namespace MfGames.Locking;

/// <summary>
/// Defines a ReaderWriterLockSlim write lock.
/// </summary>
public class NestableWriteLock : IDisposable
{
    private readonly bool lockAcquired;

    private readonly ReaderWriterLockSlim readerWriterLockSlim;

    /// <summary>
    /// Initializes a new instance of the <see cref="NestableWriteLock" /> class.
    /// </summary>
    /// <param name="readerWriterLockSlim">The reader writer lock slim.</param>
    public NestableWriteLock(ReaderWriterLockSlim readerWriterLockSlim)
    {
        // Keep track of the lock since we'll need it to release the lock.
        this.readerWriterLockSlim = readerWriterLockSlim;

        // If we already have a read or write lock, we don't do anything.
        if (readerWriterLockSlim.IsWriteLockHeld)
        {
            this.lockAcquired = false;
        }
        else
        {
            readerWriterLockSlim.EnterWriteLock();
            this.lockAcquired = true;
        }
    }

    /// <inheritdoc />
    public void Dispose()
    {
        if (this.lockAcquired)
        {
            this.readerWriterLockSlim.ExitWriteLock();
        }
    }
}