// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.

using System.Linq.Expressions;
using JetBrains.Annotations;
using Microsoft.EntityFrameworkCore.Query;

namespace EntityFrameworkCore.Jet.Query.Internal
{
    /// <summary>
    ///     <para>
    ///         This is an internal API that supports the Entity Framework Core infrastructure and not subject to
    ///         the same compatibility standards as public APIs. It may be changed or removed without notice in
    ///         any release. You should only use it directly in your code with extreme caution and knowing that
    ///         doing so can result in application failures when updating to a new Entity Framework Core release.
    ///     </para>
    ///     <para>
    ///         The service lifetime is <see cref="ServiceLifetime.Scoped" />. This means that each
    ///         <see cref="DbContext" /> instance will use its own instance of this service.
    ///         The implementation may depend on other services registered with any lifetime.
    ///         The implementation does not need to be thread-safe.
    ///     </para>
    /// </summary>
    public class JetCompiledQueryCacheKeyGenerator : RelationalCompiledQueryCacheKeyGenerator
    {
        /// <summary>
        ///     This is an internal API that supports the Entity Framework Core infrastructure and not subject to
        ///     the same compatibility standards as public APIs. It may be changed or removed without notice in
        ///     any release. You should only use it directly in your code with extreme caution and knowing that
        ///     doing so can result in application failures when updating to a new Entity Framework Core release.
        /// </summary>
        public JetCompiledQueryCacheKeyGenerator(
            [NotNull] CompiledQueryCacheKeyGeneratorDependencies dependencies,
            [NotNull] RelationalCompiledQueryCacheKeyGeneratorDependencies relationalDependencies)
            : base(dependencies, relationalDependencies)
        {
        }

        /// <summary>
        ///     This is an internal API that supports the Entity Framework Core infrastructure and not subject to
        ///     the same compatibility standards as public APIs. It may be changed or removed without notice in
        ///     any release. You should only use it directly in your code with extreme caution and knowing that
        ///     doing so can result in application failures when updating to a new Entity Framework Core release.
        /// </summary>
        public override object GenerateCacheKey(Expression query, bool async)
        {
            return new JetCompiledQueryCacheKey(
                           GenerateCacheKeyCore(query, async));
        }

        private struct JetCompiledQueryCacheKey
        {
            private readonly RelationalCompiledQueryCacheKey _relationalCompiledQueryCacheKey;

            public JetCompiledQueryCacheKey(
                RelationalCompiledQueryCacheKey relationalCompiledQueryCacheKey)
            {
                _relationalCompiledQueryCacheKey = relationalCompiledQueryCacheKey;
            }

            public override bool Equals(object? obj)
                => !(obj is null)
                   && obj is JetCompiledQueryCacheKey key
                   && Equals(key);

            private bool Equals(JetCompiledQueryCacheKey other)
                => _relationalCompiledQueryCacheKey.Equals(other._relationalCompiledQueryCacheKey);

            public override int GetHashCode()
                => _relationalCompiledQueryCacheKey.GetHashCode();
        }
    }
}
