// Copyright (c) .NET Foundation. All rights reserved.
// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.

using System;
using System.Collections.Generic;
using System.Diagnostics.CodeAnalysis;
using System.IO;
using Microsoft.AspNet.Http.Authentication;

namespace Microsoft.AspNet.Authentication
{
    public class PropertiesSerializer : IDataSerializer<AuthenticationProperties>
    {
        private const int FormatVersion = 1;

        public static PropertiesSerializer Default { get; } = new PropertiesSerializer();

        [SuppressMessage("Microsoft.Usage", "CA2202:Do not dispose objects multiple times", Justification = "Dispose is idempotent")]
        public virtual byte[] Serialize(AuthenticationProperties model)
        {
            using (var memory = new MemoryStream())
            {
                using (var writer = new BinaryWriter(memory))
                {
                    Write(writer, model);
                    writer.Flush();
                    return memory.ToArray();
                }
            }
        }

        [SuppressMessage("Microsoft.Usage", "CA2202:Do not dispose objects multiple times", Justification = "Dispose is idempotent")]
        public virtual AuthenticationProperties Deserialize(byte[] data)
        {
            using (var memory = new MemoryStream(data))
            {
                using (var reader = new BinaryReader(memory))
                {
                    return Read(reader);
                }
            }
        }

        public virtual void Write(BinaryWriter writer, AuthenticationProperties properties)
        {
            if (writer == null)
            {
                throw new ArgumentNullException(nameof(writer));
            }

            if (properties == null)
            {
                throw new ArgumentNullException(nameof(properties));
            }

            writer.Write(FormatVersion);
            writer.Write(properties.Items.Count);

            foreach (var item in properties.Items)
            {
                writer.Write(item.Key ?? string.Empty);
                writer.Write(item.Value ?? string.Empty);
            }
        }

        public virtual AuthenticationProperties Read(BinaryReader reader)
        {
            if (reader == null)
            {
                throw new ArgumentNullException(nameof(reader));
            }

            if (reader.ReadInt32() != FormatVersion)
            {
                return null;
            }

            var count = reader.ReadInt32();
            var extra = new Dictionary<string, string>(count);

            for (var index = 0; index != count; ++index)
            {
                string key = reader.ReadString();
                string value = reader.ReadString();
                extra.Add(key, value);
            }
            return new AuthenticationProperties(extra);
        }
    }
}