using System;

namespace ParadoxNotion.Serialization.FullSerializer
{
    /// <summary>
    /// <para>
    /// Enables injecting code before/after an object has been serialized. This is most
    /// useful if you want to run the default serialization process but apply a pre/post
    /// processing step.
    /// </para>
    /// <para>
    /// Multiple object processors can be active at the same time. When running they are
    /// called in a "nested" fashion - if we have processor1 and process2 added to the
    /// serializer in that order (p1 then p2), then the execution order will be
    /// p1#Before p2#Before /serialization/ p2#After p1#After.
    /// </para>
    /// </summary>
    public abstract class fsObjectProcessor
    {
        /// Is the processor interested in objects of the given type?
        /// </summary>
        /// <param name="type">The given type.</param>
        /// <returns>True if the processor should be applied, false otherwise.</returns>
        public virtual bool CanProcess(Type type) { throw new NotImplementedException(); }

        /// <summary>
        /// Called before serialization.
        /// </summary>
        /// <param name="storageType">The field/property type that is storing the instance.</param>
        /// <param name="instance">The type of the instance.</param>
        public virtual void OnBeforeSerialize(Type storageType, object instance) { }

        /// <summary>
        /// Called after serialization.
        /// </summary>
        /// <param name="storageType">The field/property type that is storing the instance.</param>
        /// <param name="instance">The type of the instance.</param>
        /// <param name="data">The data that was serialized.</param>
        public virtual void OnAfterSerialize(Type storageType, object instance, ref fsData data) { }

        /// <summary>
        /// Called before deserialization.
        /// </summary>
        /// <param name="storageType">The field/property type that is storing the instance.</param>
        /// <param name="data">The data that will be used for deserialization.</param>
        public virtual void OnBeforeDeserialize(Type storageType, ref fsData data) { }

        /// <summary>
        /// Called before deserialization has begun but *after* the object instance has been created. This will get
        /// invoked even if the user passed in an existing instance.
        /// </summary>
        /// <remarks>
        /// **IMPORTANT**: The actual instance that gets passed here is *not* guaranteed to be an a subtype of storageType, since
        /// the value for instance is whatever the active converter returned for CreateInstance() - ie, some converters will return
        /// dummy types in CreateInstance() if instance creation cannot be separated from deserialization (ie, KeyValuePair).
        /// </remarks>
        /// <param name="storageType">The field/property type that is storing the instance.</param>
        /// <param name="instance">The created object instance. No deserialization has been applied to it.</param>
        /// <param name="data">The data that will be used for deserialization.</param>
        public virtual void OnBeforeDeserializeAfterInstanceCreation(Type storageType, object instance, ref fsData data) { }

        /// <summary>
        /// Called after deserialization.
        /// </summary>
        /// <param name="storageType">The field/property type that is storing the instance.</param>
        /// <param name="instance">The type of the instance.</param>
        public virtual void OnAfterDeserialize(Type storageType, object instance) { }
    }
}
