using GB5Shared.DTO.Framework.Login;
using MMDAL.DTO.Scheduling;

namespace MMBLL.Scheduling.Engine
{
    public interface ISlotFinder
    {
        // Non-interruptible: returns a single SlotProposal covering DurationMinutes contiguously.
        // Interruptible: returns multiple proposals (segments) that together cover DurationMinutes.
        // RejectReason: "" = success, "NoShift" = no shift windows, "FullyBooked" = windows exist but capacity exhausted.
        Task<(IReadOnlyList<SlotProposal> Proposals, string RejectReason)> FindSlotAsync(
            ExecutionUnit eu, MachineCandidateDTO candidate,
            SchedulingContext context, LoginDTO login, CancellationToken ct);

        // Parallel mode (SPLITS > 1): finds simultaneous free slots across N candidates.
        // Returns N proposals (one per machine) or empty if no simultaneous window exists.
        Task<IReadOnlyList<SlotProposal>> FindParallelSlotsAsync(
            ExecutionUnit eu, IReadOnlyList<MachineCandidateDTO> candidates,
            SchedulingContext context, LoginDTO login, CancellationToken ct);
    }
}