#nullable enable

using System;
using System.Collections.Generic;

namespace ShrinkNetwork
{
    public enum ShrinkNetworkPeerKind
    {
        Unknown = 0,
        Client = 1,
        Server = 2,
        TrustedServer = 3
    }

    public enum ShrinkNetworkAuthority
    {
        Any = 0,
        ClientOnly = 1,
        ServerOnly = 2,
        TrustedServerOnly = 3
    }

    public readonly struct ShrinkNetworkPermissionRequirement
    {
        public ShrinkNetworkAuthority Authority { get; }
        public string? Permission { get; }

        public ShrinkNetworkPermissionRequirement(ShrinkNetworkAuthority authority, string? permission)
        {
            Authority = authority;
            Permission = string.IsNullOrWhiteSpace(permission) ? null : permission.Trim();
        }
    }

    internal static class ShrinkNetworkPermissionValidator
    {
        public static bool IsAllowed(ShrinkNetworkSession session, ShrinkNetworkPermissionRequirement requirement)
        {
            if (session == null)
                return false;

            if (!CheckAuthority(session.PeerKind, requirement.Authority))
                return false;

            if (!string.IsNullOrEmpty(requirement.Permission) && !session.HasPermission(requirement.Permission))
                return false;

            return true;
        }

        private static bool CheckAuthority(ShrinkNetworkPeerKind peerKind, ShrinkNetworkAuthority authority)
        {
            return authority switch
            {
                ShrinkNetworkAuthority.Any => true,
                ShrinkNetworkAuthority.ClientOnly => peerKind == ShrinkNetworkPeerKind.Client,
                ShrinkNetworkAuthority.ServerOnly => peerKind == ShrinkNetworkPeerKind.Server || peerKind == ShrinkNetworkPeerKind.TrustedServer,
                ShrinkNetworkAuthority.TrustedServerOnly => peerKind == ShrinkNetworkPeerKind.TrustedServer,
                _ => false
            };
        }
    }
}