using Comal.Stores;
using InABox.Core;
using System;
using System.Linq;
using System.IO;
using Syncfusion.Pdf.Parsing;
using System.Drawing;
using System.Drawing.Imaging;

namespace PRSStores
{
    //In order to have BeforeSave active for a specific EntityDocument, it has to be concretized from this abstract class
    public abstract class EntityDocumentStore<TEntityDocument, TEntity, TEntityLink> : BaseStore<TEntityDocument>
        where TEntityDocument : EntityDocument<TEntityLink>, new()
        where TEntityLink : EntityLink<TEntity>, new()
         where TEntity : Entity, new()
    {
        protected override void BeforeSave(TEntityDocument entity)
        {
            SaveThumbnail(entity); //current size for saved thumbnails is 256*256
            base.BeforeSave(entity);           
        }

        private void SaveThumbnail(TEntityDocument entity)
        {         
            if (entity.DocumentLink.ID == Guid.Empty)
                return;

            if (entity.Thumbnail?.Any() == true)
                return;
            
            CoreTable table = Provider.Query<Document>(new Filter<Document>(x => x.ID).IsEqualTo(entity.DocumentLink.ID),
                new Columns<Document>(x => x.Data, x => x.FileName));

            if (table.Rows.Count == 0)
                return;

            Document doc = table.Rows.FirstOrDefault().ToObject<Document>();
            if (!doc.FileName.ToLower().EndsWith("pdf"))
                return;

            try
            {
                PdfLoadedDocument loadeddoc = new PdfLoadedDocument(doc.Data);
                Bitmap image = loadeddoc.ExportAsImage(0, new SizeF(256, 256), true);
                MemoryStream stream = new MemoryStream();
                image.Save(stream, ImageFormat.Jpeg);
                entity.Thumbnail = stream.ToArray();
            }
            catch (Exception ex) 
            {
                Logger.Send(LogType.Information, UserID, ex.Message);
            }
        }
    }

}