using PostFundManagement.Application.Abstractions.Services;
using PostFundManagement.Application.Services.Communications;
using PostFundManagement.Domain;
using PostFundManagement.Domain.Abstractions;
using PostFundManagement.Infrastructure.Database;

namespace PostFundManagement.Application.Events;

public sealed class LateProjectEvent : IEvent
{
    public Guid Id { get; set; } = Guid.CreateVersion7();

    public string Name { get; set; } = nameof(LateProjectEvent);

    public DateTimeOffset EnqueueAt { get; set; } = DateTimeOffset.UtcNow;

    public string CorrelationId { get; set; } = "lateproject-reminder";

    public static LateProjectEvent Create() => new();
}

public sealed class LateProjectEventHandler(IDbContextFactory<ApplicationDbContext> contextFactory, 
    ICommunicationsService service) : INotificationHandler<LateProjectEvent>
{
    readonly int lateDays = 3;

    public async ValueTask Handle(LateProjectEvent notification, CancellationToken cancellationToken)
    {
        await using var context = await contextFactory.CreateDbContextAsync(cancellationToken);

        var lateMilestones = await context.Milestones
            .AsNoTracking()
            .Include(i => i.Project!.Programme!.Portfolio!.Organisation!.User)
            .Where(m => (DateTime.UtcNow - m.Project!.StartedAt!).Value.TotalDays < lateDays)
            .OrderBy(o => o.CreatedAt)
            .GroupBy(g => g.ProjectId)
            .AsSplitQuery()
            .ToListAsync(cancellationToken);

        if (lateMilestones is null) return;

        using var htmlTemplateReader = new StreamReader(Assembly.GetAssembly(typeof(IDomain))?
            .GetManifestResourceStream("PostFundManagement.Domain.Templates.lateprojectsmilestones.html")!);

        var template = await htmlTemplateReader.ReadToEndAsync(cancellationToken);

        foreach (var group in lateMilestones)
        {
            if (!group.Any()) continue;

            var project = group.FirstOrDefault()?.Project;

            if (project is null) continue;

            var mostLateMilestone = group.OrderBy(m => m.DueAt).FirstOrDefault();
            var missedMilestone = group.Where(m => DateTime.UtcNow > m.DueAt).FirstOrDefault();

            var messageBody = template;
            messageBody = messageBody.Replace("[ProjectName]", project.Name);
            messageBody = messageBody.Replace("[ProjectStartDate]", $"{project.StartedAt:yyyy-MM-dd}");
            messageBody = messageBody.Replace("[ProjectEndDate]", $"{project.EndedAt:yyyy-MM-dd}");
            messageBody = messageBody.Replace("[TotalLateMiletones]", $"{group.Count()}");

            // TODO: output information of most late milestone
            // TODO: output information of milestones already missed

            var organisation = mostLateMilestone?.Project?.Programme?.Portfolio?.Organisation;

            if (organisation is null) continue;

            var notificationRequest = new CreateNotificationRequest(organisation.Id, organisation.User!.Id, NotificationPlatform.Email, 
                "Project Status Update", organisation.User!.Email, messageBody, NotificationStatus.Queued);

            _ = await service.CreateNotificationAsync(notificationRequest, SystemUser, cancellationToken);
        }
    }
}