using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Xml;
using System.Xml.Serialization;
using log4net;
using Microsoft.Practices.ServiceLocation;
using Taloyhtio.GeneralApi.Common.DTO;
using Taloyhtio.GeneralApi.Common.Extensions;

namespace Taloyhtio.GeneralApi.IntegrationUtility.Services.Impl
{
    public class FileParser<T> : IFileParser<T>
        where T : class
    {
        private ILog logger = ServiceLocator.Current.GetInstance<ILog>();

        public List<T> Parse(string filePath)
        {
            try
            {
                if (string.IsNullOrEmpty(filePath))
                {
                    this.logger.Warn("File path is null or empty. It won't be parsed");
                    return new List<T>();
                }
                this.logger.InfoFormat("Open file '{0}' for parsing", filePath);
                using (var fs = File.OpenRead(filePath))
                {
                    using (var xmlReader = new XmlTextReader(fs))
                    {
                        var deserializer = new XmlSerializer(typeof(T[]));
                        if (!deserializer.CanDeserialize(xmlReader))
                        {
                            this.logger.WarnFormat("Can not deserialize file '{0}'", filePath);
                            return new List<T>();
                        }

                        var items = deserializer.Deserialize(xmlReader) as T[];
                        if (items.IsNullOrEmpty())
                        {
                            this.logger.Warn("Deserialization was successfull but no items were returned");
                            return new List<T>();
                        }
                        this.logger.InfoFormat("'{0}' item(s) were returned from the deserializer", items.Length);
                        this.logger.InfoFormat("Close file '{0}'", filePath);
                        return new List<T>(items);
                    }
                }
            }
            catch (Exception x)
            {
                this.logger.ErrorFormat(string.Format("{0}\n{1}", x.Message, x.StackTrace));
                return new List<T>();
            }
        }
    }
}