using DigitalData.Core.Abstraction.Application.Repository;
using EnvelopeGenerator.Domain.Constants;
using EnvelopeGenerator.Domain.Entities;
using MediatR;
using Microsoft.EntityFrameworkCore;
using Newtonsoft.Json;

namespace EnvelopeGenerator.Application.Notifications;

/// <summary>
/// 
/// </summary>
public interface ISendMailNotification : INotification
{
    /// <summary>
    /// 
    /// </summary>
    public EmailTemplateType TemplateType { get; }
}

/// <summary>
/// 
/// </summary>
public abstract class SendMailHandler<TNotification> : INotificationHandler<TNotification>
    where TNotification : ISendMailNotification
{
    /// <summary>
    /// 
    /// </summary>
    protected readonly IRepository<EmailTemplate> TempRepo;

    /// <summary>
    /// 
    /// </summary>
    protected virtual Dictionary<string, string> BodyPlaceHolders { get; } = new();

    /// <summary>
    /// 
    /// </summary>
    protected virtual Dictionary<string, string> SubjectPlaceHolders { get; } = new();

    /// <summary>
    /// 
    /// </summary>
    /// <param name="tempRepo"></param>
    protected SendMailHandler(IRepository<EmailTemplate> tempRepo)
    {
        TempRepo = tempRepo;
    }

    /// <summary>
    /// 
    /// </summary>
    /// <param name="notification"></param>
    /// <param name="cancel"></param>
    /// <returns></returns>
    /// <exception cref="NotImplementedException"></exception>
    public async Task Handle(TNotification notification, CancellationToken cancel)
    {
        var temp = await TempRepo
            .ReadOnly()
            .SingleOrDefaultAsync(x => x.Name == notification.TemplateType.ToString(), cancel)
                ?? throw new InvalidOperationException($"Receiver information is missing in the notification." +
                $"{typeof(TNotification)}:\n {JsonConvert.SerializeObject(notification, Format.Json.ForDiagnostics)}");

        temp.Subject = ReplacePlaceHolders(temp.Subject, SubjectPlaceHolders);

        temp.Body = ReplacePlaceHolders(temp.Body, BodyPlaceHolders);
    }

    private static string ReplacePlaceHolders(string text, Dictionary<string, string> placeHolders)
    {
        foreach (var ph in placeHolders)
            text = text.Replace(ph.Key, ph.Value);
        return text;
    }
}