using System.Collections.Generic;
using System.IO;

namespace BulkArchiveMailer.Core
{
    /// <summary>Status of one preview row / send attempt.</summary>
    public enum SendStatus
    {
        /// <summary>Exactly one archive found for this login, nothing sent for it yet - safe to send.</summary>
        Ready,

        /// <summary>A prior log entry shows this exact archive (by SHA-256) was already sent to this address.</summary>
        AlreadySent,

        /// <summary>Blocking data problem (e.g. both archive kinds present for one login) - never sendable.</summary>
        Error,

        /// <summary>File in the folder did not match the expected naming pattern - listed for visibility, not sendable.</summary>
        Skipped
    }

    /// <summary>
    /// One row of the send preview: everything needed to either display the
    /// row in the grid or hand it to MailSender.
    /// </summary>
    public sealed class SendJob
    {
        public string Login { get; set; } = "";

        public string Email { get; set; } = "";

        /// <summary>Null for Error rows caused by a login/kind conflict, and for Skipped (unrecognized file) rows.</summary>
        public ArchiveKind? Kind { get; set; }

        /// <summary>Null for conflict Error rows (see <see cref="ConflictingArchivePaths"/>) - otherwise the single archive to attach.</summary>
        public string ArchivePath { get; set; }

        /// <summary>Populated only for the "both kinds present" Error case: every archive path found for that login.</summary>
        public IReadOnlyList<string> ConflictingArchivePaths { get; set; }

        public string Subject { get; set; } = "";

        public string BodyHtml { get; set; } = "";

        public SendStatus Status { get; set; } = SendStatus.Ready;

        /// <summary>Human-readable explanation, set for Error/Skipped rows and for AlreadySent rows (when it was sent).</summary>
        public string ErrorMessage { get; set; }

        /// <summary>SHA-256 of ArchivePath's current bytes, computed when a SendLogStore is available. Used for the AlreadySent dedup key.</summary>
        public string FileSha256 { get; set; }

        /// <summary>Whether this row is even eligible to be checked/sent in the preview grid.</summary>
        public bool IsSelectable => Status == SendStatus.Ready || Status == SendStatus.AlreadySent;

        public string FileName => string.IsNullOrEmpty(ArchivePath) ? "" : Path.GetFileName(ArchivePath);

        public string KindDisplay
        {
            get
            {
                switch (Kind)
                {
                    case ArchiveKind.SshAccess:
                        return "Новый доступ (ключ + конфиг)";
                    case ArchiveKind.ConfigUpdate:
                        return "Обновление конфига";
                    default:
                        return "-";
                }
            }
        }

        public override string ToString() => $"{Login} <{Email}> [{Status}]";
    }
}