using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using CDSAE3_Lian_Lian_Kan.Forms.Interface;

namespace CDSAE3_Lian_Lian_Kan.Boards
{
    internal class Graph_Board : IBoard
    {
        class Node
        {
            public Node? LNode, RNode, UNode, DNode;
            public int x, y;
            public int value;
            public Node(int x, int y, int value)
            {
                this.x = x;
                this.y = y;
                this.value = value;
                LNode = RNode = UNode = DNode = null;
            }

            public Node(Node? lNode, Node? rNode, Node? uNode, Node? dNode, int x, int y, int value)
            {
                LNode = lNode;
                RNode = rNode;
                UNode = uNode;
                DNode = dNode;
                this.x = x;
                this.y = y;
                this.value = value;
            }
        }
        public (int, int) size { get; set; }//width,height
        Dictionary<(int,int),Node>Index = new Dictionary<(int,int), Node>();//width,height
        private Dictionary<int, List<(int, int)>> boardIndex = new Dictionary<int, List<(int, int)>>();
        Board_funcs board_Funcs = new Board_funcs();
        private int total;
        private int Total
        {
            get
            {
                return total;
            }
            set
            {
                total = value;
                if (Total == 0)
                    Etcs.gameModeForm?.Finished_Handler(this, new FinishArgs { finishType = FinishArgs.FinishType.All_done });
            }
        }
        private int[] Vals_per_Image { get; set; } = Array.Empty<int>();

        public void decrease(params (int, int)[] poss)
        {
            foreach (var (x, y) in poss)
            {
                int type = Index[(x, y)].value;
                if(Index.TryGetValue((x,y),out Node? node))
                {
                    if (node.RNode != null)
                        node.RNode.LNode = node.LNode;
                    if(node.LNode!=null)
                        node.LNode.RNode = node.RNode;
                    if(node.DNode!=null)
                        node.DNode.UNode = node.UNode;
                    if(node.UNode!=null)
                        node.UNode.DNode = node.DNode;
                    Index.Remove((x, y));
                }
                else
                    throw new Exception("Val not Found in Index");
                if (!boardIndex[type].Remove((x, y)))
                    throw new Exception("Val not Found in board_Index");
                Vals_per_Image[type]--;
                Total--;
            }
        }

        public List<List<(int, int)>> get_tip((int, int) start)
        {
            List<List<(int, int)>> ans = new List<List<(int, int)>>();
            if (boardIndex.TryGetValue(Index[start].value, out var tip))
                foreach (var pos in tip)
                {
                    var (result, path) = test(start, pos);
                    if (result && path != null)
                        ans.Add(path);
                }
            return ans;
        }

        public int[,] make_board()
        {
            size = Etcs.get_length_width();
            var (width, height) = size;
            int[,]Bd = new int[height + 2, width + 2];
            for (int i = 0; i < height + 2; i++)
                for (int j = 0; j < width + 2; j++)
                { 
                    Bd[i, j] = -1;
                    Index.Add((j, i), new Node(j, i, -1));
                }

            bool doSwap_causeByOddtotal = false;
            int sum = width * height;
            if (sum % 2 != 0)
            {
                doSwap_causeByOddtotal = true;
                sum--;
            }
            total = sum;
            int types = Etcs.Images_size();
            Vals_per_Image = board_Funcs.get_vals_per_image(Total, types);
            int last_val = -1;
            int cur_width = 1, cur_height = 1;
            var temp_val_per_Image = (int[])Vals_per_Image.Clone();
            for (int i = 0; i < sum; i++)
            {
                Bd[cur_height, cur_width] = board_Funcs.getval(ref temp_val_per_Image, ref last_val, types);
                if (boardIndex.TryGetValue(Bd[cur_height, cur_width], out var index))
                    index.Add((cur_width, cur_height));
                else
                    boardIndex.Add(Bd[cur_height, cur_width], new List<(int, int)> { (cur_width, cur_height) });
                Index[(cur_width, cur_height)].value = Bd[cur_height, cur_width]; 
                cur_width++;
                if (cur_width > width)
                {
                    cur_height++;
                    cur_width = 1;
                }
            }
            if (doSwap_causeByOddtotal)
                (Bd[height, width], Bd[(height + 1) / 2, (width + 1) / 2]) = (Bd[(height + 1) / 2, (width + 1) / 2], Bd[height, width]);
            foreach(var (index,node)in Index)
            {
                if (Index.TryGetValue((node.x - 1, node.y), out var lnode))
                    node.LNode = lnode;
                if (Index.TryGetValue((node.x + 1, node.y), out var rnode))
                    node.RNode = rnode;
                if (Index.TryGetValue((node.x, node.y - 1), out var unode))
                    node.UNode = unode;
                if (Index.TryGetValue((node.x, node.y + 1), out var dnode))
                    node.DNode = dnode;
                Index[index] = node;
            }
            return Bd;
        }

        public int[,] remake_board()
        {
            boardIndex.Clear();
            int[] temp_val_per_Image = (int[])Vals_per_Image.Clone();
            var (width, height) = size;
            int[,] Bd = new int[height + 2, width + 2];
            for (int i = 0; i < height + 2; i++)
                for (int j = 0; j < width + 2; j++)
                    Bd[i, j] = -1;
            int last_val = -1;
            foreach(var (index,node) in Index)
            {
                if(node.value==-1)
                    continue;
                node.value = board_Funcs.getval(ref temp_val_per_Image, ref last_val, Etcs.Images_size());
                Bd[node.y,node.x] = node.value;
                if(boardIndex.TryGetValue(node.value,out var list))
                    list.Add((node.x, node.y));
                else
                    boardIndex.Add(node.value, new List<(int, int)> { (node.x, node.y) });
            }
            return Bd;
        }

        public (bool, List<(int, int)>?) test((int, int) a, (int, int) b)
        {
            if(a==b)
                return (false, null);
            int xa, ya, xb, yb;
            if (Index.TryGetValue(a, out var nodeA) && Index.TryGetValue(b, out var nodeB))
            {
                if (nodeA.value != nodeB.value)
                    return (false,null);
                else
                {
                    (xa, ya) = a;
                    (xb, yb) = b;
                }
            }
            else
                return (false, null);
            Func<bool, int, int, int, bool> line_test = (bool x, int ct, int from, int to) =>
            {//ct is x (x==true)left to right ///up to down ///Index must contain from or to ///只管中间
                if (from > to)
                    (from, to) = (to, from);
                if(ct==0||(ct == size.Item1+1&&!x)||(ct==size.Item2+1&&x))
                    return true;
                if(x)
                {
                    var node = Index[(0, ct)].RNode;
                    while(node!=null)
                    {
                        if (node.x > to)
                            return true;
                        if (node.x > from && node.x < to)
                            return false;
                        node = node.RNode;
                    }
                    return true;
                }
                else
                {
                    var node = Index[(ct, 0)].DNode;
                    while (node != null)
                    {
                        if (node.y > to)
                            return true;
                        if (node.y > from && node.y < to)
                            return false;
                        node = node.DNode;
                    }
                    return true;
                }
            };
            if (xa == xb)
                if (line_test(false, xa, ya, yb))
                    return (true, new List<(int, int)> { a, b });
            if (ya == yb)
                if (line_test(true, ya, xa, xb))
                    return (true, new List<(int, int)> { a, b });
            {//two line test
                (int, int) extra_pa = (xa, yb);
                (int, int) extra_pb = (xb, ya);
                if (!Index.ContainsKey(extra_pa))
                    if (line_test(true, yb, xa, xb) && line_test(false, xa, ya, yb))
                        return (true, new List<(int, int)> { a, extra_pa, b });
                if (!Index.ContainsKey(extra_pb))
                    if (line_test(true, ya, xa, xb) && line_test(false, xb, ya, yb))
                        return (true, new List<(int, int)> { a, extra_pb, b });
            }
            (int, int)[] squareA = new (int, int)[4];
            (int, int)[] squareB = new (int, int)[4];//urdl
            {//three line test
                Func<Node, (int,int)[]> get_square = (Node node) =>
                {
                    (int, int)[] result = new (int, int)[4];
                    result[0] = (node.UNode!.x, node.UNode!.value==-1? node.UNode!.y: node.UNode!.y + 1);
                    result[1] = (node.RNode!.value==-1? node.RNode!.x: node.RNode!.x - 1, node.RNode!.y);
                    result[2] = (node.DNode!.x, node.DNode!.value==-1? node.DNode!.y: node.DNode!.y - 1);
                    result[3] = (node.LNode!.value==-1? node.LNode!.x: node.LNode!.x + 1, node.LNode!.y);
                    return result;
                };
                squareA = get_square(nodeA);
                squareB = get_square(nodeB);
                Func<(int, int), (int, int), (bool, (int, int))> intersection = ((int, int) a, (int, int) b) =>//first small last big
                {
                    if(a.Item1==a.Item2&&b.Item1==b.Item2&& a.Item1 == b.Item1)
                        return (false, (-1, -1));
                    if (a.Item1 > b.Item1)
                        (a, b) = (b, a);
                    if (a.Item2 < b.Item1)
                        return (false, (-1, -1));
                    if (a.Item2 > b.Item2)
                        return (true, (b.Item1, b.Item2));
                    return (true, (b.Item1, a.Item2));
                };
                var (throughx, xrange) = intersection((squareA[3].Item1, squareA[1].Item1), (squareB[3].Item1, squareB[1].Item1));
                var (throughy, yrange) = intersection((squareA[0].Item2, squareA[2].Item2), (squareB[0].Item2, squareB[2].Item2));
                Func<(int, int), int, List<int>> swing_check = ((int, int) range, int center) =>
                {
                    List<int> result = new List<int>();
                    if (center < range.Item1)
                    {
                        for (int k = range.Item1; k <= range.Item2; k++)
                            result.Add(k);
                        return result;
                    }
                    if (center > range.Item2)
                    {
                        for (int k = range.Item2; k >= range.Item1; k--)
                            result.Add(k);
                        return result;
                    }
                    result.Add(center);
                    Func<int, bool> inrange = (int t) => t >= range.Item1 && t <= range.Item2;
                    bool go_on = true;
                    for (int i = 1; go_on; i++)
                    {
                        go_on = false;
                        if (go_on |= inrange(center + i))
                            result.Add(center + i);
                        if (go_on |= inrange(center - i))
                            result.Add(center - i);
                    }
                    return result;
                };
                if (throughx)
                    foreach (int i in swing_check(xrange, a.Item1))
                        if (line_test(false, i, a.Item2, b.Item2))
                                return (true, new List<(int, int)> { a, (i, a.Item2), (i, b.Item2), b });
                if (throughy)
                    foreach (int i in swing_check(yrange, a.Item2))
                        if (line_test(true, i, a.Item1, b.Item1))
                                return (true, new List<(int, int)> { a, (a.Item1, i), (b.Item1, i), b });
            }
            return (false, null);


        }

        public (int, int) GetRandomBlock()
        {
            Random random = new();
            int k = random.Next(0, boardIndex.Count);
            for(int i = 0;i<boardIndex.Count(); i++)
            {
                if (boardIndex[k + i].Count != 0)
                    return boardIndex[k + i][random.Next(0, boardIndex[k + i].Count)];
            }
            return (-1, -1);
        }
    }
}