import { Component, OnInit, OnDestroy, HostListener } from '@angular/core';
import { CommonModule } from '@angular/common';
import { Router, NavigationEnd, RouterModule, RouterOutlet } from '@angular/router';
import { FormsModule } from '@angular/forms';
import { IconsModule } from '@progress/kendo-angular-icons';
import {
  SVGIcon,
  homeIcon,
  userIcon,
  groupIcon,
  graphIcon,
  buildingsOutlineIcon,
  banknoteOutlineIcon,
  dollarIcon,
  categorizeIcon,
  moneyExchangeIcon,
  fileReportIcon,
  walletOutlineIcon,
  handIcon,
  searchIcon,
  xIcon,
  chevronDownIcon,
  lockIcon,
} from '@progress/kendo-svg-icons';
import { AuthService, UserInfo } from '../../shared/services/auth.service';
import { PermissionService } from '../../core/services/permission.service';
import { PermissionAction, PermissionModules } from '../../core/models/permission.model';
import { Subject, takeUntil, filter } from 'rxjs';

interface NavItem {
  text: string;
  icon: SVGIcon;
  path: string;
  active?: boolean;
  /** When set, the item is shown only if the user has this permission. */
  permission?: { module: string; action: PermissionAction };
}

interface NavGroup {
  text: string;
  icon?: SVGIcon;
  items: NavItem[];
  expanded: boolean;
}

@Component({
  selector: 'app-user-portal',
  standalone: true,
  imports: [
    CommonModule,
    FormsModule,
    RouterModule,
    RouterOutlet,
    IconsModule,
  ],
  templateUrl: './user-portal.component.html',
  styleUrls: ['./user-portal.component.scss']
})
export class UserPortalComponent implements OnInit, OnDestroy {
  sidebarCollapsed = false;
  isMobile = false;
  currentUser: UserInfo | null = null;
  currentPageTitle = 'Dashboard';

  public searchQuery = '';

  public homeIcon: SVGIcon = homeIcon;
  public userIcon: SVGIcon = userIcon;
  public searchIcon: SVGIcon = searchIcon;
  public clearIcon: SVGIcon = xIcon;
  public chevronDownIcon: SVGIcon = chevronDownIcon;

  public mainNavItems: NavItem[] = [
    { text: 'Dashboard', icon: this.homeIcon, path: '/user-portal/dashboard' },
  ];

  public memberAdminNavItems: NavItem[] = [
    { text: 'Members', icon: groupIcon, path: '/user-portal/admin/members',
      permission: { module: PermissionModules.Members, action: 'read' } },
  ];

  public userAdminNavItems: NavItem[] = [
    { text: 'User Management', icon: userIcon, path: '/user-portal/admin/users',
      permission: { module: PermissionModules.Users, action: 'read' } },
    { text: 'Role Permissions', icon: lockIcon, path: '/user-portal/admin/permissions',
      permission: { module: PermissionModules.Permissions, action: 'read' } },
  ];

  public financeGroups: NavGroup[] = [
    {
      text: 'Overview',
      expanded: false,
      items: [
        { text: 'Finance Dashboard', icon: graphIcon,      path: '/user-portal/finance/dashboard',
          permission: { module: PermissionModules.FinanceDashboard, action: 'read' } },
        { text: 'Monthly Statement', icon: fileReportIcon, path: '/user-portal/finance/monthly-statement',
          permission: { module: PermissionModules.MonthlyStatements, action: 'read' } },
      ],
    },
    {
      text: 'Income',
      expanded: false,
      items: [
        { text: 'Offering Entry', icon: handIcon,      path: '/user-portal/finance/offering-session',
          permission: { module: PermissionModules.OfferingSessions, action: 'read' } },
        { text: 'Givings',        icon: dollarIcon,     path: '/user-portal/finance/givings',
          permission: { module: PermissionModules.Givings, action: 'read' } },
        { text: 'Giving Types',   icon: categorizeIcon, path: '/user-portal/finance/giving-categories',
          permission: { module: PermissionModules.GivingCategories, action: 'read' } },
      ],
    },
    {
      text: 'Expenses',
      expanded: false,
      items: [
        { text: 'Expenses',           icon: moneyExchangeIcon,   path: '/user-portal/finance/expenses',
          permission: { module: PermissionModules.Expenses, action: 'read' } },
        { text: 'Expense Categories', icon: categorizeIcon,      path: '/user-portal/finance/expense-categories',
          permission: { module: PermissionModules.ExpenseCategories, action: 'read' } },
        { text: 'Disbursements',      icon: banknoteOutlineIcon, path: '/user-portal/finance/disbursements',
          permission: { module: PermissionModules.Disbursements, action: 'read' } },
        { text: 'Check Register',     icon: walletOutlineIcon,   path: '/user-portal/finance/check-register',
          permission: { module: PermissionModules.Disbursements, action: 'read' } },
      ],
    },
    {
      text: 'Settings',
      expanded: false,
      items: [
        { text: 'Church Profile', icon: buildingsOutlineIcon, path: '/user-portal/finance/church-profile',
          permission: { module: PermissionModules.ChurchProfile, action: 'read' } },
      ],
    },
  ];

  public personalNavItems: NavItem[] = [
    { text: 'My Reimbursements', icon: walletOutlineIcon, path: '/user-portal/reimbursements' },
  ];

  public showMemberAdminSection = false;
  public showUserAdminSection = false;
  public showFinanceSection = false;

  private destroy$ = new Subject<void>();

  constructor(
    private authService: AuthService,
    private permissions: PermissionService,
    private router: Router
  ) { }

  ngOnInit(): void {
    this.checkScreenSize();
    this.setupUserSubscription();
    this.setupRouteSubscription();
  }

  ngOnDestroy(): void {
    this.destroy$.next();
    this.destroy$.complete();
  }

  @HostListener('window:resize', ['$event'])
  onResize(event: any): void {
    this.checkScreenSize();
  }

  private checkScreenSize(): void {
    this.isMobile = window.innerWidth <= 768;
    if (this.isMobile) {
      this.sidebarCollapsed = true;
    } else {
      // On desktop, start with sidebar expanded
      this.sidebarCollapsed = false;
    }
  }

  private setupUserSubscription(): void {
    this.authService.currentUser$
      .pipe(takeUntil(this.destroy$))
      .subscribe(user => {
        this.currentUser = user;
        // Section visibility is derived from effective permissions (super_admin → all).
        this.showMemberAdminSection = this.memberAdminNavItems.some(item => this.canShow(item));
        this.showUserAdminSection = this.userAdminNavItems.some(item => this.canShow(item));
        this.showFinanceSection = this.financeGroups
          .some(group => group.items.some(item => this.canShow(item)));
      });
  }

  /** True if a nav item should be shown — items without a permission are always visible. */
  public canShow(item: NavItem): boolean {
    if (!item.permission) {
      return true;
    }
    return this.permissions.can(item.permission.module, item.permission.action);
  }

  private setupRouteSubscription(): void {
    this.router.events
      .pipe(
        filter(event => event instanceof NavigationEnd),
        takeUntil(this.destroy$)
      )
      .subscribe((event: NavigationEnd) => {
        this.updateActiveStates(event.url);
        this.updatePageTitle();
      });

    this.updateActiveStates(this.router.url);
    this.updatePageTitle();
  }

  public navigateTo(path: string): void {
    this.router.navigate([path]);
    this.onNavigationClick();
  }

  private updateActiveStates(currentUrl: string): void {
    const financeItems: NavItem[] = [];
    this.financeGroups.forEach(group => financeItems.push(...group.items));
    const allItems = [
      ...this.mainNavItems,
      ...this.memberAdminNavItems,
      ...this.userAdminNavItems,
      ...financeItems,
      ...this.personalNavItems,
    ];
    allItems.forEach(item => (item.active = false));

    const activeItem = allItems.find(item => currentUrl.startsWith(item.path));
    if (activeItem) {
      activeItem.active = true;
    }

    // Auto-expand the finance group that contains the active page so the
    // current location is visible on load/navigation.
    const activeGroup = this.financeGroups.find(group =>
      group.items.some(item => item.active)
    );
    if (activeGroup) {
      activeGroup.expanded = true;
    }
  }

  public toggleGroup(group: NavGroup): void {
    group.expanded = !group.expanded;
  }

  public matchesSearch(text: string): boolean {
    const query = this.searchQuery.trim().toLowerCase();
    if (!query) {
      return true;
    }
    return text.toLowerCase().includes(query);
  }

  public groupHasMatch(group: NavGroup): boolean {
    return group.items.some(item => this.matchesSearch(item.text));
  }

  /** Combined search + permission filter for a single nav item. */
  public isVisible(item: NavItem): boolean {
    return this.matchesSearch(item.text) && this.canShow(item);
  }

  /** True if a finance group has at least one visible (permitted + matching) item. */
  public groupVisible(group: NavGroup): boolean {
    return group.items.some(item => this.isVisible(item));
  }

  public clearSearch(): void {
    this.searchQuery = '';
  }

  private updatePageTitle(): void {
    const url = this.router.url;
    const segments = url.split('/').filter(s => s);
    const key = segments.length >= 3
      ? `${segments[1]}/${segments[2]}`   // e.g. 'admin/members'
      : segments[1] ?? '';
    this.currentPageTitle = this.getPageTitle(key);
  }

  private getPageTitle(page: string): string {
    const titles: { [key: string]: string } = {
      'dashboard': 'Dashboard',
      'schedule': 'Schedule',
      'patients': 'Patients',
      'bed-management': 'Bed Management',
      'staff': 'Staff',
      'pharmacy': 'Pharmacy',
      'reports': 'Reports',
      'departments': 'Departments',
      'payments': 'Payments',
      'support': 'Support',
      'transactions': 'Escrow Transactions',
      'tasks': 'Tasks & Todos',
      'contacts': 'Contacts',
      'documents': 'Documents',
      'messages': 'Messages',
      'settings': 'Settings',
      'admin/members': 'Member Management',
      'admin/users': 'User Management',
      'admin/permissions': 'Role Permissions',
      'finance/dashboard': 'Finance Dashboard',
      'finance/offering-session': 'Sunday Offering Entry',
      'finance/givings': 'Givings',
      'finance/giving-categories': 'Giving Types',
      'reimbursements': 'My Reimbursements',
      'finance/expenses': 'Expenses',
      'finance/expense-categories': 'Expense Categories',
      'finance/disbursements': 'Disbursement Management',
      'finance/check-register': 'Check Register',
      'finance/monthly-statement': 'Monthly Statement',
      'finance/church-profile': 'Church Profile',
    };
    return titles[page] ?? 'Dashboard';
  }

  toggleSidebar(): void {
    this.sidebarCollapsed = !this.sidebarCollapsed;
  }

  get mainContentClass(): string {
    return this.sidebarCollapsed ? 'main-content sidebar-collapsed' : 'main-content';
  }

  onSidebarOverlayClick(): void {
    if (this.isMobile && !this.sidebarCollapsed) {
      this.sidebarCollapsed = true;
    }
  }

  onNavigationClick(): void {
    if (this.isMobile) {
      this.sidebarCollapsed = true;
    }
  }

  logout(): void {
    this.authService.logout();
    this.router.navigate(['/login']);
  }

  getDisplayName(): string {
    return this.currentUser?.email || '';
  }
}