// This is for UCSD CSE 141L, Spring 2006.  -Wei and JSampson
//
// This is some sample code to parse an assembly instruction.  Compile with
// the provided Makefile.
// To run do:
// > java Jparser <input text file>
// 

import java.util.*;
import java.io.*;
import java.lang.Runtime.*;

class Jscanner {
    public static int debug;
    private int inst_count;
    private int line_count;

    Jscanner() {
        debug = 0;
        inst_count = 0;
        line_count = 0;
    }
    
    private static void help(String error) {
        System.out.println("usage: scanner [-d] [-h] input");
        System.out.println("  [-d] debug");
        System.out.println("  [-h] help");
        System.out.println(error);
    }


    // This uses flex to tokenize strings, and return back what type of
    // token it is.  Depending on the type it prints out a different
    // message.  
    // Assumes that FILE* yyin variable has been initialized. yyin needs
    // to point to the input text file.
    private int parse_inst(Reader r, String filename)
    {
        int token = 0;
        int index;
        int oper_index = 0;
        int cii = 0;
        int cop = 0;
        int value;
        inst_count = 0;
        line_count = 1;
        boolean found_inst = false;
        
    
        Sample_flex   lex = new Sample_flex(r);

        // Keeps track of line number, and if currently parsing an 
        // instruction followed by operands.
        // yylex returns an integer with a correponding token tag
        // prints out debug message
        do {
            try {
                token = lex.yylex() ;
            } 
            catch (java.io.IOException e) {
                System.out.println("IO error scanning file \""+filename+"\"");
                System.out.println(e);
            }
            catch (Exception e) {
                System.out.println("Unexpected exception:");
                e.printStackTrace();
            }

            if(token == Token_type.NEWLINE) {
                found_inst = false;
                line_count++;
            } 
            else if(token == Token_type.TOKEN) {
                if(found_inst) {
                    System.out.println("\t operand TOKEN "+lex.getToken()+ " at line "+
                           line_count);
                } else {
                    System.out.println("I have found an instruction TOKEN "+
                                       lex.getToken()+" at line "+line_count);
                    found_inst = true;   // state machine can also implemented in flex
                }
            } 
            else if(token == Token_type.LABEL) {
                System.out.println("I have found an instruction LABEL "+
                                   lex.getToken()+" at line "+line_count);
            } 
            else if(token == lex.YYEOF || token==0) {
                // end of file reached
                break;
            }
            else {
                System.out.println("I dont recognize "+
                                   lex.getToken()+" at line "+line_count+" " + token);
            }
        } while(true);
        return inst_count;
    }

    public static void main(String argv[]) {
        Jscanner scan = new Jscanner();
        int arg_index = 0;
        if(argv.length<1) {
            help("error: wrong number of args "+argv.length);
            return;
        }
        
        while(arg_index<argv.length && 
              argv[arg_index].charAt(0)=='-') {
            if(argv[arg_index].equals("-h")) {
                help("");
                return;
            }
            else if(argv[arg_index].equals("-d")) {
                debug = 1;
                arg_index++;
            }
            else {
                help("error: unknown argument "+argv[arg_index]);
                return;
            }
            arg_index++;
        }

        if ((argv.length-arg_index)!=1) {
            help("error: wrong number of args "+(argv.length-arg_index));
            return;
        }
        try {
            Reader r = new FileReader(argv[arg_index]);
            scan.parse_inst(r, argv[arg_index]);
            r.close();
        } catch(IOException ex) {
            help("error: missing input file " + argv[arg_index]);
            return;
        }

        System.out.println("all done");
        return;
    }
}