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

namespace Rimworld_Animations
{
    public class GroupAnimationContext
    {
        public int priority = 0;

        public List<BasePawnTest> whitelist;
        public List<BasePawnTest> blacklist;

        /*
        public virtual bool CanAnimationBeUsed(List<Pawn> actors)
        {

            if (!whitelist.NullOrEmpty())
            {
                for (int i = 0; i < whitelist.Count; i++)
                {
                    // check whitelist to make sure pawn can be in this act
                    //for each whitelist item, pawntest must hold true for that pawn
                    if (!whitelist[i].PawnTest(actors[i]))
                    {
                        return false;
                    }

                }
            }

            if (!blacklist.NullOrEmpty())
            {
                for (int i = 0; i < blacklist.Count; i++)
                {
                    // check blacklist to make sure pawn can be in this act
                    // for each blacklist item, pawntest must hold false for that pawn
                    if (blacklist[i].PawnTest(actors[i]))
                    {
                        return false;
                    }

                }
            }

            return true;
        }
        */

        /*

        public List<Pawn> FindWorkingPermutation(List<Pawn> pawns, int index = 0)
        {
            //can't play anim for empty list of pawns
            if (pawns.Count == 0) return null;

            //pawns list doesn't match number in whitelist
            if (index == 0 && pawns.Count != whitelist.Count) return null;

            //if list only has one pawn and it works for that index, return it
            if (pawns.Count == 1)
            {
                return CanAnimationBeUsedFor(pawns[0], index) ? pawns : null;
            }

            for (int i = 0; i < pawns.Count; i++)
            {
                if (CanAnimationBeUsedFor(pawns[i], index))
                {
                    //remove the pawn that we know works for that context
                    List<Pawn> smallerSubset = pawns.Where((item, idx) => idx != i).ToList();

                    //try to find a working subset for the next indices
                    List<Pawn> newWorkingSubset = FindWorkingPermutation(smallerSubset, index + 1);

                    if (newWorkingSubset != null)
                    {
                        newWorkingSubset.Insert(0, pawns[i]);
                        return newWorkingSubset;
                    }
                }
            }

            return null;
        }

        */

        public List<Pawn> FindAnyWorkingSet(List<Pawn> actors)
        {
            if (actors.Count != whitelist.Count) return null;

            int numActors = actors.Count;

            Dictionary<int, List<int>> validPawnContexts = new Dictionary<int, List<int>>();

            for (int i = 0; i < numActors; i++)
            {
                validPawnContexts[i] = new List<int>();

                for (int j = 0; j < numActors; j++)
                {
                    if (CanAnimationBeUsedFor(actors[i], j))
                    {
                        //give a list of all pawn's valid potential spots
                        validPawnContexts[i].Add(j);
                    }

                }

            }

            //set all spots as empty (-1)
            int[] indexAssignedToPawn = Enumerable.Repeat(-1, numActors).ToArray();

            for (int i = 0; i < numActors; i++)
            {
                bool[] visited = new bool[numActors];

                //try to fill in each space
                //try to shove spaces out of the way, get them to look elsewhere
                if (!DfsMatch(i, visited, indexAssignedToPawn, validPawnContexts))
                {
                    return null;
                }
            }

            List<Pawn> actorOrder = new List<Pawn>();
            foreach (int actorIndex in indexAssignedToPawn)
            {
                actorOrder.Add(actors[actorIndex]);
            }
            return actorOrder;
        }

        public bool DfsMatch(int pawnIndex, bool[] visited, int[] indexAssignedToPawn, Dictionary<int, List<int>> validPawnContexts)
        {
            foreach (int index in validPawnContexts[pawnIndex])
            {
                //don't infinte loop
                if (visited[index]) continue;
                visited[index] = true;

                //fill in space or shove something else out of the way
                if (indexAssignedToPawn[index] == -1 || DfsMatch(indexAssignedToPawn[index], visited, indexAssignedToPawn, validPawnContexts))
                {
                    indexAssignedToPawn[index] = pawnIndex;
                    return true;
                }
            }

            return false;
        }



        public virtual bool CanAnimationBeUsedFor(Pawn actor, int index)
        {
            if (whitelist.NullOrEmpty()) return false;
            if (index < 0 || index >= whitelist.Count)
            {
                return false;
            }

            if (!whitelist[index].PawnTest(actor))
            {
                return false;
            }

            if (!blacklist.NullOrEmpty() && blacklist[index].PawnTest(actor))
            {
                return false;
            }

            return true;
        }

        public virtual int AnimationPriority()
        {
            return priority;
        }
        //cool class for designating contexts for animations
        // configure CanAnimationBeUsed to test whether it can be used
    }
}