import { Injectable } from '@angular/core';
import { Observable, of } from 'rxjs';
import { delay } from 'rxjs/operators';
import { AdminInvitation, AdminRole, AdminSession, AdminUser, AdminUserAuditEntry, AdminUserScope, AdminUserStatus } from '../models/admin-user.model';
import { AdminUsersGateway } from './admin-users-gateway.interface';

const BUILT_IN_ROLES: AdminRole[] = [
  { id: 'owner', name: 'Owner', permissions: ['*'], builtIn: true },
  { id: 'admin', name: 'Admin', permissions: ['products.manage', 'categories.manage', 'orders.manage', 'media.manage'], builtIn: true },
  { id: 'editor', name: 'Editor', permissions: ['products.manage', 'categories.manage', 'media.manage'], builtIn: true },
  { id: 'viewer', name: 'Viewer', permissions: ['products.view', 'orders.view'], builtIn: true },
];

@Injectable({ providedIn: 'root' })
export class AdminUsersLocalGateway implements AdminUsersGateway {
  private users: AdminUser[] | null = null;
  private roles: AdminRole[] = [...BUILT_IN_ROLES];
  private invitations: AdminInvitation[] = [];
  private sessions: Record<string, AdminSession[]> = {};
  private audit: Record<string, AdminUserAuditEntry[]> = {};

  loadUsers(): Observable<AdminUser[]> {
    return of(this.ensureUsers()).pipe(delay(50));
  }

  loadRoles(): Observable<AdminRole[]> {
    return of(this.roles).pipe(delay(50));
  }

  loadInvitations(): Observable<AdminInvitation[]> {
    return of(this.invitations).pipe(delay(50));
  }

  loadSessions(userId: string): Observable<AdminSession[]> {
    if (!this.sessions[userId]) {
      this.sessions[userId] = [
        { id: `${userId}-s1`, userId, device: 'Chrome on Windows', ip: '10.0.0.1', lastActiveAt: new Date().toISOString(), current: true },
        { id: `${userId}-s2`, userId, device: 'Telegram App on Android', ip: '10.0.0.2', lastActiveAt: new Date(Date.now() - 86400000).toISOString(), current: false },
      ];
    }
    return of(this.sessions[userId]).pipe(delay(50));
  }

  loadAudit(userId: string): Observable<AdminUserAuditEntry[]> {
    return of(this.audit[userId] ?? []).pipe(delay(50));
  }

  setUserRole(userId: string, roleId: string): Observable<AdminUser | null> {
    return this.mutateUser(userId, user => ({ ...user }), roleId, undefined);
  }

  setUserStatus(userId: string, status: AdminUserStatus): Observable<AdminUser | null> {
    return this.mutateUser(userId, user => ({ ...user }), undefined, status);
  }

  inviteUser(email: string, roleId: string, scope: AdminUserScope): Observable<AdminInvitation> {
    const invitation: AdminInvitation = {
      id: `invite-${Date.now()}`,
      email,
      roleId,
      scope,
      status: 'pending',
      invitedAt: new Date().toISOString(),
      expiresAt: new Date(Date.now() + 7 * 24 * 60 * 60 * 1000).toISOString(),
    };
    this.invitations = [invitation, ...this.invitations];
    return of(invitation).pipe(delay(50));
  }

  revokeInvitation(id: string): Observable<void> {
    this.invitations = this.invitations.map(invite => invite.id === id ? { ...invite, status: 'revoked' } : invite);
    return of(void 0).pipe(delay(50));
  }

  revokeSession(sessionId: string): Observable<void> {
    for (const userId of Object.keys(this.sessions)) {
      this.sessions[userId] = this.sessions[userId].filter(session => session.id !== sessionId);
    }
    return of(void 0).pipe(delay(50));
  }

  private mutateUser(userId: string, transform: (user: AdminUser) => AdminUser, roleId: string | undefined, status: AdminUserStatus | undefined): Observable<AdminUser | null> {
    const users = this.ensureUsers();
    const existing = users.find(user => user.id === userId);
    if (!existing) {
      return of(null);
    }
    const updated = transform({ ...existing, roleId: roleId ?? existing.roleId, status: status ?? existing.status });
    this.users = users.map(user => user.id === userId ? updated : user);
    this.audit[userId] = [
      ...(this.audit[userId] ?? []),
      roleId
        ? { eventKey: 'roleChanged', roleId, actor: 'admin', timestamp: new Date().toISOString() }
        : { eventKey: 'statusChanged', status, actor: 'admin', timestamp: new Date().toISOString() },
    ];
    return of(updated).pipe(delay(50));
  }

  private ensureUsers(): AdminUser[] {
    if (!this.users) {
      this.users = [
        { id: 'user-1', name: 'Karen Sargsyan', telegramUsername: '@karen', email: 'karen@dexar.market', scope: 'marketplace', roleId: 'owner', status: 'active', lastLoginAt: new Date().toISOString(), createdAt: new Date(Date.now() - 90 * 86400000).toISOString() },
        { id: 'user-2', name: 'Anna Petrova', telegramUsername: '@anna', email: 'anna@dexar.market', scope: 'marketplace', roleId: 'admin', status: 'active', lastLoginAt: new Date(Date.now() - 2 * 86400000).toISOString(), createdAt: new Date(Date.now() - 60 * 86400000).toISOString() },
        { id: 'user-3', name: 'Ivan Ivanov', telegramUsername: '@ivan', email: 'ivan@dexar.market', scope: 'office', roleId: 'editor', status: 'active', lastLoginAt: new Date(Date.now() - 5 * 86400000).toISOString(), createdAt: new Date(Date.now() - 30 * 86400000).toISOString() },
        { id: 'user-4', name: 'Mariam Grigoryan', telegramUsername: '@mariam', email: 'mariam@dexar.market', scope: 'office', roleId: 'viewer', status: 'suspended', lastLoginAt: null, createdAt: new Date(Date.now() - 10 * 86400000).toISOString() },
      ];
    }
    return this.users;
  }
}