//Kevin Liu
//Project Code
//Filter.java
//Comparison of Digital Image Filtering Techniques

import java.io.*;
import java.util.*;

class Filter 
{	

        public static void main(String args[])
        {              
                // args.length is equivalent to argc in C
		
                if (args.length == 1)
		{
			
                        try
			{
                                // Open the file that is the first 
                                // command line parameter
                                FileInputStream fstream = new 
					FileInputStream(args[0]);

                                // Convert our input stream to a
                                // DataInputStream
				DataInputStream in = 
                                        new DataInputStream(fstream);

                           	//Reads the pgm file and convert to a two-dimensional array
				String type = in.readLine();
				
				String size = in.readLine(); 
				size = in.readLine(); //skip the second line
				int numCol = Integer.valueOf( size.substring(0, size.indexOf(" ")) ).intValue();
				int numRow = Integer.valueOf( size.substring(size.indexOf(" ")+1) ).intValue();
				System.out.println(numRow);
				System.out.println(numCol);				

				String maxValue = in.readLine();

				if( type.equals("P2") ) //if file is pgm image
				{										
					int[][] data = new int[numRow][numCol];					
					int row;
					for(int column = 0; column < numCol; column++)
					{
						for(row = 0; row < numRow; row++)
						{
							data[row][column] = Integer.valueOf(in.readLine()).intValue();
						}
					}

					in.close();
									
					Median image = new Median(data, numRow, numCol); //create Median instance
					int[][] filtered = image.process();
					
					//attaches "filtered" to the end of the original file name and calls fileOut
					fileOutPGM(args[0].substring(0, args[0].indexOf(".")) + "filtered", filtered, 							numRow, numCol); 
				}
				//else if ( type.equals("P3") ) // if file is ppm image, header for future development
				//{
				//	int[][] data = new int[in.available()][3];					
				//}
				
				
			} 
                        catch (Exception e)
			{
				System.err.println("File input error");
			}
			
		}
                else
                                System.out.println("Invalid parameters");
		// Read in File
		
		
		
        }	 
	
	public static void fileOutPGM(String title, int[][] content, int numRow, int numCol) //writes the output file
	{
		FileOutputStream out; // declare a file output object
		PrintStream p; // declare a print stream object

                try
                {
                        // Create a new file output stream
                        // connected to "myfile.txt"
                        out = new FileOutputStream(title + ".pgm");

                        // Connect print stream to the output stream
                        p = new PrintStream( out );

			// Writes a new pgm file of the filtered image.
			p.println("P2");
			p.println("# produced by image filter implemented by Kevin");
			p.println(numCol + " " + numRow);
			p.println("255");
		
			int row;			
			for(int column = 0; column < numCol; column++)
			{
				for(row = 0; row < numRow; row++)
				{
					p.println (content[row][column]);
				}				
			} 

                        p.close();
                }
                catch (Exception e)
                {
                        System.err.println ("Error writing to file");
                }
	}

}