feat: add a campus command

Application/Cqrs/Campus/Commands/CreateCampus/CreateCampusCommand.cs

@@ -0,0 +1,10 @@
+using MediatR;
+
+namespace Mirea.Api.DataAccess.Application.Cqrs.Campus.Commands.CreateCampus;
+
+public class CreateCampusCommand : IRequest<int>
+{
+    public required string CodeName { get; set; }
+    public string? FullName { get; set; }
+    public string? Address { get; set; }
+}

Application/Cqrs/Campus/Commands/CreateCampus/CreateCampusCommandHandler.cs

@@ -0,0 +1,31 @@
+using MediatR;
+using Microsoft.EntityFrameworkCore;
+using Mirea.Api.DataAccess.Application.Common.Exceptions;
+using Mirea.Api.DataAccess.Application.Interfaces.DbContexts.Schedule;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace Mirea.Api.DataAccess.Application.Cqrs.Campus.Commands.CreateCampus;
+
+public class CreateCampusCommandHandler(ICampusDbContext dbContext) : IRequestHandler<CreateCampusCommand, int>
+{
+    public async Task<int> Handle(CreateCampusCommand request, CancellationToken cancellationToken)
+    {
+        var entity = await dbContext.Campuses.FirstOrDefaultAsync(c => c.CodeName == request.CodeName, cancellationToken: cancellationToken);
+
+        if (entity != null)
+            throw new RecordExistException(typeof(Domain.Schedule.Campus), nameof(Domain.Schedule.Campus.CodeName), entity.Id);
+
+        var campus = new Domain.Schedule.Campus()
+        {
+            CodeName = request.CodeName,
+            FullName = request.FullName,
+            Address = request.Address
+        };
+
+        var result = await dbContext.Campuses.AddAsync(campus, cancellationToken);
+        await dbContext.SaveChangesAsync(cancellationToken);
+
+        return result.Entity.Id;
+    }
+}