using System.Collections.Generic;
using NTERA.Engine.Compiler;

namespace NTERA.Engine.Runtime
{
	public class StackFrame
	{
		public Dictionary<string, Variable> Variables { get; set; }

		public List<Parameter> Parameters { get; set; }

		public FunctionDefinition SelfDefinition { get; set; }

		public bool IsAnonymous { get; set; }

		public int ExecutionIndex { get; set; }

		public IList<ExecutionNode> ExecutionNodes { get; set; }

		public StackFrame Clone(IList<ExecutionNode> nodes, bool anonymous = true)
		{
			return new StackFrame
			{
				Variables = Variables,
				Parameters = Parameters,
				SelfDefinition = SelfDefinition,
				IsAnonymous = anonymous,
				ExecutionIndex = 0,
				ExecutionNodes = nodes
			};
		}
	}

	public enum ExecutionResultType
	{
		None,
		AnonymousCall,
		FunctionReturn
	}

	public class ExecutionResult
	{
		public static ExecutionResult None { get; } = new ExecutionResult(ExecutionResultType.None);
		public static ExecutionResult AnonymousCall { get; } = new ExecutionResult(ExecutionResultType.AnonymousCall);

		public ExecutionResultType Type { get; }

		public Value? Result { get; }


		public ExecutionResult(ExecutionResultType type, Value? value = null)
		{
			Type = type;
			Result = value;
		}
	}

	public class Parameter
	{
		public Value Value { get; }
		public Variable BackingVariable { get; }
		public int[] BackingVariableIndex { get; }

		public Parameter(Value value, Variable backingVariable = null, int[] variableIndex = null)
		{
			Value = value;
			BackingVariable = backingVariable;
			BackingVariableIndex = variableIndex ?? new[] { 0 };
		}

		public static implicit operator Value(Parameter parameter)
		{
			return parameter.Value;
		}
	}
}