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

public class BatchPdfParserService : FileActionService, IFileActionService, IBatchPdfParserService
{
	public BatchPdfParserService(ServicesFactoryConfiguration servicesFactoryConfiguration)
        : base(servicesFactoryConfiguration)
	{
	}

	public RequestResponse ExecuteAction(QueueRequest queueRequest)
    {
        var requestResponse = new RequestResponse();
        try
        {
            var request = JsonConvert.DeserializeObject<BatchParsePdfRequest>(queueRequest.Request);
            requestResponse = PerformRequest(request);
            requestResponse.ReturnResponse = request;
            return requestResponse;
        }
        catch (Exception exception)
        {
            return RequestResponseHelper.ExceptionUpdateRequestResponse(requestResponse,
                                                                        queueRequest.FileOperationType,
                                                                        exception.Message);
        }
    }

    public RequestResponse PerformRequest(BatchParsePdfRequest request)
    {
        return OperationService.PerformOperation(request, IsRequestValid, BatchParsePdfs);
    }

    public void BatchParsePdfs(BatchParsePdfRequest batchParsePdfRequest)
    {
        try
        {
            var inputDocument = PdfReader.Open(batchParsePdfRequest.FullPdfPath, PdfDocumentOpenMode.Import);
            foreach(var batchPdf in batchParsePdfRequest.BatchPdfs)
            {
                ParseAndSavePdf(batchParsePdfRequest, batchPdf, inputDocument);
            }
        }
        catch (Exception exception)
        {
            Log.Error(exception, $"Failure to Batch Parse Pdfs. ParsePdfRequest:{JsonConvert.SerializeObject(batchParsePdfRequest)}");
            throw new Exception($"Failure to Batch Parse Pdfs. ExceptionMessage:{exception.Message}");
        }
    }    

    public void ParseAndSavePdf(BatchParsePdfRequest batchParsePdfRequest, BatchPdf batchPdf, PdfDocument inputDocument)
    {
        var outputDocument = AddPdfPagesToOutputDocument(batchPdf.PageStart, batchPdf.PageStop, inputDocument);
        string name = Path.GetFileNameWithoutExtension(batchParsePdfRequest.PdfName);
        var newPdfName = string.IsNullOrWhiteSpace(batchPdf.ParsedPdfname) ? $"{name}.{batchPdf.PageStart}.pdf" : batchPdf.ParsedPdfname;
        var newPath = Path.Combine(batchParsePdfRequest.RootPath, newPdfName);
        Encoding.RegisterProvider(CodePagesEncodingProvider.Instance);
        outputDocument.Save(newPath);
    }

    public PdfDocument AddPdfPagesToOutputDocument(int pageStart, int pageStop, PdfDocument inputDocument)
    {
        var startIndex = pageStart - 1;
        var stopIndex = 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]);
        }

        return outputDocument;
    }

    public RequestResponse IsRequestValid(BatchParsePdfRequest request, RequestResponse requestResponse)
    {
        requestResponse = DirectoryValidation.ValidateDirectoryExists(request.RootPath, requestResponse);
        requestResponse = FileValidation.ValidateFileExists(request.FullPdfPath, requestResponse);
        return requestResponse;
    }
}