using LiteCharms.Features.Email.Commands;
using LiteCharms.Infrastructure.Database;
using static LiteCharms.Abstractions.Constants;

namespace LiteCharms.Features.Notifications.Events.Handlers;

public class ProcessEmailNotificationsEventHandler(IDbContextFactory<ShopDbContext> contextFactory, ILogger<ProcessEmailNotificationsEvent> logger, ISender mediator) :
    INotificationHandler<ProcessEmailNotificationsEvent>
{
    public async ValueTask Handle(ProcessEmailNotificationsEvent message, CancellationToken cancellationToken)
    {
        try
        {
            using var context = await contextFactory.CreateDbContextAsync(cancellationToken);

            var notifications = await context.Notifications
                .OrderByDescending(o => o.Priority)
                .ThenBy(o => o.CreatedAt)
                .Where(n => n.CorrelationIdType == Models.CorrelationIdTypes.Email)
                .Where(n => n.Direction == Models.NotificationDirection.Outgoing)
                .Take(message.MaxRecords)
                .ToListAsync(cancellationToken);

            foreach (var notification in notifications)
            {
                var sendResult = await SendEmailAsync(notification, cancellationToken);

                if(sendResult.IsFailed)
                {
                    var errors = new List<string>(1000);

                    errors.AddRange(sendResult.Errors.Select(e => e.Message));

                    if (sendResult.Reasons?.Count > 0)
                        errors.AddRange(sendResult.Reasons.Select(e => e.Message));

                    notification.HasError = true;                    
                    notification.Errors = [.. errors];
                }

                notification.Processed = true;
            }

            await context.SaveChangesAsync(cancellationToken);
        }
        catch (Exception ex)
        {
            logger.LogError(ex, ex.Message);
        }
    }

    private async Task<Result> SendEmailAsync(Entities.Notification notification, CancellationToken cancellationToken = default)
    {
        try
        {
            var request = SendEmailCommand.Create(notification.Sender!, notification.SenderName!, ShopEmailFromAddress,
                ShopEmailFromName, notification.Subject!, notification.Message!);

            var result = await mediator.Send(request, cancellationToken);

            return result.IsFailed 
                ? Result.Fail(result.Errors) 
                : Result.Ok();
        }
        catch (Exception ex)
        {
            return Result.Fail(new Error(ex.Message).CausedBy(ex));
        }
    }
}