using System;
using System.Collections.Generic;
using System.Dynamic;
using System.Linq.Expressions;
using System.Reflection;
using System.Runtime.CompilerServices;
using AspClassic.Scripting.Utils;

namespace AspClassic.Scripting.Runtime;

public sealed class DynamicOperations
{
	private class SiteKey : IEquatable<SiteKey>
	{
		internal readonly CallSiteBinder SiteBinder;

		private readonly Type _siteType;

		public int HitCount;

		public CallSite Site;

		public SiteKey(Type siteType, CallSiteBinder siteBinder)
		{
			SiteBinder = siteBinder;
			_siteType = siteType;
		}

		public override bool Equals(object obj)
		{
			return Equals(obj as SiteKey);
		}

		public override int GetHashCode()
		{
			return SiteBinder.GetHashCode() ^ _siteType.GetHashCode();
		}

		public bool Equals(SiteKey other)
		{
			if (other == null)
			{
				return false;
			}
			if (other.SiteBinder.Equals(SiteBinder))
			{
				return other._siteType == _siteType;
			}
			return false;
		}
	}

	private const int CleanupThreshold = 20;

	private const int RemoveThreshold = 2;

	private const int StopCleanupThreshold = 10;

	private const int ClearThreshold = 50;

	private readonly LanguageContext _lc;

	private Dictionary<SiteKey, SiteKey> _sites = new Dictionary<SiteKey, SiteKey>();

	private int LastCleanup;

	private int SitesCreated;

	private Dictionary<int, Func<DynamicOperations, CallSiteBinder, object, object[], object>> _invokers = new Dictionary<int, Func<DynamicOperations, CallSiteBinder, object, object[], object>>();

	public DynamicOperations(LanguageContext lc)
	{
		ContractUtils.RequiresNotNull(lc, "lc");
		_lc = lc;
	}

	public object Invoke(object obj, params object[] parameters)
	{
		return GetInvoker(parameters.Length)(this, _lc.CreateInvokeBinder(new CallInfo(parameters.Length)), obj, parameters);
	}

	public object InvokeMember(object obj, string memberName, params object[] parameters)
	{
		return InvokeMember(obj, memberName, ignoreCase: false, parameters);
	}

	public object InvokeMember(object obj, string memberName, bool ignoreCase, params object[] parameters)
	{
		return GetInvoker(parameters.Length)(this, _lc.CreateCallBinder(memberName, ignoreCase, new CallInfo(parameters.Length)), obj, parameters);
	}

	public object CreateInstance(object obj, params object[] parameters)
	{
		return GetInvoker(parameters.Length)(this, _lc.CreateCreateBinder(new CallInfo(parameters.Length)), obj, parameters);
	}

	public object GetMember(object obj, string name)
	{
		return GetMember(obj, name, ignoreCase: false);
	}

	public T GetMember<T>(object obj, string name)
	{
		return GetMember<T>(obj, name, ignoreCase: false);
	}

	public bool TryGetMember(object obj, string name, out object value)
	{
		return TryGetMember(obj, name, ignoreCase: false, out value);
	}

	public bool ContainsMember(object obj, string name)
	{
		return ContainsMember(obj, name, ignoreCase: false);
	}

	public void RemoveMember(object obj, string name)
	{
		RemoveMember(obj, name, ignoreCase: false);
	}

	public void SetMember(object obj, string name, object value)
	{
		SetMember(obj, name, value, ignoreCase: false);
	}

	public void SetMember<T>(object obj, string name, T value)
	{
		SetMember(obj, name, value, ignoreCase: false);
	}

	public object GetMember(object obj, string name, bool ignoreCase)
	{
		CallSite<Func<CallSite, object, object>> orCreateSite = GetOrCreateSite<object, object>(_lc.CreateGetMemberBinder(name, ignoreCase));
		return orCreateSite.Target(orCreateSite, obj);
	}

	public T GetMember<T>(object obj, string name, bool ignoreCase)
	{
		CallSite<Func<CallSite, object, T>> orCreateSite = GetOrCreateSite<object, T>(_lc.CreateConvertBinder(typeof(T), null));
		CallSite<Func<CallSite, object, object>> orCreateSite2 = GetOrCreateSite<object, object>(_lc.CreateGetMemberBinder(name, ignoreCase));
		return orCreateSite.Target(orCreateSite, orCreateSite2.Target(orCreateSite2, obj));
	}

	public bool TryGetMember(object obj, string name, bool ignoreCase, out object value)
	{
		try
		{
			value = GetMember(obj, name, ignoreCase);
			return true;
		}
		catch (MissingMemberException)
		{
			value = null;
			return false;
		}
	}

	public bool ContainsMember(object obj, string name, bool ignoreCase)
	{
		object value;
		return TryGetMember(obj, name, ignoreCase, out value);
	}

	public void RemoveMember(object obj, string name, bool ignoreCase)
	{
		CallSite<Action<CallSite, object>> orCreateActionSite = GetOrCreateActionSite<object>(_lc.CreateDeleteMemberBinder(name, ignoreCase));
		orCreateActionSite.Target(orCreateActionSite, obj);
	}

	public void SetMember(object obj, string name, object value, bool ignoreCase)
	{
		CallSite<Func<CallSite, object, object, object>> orCreateSite = GetOrCreateSite<object, object, object>(_lc.CreateSetMemberBinder(name, ignoreCase));
		orCreateSite.Target(orCreateSite, obj, value);
	}

	public void SetMember<T>(object obj, string name, T value, bool ignoreCase)
	{
		CallSite<Func<CallSite, object, T, object>> orCreateSite = GetOrCreateSite<object, T, object>(_lc.CreateSetMemberBinder(name, ignoreCase));
		orCreateSite.Target(orCreateSite, obj, value);
	}

	public T ConvertTo<T>(object obj)
	{
		CallSite<Func<CallSite, object, T>> orCreateSite = GetOrCreateSite<object, T>(_lc.CreateConvertBinder(typeof(T), null));
		return orCreateSite.Target(orCreateSite, obj);
	}

	public object ConvertTo(object obj, Type type)
	{
		if (type.IsInterface || type.IsClass)
		{
			CallSite<Func<CallSite, object, object>> orCreateSite = GetOrCreateSite<object, object>(_lc.CreateConvertBinder(type, null));
			return orCreateSite.Target(orCreateSite, obj);
		}
		MemberInfo[] member = typeof(DynamicOperations).GetMember("ConvertTo");
		for (int i = 0; i < member.Length; i++)
		{
			MethodInfo methodInfo = (MethodInfo)member[i];
			if (methodInfo.IsGenericMethod)
			{
				try
				{
					return methodInfo.MakeGenericMethod(type).Invoke(this, new object[1] { obj });
				}
				catch (TargetInvocationException ex)
				{
					throw ex.InnerException;
				}
			}
		}
		throw new InvalidOperationException();
	}

	public bool TryConvertTo<T>(object obj, out T result)
	{
		try
		{
			result = ConvertTo<T>(obj);
			return true;
		}
		catch (ArgumentTypeException)
		{
			result = default(T);
			return false;
		}
		catch (InvalidCastException)
		{
			result = default(T);
			return false;
		}
	}

	public bool TryConvertTo(object obj, Type type, out object result)
	{
		try
		{
			result = ConvertTo(obj, type);
			return true;
		}
		catch (ArgumentTypeException)
		{
			result = null;
			return false;
		}
		catch (InvalidCastException)
		{
			result = null;
			return false;
		}
	}

	public T ExplicitConvertTo<T>(object obj)
	{
		CallSite<Func<CallSite, object, T>> orCreateSite = GetOrCreateSite<object, T>(_lc.CreateConvertBinder(typeof(T), true));
		return orCreateSite.Target(orCreateSite, obj);
	}

	public object ExplicitConvertTo(object obj, Type type)
	{
		CallSite<Func<CallSite, object, object>> orCreateSite = GetOrCreateSite<object, object>(_lc.CreateConvertBinder(type, true));
		return orCreateSite.Target(orCreateSite, obj);
	}

	public bool TryExplicitConvertTo(object obj, Type type, out object result)
	{
		try
		{
			result = ExplicitConvertTo(obj, type);
			return true;
		}
		catch (ArgumentTypeException)
		{
			result = null;
			return false;
		}
		catch (InvalidCastException)
		{
			result = null;
			return false;
		}
	}

	public bool TryExplicitConvertTo<T>(object obj, out T result)
	{
		try
		{
			result = ExplicitConvertTo<T>(obj);
			return true;
		}
		catch (ArgumentTypeException)
		{
			result = default(T);
			return false;
		}
		catch (InvalidCastException)
		{
			result = default(T);
			return false;
		}
	}

	public T ImplicitConvertTo<T>(object obj)
	{
		CallSite<Func<CallSite, object, T>> orCreateSite = GetOrCreateSite<object, T>(_lc.CreateConvertBinder(typeof(T), false));
		return orCreateSite.Target(orCreateSite, obj);
	}

	public object ImplicitConvertTo(object obj, Type type)
	{
		CallSite<Func<CallSite, object, object>> orCreateSite = GetOrCreateSite<object, object>(_lc.CreateConvertBinder(type, false));
		return orCreateSite.Target(orCreateSite, obj);
	}

	public bool TryImplicitConvertTo(object obj, Type type, out object result)
	{
		try
		{
			result = ImplicitConvertTo(obj, type);
			return true;
		}
		catch (ArgumentTypeException)
		{
			result = null;
			return false;
		}
		catch (InvalidCastException)
		{
			result = null;
			return false;
		}
	}

	public bool TryImplicitConvertTo<T>(object obj, out T result)
	{
		try
		{
			result = ImplicitConvertTo<T>(obj);
			return true;
		}
		catch (ArgumentTypeException)
		{
			result = default(T);
			return false;
		}
		catch (InvalidCastException)
		{
			result = default(T);
			return false;
		}
	}

	public TResult DoOperation<TTarget, TResult>(ExpressionType operation, TTarget target)
	{
		CallSite<Func<CallSite, TTarget, TResult>> orCreateSite = GetOrCreateSite<TTarget, TResult>(_lc.CreateUnaryOperationBinder(operation));
		return orCreateSite.Target(orCreateSite, target);
	}

	public TResult DoOperation<TTarget, TOther, TResult>(ExpressionType operation, TTarget target, TOther other)
	{
		CallSite<Func<CallSite, TTarget, TOther, TResult>> orCreateSite = GetOrCreateSite<TTarget, TOther, TResult>(_lc.CreateBinaryOperationBinder(operation));
		return orCreateSite.Target(orCreateSite, target, other);
	}

	public string GetDocumentation(object o)
	{
		return _lc.GetDocumentation(o);
	}

	public IList<string> GetCallSignatures(object o)
	{
		return _lc.GetCallSignatures(o);
	}

	public bool IsCallable(object o)
	{
		return _lc.IsCallable(o);
	}

	public IList<string> GetMemberNames(object obj)
	{
		return _lc.GetMemberNames(obj);
	}

	public string Format(object obj)
	{
		return _lc.FormatObject(this, obj);
	}

	public CallSite<Func<CallSite, T1, TResult>> GetOrCreateSite<T1, TResult>(CallSiteBinder siteBinder)
	{
		return GetOrCreateSite(siteBinder, CallSite<Func<CallSite, T1, TResult>>.Create);
	}

	public CallSite<Action<CallSite, T1>> GetOrCreateActionSite<T1>(CallSiteBinder siteBinder)
	{
		return GetOrCreateSite(siteBinder, CallSite<Action<CallSite, T1>>.Create);
	}

	public CallSite<Func<CallSite, T1, T2, TResult>> GetOrCreateSite<T1, T2, TResult>(CallSiteBinder siteBinder)
	{
		return GetOrCreateSite(siteBinder, CallSite<Func<CallSite, T1, T2, TResult>>.Create);
	}

	public CallSite<Func<CallSite, T1, T2, T3, TResult>> GetOrCreateSite<T1, T2, T3, TResult>(CallSiteBinder siteBinder)
	{
		return GetOrCreateSite(siteBinder, CallSite<Func<CallSite, T1, T2, T3, TResult>>.Create);
	}

	public CallSite<TSiteFunc> GetOrCreateSite<TSiteFunc>(CallSiteBinder siteBinder) where TSiteFunc : class
	{
		return GetOrCreateSite(siteBinder, CallSite<TSiteFunc>.Create);
	}

	private T GetOrCreateSite<T>(CallSiteBinder siteBinder, Func<CallSiteBinder, T> factory) where T : CallSite
	{
		SiteKey siteKey = new SiteKey(typeof(T), siteBinder);
		lock (_sites)
		{
			if (!_sites.TryGetValue(siteKey, out var value))
			{
				SitesCreated++;
				if (SitesCreated < 0)
				{
					SitesCreated = 0;
					LastCleanup = 0;
				}
				siteKey.Site = factory(siteKey.SiteBinder);
				_sites[siteKey] = siteKey;
			}
			else
			{
				siteKey = value;
			}
			siteKey.HitCount++;
			CleanupNoLock();
		}
		return (T)siteKey.Site;
	}

	private void CleanupNoLock()
	{
		if (_sites.Count <= 20 || LastCleanup >= SitesCreated - 20)
		{
			return;
		}
		LastCleanup = SitesCreated;
		int num = 0;
		foreach (SiteKey key in _sites.Keys)
		{
			num += key.HitCount;
		}
		int num2 = num / _sites.Count;
		if (num2 == 1 && _sites.Count > 50)
		{
			_sites.Clear();
			return;
		}
		List<SiteKey> list = null;
		foreach (SiteKey key2 in _sites.Keys)
		{
			if (key2.HitCount < num2 - 2)
			{
				if (list == null)
				{
					list = new List<SiteKey>();
				}
				list.Add(key2);
				if (list.Count > 10)
				{
					break;
				}
			}
		}
		if (list == null)
		{
			return;
		}
		foreach (SiteKey item in list)
		{
			_sites.Remove(item);
		}
		foreach (SiteKey key3 in _sites.Keys)
		{
			key3.HitCount = 0;
		}
	}

	private Func<DynamicOperations, CallSiteBinder, object, object[], object> GetInvoker(int paramCount)
	{
		lock (_invokers)
		{
			if (!_invokers.TryGetValue(paramCount, out var value))
			{
				ParameterExpression parameterExpression = Expression.Parameter(typeof(DynamicOperations));
				ParameterExpression parameterExpression2 = Expression.Parameter(typeof(CallSiteBinder));
				ParameterExpression parameterExpression3 = Expression.Parameter(typeof(object));
				ParameterExpression parameterExpression4 = Expression.Parameter(typeof(object[]));
				Type objectCallSiteDelegateType = ReflectionUtils.GetObjectCallSiteDelegateType(paramCount);
				ParameterExpression parameterExpression5 = Expression.Parameter(typeof(CallSite<>).MakeGenericType(objectCallSiteDelegateType));
				Expression[] array = new Expression[paramCount + 2];
				array[0] = parameterExpression5;
				array[1] = parameterExpression3;
				for (int i = 0; i < paramCount; i++)
				{
					array[i + 2] = Expression.ArrayIndex(parameterExpression4, Expression.Constant(i));
				}
				MethodInfo genericMethodDefinition = new Func<CallSiteBinder, CallSite<Func<object>>>(GetOrCreateSite<Func<object>>).Method.GetGenericMethodDefinition();
				return _invokers[paramCount] = Expression.Lambda<Func<DynamicOperations, CallSiteBinder, object, object[], object>>(Expression.Block(new ParameterExpression[1] { parameterExpression5 }, Expression.Assign(parameterExpression5, Expression.Call(parameterExpression, genericMethodDefinition.MakeGenericMethod(objectCallSiteDelegateType), parameterExpression2)), Expression.Invoke(Expression.Field(parameterExpression5, parameterExpression5.Type.GetField("Target")), array)), new ParameterExpression[4] { parameterExpression, parameterExpression2, parameterExpression3, parameterExpression4 }).Compile();
			}
			return value;
		}
	}
}