using System;
using System.Runtime.CompilerServices;
using System.Runtime.ConstrainedExecution;
using System.Runtime.InteropServices;

namespace Foodsoft.Alpm
{
    internal sealed class SafeListHandle : SafeHandle
    {
        public SafeAlpmHandle SafeAlpmHandle
        {
            [ReliabilityContract(Consistency.WillNotCorruptState, Cer.Success)]
            [PrePrepareMethod]
            get;
        } = null!;
        
        [ReliabilityContract(Consistency.WillNotCorruptState, Cer.MayFail)]
        [PrePrepareMethod]
        internal SafeListHandle(SafeAlpmHandle safeAlpmHandle)
            : base(IntPtr.Zero, true)
        {
            var success = false;
            RuntimeHelpers.PrepareConstrainedRegions();
            try { }
            finally
            {
                safeAlpmHandle.DangerousAddRef(ref success);
                if (success)
                    SafeAlpmHandle = safeAlpmHandle;
            }

            if (!success)
                throw new ObjectDisposedException(GetType().FullName);
        }

        [ReliabilityContract(Consistency.WillNotCorruptState, Cer.Success), PrePrepareMethod]
        protected override bool ReleaseHandle()
        {
            SafeAlpmHandle.DangerousRelease();
            return true;
        }

        public override bool IsInvalid
        {
            [ReliabilityContract(Consistency.WillNotCorruptState, Cer.Success), PrePrepareMethod]
            get => SafeAlpmHandle.IsInvalid;
        }
    }
}