﻿/*
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

namespace DotPulsar.Schemas
{
    using DotPulsar.Abstractions;
    using DotPulsar.Exceptions;
    using System;
    using System.Buffers;
    using System.Collections.Immutable;

    /// <summary>
    /// Schema definition for Boolean messages.
    /// </summary>
    public sealed class BooleanSchema : ISchema<bool>
    {
        private readonly static ReadOnlySequence<byte> _true;
        private readonly static ReadOnlySequence<byte> _false;

        static BooleanSchema()
        {
            _true = new ReadOnlySequence<byte>(new byte[] { 1 });
            _false = new ReadOnlySequence<byte>(new byte[] { 0 });
        }

        public BooleanSchema()
            => SchemaInfo = new SchemaInfo("Boolean", Array.Empty<byte>(), SchemaType.Boolean, ImmutableDictionary<string, string>.Empty);

        public SchemaInfo SchemaInfo { get; }

        public bool Decode(ReadOnlySequence<byte> bytes, byte[]? schemaVersion = null)
        {
            if (bytes.Length != 1)
                throw new SchemaSerializationException($"{nameof(BooleanSchema)} expected to decode 1 byte, but received {bytes} bytes");

            return bytes.First.Span[0] != 0;
        }

        public ReadOnlySequence<byte> Encode(bool message)
            => message ? _true : _false;
    }
}