// GameEngine.java
// Description: Game Engine for Terriers and Squirrels
// Author: Chris Wilcox
// Date: 4/28/2015

package myPackage;
import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Scanner;

import myPackage.Interface.eMove;

public class GameEngine { 

	// Board data
	private char board[][];
	private int width;
	private int height;
	
	// Animal data
	private ArrayList<Terrier> terriers = new ArrayList<Terrier>();
	private ArrayList<Squirrel> squirrels = new ArrayList<Squirrel>();
	
	// Constructor
	public GameEngine(String filename) {
		
		// Read file
		readFile(filename);
				
		// Setup board
		for (int row = 0; row < height; ++row) {
			for (int col = 0; col < width; ++col) {

				if (board[row][col] == 'T') {

					// Make a Terrier
					Terrier terrier = new Terrier(row, col, board);
					terriers.add(terrier);
				
				} else if (board[row][col] == 'S') {

					// Make a Squirrel
					Squirrel squirrel = new Squirrel(row, col, board);
					squirrels.add(squirrel);					
					
				}
			}
		}
	}
	
	// Returns board
	public char[][] data() {
		return board;
	}
	
	// Next move
	public boolean next() {

		// Move squirrels
		for (Squirrel s : squirrels) {
			moveSquirrel(s);
		}
		// Move terriers
		for (Terrier t : terriers) {
			
			// No need to continue
			if (squirrels.size() == 0) break;

			moveTerrier(t);
			
			// Remove squirrel, if necessary
			if (t.ateSquirrel)
			{
				for (Squirrel s : squirrels) {
					if ((s.getCurrentRow() == t.getCurrentRow()) &&
						(s.getCurrentCol() == t.getCurrentCol())) {
						System.err.print("Terrier[" + terriers.indexOf(t) + "] ate ");
						System.err.println("Squirrel[" + squirrels.indexOf(s) + "]!");
						squirrels.remove(s);
						break;
					}
				}
			}
		}
		printBoard();
		return (squirrels.size() == 0) ? true : false;
	}
	
	// Move squirrel
	private void moveSquirrel(Squirrel s) {

		// Call student code to move squirrel
		eMove e = s.move();
		updateBoard(s, e);
		System.err.print("Squirrel[" + squirrels.indexOf(s) + "] moved to ");
		System.err.println("(" + s.getCurrentRow() + "," + s.getCurrentCol() + ")");
	}
		
	// Move terrier
	private void moveTerrier(Terrier t) {
		
		// Call instructor code to move terrier
		t.move();
		System.err.print("Terrier[" + terriers.indexOf(t) + "] moved to ");
		System.err.println("(" + t.getCurrentRow() + "," + t.getCurrentCol() + ")");
	}
	
	// Update board with current location
	public void updateBoard(Squirrel s, eMove e) {

		// Get current location
		int currentRow = s.getCurrentRow();
		int currentCol = s.getCurrentCol();
		
		// Remove squirrel
		board[currentRow][currentCol] = '-';

		// Save previous position
		int saveRow = currentRow;
		int saveCol = currentCol;
		
		// Move squirrel
		switch (e) {
		case LEFT: currentCol--; break;
		case UP_LEFT: currentRow--; currentCol--; break;
		case UP: currentRow--; break;
		case UP_RIGHT: currentRow--; currentCol++; break;
		case RIGHT: currentCol++; break;
		case DOWN_RIGHT: currentRow++; currentCol++; break;
		case DOWN: currentRow++; break;
		case DOWN_LEFT: currentRow++; currentCol--; break;
		default:
		}

		// Don't collide with anything
		if (board[currentRow][currentCol] != '-') {
			currentRow = saveRow;
			currentCol = saveCol;
		}
		
		// Update location of squirrel
		s.setCurrentRow(currentRow);
		s.setCurrentCol(currentCol);
		
		// Replace squirrel
		board[currentRow][currentCol] = 'S';
	}
	
	// Read board
	private void readFile(String filename) {
		
		try {
			Scanner in = new Scanner(new File(filename));
			height = in.nextInt();
			width = in.nextInt();
			board = new char[height][width];
			for (int row = 0; row < height; row++)
				for (int col = 0; col < width; col++)
					board[row][col] = in.next().charAt(0);
			in.close();
		} catch (IOException e) {
			System.err.println("Cannot read " + filename);
			System.exit(0);
		}
		printBoard();
	}
	
	// Display board
	private void printBoard() {
		for (int row = 0; row < height; ++row) {
			System.err.print("Row " + row + ": ");
			for (int col = 0; col < width; ++col) {
				System.err.print(board[row][col] + " ");
			}
			System.err.println();
		}
	}
}