import '../../../../shared/widgets/app_card.dart';
import '../../../../shared/widgets/app_data_table.dart';
import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';

import '../../../../core/errors/failure.dart';
import '../../../../core/utils/responsive_utils.dart';
import '../../../../shared/models/permission_matrix_models.dart';
import '../../../../shared/widgets/app_button.dart';
import '../../../../shared/widgets/app_loading_view.dart';
import '../../../../shared/widgets/error_view.dart';
import '../../../../shared/widgets/page_header.dart';
import '../providers/roles_provider.dart';
import '../../../../shared/widgets/app_toast.dart';

class PermissionMatrixScreen extends ConsumerStatefulWidget {
  const PermissionMatrixScreen({super.key, required this.roleId});

  final String roleId;

  @override
  ConsumerState<PermissionMatrixScreen> createState() => _PermissionMatrixScreenState();
}

class _PermissionMatrixScreenState extends ConsumerState<PermissionMatrixScreen> {
  bool _isSaving = false;

  Future<void> _save() async {
    setState(() => _isSaving = true);
    final success =
        await ref.read(permissionMatrixProvider(widget.roleId).notifier).save();
    if (!mounted) return;
    setState(() => _isSaving = false);
    showAppToastFromSnackBar(context, 
      SnackBar(
        content: Text(success ? 'Permissions saved' : 'Failed to save permissions'),
      ),
    );
  }

  @override
  Widget build(BuildContext context) {
    final matrixAsync = ref.watch(permissionMatrixProvider(widget.roleId));

    return Padding(
      padding: const EdgeInsets.all(24),
      child: matrixAsync.when(
        loading: () => const AppLoadingView(message: 'Loading permission matrix...'),
        error: (error, _) => ErrorView.fromFailure(
          error is Failure ? error : Failure.unknown(message: error.toString()),
          onRetry: () => ref.invalidate(permissionMatrixProvider(widget.roleId)),
        ),
        data: (matrix) => Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          children: [
            PageHeader(
              title: 'Permission Matrix',
              subtitle: matrix.roleName,
              actions: [
                AppButton(
                  label: 'Save Changes',
                  expand: false,
                  isLoading: _isSaving,
                  onPressed: _save,
                ),
              ],
            ),
            Expanded(
              child: context.isMobile
                  ? _MatrixCardList(roleId: widget.roleId, matrix: matrix)
                  : _MatrixGrid(roleId: widget.roleId, matrix: matrix),
            ),
          ],
        ),
      ),
    );
  }
}

class _MatrixGrid extends ConsumerWidget {
  const _MatrixGrid({required this.roleId, required this.matrix});

  final String roleId;
  final RolePermissionMatrix matrix;

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    return AppDataTable<PermissionMatrixModuleRow>(
      wrapInCard: true,
      columns: [
        AppDataColumn(
          id: 'module',
          label: 'Module',
          sortKey: 'module',
          flex: 3,
          enableSearch: false,
          searchText: (row) => row.name,
          cellBuilder: (_, row) => AppTableCell.text(row.name),
        ),
        ...matrix.actionColumns.map(
          (action) => AppDataColumn(
            label: permissionActionLabel(action),
            flex: 1,
            alignment: Alignment.center,
            enableSearch: false,
            cellBuilder: (_, row) {
              final applicable = isPermissionActionApplicable(
                row.code,
                action,
                columnActions: matrix.actionColumns,
              );
              return Checkbox(
                value: applicable ? (row.granted[action] ?? false) : false,
                visualDensity: VisualDensity.compact,
                materialTapTargetSize: MaterialTapTargetSize.shrinkWrap,
                onChanged: applicable
                    ? (checked) => ref
                        .read(permissionMatrixProvider(roleId).notifier)
                        .toggleAction(row.moduleId, action, checked ?? false)
                    : null,
              );
            },
          ),
        ),
      ],
      rows: matrix.modules,
    );
  }
}

class _MatrixCardList extends ConsumerWidget {
  const _MatrixCardList({required this.roleId, required this.matrix});

  final String roleId;
  final RolePermissionMatrix matrix;

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    return ListView.separated(
      itemCount: matrix.modules.length,
      separatorBuilder: (_, __) => const SizedBox(height: 12),
      itemBuilder: (context, index) {
        final row = matrix.modules[index];
        return AppCard(
          child: ExpansionTile(
            title: Text(row.name),
            children: matrix.actionColumns
                .map(
                  (action) {
                    final applicable = isPermissionActionApplicable(
                      row.code,
                      action,
                      columnActions: matrix.actionColumns,
                    );
                    return _PermissionSwitch(
                      label: permissionActionLabel(action),
                      value: applicable ? (row.granted[action] ?? false) : false,
                      onChanged: applicable
                          ? (v) => ref
                              .read(permissionMatrixProvider(roleId).notifier)
                              .toggleAction(row.moduleId, action, v)
                          : null,
                    );
                  },
                )
                .toList(),
          ),
        );
      },
    );
  }
}

class _PermissionSwitch extends StatelessWidget {
  const _PermissionSwitch({
    required this.label,
    required this.value,
    required this.onChanged,
  });

  final String label;
  final bool value;
  final ValueChanged<bool>? onChanged;

  @override
  Widget build(BuildContext context) {
    return SwitchListTile(
      title: Text(label),
      value: value,
      onChanged: onChanged,
    );
  }
}