feat: add envelope delete command and API endpoint

EnvelopeGenerator.Application/Envelopes/Commands/DeleteEnvelopeCommand.cs

@@ -0,0 +1,25 @@
+using System.ComponentModel.DataAnnotations;
+using EnvelopeGenerator.Domain.Constants;
+using MediatR;
+
+namespace EnvelopeGenerator.Application.Envelopes.Commands;
+
+public record DeleteEnvelopeResultDto(int EnvelopeId, EnvelopeStatus AppliedStatus, bool IsNoOp);
+
+public record DeleteEnvelopeCommand : IRequest<DeleteEnvelopeResultDto>
+{
+    [Required]
+    public int EnvelopeId { get; init; }
+
+    [Required]
+    [MinLength(1)]
+    public string Reason { get; init; } = string.Empty;
+
+    internal int UserId { get; private set; }
+
+    public DeleteEnvelopeCommand WithAuth(int userId)
+    {
+        UserId = userId;
+        return this;
+    }
+}

EnvelopeGenerator.Application/Envelopes/Commands/DeleteEnvelopeCommandHandler.cs

@@ -0,0 +1,83 @@
+using EnvelopeGenerator.Application.Common.Notifications.EnvelopeDeleted;
+using DigitalData.Core.Abstraction.Application.Repository;
+using DigitalData.Core.Exceptions;
+using EnvelopeGenerator.Application.Histories.Commands;
+using EnvelopeGenerator.Domain.Constants;
+using EnvelopeGenerator.Domain.Entities;
+using MediatR;
+using Microsoft.EntityFrameworkCore;
+using System.Linq;
+
+namespace EnvelopeGenerator.Application.Envelopes.Commands;
+
+public class DeleteEnvelopeCommandHandler : IRequestHandler<DeleteEnvelopeCommand, DeleteEnvelopeResultDto>
+{
+    private readonly IRepository<Envelope> _envelopeRepository;
+    private readonly IMediator _mediator;
+
+    public DeleteEnvelopeCommandHandler(
+        IRepository<Envelope> envelopeRepository,
+        IMediator mediator)
+    {
+        _envelopeRepository = envelopeRepository;
+        _mediator = mediator;
+    }
+
+    public async Task<DeleteEnvelopeResultDto> Handle(DeleteEnvelopeCommand request, CancellationToken cancel)
+    {
+        var reason = request.Reason?.Trim();
+        if (string.IsNullOrWhiteSpace(reason))
+            throw new BadRequestException("Please provide a reason.");
+
+        var envelope = await _envelopeRepository.Query
+            .Include(e => e.User)
+            .Include(e => e.EnvelopeReceivers)
+                .ThenInclude(er => er.Receiver)
+            .FirstOrDefaultAsync(e => e.Id == request.EnvelopeId, cancel)
+            ?? throw new NotFoundException($"Envelope {request.EnvelopeId} not found.");
+
+        if (envelope.UserId != request.UserId)
+            throw new ForbiddenException();
+
+        if (envelope.Status is EnvelopeStatus.EnvelopeDeleted or EnvelopeStatus.EnvelopeWithdrawn)
+            return new DeleteEnvelopeResultDto(envelope.Id, envelope.Status, IsNoOp: true);
+
+        var targetStatus = envelope.Status > EnvelopeStatus.EnvelopeSaved
+            ? EnvelopeStatus.EnvelopeWithdrawn
+            : EnvelopeStatus.EnvelopeDeleted;
+
+        envelope.Status = targetStatus;
+        envelope.Comment = reason;
+        envelope.ChangedWhen = DateTime.Now;
+
+        await _envelopeRepository.UpdateAsync(envelope, e => e.Id == envelope.Id, cancel);
+
+        var userReference = envelope.User?.Email;
+        if (string.IsNullOrWhiteSpace(userReference))
+            throw new BadRequestException("Envelope sender email is missing.");
+
+        await _mediator.Send(new CreateHistoryCommand
+        {
+            EnvelopeId = envelope.Id,
+            UserReference = userReference,
+            Status = targetStatus,
+            Comment = reason
+        }, cancel);
+
+        foreach (var envelopeReceiver in envelope.EnvelopeReceivers ?? Enumerable.Empty<EnvelopeReceiver>())
+        {
+            if (envelopeReceiver.Receiver is null)
+                continue;
+
+            await _mediator.Publish(new EnvelopeDeletedNotification
+            {
+                Envelope = envelope,
+                EnvelopeReceiver = envelopeReceiver,
+                Reason = reason,
+                SenderReference = userReference
+            }, cancel);
+        }
+
+        return new DeleteEnvelopeResultDto(envelope.Id, targetStatus, IsNoOp: false);
+    }
+}