package assignment09;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Arrays;

/**
 * Represents a PacMan Map in graph form from a formatted text file
 *
 * @author Benjamin Wadsworth and Adrian Sahbaz
 * @uid u0991657 and u0963488
 * @date 3/30/2017
 * @class CS 2420
 * @assignment 9 - PacMan
 * @pledge I pledge that the work done here was my own and that I have learned how to write this
 *         program, such that I could throw it out and restart and finish it in a timely manner. I
 *         am not turning in any work that I cannot understand, describe, or recreate. I further
 *         acknowledge that I contributed substantially to all code handed in and vouch for it's
 *         authenticity. Benjamin Wadsworth
 */
public class Graph
{
    private static final char X = (char) 0xFFFF;
    private int start;
    private int goal;

    private ArrayList<Node> graph;

    public Graph(File file) throws IOException
    {
        //Find rows/columns from first line
        int r = 0;
        int c = 0;
        BufferedReader br = new BufferedReader(new FileReader(file));
        if (br.ready())
        {
            String[] s = br.readLine().split(" ");
            if (s.length != 2)
            {
                throw new IOException("No row/column declaration!");
            }

            r = Integer.parseInt(s[0]);
            c = Integer.parseInt(s[1]);
        }
        else
        {
            throw new IOException("No file data!");
        }

        //Read each line, creating new nodes for all spaces and assign edges from previous
        int lines = 0;
        ArrayList<Node> temp = new ArrayList<>();
        char[] last = new char[c];
        Arrays.fill(last, X);
        char counter = 0;
        while (br.ready())
        {
            char[] chars = br.readLine().toCharArray();
            if (chars.length != c)
            {
                throw new IOException("Improper Column on line " + (lines + 1));
            }

            //Check each index for content and assign nodes
            for (int i = 0; i < chars.length; i++)
            {
                switch (chars[i])
                {
                    //Normal Node
                    case ' ':
                    {
                        chars[i] = counter;
                        Node next = new Node();
                        //Associate with its left
                        if (i != 0 && chars[i-1] != X)
                        {
                            Node left = temp.get(chars[i-1]);
                            next.edges.add(left);
                            left.edges.add(next);
                        }
                        //Associate with top
                        if (last[i] != X)
                        {
                            Node top = temp.get(last[i]);
                            next.edges.add(top);
                            top.edges.add(next);
                        }
                        temp.add(new Node());
                        counter ++;
                        break;
                    }
                    //Wall, replace to end and ignore
                    case 'X':
                    {
                        chars[i] = X;
                        break;
                    }
                    //Normal node, plus assign start
                    case 'S':
                    {
                        chars[i] = counter;
                        Node next = new Node();
                        //Associate with its left
                        if (i != 0 && chars[i-1] != X)
                        {
                            Node left = temp.get(chars[i-1]);
                            next.edges.add(left);
                            left.edges.add(next);
                        }
                        //Associate with top
                        if (last[i] != X)
                        {
                            Node top = temp.get(last[i]);
                            next.edges.add(top);
                            top.edges.add(next);
                        }
                        temp.add(new Node());
                        start = counter;
                        counter ++;
                        break;
                    }
                    //Normal node, plus assign goal
                    case 'G':
                    {
                        chars[i] = counter;
                        Node next = new Node();
                        //Associate with its left
                        if (i != 0 && chars[i-1] != X)
                        {
                            Node left = temp.get(chars[i-1]);
                            next.edges.add(left);
                            left.edges.add(next);
                        }
                        //Associate with top
                        if (last[i] != X)
                        {
                            Node top = temp.get(last[i]);
                            next.edges.add(top);
                            top.edges.add(next);
                        }
                        temp.add(new Node());
                        goal = counter;
                        counter ++;
                        break;
                    }
                    //Not Recognized
                    default:
                    {
                        throw new IOException("Incorrect Character at " + (lines + 1) + " " +  (i + 1));
                    }
                }
            }
            //Put the line just read into the last line variable
            last = chars;
            lines ++;
        }
        if (lines != r)
        {
            throw new IOException("Too Many Lines!");
        }
        graph = temp;

        br.close();
    }

    /**
     * Represents a node within the graph
     */
    public class Node
    {
        //ArrayList<Node> edges;
    	ArrayList<Integer> edges;
        boolean visited;

        Node ()
        {
            visited = false;
            edges = new ArrayList<>();
        }
    }
}