package com.ex1t.core;

import java.io.BufferedReader;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStreamReader;

/**
 * Map Builder, build map from file or database
 * @author Shaolan
 *
 */
public class MapBuilder {
    /**
     * The target product of our builder
     * @see MapBuilder#getProduct()
     * @see MapBuilder#buildFromFile(String)
     * @see MapBuilder#buildFromDatabase(String)
     */
    private Map product;

    /**
     * Private constructor
     */
    private MapBuilder(){
        product = new Map();
    }

    /**
     * Read a area from the given stream.
     * @param in The stream which contain area
     * @param a the Area to build
     * @throws MapFileException
     */
    private void readArea(BufferedReader in,Area a) throws MapFileException {
        for (int i = 0 ; i < a.getWidth() ; i++){
            try {
                String line = in.readLine();
                for (int j = 0 ; j < a.getHeight() ; j++){
                    Integer c = Integer.valueOf(line.charAt(j));
                    a.setMapping(i, j, c);
                }
            }
            catch(NumberFormatException e){ throw new MapFileException("Area incorrect : wrong mapping data(not a number ?).");}
            catch(IOException e){ throw new MapFileException("Area incorrect : missing information."); }
        }
    }

    /**
     * Parse the given Area header (contain the width and height of the area).
     * @param header Area header
     * @return A new area object, build with header data
     * @throws MapFileException
     */
    private Area readAreaHeader(String header) throws MapFileException{
        Area a = null;
        try {
            String headerData[] = header.split("|");
            Integer w = Integer.valueOf(headerData[0]);
            Integer h = Integer.valueOf(headerData[1]);
            a = new Area(w,h);
        }
        catch(NumberFormatException e){ throw new MapFileException("Area header incorrect : Wrong area size (not a number ?).");}
        catch(NullPointerException e){ throw new MapFileException("Area header incorrect : missing information."); }
        return a;
    }

    /**
     * Read all map assume that header have been read.
     * @param in
     * @throws MapFileException
     */
    private void readMap(BufferedReader in) throws MapFileException {
        for (int i = 0 ; i < product.getArea().length ; i++ ){
            try {
                Area a = readAreaHeader(in.readLine());
                readArea(in,a);
                product.setArea(i,a);
            }
            catch(IOException e){ throw new MapFileException("Error when read area " + i); }
            catch(MapFileException e){ throw e;}
        }
    }

    /**
     * Read and parse the header of the map file (contain number of area).
     * @param header
     * @throws MapFileException
     */
    private void readMapHeader(String header) throws MapFileException {
        try {
            Integer n = Integer.valueOf(header);
            product.setAreaNumber(n);
        }
        catch(NumberFormatException e){ throw new MapFileException("Map File header incorrect."); }
    }

    private Map getProduct() { return product; }

    /**
     * Build a Map from a given file
     * @param path
     * @return the built map
     */
    public static Map buildFromFile(String path){
        MapBuilder director = new MapBuilder();
        try{
            BufferedReader in = new BufferedReader(new InputStreamReader(new FileInputStream(path)));
            director.readMapHeader(in.readLine());
            director.readMap(in);
            return director.getProduct();
        }
        catch(IOException e){ return null; }
        catch(MapFileException e) { return null; }
    }

    /**
     * Build a map from database entry
     * @param id
     * @return
     */
    public static Map buildFromDatabase(String id){
        return new Map();
    }
}