import { Injectable, ComponentRef, ViewContainerRef, ApplicationRef, createComponent, EnvironmentInjector, inject, signal } from '@angular/core';
import html2canvas from 'html2canvas';
import jsPDF from 'jspdf';
import { Eintrittskarte } from '@infinimotion/model-frontend';

@Injectable({
  providedIn: 'root',
})
export class PdfService {
  private ticketsGreatedSignal = signal(0);
  private totalTicketsSignal = signal(0);

  readonly ticketsGreated = this.ticketsGreatedSignal.asReadonly();
  readonly totalTickets = this.totalTicketsSignal.asReadonly();

  appRef = inject(ApplicationRef);
  injector = inject(EnvironmentInjector);

  async genTicket(tickets: Eintrittskarte[], ticketComponent: any): Promise<void> {
    if (tickets.length === 0) {
      throw new Error('Keine Tickets zum Generieren vorhanden');
    }

    this.ticketsGreatedSignal.set(0)
    this.totalTicketsSignal.set(tickets.length)

    // Container für temporäres Rendering erstellen
    const container = document.createElement('div');
    container.style.position = 'fixed';
    container.style.left = '-9999px';
    container.style.top = '0';
    document.body.appendChild(container);

    const componentRefs: ComponentRef<any>[] = [];

    try {
      // Ticket-Format: 210mm x 99mm
      const ticketWidthMM = 210;
      const ticketHeightMM = 99;

      const pdf = new jsPDF({
        orientation: 'landscape',
        unit: 'mm',
        format: [ticketWidthMM, ticketHeightMM]
      });

      for (let i = 0; i < tickets.length; i++) {
        const ticket = tickets[i];

        // Komponente dynamisch erstellen
        const componentRef = createComponent(ticketComponent, {
          environmentInjector: this.injector
        });

        // Ticket-Daten an die Komponente übergeben
        (componentRef.instance as any).ticket = ticket;

        // Komponente ins DOM einfügen
        this.appRef.attachView(componentRef.hostView);
        container.appendChild(componentRef.location.nativeElement);
        componentRefs.push(componentRef);

        // Change Detection triggern
        componentRef.changeDetectorRef.detectChanges();

        // Kurz warten, damit alles gerendert ist
        await new Promise(requestAnimationFrame);

        // HTML zu Canvas konvertieren
        const canvas = await html2canvas(componentRef.location.nativeElement, {
          scale: 2,
          backgroundColor: '#ffffff',
          logging: false,
          useCORS: true
        });

        const imgData = canvas.toDataURL('image/png');

        if (i > 0) {
          pdf.addPage([ticketWidthMM, ticketHeightMM], 'landscape');
        }

        // Bild ins PDF einfügen
        pdf.addImage(imgData, 'PNG', 0, 0, ticketWidthMM, ticketHeightMM);

        this.ticketsGreatedSignal.set(this.ticketsGreatedSignal() + 1)
      }

      const fileName = this.generateFileName(tickets);
      pdf.save(fileName);

    } catch (error) {
      console.error('Fehler beim Generieren des PDFs:', error);
      throw new Error('Das PDF konnte nicht erstellt werden. Bitte versuche es erneut.');
    } finally {
      componentRefs.forEach(ref => {
        this.appRef.detachView(ref.hostView);
        ref.destroy();
      });
      document.body.removeChild(container);
    }
  }

  private generateFileName(tickets: Eintrittskarte[]): string {
    const orderCode = tickets[0].order.code;
    const timestamp = new Date().getTime();

    return `Ticket_${orderCode}_${timestamp}.pdf`;
  }

  downloadTextFile(content: string, filename: string = 'textdatei.txt'): void {

    const blob = new Blob([content], { type: 'text/plain;charset=utf-8' });
    const url = window.URL.createObjectURL(blob);

    const link = document.createElement('a');
    link.href = url;
    link.download = filename;

    document.body.appendChild(link);
    link.click();
    document.body.removeChild(link);

    window.URL.revokeObjectURL(url);
  }

  downloadJsonFile(data: any, filename: string = 'data.json'): void {
    const content = JSON.stringify(data, null, 2);
    const blob = new Blob([content], { type: 'application/json' });
    const url = window.URL.createObjectURL(blob);

    const link = document.createElement('a');
    link.href = url;
    link.download = filename;
    document.body.appendChild(link);
    link.click();
    document.body.removeChild(link);
    window.URL.revokeObjectURL(url);
  }
}