public class RegOps
{
    public static Course lookupCourseByName(Course[] catalog, String courseName)
    {
           for( int i = 0; i < catalog.length ; i++)
           {
               String course = catalog[i].getName();
               if(course.equals(courseName))
               {
                     return catalog[i];
               }

           }

         return null;
    }

    public static Course[] lookupCoursesByDept(Course[] catalog, int dept)
    {
         int count = 0;

         for(int n = 0; n < catalog.length ; n++)
         {
             int deptnum = catalog[n].getDepartment();
             if(deptnum == dept)
             {
                 count++;
             }
         }

         Course[] deptcourses = new Course[count];
         count = 0;

         for( int i = 0; i < catalog.length ; i++)
         {
             int deptnum = catalog[i].getDepartment();
             if(deptnum == dept)
             {
                deptcourses[count] = catalog[i];
                count++;
             }
         }

         if(count != 0)
         {
             return deptcourses;
         }
         else
         {
             return null;
         }


    }

    public static void sortByNumber(Course[] catalog)
    {
         Course FirstUnit = catalog[0];
         int i = 0;
         for(i = 0; i < catalog.length ; i++)
         {
             int trade = 0;
             Course StoreUnit = catalog[i];
             int Stored = catalog[i].getDepartment();
             for(int t = i+1; t < catalog.length ; t++)
             {
                 int Current = catalog[t].getDepartment();
                 if(Stored > Current)
                 {
                     Stored = Current;
                     StoreUnit = catalog[t];
                     trade = t;
                 }
                 else if(Current == Stored)
                 {
                     if(catalog[trade].getCourseNumber() > catalog[t].getCourseNumber())
                     {
                         Stored = Current;
                         StoreUnit = catalog[t];
                         trade = t;
                     }
                 }
             }
             catalog[trade] = catalog[i];
             catalog[i] = StoreUnit;
             if( i == 0)
             {
                 FirstUnit = catalog[i];
             }
         }
         catalog[0] = FirstUnit;
         System.out.println(catalog);
    }

    public static void sortByTime(Course[] catalog)
    {
         Course FirstUnit = catalog[0];
         int i = 0;
         for(i = 0; i < catalog.length ; i++)
         {
             int trade = 0;
             Course StoreUnit = catalog[i];
             int Stored = catalog[i].getDay();
             for(int t = i+1; t < catalog.length ; t++)
             {
                 int  Current = catalog[t].getDay();
                 if(Current == 'S')
                 {Current = 6;}
                 if(Current == 'F')
                 {Current = 5;}
                 if(Current == 'H')
                 {Current = 4;}
                 if(Current =='M')
                 {Current = 1;}
                 if(Current == 'T')
                 {Current = 2;}
                 if(Current =='W')
                 {Current = 3;}
                 if(Stored > Current)
                 {
                     Stored = Current;
                     StoreUnit = catalog[t];
                     trade = t;
                 }
                 else if(Current == Stored)
                 {
                     if(catalog[trade].getPeriod() > catalog[t].getPeriod())
                     {
                         System.out.println(catalog[t].getPeriod()+" "+catalog[trade].getPeriod());
                         Stored = Current;
                         StoreUnit = catalog[t];
                         trade = t;

                     }
                 }
             }
             catalog[trade] = catalog[i];
             catalog[i] = StoreUnit;
             if( i == 0)
             {
                 FirstUnit = catalog[i];
             }
         }
         catalog[0] = FirstUnit;
         System.out.println(catalog);
    }

    public static boolean addCourse(
        Course[] catalog,
        Course[] mySchedule,
        int myNumCourses,
        int dept,
        int courseNum)
    {
         if(myNumCourses >= mySchedule.length)
         {
             return false;
         }
             for(int n = 0; n < mySchedule.length ; n++)
            {
                 if(mySchedule[n] == null)
                {}
                 else if(dept == mySchedule[n].getDepartment() && courseNum == mySchedule[n].getCourseNumber())
                {
                     return false;
                }
            }

        for(int i = 0; i < catalog.length ; i++)
        {
             if(dept == catalog[i].getDepartment() && courseNum == catalog[i].getCourseNumber())
            {
                 mySchedule[myNumCourses] = catalog[i];
                 return true;
            }
        }
         return false;


    }

    public static boolean dropCourse(
        Course[] mySchedule,
        int myNumCourses,
        int dept,
        int courseNum)
    {
         for(int i = 0 ; i < mySchedule.length ; i++)
        {
             if(mySchedule[i] == null)
             {}
             else if(dept == mySchedule[i].getDepartment() && courseNum == mySchedule[i].getCourseNumber())
             {
                 mySchedule[i] = null;
                 mySchedule[i] = mySchedule[myNumCourses-1];
                 mySchedule[myNumCourses-1] = null;
                 return true;
             }
        }
        return false;
    }

    public static int countCredits(Course[] mySchedule, int myNumCourses)
    {
         int totalcredits = 0;
         for(int i = 0; i < myNumCourses ; i++)
         {
             if(mySchedule[i] != null)
             {
             int credits = mySchedule[i].getCredits();
             totalcredits = totalcredits + credits ;
             }
         }
         return totalcredits;
    }
}