package lectures.parsing_grammars;
import util.annotations.WebDocuments;

import java.util.Scanner;

import lectures.inheritance.abstract_classes.AFreshmanSeminar;
import lectures.inheritance.abstract_classes.ARegularCourse;
import lectures.inheritance.abstract_classes.Course;
import lectures.inheritance.abstract_classes.courselist.ACourseList;
import lectures.inheritance.abstract_classes.courselist.CourseList;
import lectures.main_consoleinput.Console;
// Each parsing method has a comment indicating which Non terminal it is processing
// A non terminal may be the LHS for several productions
// It calls parsing methods for non terminals appearing on the right hand side of each of these
// productions

@WebDocuments({"Lectures/ParsingGrammars.pptx", "Lectures/ParsingGrammars.pdf", "Videos/ParsingGrammars.avi"})
public class ACourseParser implements CourseParser {
    Scanner scanner = new Scanner(;
    //<CourseList> -> <Course>*.
    public CourseList parseCourseList() {
        CourseList courseList = new ACourseList();
        String nextToken;
        while (true) {
            nextToken = scanner.nextLine();
            if (".".equals(nextToken)) {
                break; // terminate on .
            } else {
                // call the parser for <Course> until a .is input
                // add the return course to the parse tree representing the course list
        return courseList;
    // <Course> -> <RC> | <FS>
    // A there is alternation, we have if statements and a different behavior for each alternation
    // The first terminal in each alternative is used to determine the path
    public Course parseCourse (String firstToken) {
        if ("FS".equals(firstToken.toUpperCase())) {
            return parseFreshmanSeminar(); 
        } else if ("RC".equals(firstToken.toUpperCase())) {
            return parseRegularCourse();
        } else {
            return null; // in case the user makes an error, this program is not really error resilient
    //<FS>  -> FS  <Title> <Dept>
    // by the time we reach here, we have already read or consumed the teminal FS
    public Course parseFreshmanSeminar () {
        String title = scanner.nextLine();
        String dept = scanner.nextLine();
        return new AFreshmanSeminar(title, dept); // returning a parse tree node
    //<RC>  -> RC  <Title> <Dept> <Number>
    public Course parseRegularCourse () {
        String title = scanner.nextLine();
        String dept = scanner.nextLine();
        int number = Integer.parseInt(scanner.nextLine());      
        return new ARegularCourse (title, dept, number); // returning a different kind of parse tree node