using System;
using System.Collections;
using System.Collections.Generic;
using ProtoBuf.Meta;

namespace ProtoBuf;

public abstract class Extensible : IExtensible
{
	private IExtension extensionObject;

	IExtension IExtensible.GetExtensionObject(bool createIfMissing)
	{
		return GetExtensionObject(createIfMissing);
	}

	protected virtual IExtension GetExtensionObject(bool createIfMissing)
	{
		return GetExtensionObject(ref extensionObject, createIfMissing);
	}

	public static IExtension GetExtensionObject(ref IExtension extensionObject, bool createIfMissing)
	{
		if (createIfMissing && extensionObject == null)
		{
			extensionObject = new BufferExtension();
		}
		return extensionObject;
	}

	public static void AppendValue<TValue>(IExtensible instance, int tag, TValue value)
	{
		AppendValue(instance, tag, DataFormat.Default, value);
	}

	public static void AppendValue<TValue>(IExtensible instance, int tag, DataFormat format, TValue value)
	{
		ExtensibleUtil.AppendExtendValue(RuntimeTypeModel.Default, instance, tag, format, value);
	}

	public static TValue GetValue<TValue>(IExtensible instance, int tag)
	{
		return GetValue<TValue>(instance, tag, DataFormat.Default);
	}

	public static TValue GetValue<TValue>(IExtensible instance, int tag, DataFormat format)
	{
		TryGetValue<TValue>(instance, tag, format, out var value);
		return value;
	}

	public static bool TryGetValue<TValue>(IExtensible instance, int tag, out TValue value)
	{
		return TryGetValue<TValue>(instance, tag, DataFormat.Default, out value);
	}

	public static bool TryGetValue<TValue>(IExtensible instance, int tag, DataFormat format, out TValue value)
	{
		return TryGetValue<TValue>(instance, tag, format, allowDefinedTag: false, out value);
	}

	public static bool TryGetValue<TValue>(IExtensible instance, int tag, DataFormat format, bool allowDefinedTag, out TValue value)
	{
		value = default(TValue);
		bool result = false;
		foreach (TValue extendedValue in ExtensibleUtil.GetExtendedValues<TValue>(instance, tag, format, singleton: true, allowDefinedTag))
		{
			value = extendedValue;
			result = true;
		}
		return result;
	}

	public static IEnumerable<TValue> GetValues<TValue>(IExtensible instance, int tag)
	{
		return ExtensibleUtil.GetExtendedValues<TValue>(instance, tag, DataFormat.Default, singleton: false, allowDefinedTag: false);
	}

	public static IEnumerable<TValue> GetValues<TValue>(IExtensible instance, int tag, DataFormat format)
	{
		return ExtensibleUtil.GetExtendedValues<TValue>(instance, tag, format, singleton: false, allowDefinedTag: false);
	}

	public static bool TryGetValue(TypeModel model, Type type, IExtensible instance, int tag, DataFormat format, bool allowDefinedTag, out object value)
	{
		value = null;
		bool result = false;
		foreach (object extendedValue in ExtensibleUtil.GetExtendedValues(model, type, instance, tag, format, singleton: true, allowDefinedTag))
		{
			value = extendedValue;
			result = true;
		}
		return result;
	}

	public static IEnumerable GetValues(TypeModel model, Type type, IExtensible instance, int tag, DataFormat format)
	{
		return ExtensibleUtil.GetExtendedValues(model, type, instance, tag, format, singleton: false, allowDefinedTag: false);
	}

	public static void AppendValue(TypeModel model, IExtensible instance, int tag, DataFormat format, object value)
	{
		ExtensibleUtil.AppendExtendValue(model, instance, tag, format, value);
	}
}