using System;
using System.Runtime.InteropServices;

namespace Foodsoft.Alpm
{
    public class Depend : IEquatable<Depend>
    {
        internal unsafe Depend(IntPtr ptr)
        {
            var native = (NativeDepend*) ptr;
            Name = Marshal.PtrToStringUTF8(native->name)!;
            Version = Marshal.PtrToStringUTF8(native->version)!;
            Description = Marshal.PtrToStringUTF8(native->description)!;
            NameHash = (long)native->name_hash;
            Mod = native->mod;
        }

        public string Name { get; }
        public string Version { get; }
        public string Description { get; }
        public Int64 NameHash { get; }
        public ModType Mod { get; }

        public bool Equals(Depend? other)
        {
            return !ReferenceEquals(other, null) && ReferenceEquals(this, other) &&
                   Name == other.Name && Version == other.Version && Mod == other.Mod;
        }

        public override bool Equals(object? obj)
        {
            return obj is Depend other && Equals(other);
        }

        public override int GetHashCode()
        {
            return HashCode.Combine(Name, Version, (int) Mod);
        }

        [StructLayout(LayoutKind.Sequential)]
        private readonly struct NativeDepend
        {
            internal readonly IntPtr name;
            internal readonly IntPtr version;
            internal readonly IntPtr description;
            internal readonly ulong name_hash;
            internal readonly ModType mod;
        }
    }

    public enum ModType
    {
        Any = 1,
        Equal,
        GreaterThanOrEqual,
        LessThanOrEqual,
        GreaterThan,
        LessThan
    }
}