using System;
using System.Threading.Tasks;
using Microsoft.Extensions.Options;
using SendGrid;
using SendGrid.Helpers.Mail;

namespace gehGassi.Web.Services
{
    /// <summary>
    /// Schnittstellenbeschreibung für einen Service der den Email-Versand ermöglicht
    /// </summary>
    public interface IEmailSender
    {
        /// <summary>
        /// Sendet eine Email an eine Adresse
        /// </summary>
        /// <param name="email">E-Mail Adresse</param>
        /// <param name="subject">Betreff</param>
        /// <param name="message">Nachricht</param>
        /// <returns>Task</returns>
        Task SendEmailAsync(string email, string subject, string message);
        
        /// <summary>
        /// Sendet eine Email an eine Adresse
        /// </summary>
        /// <param name="email">E-Mail Adresse</param>
        /// <param name="subject">Betreff</param>
        /// <param name="message">Nachricht</param>
        /// <param name="attachement">Attachement-File</param>
        /// <param name="attachementName">Dateiname des Attachement</param>
        /// <returns>Task</returns>
        Task SendEmailAsync(string email, string subject, string message, byte[] attachement, string attachementName);

        /// <summary>
        /// Sendet eine Email an eine Adresse
        /// </summary>
        /// <param name="from">Absender-Name</param>
        /// <param name="fromEmail">Absender Email</param>
        /// <param name="to">Ziel-Name</param>
        /// <param name="toEmail">Ziel Email</param>
        /// <param name="subject">Betreff</param>
        /// <param name="message">Nachricht</param>
        /// <returns>Task</returns>
        Task SendEmailAsync(string from, string fromEmail, string to, string toEmail, string subject, string message);
    }

    /// <summary>
    /// Service der den Email-Versand ermöglicht
    /// </summary>
    public class EmailSender : IEmailSender
    {
        private readonly IOptions<Helper.EmailSenderOptions> _emailOptions;

        /// <summary>
        /// ERstellt eine Instanz
        /// </summary>
        /// <param name="emailOptions">Einstellungen für den Email-Versand</param>
        public EmailSender(IOptions<Helper.EmailSenderOptions> emailOptions)
        {
            _emailOptions = emailOptions;
        }

        /// <summary>
        /// Sendet eine Email an eine Adresse
        /// </summary>
        /// <param name="email">E-Mail Adresse</param>
        /// <param name="subject">Betreff</param>
        /// <param name="message">Nachricht</param>
        /// <returns>Task</returns>
        public async Task SendEmailAsync(string email, string subject, string message)
        {
            var client = new SendGridClient(_emailOptions.Value.SendGridKey);
            var msg = new SendGridMessage()
            {
                From = new EmailAddress(_emailOptions.Value.Email, _emailOptions.Value.Name),
                Subject = subject,
                PlainTextContent = message,
                HtmlContent = message
            };
            msg.AddTo(new EmailAddress(email));

            var response = await client.SendEmailAsync(msg);
        }

        /// <summary>
        /// Sendet eine Email an eine Adresse
        /// </summary>
        /// <param name="email">E-Mail Adresse</param>
        /// <param name="subject">Betreff</param>
        /// <param name="message">Nachricht</param>
        /// <param name="attachement">Attachement-File</param>
        /// <param name="attachementName">Dateiname des Attachement</param>
        /// <returns>Task</returns>
        public async Task SendEmailAsync(string email, string subject, string message, byte[] attachement, string attachementName)
        {
            var client = new SendGridClient(_emailOptions.Value.SendGridKey);
            var msg = new SendGridMessage()
            {
                From = new EmailAddress(_emailOptions.Value.Email, _emailOptions.Value.Name),
                Subject = subject,
                PlainTextContent = message,
                HtmlContent = message
            };
            if (attachement is { Length: > 0 } && !string.IsNullOrWhiteSpace(attachementName))
            {
                var file = Convert.ToBase64String(attachement);
                msg.AddAttachment(attachementName, file);
            }
            msg.AddTo(new EmailAddress(email));

            var response = await client.SendEmailAsync(msg).ConfigureAwait(false);
        }

        /// <summary>
        /// Sendet eine Email an eine Adresse
        /// </summary>
        /// <param name="from">Absender-Name</param>
        /// <param name="fromEmail">Absender Email</param>  
        /// <param name="to">Ziel-Name</param>
        /// <param name="toEmail">Ziel Email</param>
        /// <param name="subject">Betreff</param>
        /// <param name="message">Nachricht</param>
        /// <returns>Task</returns>
        public async Task SendEmailAsync(string from, string fromEmail, string to, string toEmail, string subject, string message)
        {
            var client = new SendGridClient(_emailOptions.Value.SendGridKey);
            var msg = new SendGridMessage()
            {
                From = new EmailAddress(fromEmail, from),
                Subject = subject,
                PlainTextContent = message,
                HtmlContent = message
            };
            msg.AddTo(new EmailAddress(toEmail, to));

            var response = await client.SendEmailAsync(msg);
        }
    }
}