using System;
using System.Collections.Generic;

namespace Flocking
{
    public class Mission
    {
        public string missionName;

        private List<SubMission> subMissions;   // submissions that must be completed one after the other
        private List<Goal.State> status;        // status of each submission

        private int activeIndex = 0; // index of the active sub-mission

        public Mission()
        {
            subMissions = new List<SubMission>();
            status = new List<Goal.State>();
        }

        /// <summary>
        /// Adds a sub mission to this mission.
        /// </summary>
        public void AddSubMission(SubMission s)
        {
            subMissions.Add(s);
            status.Add(Goal.State.InProgress);
        }

        public void Update(float dt)
        {
            if( GetState() != Goal.State.Accomplished )
            {
                // update the active sub-mission
                var activeSubMission = subMissions[activeIndex];
                activeSubMission.Update(dt);

                // if the active sub-mission was completed, move on to the next
                if( activeSubMission.GetState() == Goal.State.Accomplished )
                {
                    status[activeIndex] = Goal.State.Accomplished;
                    ++activeIndex;
                }
                else if( activeSubMission.GetState() == Goal.State.Failed )
                {
                    status[activeIndex] = Goal.State.Failed;
                    ++activeIndex;
                }

            }
        }

        public Goal.State GetState()
        {
            // first, check the list of accomplished/failed missions. If one of those has Failed, return Failed
            for(int i = 0; i < activeIndex; ++i)
                if( status[i] == Goal.State.Failed )
                    return Goal.State.Failed;

            // to determine if the mission is still in progress, check the last's sub-missions status
            // if it's In-Progress, the whole mission is in progress
            if( status[status.Count - 1] == Goal.State.InProgress )
                return Goal.State.InProgress;

            // if we reached this point, the mission was successful
            return Goal.State.Accomplished;
        }
    }
}