using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Runtime.CompilerServices;
using System.Runtime.InteropServices;

namespace Foodsoft.Alpm
{
    internal static class Wrapper
    {
        internal static unsafe IntPtr ListNext(IntPtr list) => ((alpm_list_t*) list)->next;
        internal static unsafe IntPtr ListData(IntPtr list) => ((alpm_list_t*) list)->data;

        internal static TResult UseHandle<TResult>(this SafeHandle handle, IntPtr ptr, Func<IntPtr, TResult> op)
        {
            var release = false;

            RuntimeHelpers.PrepareConstrainedRegions();
            try
            {
                handle.DangerousAddRef(ref release);
                if (!release) throw new ObjectDisposedException(handle.GetType().FullName);
                return op(ptr);
            }
            finally
            {
                if (release)
                    handle.DangerousRelease();
            }
        }

        internal static TResult UseHandle<TResult>(this SafeHandle handle, Func<IntPtr, TResult> op) =>
            handle.UseHandle(handle.DangerousGetHandle(), op);

        internal static void SetStringCollection(IEnumerable<string> value, SafeAlpmHandle safeAlpmHandle, Func<string, int> op)
        {
            // ReSharper disable once LoopCanBeConvertedToQuery
            foreach (var s in value)
            {
                if (op(s) < 0)
                    throw new AlpmException(safeAlpmHandle);
            }
        }
        
    }
}