormRow(
                      left: _buildDropdown(
                        label: 'Plant / Unit',
                        value: _selectedPlantId,
                        options: formState.plants,
                        masterId: 'locations',
                        initialValues: const {'type': 'plant'},
                        onChanged: (v) => setState(() => _selectedPlantId = v),
                      ),
                      right: _buildDropdown(
                        label: 'Reporting To',
                        value: _selectedReportingToId,
                        options: formState.managers,
                        hint: formState.managers.isEmpty
                            ? 'No managers available'
                            : 'Select manager',
                        onChanged: (v) =>
                            setState(() => _selectedReportingToId = v),
                      ),
                    ),
                  ],
                ),
                SidePanelSection(
                  title: 'PASSWORD',
                  children: [
                    AppTextField(
                      controller: _passwordController,
                      label: widget.isEditing
                          ? 'New Password'
                          : 'Temporary Password *',
                      hint: '8+ chars, upper, lower, digit, special',
                      obscureText: _obscurePassword,
                      suffixIcon: IconButton(
                        tooltip: _obscurePassword
                            ? 'Show password'
                            : 'Hide password',
                        icon: Icon(
                          _obscurePassword
                              ? Icons.visibility_outlined
                              : Icons.visibility_off_outlined,
                          size: 20,
                        ),
                        onPressed: () => setState(
                          () => _obscurePassword = !_obscurePassword,
                        ),
                      ),
                      validator: widget.isEditing
                          ? Validators.optionalPassword
                          : Validators.password,
                    ),
                    const SizedBox(height: 4),
                    Text(
                      widget.isEditing
                          ? 'Leave blank to keep the current password.'
                          : 'User will be asked to change this on first login.',
                      style: Theme.of(context).textTheme.bodySmall?.copyWith(
                            color:
                                Theme.of(context).colorScheme.onSurfaceVariant,
                          ),
                    ),
                  ],
                ),
              ],
            ),
          );
        },
      ),
    );
  }
}