Install-Package Spire.PDF

using System;
using System.Collections.Generic;
using System.Drawing;
using System.IO;
using Spire.Additions.Qt;
using Spire.Pdf.Graphics;
using Spire.Pdf.HtmlConverter;

namespace CreatePdfFromHtmlTemplate
{
    class Program
    {
        static void Main(string[] args)
        {
            // Path to the HTML template file
            string htmlFilePath = "invoice_template.html";

            // Step 1: Read the HTML template from file
            if (!File.Exists(htmlFilePath))
            {
                Console.WriteLine("Error: HTML template file not found.");
                return;
            }

            string htmlTemplate = File.ReadAllText(htmlFilePath);

            // Step 2: Define dynamic data for invoice placeholders
            Dictionary<string, string> invoiceData = new Dictionary<string, string>()
            {
                { "INVOICE_NUMBER", "INV-2025-001" },
                { "INVOICE_DATE", DateTime.Now.ToString("yyyy-MM-dd") },
                { "BILLER_NAME", "John Doe" },
                { "BILLER_ADDRESS", "123 Main Street, New York, USA" },
                { "BILLER_EMAIL", "john.doe@example.com" },
                { "ITEM_DESCRIPTION", "Consulting Services" },
                { "ITEM_QUANTITY", "10" },
                { "ITEM_UNIT_PRICE", "$100" },
                { "ITEM_TOTAL", "$1000" },
                { "SUBTOTAL", "$1000" },
                { "TAX_RATE", "5" },
                { "TAX", "$50" },
                { "TOTAL", "$1050" }
            };

            // Step 3: Replace placeholders in the HTML template with real values
            string populatedInvoice = PopulateInvoice(htmlTemplate, invoiceData);

            // Optional: Save the populated HTML for debugging or review
            File.WriteAllText("invoice_ready.html", populatedInvoice);

            // Step 4: Specify the plugin path for the HTML to PDF conversion
            string pluginPath = @"C:\plugins-windows-x64\plugins";
            HtmlConverter.PluginPath = pluginPath;

            // Step 5: Define output PDF file path
            string outputFile = "InvoiceOutput.pdf";

            try
            {
                // Step 6: Convert the HTML string to PDF
                HtmlConverter.Convert(
                    populatedInvoice,
                    outputFile,
                    enableJavaScript: true,
                    timeout: 100000,                // 100 seconds
                    pageSize: new SizeF(595, 842),  // A4 size in points
                    margins: new PdfMargins(20),    // 20-point margins
                    loadHtmlType: LoadHtmlType.SourceCode
                );

                Console.WriteLine($"PDF generated successfully: {outputFile}");
            }
            catch (Exception ex)
            {
                Console.WriteLine($"Error during PDF generation: {ex.Message}");
            }
        }

        /// <summary>
        /// Helper method: Replaces placeholders in the HTML with actual data values.
        /// </summary>
        private static string PopulateInvoice(string template, Dictionary<string, string> data)
        {
            string result = template;
            foreach (var entry in data)
            {
                result = result.Replace("{" + entry.Key + "}", entry.Value);
            }
            return result;
        }
    }
}