using System;
using System.IO;
using System.Text;
using PdfSharp.Pdf;
using PdfSharp.Pdf.IO;
using Serilog;
using Newtonsoft.Json;
using LCU.Library.Internal.Exceptions;
using LCU.Library.Internal.FileOperationsModels.Models;
namespace LCU.Api.Internal.FileOperations.Services.PdfServices;

public class PdfParserService : IPdfParserService
{
    public string ParsePdf(ParsePdfRequest parsePdfRequest)
    {
        try
        {
            var fullPath = Path.Combine(parsePdfRequest.RootPath, parsePdfRequest.PdfName);
            var inputDocument = PdfReader.Open(fullPath, PdfDocumentOpenMode.Import);
            
            
            var startIndex = parsePdfRequest.PageStart - 1;
            var stopIndex = parsePdfRequest.PageStop - 1;
            var outputDocument = new PdfDocument();
            for (int page = startIndex; page <= stopIndex; page++)
            {
                outputDocument.Version = inputDocument.Version;
                outputDocument.Info.Title = inputDocument.Info.Title;
                outputDocument.Info.Creator = inputDocument.Info.Creator;
                outputDocument.AddPage(inputDocument.Pages[page]);
            }

            string name = Path.GetFileNameWithoutExtension(parsePdfRequest.PdfName);
            var newPdfName = string.IsNullOrWhiteSpace(parsePdfRequest.ParsedPdfname) ? $"{name}.{parsePdfRequest.PageStart}.pdf" : parsePdfRequest.ParsedPdfname;
            var newPath = Path.Combine(parsePdfRequest.RootPath, newPdfName);
            Encoding.RegisterProvider(CodePagesEncodingProvider.Instance);
            outputDocument.Save(newPath);

            return newPdfName;
        }
        catch (Exception exception)
        {
            Log.Error(exception, $"Failure to Parse Pdf. ParsePdfRequest:{JsonConvert.SerializeObject(parsePdfRequest)}");
            throw new ServiceException($"Failure to Parse Pdf. ExceptionMessage:{exception.Message}");
        }
    }
}