import java.io.File;
import java.io.FileNotFoundException;
import java.util.Scanner;

/* EmployeesGrossPay.java
** Java application that reports the gross pay for each employee for which
** data is present in a specified data file.  Its main purpose is to illustrate
** the use of a Scanner object in doing "file processing", as discussed in 
** Chapter 6 of the Reges & Stepp textbook.
**
** The name of the data file is provided via a command line argument (what
** jGrasp calls a "run argument"), but if no such argument is provided, a 
** default name is used.
**
** The data file is assumed to be formatted such that each line/record 
** contains the data pertaining to one employee, including 
**
** --an employee ID (an integer, but not representing any quantity, so we
**   treat it as a String),
** --a name (necessarily a single token, meaning that no spaces may appear
**   in it),
** --an hourly wage (real number),
** --number of work periods recorded (integer), 
** --a sequence of hours-worked values, one for each work period (double).
**
** What follows is sample data to illustrate the expected format. (The column
** headings and the surrounding box are NOT part of the data.  The "#p" column
** heading means "number of work periods".)
** 
**   ID   Name   wage  #p      hours worked
** +-----------------------------------------------+
** |6435 Smith   21.50  5  8.4 7.4 9.7 4.7 10.9    |
** |0375 Jones   16.0   6  8.0 7.5 8.5 2.5 9.3 8.1 |
** |4986 Thomas  15.75  3  8.4 4.6 10.3            |
** +-----------------------------------------------+
*/

public class EmployeesGrossPay {

   private static Scanner input;

   /* Note: It is necessary to include the "throws" clause in the method heading
   ** because FileNotFoundException is a "checked" exception.
   */
   public static void main(String[] args) throws FileNotFoundException
   {
      // Establish the name of the input file.
      String DEFAULT_FILE_NAME = "employees.txt";
      String fileName;
      if (args.length != 0) { // If there is a "run argument", it (args[0])
         fileName = args[0];  // is taken to be the name of the input file.
      }
      else {                           // Otherwise, data is read from the
         fileName = DEFAULT_FILE_NAME; // file whose name is the default.
      }
    
      // Create a Scanner object that can read from the input file.
      input = new Scanner(new File(fileName));

      // Process the records in the input file.
      while (input.hasNext()) {
         processEmployee();
      }
      System.out.println("\nProgram terminating.");
   }

   /* Computes and reports the gross pay of a single employee. 
   ** In doing so, it consumes the current record/line of the input data,
   ** which is read using the 'input' Scanner object.
   */
   private static void processEmployee() {
      input.next();                           // Read (but ignore) employee's ID
      String emplName = input.next();         // Read (and store) employee's name 
      double hourlyWage = input.nextDouble(); // Read (and store) employee's hourly wage
      int numWorkPeriods = input.nextInt();   // Read (and store) employee's # work periods

      // Read hours worked for each work period and compute the total.
      double hoursWorked = 0;
      for (int i=1; i <= numWorkPeriods; i++) {
         hoursWorked = hoursWorked + input.nextDouble();
      }

      // Having computed total hours worked, compute the employee's gross pay.
      double grossPay = grossPay(hourlyWage, hoursWorked);

      // Print the employee's name and gross pay.
      System.out.printf("%s: %5.2f\n", emplName, grossPay); 
   }

   /* Given an employee's hours worked and hourly wage, returns the
   ** corresponding gross pay.  
   */
   private static double grossPay(double hours, double wage) {
      final double OT_HOURS_THRESHOLD = 40.0;
      final double OT_WAGE_RATIO = 1.5;
      double regularHours, overtimeHours;
      if (hours > OT_HOURS_THRESHOLD) { 
         regularHours = OT_HOURS_THRESHOLD;
         overtimeHours = hours - OT_HOURS_THRESHOLD;
      }
      else { 
         regularHours = hours;
         overtimeHours = 0;
      }
      return (regularHours + (OT_WAGE_RATIO * overtimeHours)) * wage;
   }

}