using AutoMapper;
using MediatR;
using mws.backend.dotnet.application.Audit;
using mws.backend.dotnet.application.Common;
using mws.backend.dotnet.domain.Tasks;
using TaskPriority = mws.backend.dotnet.domain.Tasks.TaskPriority;
using TaskStatus = mws.backend.dotnet.domain.Tasks.TaskStatus;

namespace mws.backend.dotnet.application.Tasks;

public record CreateTaskCommand(Guid UserId, Guid ProjectId, CreateTaskRequest Request) : IRequest<TaskDto>, IAuditableRequest
{
    public string Action => "Task.Create";
    public string EntityType => "Task";
    public string? EntityName => Request.Title;
}

public class CreateTaskHandler(IUnitOfWork uow, IMapper mapper) : IRequestHandler<CreateTaskCommand, TaskDto>
{
    public async Task<TaskDto> Handle(CreateTaskCommand command, CancellationToken ct)
    {
        await TaskAccess.EnsureMemberAccessAsync(uow, command.UserId, command.ProjectId, ct);

        var request = command.Request;
        if (string.IsNullOrWhiteSpace(request.Title))
        {
            throw new BadRequestException("Task title is required");
        }

        if (request.AssigneeId.HasValue && !await uow.Projects.IsMemberAsync(command.ProjectId, request.AssigneeId.Value, ct))
        {
            throw new BadRequestException("Assignee must be a member of the project");
        }

        var now = DateTime.UtcNow;
        var task = new TaskItem
        {
            Id = Guid.NewGuid(),
            ProjectId = command.ProjectId,
            Title = request.Title.Trim(),
            Description = request.Description,
            Status = request.Status ?? TaskStatus.Todo,
            Priority = request.Priority ?? TaskPriority.Medium,
            AssigneeId = request.AssigneeId,
            DueDate = request.DueDate,
            CreatedBy = command.UserId,
            CreatedAt = now,
            UpdatedAt = now,
        };

        uow.Tasks.Add(task);
        await uow.SaveChangesAsync(ct);
        return await TaskAccess.GetDtoAsync(uow, mapper, task.Id, ct);
    }
}