using Microsoft.CodeAnalysis;
using Microsoft.CodeAnalysis.CSharp;
using Microsoft.CodeAnalysis.CSharp.Syntax;
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Tango.Scripting
{
    public class ScriptParser
    {
        public List<ScriptVariable> ParseScript(String code)
        {
            List<ScriptVariable> vars = new List<ScriptVariable>();

            SyntaxTree tree = CSharpSyntaxTree.ParseText(code);
            var root = (CompilationUnitSyntax)tree.GetRoot();

            List<VariableDeclaratorSyntax> variables = new List<VariableDeclaratorSyntax>();
            FillVariables(variables, root.Members[0]);
            variables = variables.Distinct().ToList();

            foreach (var item in variables)
            {
                ScriptVariable v = new ScriptVariable();
                v.Name = item.Identifier.ToString();

                if (item.Initializer.Value.GetType() == typeof(ObjectCreationExpressionSyntax))
                {
                    v.Type = (item.Initializer.Value as ObjectCreationExpressionSyntax).Type.ToString();
                }
                else if (item.Initializer.Value.GetType() == typeof(InvocationExpressionSyntax))
                {
                    v.Type = (((item.Initializer.Value as InvocationExpressionSyntax).Expression as MemberAccessExpressionSyntax).Name as GenericNameSyntax).TypeArgumentList.Arguments[0].ToString();
                }

                vars.Add(v);
            }

            return vars;
        }

        private void FillVariables(List<VariableDeclaratorSyntax> variables, SyntaxNode node)
        {
            foreach (var item in node.DescendantNodes(x => true))
            {
                if (item.GetType() == typeof(VariableDeclaratorSyntax))
                {
                    variables.Add(item as VariableDeclaratorSyntax);
                }
                else
                {
                    FillVariables(variables, item);
                }
            }
        }
    }

    public class ScriptVariable
    {
        public String Name { get; set; }
        public String Type { get; set; }

        public override string ToString()
        {
            return String.Format("{0} : {1}", Type, Name);
        }
    }
}