using System.Net;
using System.Net.Mail;

namespace ConsoleApp1;

public class MailService(SmtpSettings smtpSettings)
{
    /// <summary>
    /// Sends a plain text email to the specified recipient.
    /// </summary>
    /// <param name="to">The recipient's email address.</param>
    /// <param name="subject">The subject of the email.</param>
    /// <param name="body">The body of the email.</param>
    public async Task SendEmailText(string to, string subject, string body)
    {
        await SendEmailInternal(to, subject, body, isHtml: false);
    }

    /// <summary>
    /// Sends an HTML email to the specified recipient using a file as the body.
    /// </summary>
    /// <param name="to">The recipient's email address.</param>
    /// <param name="subject">The subject of the email.</param>
    /// <param name="filePath">The file path of the HTML file to be used as the body of the email.</param>
    /// <param name="replacements">Optional dictionary of placeholder replacements to be applied to the HTML body.</param>
    public async Task SendEmailHtmlFile(string to, string subject, string filePath,
        Dictionary<string, string>? replacements = null)
    {
        string body = await File.ReadAllTextAsync(filePath);

        if (replacements != null)
        {
            foreach (var replacement in replacements)
            {
                body = body.Replace($"{{{replacement.Key}}}", replacement.Value);
            }
        }

        await SendEmailInternal(to, subject, body, isHtml: true);
    }

    /// <summary>
    /// Sends an email to the specified recipient.
    /// </summary>
    /// <param name="to">The recipient's email address.</param>
    /// <param name="subject">The subject of the email.</param>
    /// <param name="body">The body of the email.</param>
    /// <param name="isHtml">Indicates whether the body of the email is HTML.</param>
    private async Task SendEmailInternal(string to, string subject, string body, bool isHtml)
    {
        using var client = new SmtpClient(smtpSettings.SmtpServer, smtpSettings.SmtpPort);
        
        client.Credentials = new NetworkCredential(smtpSettings.SmtpUser, smtpSettings.SmtpPassword);
        client.EnableSsl = true;

        var mailMessage = new MailMessage
        {
            From = new MailAddress(smtpSettings.SmtpFrom),
            Subject = subject,
            Body = body,
            IsBodyHtml = isHtml
        };

        mailMessage.To.Add(to);
        await client.SendMailAsync(mailMessage);
    }
}