using System;

namespace Aging.Infrastructure.Contracts
{
    /// <summary>
    /// 预约状态枚举
    /// </summary>
    public enum ReservationState
    {
        /// <summary>
        /// 活跃状态
        /// </summary>
        Active,

        /// <summary>
        /// 已释放
        /// </summary>
        Released,

        /// <summary>
        /// 冲突状态
        /// </summary>
        Conflicted
    }

    /// <summary>
    /// 长期预约实体，表示对某个硬件资源的持久占用。
    /// 预约期间，其他所有者无法获取该资源。
    /// </summary>
    public sealed class ResourceReservation
    {
        /// <summary>
        /// 预约唯一标识
        /// </summary>
        public string ReservationId { get; }

        /// <summary>
        /// 被预约的资源键
        /// </summary>
        public ResourceKey Resource { get; }

        /// <summary>
        /// 预约所有者令牌
        /// </summary>
        public ResourceOwnerToken Owner { get; }

        /// <summary>
        /// 预约状态
        /// </summary>
        public ReservationState State { get; set; }

        /// <summary>
        /// 预约创建时间
        /// </summary>
        public DateTime ReservedAt { get; }

        /// <summary>
        /// 预约描述（可选）
        /// </summary>
        public string? Description { get; set; }

        /// <summary>
        /// 初始化资源预约实例
        /// </summary>
        /// <param name="resource">资源键</param>
        /// <param name="owner">所有者令牌</param>
        /// <param name="description">预约描述（可选）</param>
        public ResourceReservation(ResourceKey resource, ResourceOwnerToken owner, string? description = null)
        {
            ReservationId = Guid.NewGuid().ToString();
            Resource = resource ?? throw new ArgumentNullException(nameof(resource));
            Owner = owner ?? throw new ArgumentNullException(nameof(owner));
            State = ReservationState.Active;
            ReservedAt = DateTime.UtcNow;
            Description = description;
        }
    }
}