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 now = DateTime.UtcNow;
        var overdueCutoff = lateDays > 0 ? now.AddDays(-lateDays) : now;

        // Query overdue milestones that are not yet approved
        // Execute ToListAsync before GroupBy so EF Core does not fail SQL translation
        var overdueMilestones = await context.Milestones
            .AsNoTracking()
            .Include(i => i.Project)
                .ThenInclude(p => p!.Programme)
                    .ThenInclude(pr => pr!.Owner)
            .Include(i => i.Project)
                .ThenInclude(p => p!.Programme)
                    .ThenInclude(pr => pr!.Portfolio)
                        .ThenInclude(po => po!.Organisation)
                            .ThenInclude(o => o!.User)
            .Where(m => m.Status != ApprovalStatus.Approved && m.DueAt <= overdueCutoff)
            .OrderBy(o => o.DueAt)
            .ToListAsync(cancellationToken);

        if (overdueMilestones.Count == 0) return;

        var lateMilestonesByProject = overdueMilestones.GroupBy(g => g.ProjectId);

        var partnerResourceStream = typeof(IDomain).Assembly
            .GetManifestResourceStream("PostFundManagement.Domain.Templates.lateprojectsmilestones.html");

        if (partnerResourceStream is null) return;

        using var partnerHtmlTemplateReader = new StreamReader(partnerResourceStream);
        var partnerTemplate = await partnerHtmlTemplateReader.ReadToEndAsync(cancellationToken);

        var programmeResourceStream = typeof(IDomain).Assembly
            .GetManifestResourceStream("PostFundManagement.Domain.Templates.noncompliantprojects-prog.html");

        string? programmeTemplate = null;
        if (programmeResourceStream is not null)
        {
            using var programmeHtmlTemplateReader = new StreamReader(programmeResourceStream);
            programmeTemplate = await programmeHtmlTemplateReader.ReadToEndAsync(cancellationToken);
        }

        foreach (var group in lateMilestonesByProject)
        {
            var milestones = group.ToList();

            if (milestones.Count == 0) continue;

            var project = milestones[0].Project;

            if (project is null) continue;

            var mostLateMilestone = milestones.OrderBy(m => m.DueAt).FirstOrDefault();

            var daysOverdue = mostLateMilestone != null
                ? (int)Math.Max(0, (now - mostLateMilestone.DueAt).TotalDays)
                : 0;

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

            if (organisation is null) continue;

            var recipientId = organisation.UserId ?? organisation.CreatedBy;
            var recipientEmail = organisation.User?.Email ?? organisation.Email;

            if (string.IsNullOrWhiteSpace(recipientEmail) || recipientId == Guid.Empty) continue;

            var tableRowsBuilder = new StringBuilder();
            foreach (var milestone in milestones.OrderBy(m => m.DueAt))
            {
                var delay = (int)Math.Max(0, (now - milestone.DueAt).TotalDays);
                var statusText = milestone.Status.ToString();
                var milestoneName = WebUtility.HtmlEncode(milestone.Name ?? "Milestone Deliverable");

                tableRowsBuilder.AppendLine($@"
                    <tr style=""border-bottom: 1px solid #e2e8f0;"">
                        <td style=""padding: 10px 14px; font-weight: 500; color: #1e293b;"">{milestoneName}</td>
                        <td style=""padding: 10px 14px; color: #64748b; font-size: 13px;"">{milestone.DueAt:yyyy-MM-dd}</td>
                        <td style=""padding: 10px 14px; color: #dc2626; font-weight: 600; font-size: 13px;"">+{delay} d</td>
                        <td style=""padding: 10px 14px; font-size: 12px;""><span style=""background-color: #fee2e2; color: #991b1b; padding: 2px 8px; border-radius: 9999px; font-weight: 600;"">{statusText}</span></td>
                    </tr>");
            }

            // 1. Send notice to Partner / Recipient Organisation
            var messageBody = partnerTemplate;
            messageBody = messageBody.Replace("[OrganisationName]", WebUtility.HtmlEncode(organisation.Name ?? "Partner"));
            messageBody = messageBody.Replace("[RecipientName]", WebUtility.HtmlEncode(organisation.Name ?? "Partner"));
            messageBody = messageBody.Replace("[ProjectName]", WebUtility.HtmlEncode(project.Name ?? "Project"));
            messageBody = messageBody.Replace("[ProjectStartDate]", project.StartedAt.HasValue ? $"{project.StartedAt:yyyy-MM-dd}" : "Not Specified");
            messageBody = messageBody.Replace("[ProjectEndDate]", project.EndedAt.HasValue ? $"{project.EndedAt:yyyy-MM-dd}" : "Not Specified");
            messageBody = messageBody.Replace("[TotalLateMilestones]", milestones.Count.ToString());
            messageBody = messageBody.Replace("[TotalLateMiletones]", milestones.Count.ToString());
            messageBody = messageBody.Replace("[MostLateMilestoneName]", WebUtility.HtmlEncode(mostLateMilestone?.Name ?? "N/A"));
            messageBody = messageBody.Replace("[MostLateMilestoneDueDate]", mostLateMilestone != null ? $"{mostLateMilestone.DueAt:yyyy-MM-dd}" : "N/A");
            messageBody = messageBody.Replace("[MostLateMilestoneDaysOverdue]", daysOverdue.ToString());
            messageBody = messageBody.Replace("[LateMilestonesTable]", tableRowsBuilder.ToString());
            messageBody = messageBody.Replace("[PortalUrl]", "https://partner.ifri.khongisa.co.za");
            messageBody = messageBody.Replace("[Year]", now.Year.ToString());

            var notificationRequest = new CreateNotificationRequest(organisation.Id, recipientId, NotificationPlatform.Email,
                $"Overdue Milestone Alert: {project.Name}", recipientEmail, messageBody, NotificationStatus.Queued);

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

            // 2. Construct and send escalation notification for the Programme Manager (FR-M07-009)
            if (!string.IsNullOrWhiteSpace(programmeTemplate))
            {
                var programme = project.Programme;
                var programmeManager = programme?.Owner;
                var programmeManagerId = programme?.OwnedBy ?? programmeManager?.Id;
                var programmeManagerEmail = programmeManager?.Email;

                if (programmeManagerId.HasValue && programmeManagerId.Value != Guid.Empty && !string.IsNullOrWhiteSpace(programmeManagerEmail))
                {
                    var progMessageBody = programmeTemplate;
                    progMessageBody = progMessageBody.Replace("[ProgrammeManagerName]", WebUtility.HtmlEncode(programmeManagerEmail ?? "Programme Manager"));
                    progMessageBody = progMessageBody.Replace("[ProgrammeName]", WebUtility.HtmlEncode(programme?.Name ?? "Programme"));
                    progMessageBody = progMessageBody.Replace("[PortfolioName]", WebUtility.HtmlEncode(programme?.Portfolio?.Name ?? "Portfolio"));
                    progMessageBody = progMessageBody.Replace("[OrganisationName]", WebUtility.HtmlEncode(organisation.Name ?? "Partner"));
                    progMessageBody = progMessageBody.Replace("[ProjectName]", WebUtility.HtmlEncode(project.Name ?? "Project"));
                    progMessageBody = progMessageBody.Replace("[ProjectStartDate]", project.StartedAt.HasValue ? $"{project.StartedAt:yyyy-MM-dd}" : "Not Specified");
                    progMessageBody = progMessageBody.Replace("[ProjectEndDate]", project.EndedAt.HasValue ? $"{project.EndedAt:yyyy-MM-dd}" : "Not Specified");
                    progMessageBody = progMessageBody.Replace("[TotalLateMilestones]", milestones.Count.ToString());
                    progMessageBody = progMessageBody.Replace("[TotalLateMiletones]", milestones.Count.ToString());
                    progMessageBody = progMessageBody.Replace("[MostLateMilestoneName]", WebUtility.HtmlEncode(mostLateMilestone?.Name ?? "N/A"));
                    progMessageBody = progMessageBody.Replace("[MostLateMilestoneDueDate]", mostLateMilestone != null ? $"{mostLateMilestone.DueAt:yyyy-MM-dd}" : "N/A");
                    progMessageBody = progMessageBody.Replace("[MostLateMilestoneDaysOverdue]", daysOverdue.ToString());
                    progMessageBody = progMessageBody.Replace("[LateMilestonesTable]", tableRowsBuilder.ToString());
                    progMessageBody = progMessageBody.Replace("[ConsoleUrl]", "https://console.ifri.khongisa.co.za");
                    progMessageBody = progMessageBody.Replace("[PortalUrl]", "https://partner.ifri.khongisa.co.za");
                    progMessageBody = progMessageBody.Replace("[Year]", now.Year.ToString());

                    var progNotificationRequest = new CreateNotificationRequest(
                        organisation.Id,
                        programmeManagerId.Value,
                        NotificationPlatform.Email,
                        $"[Escalation] Overdue Milestones: {project.Name} ({programme?.Name})",
                        programmeManagerEmail,
                        progMessageBody,
                        NotificationStatus.Queued);

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