using System;
using System.Collections.Generic;
using AspClassic.Scripting.Utils;

namespace AspClassic.Scripting;

public static class SymbolTable
{
	private const int InitialTableSize = 256;

	internal const int CaseVersionMask = -16777216;

	internal const int CaseVersionIncrement = 16777216;

	private static readonly object _lockObj = new object();

	private static readonly Dictionary<string, int> _idDict = new Dictionary<string, int>(256);

	private static readonly Dictionary<string, int> _invariantDict = new Dictionary<string, int>(256, StringComparer.OrdinalIgnoreCase);

	private static readonly Dictionary<int, string> _fieldDict = CreateFieldDictionary();

	private static int _nextCaseInsensitiveId = 1;

	private static Dictionary<int, string> CreateFieldDictionary()
	{
		Dictionary<int, string> dictionary = new Dictionary<int, string>(256);
		dictionary[0] = null;
		return dictionary;
	}

	public static SymbolId StringToId(string value)
	{
		ContractUtils.RequiresNotNull(value, "value");
		int value2;
		lock (_lockObj)
		{
			if (!_idDict.TryGetValue(value, out value2))
			{
				if (!_invariantDict.TryGetValue(value, out value2))
				{
					if (_nextCaseInsensitiveId == 16777215)
					{
						throw Error.CantAddIdentifier(value);
					}
					value2 = _nextCaseInsensitiveId++ | 0x1000000;
				}
				else
				{
					if (((uint)value2 & -16777216) == -16777216)
					{
						throw Error.CantAddCasing(value);
					}
					value2 += 16777216;
				}
				_invariantDict[value] = value2;
				_idDict[value] = value2;
				_fieldDict[value2] = value;
			}
		}
		return new SymbolId(value2);
	}

	public static SymbolId StringToCaseInsensitiveId(string value)
	{
		return StringToId(value).CaseInsensitiveIdentifier;
	}

	public static SymbolId[] QualifiedStringToIds(string values)
	{
		if (values != null)
		{
			string[] array = values.Split('.');
			SymbolId[] array2 = new SymbolId[array.Length];
			for (int i = 0; i < array.Length; i++)
			{
				ref SymbolId reference = ref array2[i];
				reference = StringToId(array[i]);
			}
			return array2;
		}
		return null;
	}

	public static string IdToString(SymbolId id)
	{
		lock (_fieldDict)
		{
			if (id.IsCaseInsensitive)
			{
				return _fieldDict[id.Id | 0x1000000];
			}
			return _fieldDict[id.Id];
		}
	}

	public static bool ContainsId(SymbolId id)
	{
		lock (_fieldDict)
		{
			if (id.IsCaseInsensitive)
			{
				return _fieldDict.ContainsKey(id.Id | 0x1000000);
			}
			return _fieldDict.ContainsKey(id.Id);
		}
	}

	public static string[] IdsToStrings(IList<SymbolId> ids)
	{
		string[] array = new string[ids.Count];
		for (int i = 0; i < ids.Count; i++)
		{
			if (ids[i] == SymbolId.Empty)
			{
				array[i] = null;
			}
			else
			{
				array[i] = IdToString(ids[i]);
			}
		}
		return array;
	}

	public static SymbolId[] StringsToIds(IList<string> values)
	{
		SymbolId[] array = new SymbolId[values.Count];
		for (int i = 0; i < values.Count; i++)
		{
			if (values[i] == null)
			{
				ref SymbolId reference = ref array[i];
				reference = SymbolId.Empty;
			}
			else
			{
				ref SymbolId reference2 = ref array[i];
				reference2 = StringToId(values[i]);
			}
		}
		return array;
	}

	public static bool StringHasId(string symbol)
	{
		ContractUtils.RequiresNotNull(symbol, "symbol");
		lock (_lockObj)
		{
			return _idDict.ContainsKey(symbol);
		}
	}

	public static SymbolId StringToIdOrEmpty(string value)
	{
		if (value == null)
		{
			return SymbolId.Empty;
		}
		return StringToId(value);
	}
}