import { Component, computed, ChangeDetectionStrategy, signal, OnDestroy, inject } from '@angular/core';
import { DecimalPipe } from '@angular/common';
import { Router, RouterLink } from '@angular/router';
import { FormsModule } from '@angular/forms';
import { CartService, ApiService, LanguageService, AuthService } from '../../services';
import { Item, CartItem } from '../../models';
import { interval, of, Subscription } from 'rxjs';
import { catchError, exhaustMap, switchMap, take, timeout } from 'rxjs/operators';
import { EmptyCartIconComponent } from '../../components/empty-cart-icon/empty-cart-icon.component';
import { TelegramLoginComponent } from '../../components/telegram-login/telegram-login.component';
import { environment } from '../../../environments/environment';
import { getDiscountedPrice, getMainImage, trackByItemId, getBadgeClass, getTranslatedField } from '../../utils/item.utils';
import { LangRoutePipe } from '../../pipes/lang-route.pipe';
import { TranslatePipe } from '../../i18n/translate.pipe';
import { TranslateService } from '../../i18n/translate.service';
import { PAYMENT_POLL_INTERVAL_MS, PAYMENT_MAX_CHECKS, PAYMENT_TIMEOUT_CLOSE_MS, PAYMENT_ERROR_CLOSE_MS, LINK_COPIED_DURATION_MS } from '../../config/constants';

@Component({
  selector: 'app-cart',
  imports: [DecimalPipe, RouterLink, FormsModule, EmptyCartIconComponent, TelegramLoginComponent, LangRoutePipe, TranslatePipe],
  templateUrl: './cart.component.html',
  styleUrls: ['./cart.component.scss'],
  changeDetection: ChangeDetectionStrategy.OnPush
})
export class CartComponent implements OnDestroy {
  items;
  itemCount;
  totalPrice;
  termsAccepted = false;
  isnovo = environment.theme === 'novo';
  
  private i18n = inject(TranslateService);
  private authService = inject(AuthService);
  
  isAuthenticated = this.authService.isAuthenticated;

  // Swipe state
  swipedItemId = signal<number | null>(null);

  // Payment popup states
  showPaymentPopup = signal<boolean>(false);
  paymentStatus = signal<'creating' | 'waiting' | 'success' | 'timeout' | 'error'>('creating');
  qrCodeUrl = signal<string>('');
  paymentUrl = signal<string>('');
  paymentId = signal<string>('');
  linkCopied = signal<boolean>(false);
  
  // Email collection after successful payment
  userEmail = signal<string>('');
  userPhone = signal<string>('');
  emailTouched = signal<boolean>(false);
  phoneTouched = signal<boolean>(false);
  emailError = signal<string>('');
  phoneError = signal<string>('');
  emailSubmitting = signal<boolean>(false);
  paidItems: CartItem[] = [];
  
  maxChecks = PAYMENT_MAX_CHECKS;
  private pollingSubscription?: Subscription;
  private closeTimeout?: ReturnType<typeof setTimeout>;
  private qrPartnerId = '';

  constructor(
    private cartService: CartService,
    private apiService: ApiService,
    private router: Router,
    private langService: LanguageService
  ) {
    this.items = this.cartService.items;
    this.itemCount = this.cartService.itemCount;
    this.totalPrice = this.cartService.totalPrice;
  }

  requestLogin(): void {
    this.authService.requestLogin();
  }

  ngOnDestroy(): void {
    this.stopPolling();
    if (this.closeTimeout) {
      clearTimeout(this.closeTimeout);
    }
  }

  removeItem(itemID: number): void {
    this.cartService.removeItem(itemID);
    this.swipedItemId.set(null);
  }

  updateQuantity(itemID: number, quantity: number): void {
    this.cartService.updateQuantity(itemID, quantity);
  }

  increaseQuantity(itemID: number, currentQuantity: number): void {
    this.updateQuantity(itemID, currentQuantity + 1);
  }

  decreaseQuantity(itemID: number, currentQuantity: number): void {
    if (currentQuantity <= 1) {
      this.removeItem(itemID);
    } else {
      this.updateQuantity(itemID, currentQuantity - 1);
    }
  }

  onSwipeStart(itemID: number, event: TouchEvent): void {
    const item = event.currentTarget as HTMLElement;
    const startX = event.touches[0].clientX;
    
    const onMove = (e: TouchEvent) => {
      const currentX = e.touches[0].clientX;
      const diff = startX - currentX;
      
      if (diff > 50) {
        this.swipedItemId.set(itemID);
        cleanup();
      } else if (diff < -10) {
        this.swipedItemId.set(null);
        cleanup();
      }
    };
    
    const cleanup = () => {
      document.removeEventListener('touchmove', onMove);
      document.removeEventListener('touchend', cleanup);
    };
    
    document.addEventListener('touchmove', onMove);
    document.addEventListener('touchend', cleanup);
  }

  clearCart(): void {
    if (confirm(this.i18n.t('cart.confirmClear'))) {
      this.cartService.clearCart();
    }
  }

  readonly getMainImage = getMainImage;
  readonly trackByItemId = trackByItemId;
  readonly getDiscountedPrice = getDiscountedPrice;
  readonly getBadgeClass = getBadgeClass;

  itemName(item: Item): string { return getTranslatedField(item, 'name', this.langService.currentLanguage()); }
  itemDesc(item: Item): string { return getTranslatedField(item, 'simpleDescription', this.langService.currentLanguage()); }
  get currentCurrency(): string { return this.langService.currentCurrency(); }

  checkout(): void {
    if (!this.termsAccepted) {
      alert(this.i18n.t('cart.acceptTerms'));
      return;
    }
    // Auth gate: require Telegram login before payment
    if (!this.authService.isAuthenticated()) {
      this.authService.requestLogin();
      return;
    }
    this.openPaymentPopup();
  }

  openPaymentPopup(): void {
    this.showPaymentPopup.set(true);
    this.paymentStatus.set('creating');
    this.qrPartnerId = '';
    this.paymentId.set('');
    this.qrCodeUrl.set('');
    this.paymentUrl.set('');
    this.linkCopied.set(false);
    this.userEmail.set('');
    this.userPhone.set('');
    this.emailTouched.set(false);
    this.phoneTouched.set(false);
    this.emailError.set('');
    this.phoneError.set('');
    this.emailSubmitting.set(false);
    this.paidItems = [...this.items()];
    this.createPayment();
  }

  closePaymentPopup(): void {
    this.showPaymentPopup.set(false);
    this.stopPolling();
    if (this.closeTimeout) {
      clearTimeout(this.closeTimeout);
      this.closeTimeout = undefined;
    }
  }

  retryPayment(): void {
    if (this.closeTimeout) {
      clearTimeout(this.closeTimeout);
      this.closeTimeout = undefined;
    }

    this.paymentStatus.set('creating');
    this.qrPartnerId = '';
    this.paymentId.set('');
    this.qrCodeUrl.set('');
    this.paymentUrl.set('');
    this.linkCopied.set(false);
    this.createPayment();
  }

  createPayment(): void {
    const sessionId = this.authService.session()?.sessionId || '';
    const partnerQrId = this.getPartnerQrId();
    if (!partnerQrId) {
      this.setPaymentError();
      return;
    }

    const cartItems = this.items().map((item: CartItem) => ({
      itemID: item.itemID,
      quantity: item.quantity,
      colour: item.colour || '',
      size: item.size || '',
      price: item.discount > 0
        ? item.price * (1 - item.discount / 100)
        : item.price,
    }));

    const syncCart$ = sessionId
      ? this.apiService.addToCart(sessionId, cartItems).pipe(
          catchError((err) => {
            console.error('Error syncing cart:', err);
            return of(null);
          })
        )
      : of(null);

    const userIdValue = this.getUrlParam('userid-value') || undefined;
    const authorizationKey = this.getUrlParam('authorization-key') || undefined;
    const qrPayload = {
      qrtype: 'QRDynamic' as const,
      amount: Number(this.totalPrice()),
      currency: 'RUB' as const,
      partnerqrID: partnerQrId,
      qrDescription: `Order ${this.generateOrderId()}, total: ${this.totalPrice().toFixed(2)} RUB`,
      Userid: userIdValue ?? this.getPaymentUserId(),
      Reference: this.getUrlParam('ref') || (typeof window !== 'undefined' ? window.location.hostname : ''),
      RedirectUrl: 'https://fastcheck.store?id=fast-c202-4062-bcfb-8b4c8cc59adc',
    };

    syncCart$
      .pipe(
        switchMap(() => this.apiService.createPayment(qrPayload, { authorizationKey, userIdValue }))
      )
      .subscribe({
          next: (response) => {
            const qrId = this.apiService.resolvePaymentQrId(response);
            const qrUrl = this.apiService.resolvePaymentQrUrl(response);
            const paymentLink = this.apiService.resolvePaymentLink(response);

            if (!qrId || !qrUrl) {
              console.error('Payment response missing qr fields:', response);
              this.setPaymentError();
              return;
            }

            this.qrPartnerId = partnerQrId;
            this.paymentId.set(qrId);
            this.qrCodeUrl.set(qrUrl);
            this.paymentUrl.set(paymentLink);

            if (paymentLink && typeof window !== 'undefined' && window.innerWidth < 768) {
              window.location.href = paymentLink;
              return;
            }

            this.paymentStatus.set('waiting');
            this.startPolling();
          },
          error: (err) => {
            console.error('Error creating payment:', err);
            this.setPaymentError();
          }
        });
  }

  startPolling(): void {
    this.stopPolling();
    if (!this.qrPartnerId || !this.paymentId()) {
      this.setPaymentError();
      return;
    }

    this.pollingSubscription = interval(PAYMENT_POLL_INTERVAL_MS)
      .pipe(
        take(this.maxChecks), // maximum 36 checks (3 minutes)
        exhaustMap(() => {
          return this.apiService.checkPaymentStatus(this.qrPartnerId, this.paymentId()).pipe(
            timeout(8000),
            catchError((err) => {
              console.error('Error checking payment status:', err);
              return of(null);
            })
          );
        })
      )
      .subscribe({
        next: (response) => {
          if (!response) {
            return;
          }

          const paymentStatus = response.paymentStatus?.toUpperCase();
          const paymentCode = response.code?.toUpperCase();

          if (paymentStatus === 'EXPIRED' || paymentStatus === 'CANCELLED' || paymentStatus === 'REJECTED') {
            this.paymentStatus.set('timeout');
            this.stopPolling();
            if (this.closeTimeout) clearTimeout(this.closeTimeout);
            this.closeTimeout = setTimeout(() => {
              this.closePaymentPopup();
            }, PAYMENT_TIMEOUT_CLOSE_MS);
            return;
          }

          // Check if payment is successful
          if (paymentStatus === 'COMPLETED' || paymentStatus === 'APPROVED') {
            this.paymentStatus.set('success');
            this.stopPolling();
            // Clear cart but don't close popup - wait for email submission
            this.cartService.clearCart();
          }
          // Continue checking for 3 minutes regardless of other statuses
        },
        complete: () => {
          this.stopPolling();
          // If all checks are done but payment not completed
          if (this.paymentStatus() === 'waiting') {
            this.paymentStatus.set('timeout');
            // Close popup after showing timeout message
            if (this.closeTimeout) clearTimeout(this.closeTimeout);
            this.closeTimeout = setTimeout(() => {
              this.closePaymentPopup();
            }, PAYMENT_TIMEOUT_CLOSE_MS);
          }
        }
      });
  }

  stopPolling(): void {
    if (this.pollingSubscription) {
      this.pollingSubscription.unsubscribe();
      this.pollingSubscription = undefined;
    }
  }

  private setPaymentError(): void {
    this.paymentStatus.set('error');
    this.stopPolling();
    this.qrPartnerId = '';
    if (this.closeTimeout) {
      clearTimeout(this.closeTimeout);
      this.closeTimeout = undefined;
    }
  }

  copyPaymentLink(): void {
    const url = this.paymentUrl();
    if (url) {
      navigator.clipboard.writeText(url).then(() => {
        this.linkCopied.set(true);
        setTimeout(() => this.linkCopied.set(false), LINK_COPIED_DURATION_MS);
      }).catch(err => {
        console.error(this.i18n.t('cart.copyError'), err);
      });
    }
  }

  submitEmail(): void {
    // Mark both fields as touched
    this.emailTouched.set(true);
    this.phoneTouched.set(true);
    
    // Validate both fields
    this.validateEmail();
    const digitsOnly = this.userPhone().replace(/\D/g, '');
    this.validatePhone(digitsOnly);
    
    // Check if there are any errors
    if (this.emailError() || this.phoneError()) {
      return;
    }
    
    const email = this.userEmail().trim();
    const phoneRaw = this.userPhone().replace(/\D/g, ''); // Remove all formatting, send only digits
    
    this.emailSubmitting.set(true);
    
    const emailData = {
      email: email,
      phone: phoneRaw,
      telegramUserId: this.getTelegramUserId(),
      items: this.paidItems.map((item: CartItem) => ({
        itemID: item.itemID,
        name: item.name,
        price: item.discount > 0 
          ? item.price * (1 - item.discount / 100)
          : item.price,
        currency: item.currency,
        quantity: item.quantity
      }))
    };
    
    this.apiService.submitPurchaseEmail(emailData).subscribe({
      next: () => {
        this.emailSubmitting.set(false);
        // Show success message
        alert(this.i18n.t('cart.emailSuccess'));
        // Close popup and redirect to home page
        setTimeout(() => {
          this.closePaymentPopup();
          const lang = this.langService.currentLanguage();
          this.router.navigate([`/${lang}`]);
        }, 500);
      },
      error: (err) => {
        console.error('Error submitting email:', err);
        this.emailSubmitting.set(false);
        alert(this.i18n.t('cart.emailError'));
      }
    });
  }

  private getTelegramUserId(): string | null {
    const sessionTelegramUserId = this.authService.session()?.telegramUserId;
    if (sessionTelegramUserId) {
      return sessionTelegramUserId.toString();
    }

    if (typeof window !== 'undefined' && window.Telegram?.WebApp?.initDataUnsafe?.user) {
      return window.Telegram.WebApp.initDataUnsafe.user.id.toString();
    }

    return null;
  }

  private getTelegramUsername(): string {
    const sessionUsername = this.authService.session()?.username;
    if (sessionUsername) {
      return sessionUsername;
    }

    if (typeof window !== 'undefined' && window.Telegram?.WebApp?.initDataUnsafe?.user) {
      return window.Telegram.WebApp.initDataUnsafe.user.username || 'nontelegram';
    }

    return 'nontelegram';
  }

  private getPaymentUserId(): string {
    return this.getTelegramUserId() ?? `web_${Date.now()}`;
  }

  private getPartnerQrId(): string {
    const fromQuery = this.getUrlParam('id');
    if (fromQuery) return fromQuery;
    const envValue = (environment as any)['partnerqrID'];
    return typeof envValue === 'string' ? envValue : '';
  }

  private getUrlParam(name: string): string | null {
    if (typeof window === 'undefined') return null;
    return new URLSearchParams(window.location.search).get(name);
  }

  private generateOrderId(): string {
    const timestamp = Date.now();
    const random = Math.random().toString(36).substring(2, 8);
    return `order_${timestamp}_${random}`;
  }

  onPhoneInput(event: Event): void {
    const input = event.target as HTMLInputElement;
    let value = input.value.replace(/\D/g, ''); // Remove all non-digits
    
    // Auto-add +7 for Russian numbers
    if (value.length > 0 && !value.startsWith('7') && !value.startsWith('8')) {
      value = '7' + value;
    }
    
    // Convert 8 to 7 for Russian format
    if (value.startsWith('8')) {
      value = '7' + value.substring(1);
    }
    
    // Format: +7 (XXX) XXX-XX-XX
    let formatted = '';
    if (value.length > 0) {
      formatted = '+7';
      if (value.length > 1) {
        formatted += ' (' + value.substring(1, 4);
      }
      if (value.length >= 4) {
        formatted += ') ' + value.substring(4, 7);
      }
      if (value.length >= 7) {
        formatted += '-' + value.substring(7, 9);
      }
      if (value.length >= 9) {
        formatted += '-' + value.substring(9, 11);
      }
    }
    
    this.userPhone.set(formatted);
    this.validatePhone(value);
  }

  onPhoneBlur(): void {
    this.phoneTouched.set(true);
    const digitsOnly = this.userPhone().replace(/\D/g, '');
    this.validatePhone(digitsOnly);
  }

  validatePhone(digitsOnly: string): void {
    if (!this.phoneTouched() && digitsOnly.length === 0) {
      this.phoneError.set('');
      return;
    }

    if (digitsOnly.length === 0) {
      this.phoneError.set(this.i18n.t('cart.phoneRequired'));
    } else if (digitsOnly.length < 11) {
      this.phoneError.set(this.i18n.t('cart.phoneMoreDigits', { count: 11 - digitsOnly.length }));
    } else if (digitsOnly.length > 11) {
      this.phoneError.set(this.i18n.t('cart.phoneTooMany'));
    } else {
      this.phoneError.set('');
    }
  }

  onEmailInput(event: Event): void {
    const input = event.target as HTMLInputElement;
    this.userEmail.set(input.value);
    if (this.emailTouched()) {
      this.validateEmail();
    }
  }

  onEmailBlur(): void {
    this.emailTouched.set(true);
    this.validateEmail();
  }

  validateEmail(): void {
    const email = this.userEmail().trim();
    
    if (!this.emailTouched() && email.length === 0) {
      this.emailError.set('');
      return;
    }

    if (email.length === 0) {
      this.emailError.set(this.i18n.t('cart.emailRequired'));
    } else if (email.length < 5) {
      this.emailError.set(this.i18n.t('cart.emailTooShort'));
    } else if (email.length > 100) {
      this.emailError.set(this.i18n.t('cart.emailTooLong'));
    } else if (!email.includes('@')) {
      this.emailError.set(this.i18n.t('cart.emailNeedsAt'));
    } else if (!email.includes('.')) {
      this.emailError.set(this.i18n.t('cart.emailNeedsDomain'));
    } else {
      const emailRegex = /^[^\s@]+@[^\s@]+\.[^\s@]+$/;
      if (!emailRegex.test(email)) {
        this.emailError.set(this.i18n.t('cart.emailInvalid'));
      } else {
        this.emailError.set('');
      }
    }
  }
}