import 'package:flutter_riverpod/flutter_riverpod.dart';

import '../../../../core/utils/column_search_paging.dart';
import '../../../../core/utils/table_search.dart';

import '../../../../shared/models/permission_matrix_models.dart';
import '../../../../shared/models/user_management_models.dart';
import '../../data/repositories/role_repository_impl.dart';
import '../../domain/usecases/role_usecases.dart';

class RolesListState {
  const RolesListState({
    this.roles = const [],
    this.search = '',
    this.page = 1,
    this.limit = 10,
  });

  final List<RoleCardModel> roles;
  final String search;
  final int page;
  final int limit;

  List<RoleCardModel> get filteredRoles {
    // Roles are already filtered by the API when [search] is set.
    return roles;
  }

  int get total => filteredRoles.length;

  int get totalPages {
    if (total == 0) return 1;
    return (total / limit).ceil();
  }

  List<RoleCardModel> get pagedRoles {
    final all = filteredRoles;
    if (all.isEmpty) return const [];
    final start = ((page - 1) * limit).clamp(0, all.length);
    final end = (start + limit).clamp(0, all.length);
    return all.sublist(start, end);
  }

  RolesListState copyWith({
    List<RoleCardModel>? roles,
    String? search,
    int? page,
    int? limit,
  }) {
    return RolesListState(
      roles: roles ?? this.roles,
      search: search ?? this.search,
      page: page ?? this.page,
      limit: limit ?? this.limit,
    );
  }
}

final getRoleCardsUseCaseProvider = Provider((ref) {
  return GetRoleCardsUseCase(ref.watch(roleRepositoryProvider));
});

final deleteRoleUseCaseProvider = Provider((ref) {
  return DeleteRoleUseCase(ref.watch(roleRepositoryProvider));
});

final getPermissionCatalogUseCaseProvider = Provider((ref) {
  return GetPermissionCatalogUseCase(ref.watch(roleRepositoryProvider));
});

final getPermissionMatrixUseCaseProvider = Provider((ref) {
  return GetPermissionMatrixUseCase(ref.watch(roleRepositoryProvider));
});

final savePermissionMatrixUseCaseProvider = Provider((ref) {
  return SavePermissionMatrixUseCase(ref.watch(roleRepositoryProvider));
});

final permissionCatalogProvider =
    FutureProvider<List<PermissionModuleCatalog>>((ref) async {
  final result = await ref.read(getPermissionCatalogUseCaseProvider)();
  if (result.failure != null) throw result.failure!;
  return result.data ?? const [];
});

final rolesListProvider =
    AsyncNotifierProvider<RolesListNotifier, RolesListState>(RolesListNotifier.new);

class RolesListNotifier extends AsyncNotifier<RolesListState> {
  final _columnSearch = ColumnSearchPaging(defaultLimit: 10);

  @override
  Future<RolesListState> build() async {
    ref.keepAlive();
    return _load();
  }

  Future<RolesListState> _load({String? search}) async {
    final result = await ref.read(getRoleCardsUseCaseProvider)(search: search);
    if (result.failure != null) throw result.failure!;
    return RolesListState(roles: result.data ?? [], search: search ?? '');
  }

  Future<void> refresh() async {
    final current = state.valueOrNull;
    if (current == null) {
      state = const AsyncLoading();
    }
    try {
      state = AsyncData(await _load(search: current?.search));
    } catch (e, st) {
      state = AsyncError(e, st);
    }
  }

  Future<bool> deleteRole(String id) async {
    final result = await ref.read(deleteRoleUseCaseProvider)(id);
    if (result.failure != null) return false;
    await refresh();
    return true;
  }

  Future<void> setSearch(String search) async {
    final current = state.valueOrNull;
    if (current == null) return;
    final normalized = TableSearch.normalize(search);
    state = const AsyncLoading();
    try {
      final loaded = await _load(search: normalized);
      state = AsyncData(loaded.copyWith(page: 1, limit: current.limit));
    } catch (e, st) {
      state = AsyncError(e, st);
    }
  }

  Future<void> ensureColumnSearchDataset() async {
    final current = state.valueOrNull;
    if (current == null) return;
    final limit = _columnSearch.beginFullDataset(
      currentLimit: current.limit,
      total: current.total,
    );
    if (limit == null) return;
    state = const AsyncLoading();
    try {
      final loaded = await _load(search: '');
      state = AsyncData(
        loaded.copyWith(
          page: 1,
          limit: loaded.total > 0 ? loaded.total : limit,
        ),
      );
    } catch (e, st) {
      state = AsyncError(e, st);
    }
  }

  void clearColumnSearchDataset() {
    final current = state.valueOrNull;
    if (current == null) return;
    final limit = _columnSearch.endFullDataset();
    if (limit == null) return;
    state = AsyncData(current.copyWith(page: 1, limit: limit, search: ''));
  }

  void setPage(int page) {
    final current = state.valueOrNull;
    if (current == null) return;
    state = AsyncData(current.copyWith(page: page));
  }

  void setPageSize(int limit) {
    final current = state.valueOrNull;
    if (current == null) return;
    state = AsyncData(current.copyWith(limit: limit, page: 1));
  }
}

final permissionMatrixProvider = AsyncNotifierProvider.family<
    PermissionMatrixNotifier,
    RolePermissionMatrix,
    String>(PermissionMatrixNotifier.new);

class PermissionMatrixNotifier
    extends FamilyAsyncNotifier<RolePermissionMatrix, String> {
  @override
  Future<RolePermissionMatrix> build(String arg) async {
    final useCase = ref.read(getPermissionMatrixUseCaseProvider);
    final result = await useCase(arg);
    if (result.failure != null) throw result.failure!;
    return result.data!;
  }

  void toggleAction(String moduleId, String action, bool value) {
    final current = state.valueOrNull;
    if (current == null) return;

    final normalizedAction = action.toLowerCase();
    final updated = current.modules.map((row) {
      if (row.moduleId != moduleId) return row;
      if (!isPermissionActionApplicable(
        row.code,
        action,
        columnActions: current.actionColumns,
      )) {
        return row;
      }
      final granted = Map<String, bool>.from(row.granted);
      granted[normalizedAction] = value;

      // CREATE / EDIT / DELETE / APPROVE / EXPORT imply VIEW.
      const impliesView = {
        'create',
        'edit',
        'delete',
        'approve',
        'export',
      };
      if (value &&
          impliesView.contains(normalizedAction) &&
          isPermissionActionApplicable(
            row.code,
            'view',
            columnActions: current.actionColumns,
          )) {
        granted['view'] = true;
      }

      return row.copyWith(granted: granted);
    }).toList();

    state = AsyncData(current.copyWith(modules: updated));
  }

  Future<bool> save() async {
    final current = state.valueOrNull;
    if (current == null) return false;

    final useCase = ref.read(savePermissionMatrixUseCaseProvider);
    final result = await useCase(arg, current);
    if (result.failure != null) return false;
    ref.invalidateSelf();
    await future;
    return true;
  }
}