using System.Collections.Generic;
using System.Data.Common;
using System.Threading;
using System.Threading.Tasks;
using GB5Shared.DTO.Draft;
using GB5Shared.DTO.Framework.Login;

namespace GB5Shared.Draft
{
    public interface IDraftRowDAL
    {
        /// <summary>Returns 0 if no draft exists for this session.</summary>
        Task<int> GetDraftIdBySessionAsync(string sessionGuid, LoginDTO login, CancellationToken ct);

        /// <summary>Returns the draft header for the given session, or null if not found.</summary>
        Task<DraftHeaderDTO?> GetDraftHeaderAsync(string sessionGuid, LoginDTO login, CancellationToken ct);

        /// <summary>
        /// MERGE-upserts the draft header. @draftId must be pre-allocated
        /// by the BLL via AutoNumber for new sessions (0 = not yet allocated
        /// means the caller checks first). Returns the actual DraftId stored.
        /// </summary>
        Task<int> UpsertHeaderAsync(DraftSessionDTO dto, int draftId, LoginDTO login, CancellationToken ct);

        /// <summary>
        /// MERGE-upserts one dirty row into TDRAFT_ROWS.
        /// RowState=Unchanged and RowState=Deleted must be rejected by the BLL before this is called.
        /// </summary>
        Task UpsertRowAsync(DraftRowDTO dto, LoginDTO login, CancellationToken ct);

        /// <summary>
        /// Hard-deletes a single row from TDRAFT_ROWS by SessionGuid + RowGuid.
        /// Called by the BLL when RowState=Deleted arrives on UpsertRow.
        /// </summary>
        Task DeleteRowAsync(string sessionGuid, Guid rowGuid, LoginDTO login, CancellationToken ct);

        /// <summary>Returns all dirty rows for a session ordered for tree reconstruction.</summary>
        Task<IEnumerable<DraftRowDTO>> GetDraftRowsAsync(string sessionGuid, LoginDTO login, CancellationToken ct);

        /// <summary>Returns draft pool items (Active/Suspended/Transferred) for menu + user.</summary>
        Task<IEnumerable<DraftPoolItemDTO>> GetDraftPoolAsync(int menuId, LoginDTO login, CancellationToken ct);

        /// <summary>
        /// Deletes TDRAFT_ROWS then TDRAFT for the session.
        /// tx is optional — pass when called inside an entity save transaction.
        /// </summary>
        Task CleanupAsync(string sessionGuid, byte actionType, LoginDTO login, DbTransaction? tx, CancellationToken ct);

        /// <summary>
        /// Transfers draft to targetUserId. SP validates ownership at DB level.
        /// Application-layer ownership check should precede this call.
        /// </summary>
        Task ShareAsync(DraftShareDTO dto, LoginDTO login, CancellationToken ct);

        /// <summary>Returns count of sessions expired and deleted in this batch.</summary>
        Task<int> CleanupOrphansAsync(int retentionHours, int batchSize, LoginDTO login, CancellationToken ct);

        /// <summary>Returns 1 if the session exists and requesting user is the owner.</summary>
        Task<int> CheckOwnershipAsync(string sessionGuid, LoginDTO login, CancellationToken ct);
    }
}