import java.io.*;

public class OctaveBot{

	static final int INTEGRATE = 0 , SUM = 1 , REST = 2 , DERIVATE = 3 , HELP = 4 , EXPRESSION = 5,LOVE = 6;
	private int type;
	private String message;

	OctaveBot(String msg , int type){
		this.type = type;
		message = msg;
	}

	public String sendMsg(){
		Runtime r = Runtime.getRuntime();

        	try {
			
            		
			switch(type){
			case HELP:
				return  "\n==============================================================================\n"+
					"=================================OCTAVE BOT===================================\n"+
					"==============================================================================\n\n"+
					"  Hi, I'm OctaveBot. Here are the instructions you can use: \n\n"+ 
					"  <script>                                        Solves the script with Octave.\n\n"+
					"  integrate <equation> <function name> <variable> Write the expression for the\n"+
					"                                                  non-numerical-integral. \n"+
					"                                                  You can also use integrar\n"+
					"                                                  or int.\n"+
					"  derivate <equation> <function name> <variable>  Write the expression for the\n"+
					"                                                  non-numerical-derivate. \n"+
					"                                                  You can also use dif\n"+
					"                                                  ,differential or diff.\n\n"+
					"  Separate <> with one space not coma. Don't use spaces on equation.\n\n"+
					"  Examples:\n"+
					"            @octave diff f=x^2 f x\n"+
					"            @octave int f=x^2 f x\n"+
					"            @octave x=2;y=1;f=x*y\n"+
					"==============================================================================\n\n";
			case EXPRESSION:{
				String[] cmd = {"octave","--eval","pkg load symbolic;" + message};
				Process p = r.exec(cmd);
            			p.waitFor();
            			BufferedReader b = new BufferedReader(new InputStreamReader(p.getInputStream()));
            			String line = "", send = "";
	    			int i =0; 
            			while ((line = b.readLine()) != null) {
                    			send ="\n"+ send + line;
					i++;
				}
				return send;
				}
			case INTEGRATE:{
				String[] s = message.split(" ");
				if(s.length==4){
				String[] s3 = s[3].split("\n");
				System.out.println("syms "+s3[0]+ " ;" + s[1] + " ;" +s[2].toUpperCase()+"=int("+s[2] +","+ s3[0] +")");
				String[] cmd = {"octave","--eval","pkg load symbolic; syms "+s3[0]+ " ;" + s[1] + " ;" +s[2].toUpperCase()+"=int("+s[2] +","+ s3[0] +")"};
				Process p = r.exec(cmd);
            			p.waitFor();
            			BufferedReader b = new BufferedReader(new InputStreamReader(p.getInputStream()));
            			String line = "", send = "";
	    			int i =0; 
            			while ((line = b.readLine()) != null) {
					if(i>5)
                    			send = send + line +"\n";
					else if(i==5) send = "\n"+line+"\n";
					i++;
				}
				return send;}
				else return "Error on input format.";
				}
			case DERIVATE:{
				String[] s = message.split(" ");
				if(s.length==4){
				String[] s3 = s[3].split("\n");
				System.out.println("syms "+s3[0]+ " ;" + s[1] + " ;" +s[2].toUpperCase()+"=int("+s[2] +","+ s3[0] +")");
				String[] cmd = {"octave","--eval","pkg load symbolic; syms "+s3[0]+ " ;" + s[1] + " ;d" +s[2]+"=diff("+s[2] +","+ s3[0] +")"};
				Process p = r.exec(cmd);
            			p.waitFor();
            			BufferedReader b = new BufferedReader(new InputStreamReader(p.getInputStream()));
            			String line = "", send = "";
	    			int i =0; 
            			while ((line = b.readLine()) != null) {
					if(i>5)
                    			send = send + line +"\n";
					else if(i==5) send = "\n"+line+"\n";
					i++;
				}
				
				return send;}
				else return "Error on input format.";
				}
			case LOVE:
				return "Baby don't hurt me.";
            		}
			
        	} catch (IOException e) {
           	 	e.printStackTrace();
        	} catch (InterruptedException e) {
            		e.printStackTrace();
        	}
		return null;
	}
}