using System;
using System.Collections.Generic;

namespace AspClassic.Scripting.Runtime;

[Serializable]
public struct ContextId : IEquatable<ContextId>
{
	private int _id;

	private static Dictionary<object, ContextId> _contexts = new Dictionary<object, ContextId>();

	private static int _maxId = 1;

	public static readonly ContextId Empty = default(ContextId);

	public int Id => _id;

	internal ContextId(int id)
	{
		_id = id;
	}

	public static ContextId RegisterContext(object identifier)
	{
		lock (_contexts)
		{
			if (_contexts.TryGetValue(identifier, out var _))
			{
				throw Error.LanguageRegistered();
			}
			ContextId result = default(ContextId);
			result._id = _maxId++;
			return result;
		}
	}

	public static ContextId LookupContext(object identifier)
	{
		lock (_contexts)
		{
			if (_contexts.TryGetValue(identifier, out var value))
			{
				return value;
			}
		}
		return Empty;
	}

	public bool Equals(ContextId other)
	{
		return _id == other._id;
	}

	public override int GetHashCode()
	{
		return _id;
	}

	public override bool Equals(object obj)
	{
		if (!(obj is ContextId contextId))
		{
			return false;
		}
		return contextId._id == _id;
	}

	public static bool operator ==(ContextId self, ContextId other)
	{
		return self.Equals(other);
	}

	public static bool operator !=(ContextId self, ContextId other)
	{
		return !self.Equals(other);
	}
}