// ==========================================================================
//  Squidex Headless CMS
// ==========================================================================
//  Copyright (c) Squidex UG (haftungsbeschraenkt)
//  All rights reserved. Licensed under the MIT license.
// ==========================================================================

using System;
using System.Collections.Generic;
using System.Linq;
using Squidex.Infrastructure.Collections;

namespace Squidex.Infrastructure.Security
{
    public sealed class PermissionSet : ReadonlyList<Permission>
    {
        public static readonly PermissionSet Empty = new PermissionSet(Array.Empty<string>());

        private readonly Lazy<string> display;

        public PermissionSet(params Permission[] permissions)
            : this(permissions?.ToList()!)
        {
        }

        public PermissionSet(params string[] permissions)
            : this(permissions?.Select(x => new Permission(x)).ToList()!)
        {
        }

        public PermissionSet(IEnumerable<string> permissions)
            : this(permissions?.Select(x => new Permission(x)).ToList()!)
        {
        }

        public PermissionSet(IEnumerable<Permission> permissions)
            : this(permissions?.ToList()!)
        {
        }

        public PermissionSet(IList<Permission> permissions)
            : base(permissions)
        {
            display = new Lazy<string>(() => string.Join(";", this));
        }

        public PermissionSet Add(string permission)
        {
            Guard.NotNullOrEmpty(permission, nameof(permission));

            return Add(new Permission(permission));
        }

        public PermissionSet Add(Permission permission)
        {
            Guard.NotNull(permission, nameof(permission));

            return new PermissionSet(this.Union(Enumerable.Repeat(permission, 1)).Distinct());
        }

        public bool Allows(Permission? other)
        {
            if (other == null)
            {
                return false;
            }

            return this.Any(x => x.Allows(other));
        }

        public bool Includes(Permission? other)
        {
            if (other == null)
            {
                return false;
            }

            return this.Any(x => x.Includes(other));
        }

        public override string ToString()
        {
            return display.Value;
        }

        public IEnumerable<string> ToIds()
        {
            return this.Select(x => x.Id);
        }
    }
}