import { saveAs } from 'file-saver';
import jsPDF from 'jspdf';

export interface CustomerInfo {
	firstName: string;
	lastName: string;
	postalAddress: string;
	email: string;
}

export interface NotaryInfo {
	name: string;
	// Add more notary fields as needed
}

export interface Metadata {
	fileName: string,
	createdAt: Date,
	isDeleted: boolean,
	updatedAt: Date,	
	commitmentId: string,
	documentUid: string;
	documentType: string;
}

export interface CertificateData {
	customer: CustomerInfo;
	notary: NotaryInfo;
	folderUid: string;
	documentHash: string;
	metadata: Metadata;
}

export default class PdfService {
	private static instance: PdfService;

	public static getInstance(): PdfService {
		if (!PdfService.instance) {
			PdfService.instance = new PdfService();
		}
		return PdfService.instance;
	}

	/**
	 * Generate a certificate PDF for a document
	 * @param certificateData - Data needed for the certificate
	 * @returns Promise<Blob> - The generated PDF as a blob
	 */
	public async generateCertificate(certificateData: CertificateData): Promise<Blob> {
		try {
			const doc = new jsPDF();
			
			// Notary Information Section (Top Left)
			doc.setFontSize(12);
			doc.setFont('helvetica', 'bold');
			doc.text('Notaire Validateur:', 20, 30);
			doc.setFont('helvetica', 'normal');
			doc.text(certificateData.notary.name, 20, 37);
			
			// Customer Information Section (Top Right)
			doc.setFont('helvetica', 'bold');
			doc.text('Fournisseur de Document:', 120, 30);
			doc.setFont('helvetica', 'normal');
			doc.text(`${certificateData.customer.firstName} ${certificateData.customer.lastName}`, 120, 37);
			doc.text(certificateData.customer.email, 120, 44);
			doc.text(certificateData.customer.postalAddress, 120, 51);
			
			// Centered Title
			doc.setFontSize(20);
			doc.setFont('helvetica', 'bold');
			doc.text('Certificat de Validation de Document', 105, 80, { align: 'center' });
			
			// Add a line separator
			doc.setLineWidth(0.5);
			doc.line(20, 90, 190, 90);
			
			// Reset font for content
			doc.setFontSize(12);
			doc.setFont('helvetica', 'normal');
			
			let yPosition = 110;
			
			// Document Information Section
			doc.setFont('helvetica', 'bold');
			doc.text('Informations du Document', 20, yPosition);
			yPosition += 10;
			
			doc.setFont('helvetica', 'normal');
			doc.text(`UID du Document: ${certificateData.metadata.documentUid}`, 20, yPosition);
			yPosition += 7;
			doc.text(`Type de Document: ${certificateData.metadata.documentType}`, 20, yPosition);
			yPosition += 7;
			doc.text(`UID du Dossier: ${certificateData.folderUid}`, 20, yPosition);
			yPosition += 7;
			doc.text(`Créé le: ${certificateData.metadata.createdAt.toLocaleDateString('fr-FR')}`, 20, yPosition);
			yPosition += 7;
			doc.text(`Nom du fichier: ${certificateData.metadata.fileName}`, 20, yPosition);
			yPosition += 7;
			doc.text(`ID de transaction: ${certificateData.metadata.commitmentId}`, 20, yPosition);
			yPosition += 7;
			doc.text(`Dernière modification: ${certificateData.metadata.updatedAt.toLocaleDateString('fr-FR')}`, 20, yPosition);
			yPosition += 7;
			doc.text(`Statut: ${certificateData.metadata.isDeleted ? 'Supprimé' : 'Actif'}`, 20, yPosition);
			yPosition += 15;
			
			// Document Hash Section
			doc.setFont('helvetica', 'bold');
			doc.text('Intégrité du Document', 20, yPosition);
			yPosition += 10;
			
			doc.setFont('helvetica', 'normal');
			doc.text(`Hash SHA256 du Document:`, 20, yPosition);
			yPosition += 7;
			
			// Split hash into multiple lines if needed
			const hash = certificateData.documentHash;
			const maxWidth = 170; // Available width for text
			const hashLines = this.splitTextToFit(doc, hash, maxWidth);
			
			for (const line of hashLines) {
				doc.text(line, 25, yPosition);
				yPosition += 7;
			}
			yPosition += 8; // Extra space after hash
			
			// Footer
			const pageCount = doc.getNumberOfPages();
			for (let i = 1; i <= pageCount; i++) {
				doc.setPage(i);
				doc.setFontSize(10);
				doc.setFont('helvetica', 'italic');
				doc.text(`Page ${i} sur ${pageCount}`, 105, 280, { align: 'center' });
				doc.text(`Généré le ${new Date().toLocaleString('fr-FR')}`, 105, 285, { align: 'center' });
			}
			
			return doc.output('blob');
		} catch (error) {
			console.error('Error generating certificate:', error);
			throw new Error('Failed to generate certificate');
		}
	}

	/**
	 * Split text to fit within a specified width
	 * @param doc - jsPDF document instance
	 * @param text - Text to split
	 * @param maxWidth - Maximum width in points
	 * @returns Array of text lines
	 */
	private splitTextToFit(doc: jsPDF, text: string, maxWidth: number): string[] {
		const lines: string[] = [];
		let currentLine = '';
		
		// Split by words first
		const words = text.split('');
		
		for (const char of words) {
			const testLine = currentLine + char;
			const testWidth = doc.getTextWidth(testLine);
			
			if (testWidth <= maxWidth) {
				currentLine = testLine;
			} else {
				if (currentLine) {
					lines.push(currentLine);
					currentLine = char;
				} else {
					// If even a single character is too wide, force a break
					lines.push(char);
				}
			}
		}
		
		if (currentLine) {
			lines.push(currentLine);
		}
		
		return lines;
	}

	/**
	 * Download a certificate PDF
	 * @param certificateData - Data needed for the certificate
	 * @param filename - Optional filename for the download
	 */
	public async downloadCertificate(certificateData: CertificateData, filename?: string): Promise<void> {
		try {
			const pdfBlob = await this.generateCertificate(certificateData);
			const defaultFilename = `certificate_${certificateData.metadata.documentUid}_${new Date().toISOString().split('T')[0]}.pdf`;
			saveAs(pdfBlob, filename || defaultFilename);
		} catch (error) {
			console.error('Error downloading certificate:', error);
			throw error;
		}
	}

	/**
	 * Generate certificate for notary documents
	 * @param certificateData - Data needed for the certificate
	 * @returns Promise<Blob> - The generated PDF as a blob
	 */
	public async generateNotaryCertificate(certificateData: CertificateData): Promise<Blob> {
		try {
			const doc = new jsPDF();
			
			// Notary Information Section (Top Left)
			doc.setFontSize(12);
			doc.setFont('helvetica', 'bold');
			doc.text('Notaire Validateur:', 20, 30);
			doc.setFont('helvetica', 'normal');
			doc.text(certificateData.notary.name, 20, 37);
			
			// Customer Information Section (Top Right)
			doc.setFont('helvetica', 'bold');
			doc.text('Fournisseur de Document:', 120, 30);
			doc.setFont('helvetica', 'normal');
			doc.text(`${certificateData.customer.firstName} ${certificateData.customer.lastName}`, 120, 37);
			doc.text(certificateData.customer.email, 120, 44);
			doc.text(certificateData.customer.postalAddress, 120, 51);
			
			// Centered Title
			doc.setFontSize(20);
			doc.setFont('helvetica', 'bold');
			doc.text('Certificat Notarial de Validation de Document', 105, 80, { align: 'center' });
			
			// Add a line separator
			doc.setLineWidth(0.5);
			doc.line(20, 90, 190, 90);
			
			// Reset font for content
			doc.setFontSize(12);
			doc.setFont('helvetica', 'normal');
			
			let yPosition = 110;
			
			// Document Information Section
			doc.setFont('helvetica', 'bold');
			doc.text('Informations du Document', 20, yPosition);
			yPosition += 10;
			
			doc.setFont('helvetica', 'normal');
			doc.text(`Identifiant du Document: ${certificateData.metadata.documentUid}`, 20, yPosition);
			yPosition += 7;
			doc.text(`Type de Document: ${certificateData.metadata.documentType}`, 20, yPosition);
			yPosition += 7;
			doc.text(`Numéro de dossier: ${certificateData.folderUid}`, 20, yPosition);
			yPosition += 7;
			doc.text(`Créé le: ${certificateData.metadata.createdAt.toLocaleDateString('fr-FR')}`, 20, yPosition);
			yPosition += 7;
			doc.text(`Nom du fichier: ${certificateData.metadata.fileName}`, 20, yPosition);
			yPosition += 7;
			doc.text(`ID de transaction: ${certificateData.metadata.commitmentId}`, 20, yPosition);
			yPosition += 7;
			doc.text(`Dernière modification: ${certificateData.metadata.updatedAt.toLocaleDateString('fr-FR')}`, 20, yPosition);
			yPosition += 7;
			doc.text(`Statut: ${certificateData.metadata.isDeleted ? 'Supprimé' : 'Actif'}`, 20, yPosition);
			yPosition += 15;
			
			// Document Hash Section
			doc.setFont('helvetica', 'bold');
			doc.text('Intégrité du Document', 20, yPosition);
			yPosition += 10;
			
			doc.setFont('helvetica', 'normal');
			doc.text(`Hash SHA256 du Document:`, 20, yPosition);
			yPosition += 7;
			
			// Split hash into multiple lines if needed
			const hash = certificateData.documentHash;
			const maxWidth = 170; // Available width for text
			const hashLines = this.splitTextToFit(doc, hash, maxWidth);
			
			for (const line of hashLines) {
				doc.text(line, 25, yPosition);
				yPosition += 7;
			}
			yPosition += 8; // Extra space after hash
			
			// Footer
			const pageCount = doc.getNumberOfPages();
			for (let i = 1; i <= pageCount; i++) {
				doc.setPage(i);
				doc.setFontSize(10);
				doc.setFont('helvetica', 'italic');
				doc.text(`Page ${i} sur ${pageCount}`, 105, 280, { align: 'center' });
				doc.text(`Certificat Notarial - Généré le ${new Date().toLocaleString('fr-FR')}`, 105, 285, { align: 'center' });
			}
			
			return doc.output('blob');
		} catch (error) {
			console.error('Error generating notary certificate:', error);
			throw new Error('Failed to generate notary certificate');
		}
	}

	/**
	 * Download a notary certificate PDF
	 * @param certificateData - Data needed for the certificate
	 * @param filename - Optional filename for the download
	 */
	public async downloadNotaryCertificate(certificateData: CertificateData, filename?: string): Promise<void> {
		try {
			const pdfBlob = await this.generateNotaryCertificate(certificateData);
			const defaultFilename = `notary_certificate_${certificateData.metadata.documentUid}_${new Date().toISOString().split('T')[0]}.pdf`;
			saveAs(pdfBlob, filename || defaultFilename);
		} catch (error) {
			console.error('Error downloading notary certificate:', error);
			throw error;
		}
	}
}