using Aging.Infrastructure.Contracts;

namespace Aging.Infrastructure.Core
{
    /// <summary>
    /// 操作租约实现。
    /// 提供短期资源占用保证，支持同步和异步释放。
    /// 释放时通过回调通知 ResourceManager。
    /// </summary>
    public sealed class OperationLease : IOperationLease
    {
        private readonly Action? _onRelease;
        private bool _disposed;

        /// <inheritdoc/>
        public string LeaseId { get; }

        /// <inheritdoc/>
        public ResourceKey Resource { get; }

        /// <inheritdoc/>
        public ResourceOwnerToken Owner { get; }

        /// <inheritdoc/>
        public DateTime AcquiredAt { get; }

        /// <inheritdoc/>
        public DateTime? ExpiresAt { get; }

        /// <inheritdoc/>
        public bool IsValid => !_disposed && !IsExpired();

        /// <summary>
        /// 初始化操作租约实例
        /// </summary>
        /// <param name="resource">资源键</param>
        /// <param name="owner">所有者令牌</param>
        /// <param name="onRelease">释放时的回调通知</param>
        /// <param name="leaseDurationSeconds">租约有效期（秒），默认30秒</param>
        public OperationLease(
            ResourceKey resource,
            ResourceOwnerToken owner,
            Action? onRelease = null,
            int leaseDurationSeconds = 30)
        {
            LeaseId = Guid.NewGuid().ToString();
            Resource = resource ?? throw new ArgumentNullException(nameof(resource));
            Owner = owner ?? throw new ArgumentNullException(nameof(owner));
            AcquiredAt = DateTime.UtcNow;
            ExpiresAt = leaseDurationSeconds > 0
                ? AcquiredAt.AddSeconds(leaseDurationSeconds)
                : null;
            _onRelease = onRelease;
            _disposed = false;
        }

        /// <summary>
        /// 检查租约是否已过期
        /// </summary>
        private bool IsExpired()
        {
            if (!ExpiresAt.HasValue)
                return false;
            return DateTime.UtcNow > ExpiresAt.Value;
        }

        /// <inheritdoc/>
        public void Dispose()
        {
            if (_disposed) return;
            _disposed = true;
            _onRelease?.Invoke();
        }

        /// <inheritdoc/>
        public ValueTask DisposeAsync()
        {
            Dispose();
            return default;
        }
    }
}