using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Tango.Scripting
{
    public class ScriptSession
    {
        private Action _abortAction;

        public event EventHandler<ScriptSessionStateChangedEventArgs> StateChanged;

        public Script Script { get; private set; }

        public String EffectiveCode { get; set; }

        public ScriptSessionState State { get; set; }

        public ScriptSession(Script script, String effectiveCode, Action abortAction)
        {
            _abortAction = abortAction;
            Script = script;
            EffectiveCode = effectiveCode;
        }

        public void Abort()
        {
            _abortAction();
            State = ScriptSessionState.Aborted;
            RaiseStateChanged();
        }

        internal void Failed(Exception ex)
        {
            State = ScriptSessionState.Failed;
            RaiseStateChanged(null, ex);
        }

        internal void Completed(object returnValue)
        {
            State = ScriptSessionState.Completed;
            RaiseStateChanged(returnValue, null);
        }

        private void RaiseStateChanged(object returnValue = null, Exception ex = null)
        {
            StateChanged?.Invoke(this, 
                new ScriptSessionStateChangedEventArgs()
                {
                    ReturnValue = returnValue,
                    State = State,
                    Exception = ex
                });
        }
    }
}