import type { AdminUserViewData } from '@/lib/view-data/AdminUserViewData';
import type { DashboardStatsViewData } from '@/lib/view-data/DashboardStatsViewData';
import { ViewModel } from "../contracts/view-models/ViewModel";
import { UserStatusDisplay } from "../display-objects/UserStatusDisplay";
import { UserRoleDisplay } from "../display-objects/UserRoleDisplay";
import { DateDisplay } from "../display-objects/DateDisplay";
import { ActivityLevelDisplay } from "../display-objects/ActivityLevelDisplay";

/**
 * AdminUserViewModel
 *
 * View Model for admin user management.
 * Transforms API DTO into UI-ready state with formatting and derived fields.
 */
export class AdminUserViewModel extends ViewModel {
  id: string;
  email: string;
  displayName: string;
  roles: string[];
  status: string;
  isSystemAdmin: boolean;
  createdAt: Date;
  updatedAt: Date;
  lastLoginAt?: Date;
  primaryDriverId?: string;

  // UI-specific derived fields (primitive outputs only)
  readonly roleBadges: string[];
  readonly statusBadgeLabel: string;
  readonly statusBadgeVariant: string;
  readonly lastLoginFormatted: string;
  readonly createdAtFormatted: string;

  constructor(viewData: AdminUserViewData) {
    super();
    this.id = viewData.id;
    this.email = viewData.email;
    this.displayName = viewData.displayName;
    this.roles = viewData.roles;
    this.status = viewData.status;
    this.isSystemAdmin = viewData.isSystemAdmin;
    this.createdAt = new Date(viewData.createdAt);
    this.updatedAt = new Date(viewData.updatedAt);
    this.lastLoginAt = viewData.lastLoginAt ? new Date(viewData.lastLoginAt) : undefined;
    this.primaryDriverId = viewData.primaryDriverId;

    // Derive role badges using Display Object
    this.roleBadges = this.roles.map(role => UserRoleDisplay.roleLabel(role));

    // Derive status badge using Display Object
    this.statusBadgeLabel = UserStatusDisplay.statusLabel(this.status);
    this.statusBadgeVariant = UserStatusDisplay.statusVariant(this.status);

    // Format dates using Display Object
    this.lastLoginFormatted = this.lastLoginAt
      ? DateDisplay.formatShort(this.lastLoginAt)
      : 'Never';
    this.createdAtFormatted = DateDisplay.formatShort(this.createdAt);
  }
}

/**
 * DashboardStatsViewModel
 *
 * View Model for admin dashboard statistics.
 * Provides formatted statistics and derived metrics for UI.
 */
export class DashboardStatsViewModel extends ViewModel {
  totalUsers: number;
  activeUsers: number;
  suspendedUsers: number;
  deletedUsers: number;
  systemAdmins: number;
  recentLogins: number;
  newUsersToday: number;
  userGrowth: {
    label: string;
    value: number;
    color: string;
  }[];
  roleDistribution: {
    label: string;
    value: number;
    color: string;
  }[];
  statusDistribution: {
    active: number;
    suspended: number;
    deleted: number;
  };
  activityTimeline: {
    date: string;
    newUsers: number;
    logins: number;
  }[];

  // UI-specific derived fields (primitive outputs only)
  readonly activeRate: number;
  readonly activeRateFormatted: string;
  readonly adminRatio: string;
  readonly activityLevelLabel: string;
  readonly activityLevelValue: 'low' | 'medium' | 'high';

  constructor(viewData: DashboardStatsViewData) {
    super();
    this.totalUsers = viewData.totalUsers;
    this.activeUsers = viewData.activeUsers;
    this.suspendedUsers = viewData.suspendedUsers;
    this.deletedUsers = viewData.deletedUsers;
    this.systemAdmins = viewData.systemAdmins;
    this.recentLogins = viewData.recentLogins;
    this.newUsersToday = viewData.newUsersToday;
    this.userGrowth = viewData.userGrowth;
    this.roleDistribution = viewData.roleDistribution;
    this.statusDistribution = viewData.statusDistribution;
    this.activityTimeline = viewData.activityTimeline;

    // Derive active rate
    this.activeRate = this.totalUsers > 0 ? (this.activeUsers / this.totalUsers) * 100 : 0;
    this.activeRateFormatted = `${Math.round(this.activeRate)}%`;

    // Derive admin ratio
    const nonAdmins = Math.max(1, this.totalUsers - this.systemAdmins);
    this.adminRatio = `1:${Math.floor(nonAdmins / Math.max(1, this.systemAdmins))}`;

    // Derive activity level using Display Object
    const engagementRate = this.totalUsers > 0 ? (this.recentLogins / this.totalUsers) * 100 : 0;
    this.activityLevelLabel = ActivityLevelDisplay.levelLabel(engagementRate);
    this.activityLevelValue = ActivityLevelDisplay.levelValue(engagementRate);
  }
}

/**
 * UserListViewModel
 *
 * View Model for user list with pagination and filtering state.
 */
export class UserListViewModel extends ViewModel {
  users: AdminUserViewModel[];
  total: number;
  page: number;
  limit: number;
  totalPages: number;

  // UI-specific derived fields (primitive outputs only)
  readonly hasUsers: boolean;
  readonly showPagination: boolean;
  readonly startIndex: number;
  readonly endIndex: number;

  constructor(data: {
    users: AdminUserViewData[];
    total: number;
    page: number;
    limit: number;
    totalPages: number;
  }) {
    super();
    this.users = data.users.map(viewData => new AdminUserViewModel(viewData));
    this.total = data.total;
    this.page = data.page;
    this.limit = data.limit;
    this.totalPages = data.totalPages;

    // Derive UI state
    this.hasUsers = this.users.length > 0;
    this.showPagination = this.totalPages > 1;
    this.startIndex = this.users.length > 0 ? (this.page - 1) * this.limit + 1 : 0;
    this.endIndex = this.users.length > 0 ? (this.page - 1) * this.limit + this.users.length : 0;
  }
}