using System;

namespace Aging.Infrastructure.Contracts
{
    /// <summary>
    /// 所有者类型枚举
    /// </summary>
    public enum OwnerType
    {
        /// <summary>
        /// 生产模式（正常老化测试流程）
        /// </summary>
        Production,

        /// <summary>
        /// 维护模式（调试/维护会话）
        /// </summary>
        Maintenance
    }

    /// <summary>
    /// 所有者令牌，标识资源预约的归属。
    /// 用于区分不同会话对硬件资源的所有权。
    /// </summary>
    public sealed class ResourceOwnerToken
    {
        /// <summary>
        /// 令牌唯一标识
        /// </summary>
        public string TokenId { get; }

        /// <summary>
        /// 所有者类型（生产/维护）
        /// </summary>
        public OwnerType OwnerType { get; }

        /// <summary>
        /// 所有者标识（RunID 或 DebugSessionID）
        /// </summary>
        public string OwnerId { get; }

        /// <summary>
        /// 世代号，每次新预约递增，防止重放攻击
        /// </summary>
        public long Generation { get; set; }

        /// <summary>
        /// 令牌签发时间
        /// </summary>
        public DateTime IssuedAt { get; }

        /// <summary>
        /// 令牌过期时间（可选）
        /// </summary>
        public DateTime? ExpiresAt { get; }

        /// <summary>
        /// 初始化所有者令牌实例
        /// </summary>
        /// <param name="ownerType">所有者类型</param>
        /// <param name="ownerId">所有者标识</param>
        /// <param name="expiresAt">过期时间（可选）</param>
        public ResourceOwnerToken(OwnerType ownerType, string ownerId, DateTime? expiresAt = null)
        {
            TokenId = Guid.NewGuid().ToString();
            OwnerType = ownerType;
            OwnerId = ownerId ?? throw new ArgumentNullException(nameof(ownerId));
            Generation = 0;
            IssuedAt = DateTime.UtcNow;
            ExpiresAt = expiresAt;
        }

        /// <summary>
        /// 检查令牌是否已过期
        /// </summary>
        /// <returns>过期返回 true；未设置过期时间或尚未过期返回 false</returns>
        public bool IsExpired()
        {
            if (!ExpiresAt.HasValue)
                return false;
            return DateTime.UtcNow > ExpiresAt.Value;
        }
    }
}