using System;
using System.Configuration;
using System.Diagnostics;
using System.Net.Mail;

namespace ChadSoft.Edificator
{
    internal class MailService : IMailService
    {
        private const string DefaultSubjectFormat = "[Wisdom] {0}";
        
        private readonly SmtpClient _mailClient;
        private readonly string _senderEmailAddress;
        private readonly string _recipientEmailAddresses;

        private static readonly string _subjectFormat = ConfigurationManager.AppSettings["MailService.SubjectFormat"];
        protected static string SubjectFormat
        {
            get
            {
                return string.IsNullOrEmpty(_subjectFormat) ? DefaultSubjectFormat : _subjectFormat;
            }
        }

        public MailService(string host, string senderEmailAddress, string recipientEmailAddresses)
            : this(new SmtpClient(host), senderEmailAddress, recipientEmailAddresses)
        {
        }

        public MailService(SmtpClient mailClient, string senderEmailAddress, string recipientEmailAddresses)
        {
            _mailClient = mailClient;
            _senderEmailAddress = senderEmailAddress;
            _recipientEmailAddresses = recipientEmailAddresses;
        }


        public void Mail(WisdomBit bitOfWisdom)
        {
            Mail(bitOfWisdom, _recipientEmailAddresses);
        }

        public void Mail(WisdomBit bitOfWisdom, string recipientAddresses)
        {
            MailMessage emailMessage = CreateEmailMessage(bitOfWisdom, recipientAddresses);
            SendMessage(emailMessage);

            Debug.WriteLine(string.Format("Bit of Wisdom '{0}' sent to {1}", emailMessage.Subject, recipientAddresses));
        }

        protected virtual MailMessage CreateEmailMessage(WisdomBit bitOfWisdom, string recipientAddresses)
        {
            if (string.IsNullOrEmpty(recipientAddresses))
                throw new ArgumentNullException("recipientAddresses");

            string subject = string.Format(SubjectFormat, bitOfWisdom.Title);
            string body = string.Format("<h1><a href='{0}'>{1}</a></h1><div>{2}</div>",
                                        bitOfWisdom.Uri.AbsoluteUri, bitOfWisdom.Title, bitOfWisdom.Content);

            MailMessage message = new MailMessage(_senderEmailAddress, recipientAddresses, subject, body) { IsBodyHtml = true };
            return message;
        }

        protected virtual void SendMessage(MailMessage emailMessage)
        {
            _mailClient.Send(emailMessage);
        }
    }
}