import 'package:flutter_riverpod/flutter_riverpod.dart';

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

import '../../domain/entities/rbac_entities.dart';

enum RbacTab { users, roles, permissions }

class RbacState {
  const RbacState({
    this.users = const [],
    this.roles = const [],
    this.selectedTab = RbacTab.users,
    this.selectedRoleId = 'super_admin',
    this.searchQuery = '',
    this.roleFilter = 'All Roles',
    this.departmentFilter = 'All Departments',
    this.statusFilter = 'All Statuses',
    this.currentPage = 0,
    this.pageSize = 10,
  });

  final List<ManagedUser> users;
  final List<ManagedRole> roles;
  final RbacTab selectedTab;
  final String selectedRoleId;
  final String searchQuery;
  final String roleFilter;
  final String departmentFilter;
  final String statusFilter;
  final int currentPage;
  final int pageSize;

  int get totalUsers => users.length;
  int get activeUsers =>
      users.where((u) => u.status == UserAccountStatus.active).length;
  int get inactiveUsers =>
      users.where((u) => u.status == UserAccountStatus.inactive).length;
  int get lockedUsers =>
      users.where((u) => u.status == UserAccountStatus.locked).length;

  List<ManagedUser> get filteredUsers {
    return users.where((user) {
      final q = searchQuery.toLowerCase();
      final matchesSearch = q.isEmpty ||
          user.name.toLowerCase().contains(q) ||
          user.email.toLowerCase().contains(q) ||
          user.employeeCode.toLowerCase().contains(q);
      final matchesRole =
          roleFilter == 'All Roles' || user.roleName == roleFilter;
      final matchesDept = departmentFilter == 'All Departments' ||
          user.department == departmentFilter;
      final matchesStatus = statusFilter == 'All Statuses' ||
          user.status.label == statusFilter;
      return matchesSearch && matchesRole && matchesDept && matchesStatus;
    }).toList();
  }

  List<ManagedUser> get pagedUsers {
    final filtered = filteredUsers;
    final start = currentPage * pageSize;
    if (start >= filtered.length) return [];
    final end = (start + pageSize).clamp(0, filtered.length);
    return filtered.sublist(start, end);
  }

  int get totalPages => (filteredUsers.length / pageSize).ceil().clamp(1, 999);

  ManagedRole? get selectedRole {
    for (final role in roles) {
      if (role.id == selectedRoleId) return role;
    }
    return roles.isNotEmpty ? roles.first : null;
  }

  RbacState copyWith({
    List<ManagedUser>? users,
    List<ManagedRole>? roles,
    RbacTab? selectedTab,
    String? selectedRoleId,
    String? searchQuery,
    String? roleFilter,
    String? departmentFilter,
    String? statusFilter,
    int? currentPage,
    int? pageSize,
  }) {
    return RbacState(
      users: users ?? this.users,
      roles: roles ?? this.roles,
      selectedTab: selectedTab ?? this.selectedTab,
      selectedRoleId: selectedRoleId ?? this.selectedRoleId,
      searchQuery: searchQuery ?? this.searchQuery,
      roleFilter: roleFilter ?? this.roleFilter,
      departmentFilter: departmentFilter ?? this.departmentFilter,
      statusFilter: statusFilter ?? this.statusFilter,
      currentPage: currentPage ?? this.currentPage,
      pageSize: pageSize ?? this.pageSize,
    );
  }
}

final rbacProvider = StateNotifierProvider<RbacNotifier, RbacState>((ref) {
  return RbacNotifier();
});

class RbacNotifier extends StateNotifier<RbacState> {
  RbacNotifier()
      : super(RbacState(
          users: List.of(defaultUsers),
          roles: List.of(defaultRoles),
        )) {
    _recountRoleUsers();
  }

  void setTab(RbacTab tab) => state = state.copyWith(selectedTab: tab, currentPage: 0);

  void setSearch(String query) =>
      state = state.copyWith(searchQuery: TableSearch.normalize(query), currentPage: 0);

  void setRoleFilter(String filter) =>
      state = state.copyWith(roleFilter: filter, currentPage: 0);

  void setDepartmentFilter(String filter) =>
      state = state.copyWith(departmentFilter: filter, currentPage: 0);

  void setStatusFilter(String filter) =>
      state = state.copyWith(statusFilter: filter, currentPage: 0);

  void setPage(int page) => state = state.copyWith(currentPage: page);

  void selectRole(String roleId) => state = state.copyWith(selectedRoleId: roleId);

  void togglePermission(String module, RbacAction action) {
    final role = state.selectedRole;
    if (role == null) return;

    final key = permissionKey(module, action);
    final updated = Set<String>.from(role.permissions);
    if (updated.contains(key)) {
      updated.remove(key);
    } else {
      updated.add(key);
    }

    final roles = state.roles.map((r) {
      if (r.id == role.id) return r.copyWith(permissions: updated);
      return r;
    }).toList();

    state = state.copyWith(roles: roles);
  }

  void savePermissions() {
    // Permissions already in state; would sync to API here.
  }

  void addUser(ManagedUser user) {
    state = state.copyWith(users: [...state.users, user]);
    _recountRoleUsers();
  }

  void addRole(ManagedRole role) {
    state = state.copyWith(
      roles: [...state.roles, role],
      selectedRoleId: role.id,
    );
  }

  void deleteRole(String roleId) {
    if (roleId == 'super_admin') return;
    state = state.copyWith(
      roles: state.roles.where((r) => r.id != roleId).toList(),
    );
    _recountRoleUsers();
  }

  void _recountRoleUsers() {
    final roles = state.roles.map((role) {
      final count =
          state.users.where((u) => u.roleId == role.id).length;
      return role.copyWith(userCount: count);
    }).toList();
    state = state.copyWith(roles: roles);
  }
}