

using System;
using MongoDB.Bson.IO;

namespace MongoDB.Bson.Serialization.Conventions
{
    /// <summary>
    /// Represents a discriminator convention.
    /// </summary>
    public interface IDiscriminatorConvention
    {
        /// <summary>
        /// Gets the discriminator element name.
        /// </summary>
        string ElementName { get; }

        /// <summary>
        /// Gets the actual type of an object by reading the discriminator from a BsonReader.
        /// </summary>
        /// <param name="bsonReader">The reader.</param>
        /// <param name="nominalType">The nominal type.</param>
        /// <returns>The actual type.</returns>
        Type GetActualType(BsonReader bsonReader, Type nominalType);

        /// <summary>
        /// Gets the discriminator value for an actual type.
        /// </summary>
        /// <param name="nominalType">The nominal type.</param>
        /// <param name="actualType">The actual type.</param>
        /// <returns>The discriminator value.</returns>
        BsonValue GetDiscriminator(Type nominalType, Type actualType);
    }
}
