using System;
using System.Configuration;
using System.IO;
using System.Linq;
using System.Net.Mail;
using LeafWeb.Core.DAL;
using LeafWeb.Core.Entities;
using NLog;

namespace LeafWeb.Web.Services
{
	public class EmailNotificationService : IDisposable
	{
		private static readonly Logger Logger = LogManager.GetCurrentClassLogger();

		private readonly string _emaialFromAddress;

		private readonly SmtpClient _smtpClient;

		private readonly DataService _dataService;

		public EmailNotificationService(DataService dataService)
		{
			_dataService = dataService;

			_smtpClient = new SmtpClient();

			_emaialFromAddress = ConfigurationManager.AppSettings["EmailFromAddress"];
		}

		public EmailNotificationService() : this(new DataService())
		{ }

		public void SendLeafWebError(int leafInputId, string errorMessage)
		{
			var leafInput = _dataService.GetLeafInput(leafInputId);
			var body = $"Your leaf analysis job, {leafInput.Identifier}, encountered the following errors." + Environment.NewLine
				+ "You will need to correct your input and resubmit." + Environment.NewLine + Environment.NewLine
				+ errorMessage;
			var message = new MailMessage(_emaialFromAddress, leafInput.Email, "LeafWeb processing error", body);
			SendMessage(message);
		}

		public void SendLeafWebComplete(int leafInputId)
		{
			var leafInput = _dataService.GetLeafInput(leafInputId);
			var body = $"Your leaf analysis job, {leafInput.Identifier}, has completed." + Environment.NewLine;
			var message = new MailMessage(_emaialFromAddress, leafInput.Email, "LeafWeb results", body);

			var fileStreams =
				(from outputFile in
					leafInput.OutputFiles
					select Tuple.Create(outputFile, new MemoryStream(outputFile.Contents))).ToList();

			try
			{
				foreach (var fileStream in fileStreams)
				{
					var attachment = new Attachment(fileStream.Item2, fileStream.Item1.Filename);
					message.Attachments.Add(attachment);
				}

				SendMessage(message);
			}
			finally
			{
				// can't dispose those memory streams until the message is sent
				foreach (var stream in fileStreams.Select(f => f.Item2))
				{
					stream.Dispose();
				}
			}
		}

		private void SendMessage(MailMessage mailMessage)
		{
			try
			{
				Logger.Debug("Email sending to " + mailMessage.To + ", subject: " + mailMessage.Subject);
				_smtpClient.Send(mailMessage);
			}
			catch (SmtpException ex)
			{
				Logger.Error(ex, "Failed to send mail: {0}", ex.Message);
			}
		}

		public void Dispose()
		{
			_dataService.Dispose();
		}
	}
}