using System;
using System.Collections.Generic;
using System.Linq;


namespace GwaRL
{
    public class DungeonMap : DungeonSpace
    {
        public int[] terrain;
        public int[] decals;
        public int[] distancemap;
        public DungeonMap()
        {
            this.size = new int[] { 60, 60 };
            this.terrain = new int[3600];
            for (int i = 0; i < this.terrain.Length; i++)
            {
                this.terrain[i] = 1;
            }
            this.decals = new int[3600];
            this.distancemap = new int[3600];
        }
        public DungeonMap(int[] size)
        {
            this.size = size;
            this.terrain = new int[size[0]*size[1]];
            for (int i = 0; i < this.terrain.Length; i++)
            {
                this.terrain[i] = 1;
            }
            this.decals = new int[size[0] * size[1]];
            this.distancemap = new int[size[0] * size[1]];
        }
        public DungeonMap(int[] size, int[] terrain)
        {
            this.size = size;
            this.terrain = terrain;
            this.decals = new int[size[0] * size[1]];
            this.distancemap = new int[size[0] * size[1]];
        }
        public DungeonMap(int[] size, int[] terrain,int[] decals)
        {
            this.size = size;
            this.terrain = terrain;
            this.decals = decals;
            this.distancemap = new int[size[0] * size[1]];
        }
        public string gettile(int position) {
            string tile;
            switch (this.terrain[position])
            {
                case 0:
                    tile = "floor";
                    break;
                case 1:
                    tile = "wall";
                    break;
                case 2:
                    tile = "stairup";
                    break;
                case 3:
                    tile = "stairdown";
                    break;
                default:
                    tile = "none";
                    break;
            }
            return tile;
        }
        public void settile(int position, string tile) {
            switch (tile)
            {
                case "floor":
                    this.terrain[position] = 0;
                    break;
                case "wall":
                    this.terrain[position] = 1;
                    break;
                case "stairup":
                    this.terrain[position] = 2;
                    break;
                case "stairdown":
                    this.terrain[position] = 3;
                    break;
                default:
                    this.terrain[position] = 0;
                    break;
            }
        }
        public string[] getarea(int[] positions)
        {
            string[] tiles = new string[positions.Length];
            for (int i=0;i<tiles.Length;i++)
            {
                tiles[i] = this.gettile(positions[i]);
            }
            return tiles;
        }
        public void setarea(int[] positions, string[] tiles) {
            foreach (int position in positions)
            {
                this.settile(position,tiles[position]);
            }
        }

        //return array with index of every square in line of sight
        public List<int> getlineofsightfrom(int position)
        {
            List<int> neartiles = this.getnearindices(position,9);
            List<int> visible = new List<int>();
            for (int i=0;i<neartiles.Count;i++)
            {
                if (this.checklosbetween(position, neartiles[i]) == true)
                {
                    visible.Add(neartiles[i]);
                }
            }
            return visible;
        }
        public bool checklosbetween(int indexfrom,int indexto)
        {
            bool los = true;
            Line line = this.getline(indexfrom, indexto);
            if (line.distance > 9) los = false;
            for (int i = 0; i < line.distance; i++)
            {
                if (line.npaths == 2)
                {
                    if (this.gettile(line.path[0][i]) == "wall" && this.gettile(line.path[1][i]) == "wall") los = false;
                }
                else if (this.gettile(line.path[0][i]) == "wall") los = false;
            }
            return los;
        }

        //djikstra map
        public void builddistancemap(int goal)
        {
            //prepare the array. -1 denotes untreated square.
            for (int i = 0; i < this.terrain.Length; i++)
            {
                this.distancemap[i] = -1;
            }
            this.distancemap[goal] = 0;
            //take all the squares surrounding the goal/origin
            List<int> edge = new List<int>(this.getnearindices(goal,1));
            int step = 1;
            while (edge.Count>0)
            {
                int discard = 0;
                int edgecount = edge.Count;
                for (int i = 0; i < edgecount; i++)
                {
                    if (this.terrain[edge[i-discard]] != 1 && this.distancemap[edge[i-discard]] < 0)
                    {
                        this.distancemap[edge[i-discard]] = step;
                    }
                    else
                    {
                        edge.RemoveAt(i - discard);
                        discard++;
                    }
                }
                //record this here to stop it continuing to loop over the new elements it adds
                edgecount = edge.Count;
                for (int i = 0; i < edgecount; i++)
                {
                    List<int> neartiles = this.getnearindices(edge[i], 1);
                    foreach (int tileindex in neartiles)
                    {
                        if (this.terrain[tileindex] != 1 &&
                            this.distancemap[tileindex] < 0 &&
                            !edge.Contains(tileindex))
                        {
                            edge.Add(tileindex);
                        }
                    }
                }
                step++;
            }
        }
        public List<int> buildpath(int origin) {
            int goal = new List<int>(this.distancemap).IndexOf(0);
            List<int> path = new List<int>();
            bool nopath = false;
            int stepsleft = this.distancemap[origin];
            int currenttile = origin;
            if (stepsleft > 0) while (stepsleft > 0 && nopath == false)
                {
                    List<int> adjacenttiles = new List<int>(this.getnearindices(currenttile,1));
                    adjacenttiles.RemoveAt(4);
                    List<int> tiles = new List<int>();
                    List<int> directions = new List<int>();
                    List<int> moduli = new List<int>();
                    for (int i = 0; i < adjacenttiles.Count; i++)
                    {
                        if (this.distancemap[adjacenttiles[i]]>=0&&this.distancemap[adjacenttiles[i]]<stepsleft)
                        {
                            tiles.Add(adjacenttiles[i]);
                            directions.Add(this.getdirection(currenttile,adjacenttiles[i]));
                            moduli.Add(Math.Abs(this.getx(adjacenttiles[i]) -this.getx(goal))+ Math.Abs(this.gety(adjacenttiles[i]) - this.gety(goal)));
                        }
                    }
                    if (tiles.Count > 0)
                    {
                        int minimum = moduli.IndexOf(moduli.Min());
                        currenttile = tiles[minimum];
                        path.Add(directions[minimum]);
                        stepsleft--;
                    }
                    else nopath = true;
                }
            return path;
        }
        public List<int> reversepath(List<int> path)
        {
            List<int> newpath = new List<int>();
            for (int i = path.Count-1; i >= 0; i--)
            {
                if (path[i]>0&&path[i]<10) newpath.Add(10 - path[i]);
            }
            return newpath;
        }
        
    }
}