#include <cstdlib>
#include <iostream>
#include <iomanip>
#include <cmath>

using namespace std;

//declare function prototypes
void displayWelcomeMessage();
void getInput(double *EmployeeID, double *hoursWorked, double *payRate, char *unionCode, char A, char B, char C, double *regularPay, double *overtimePay);
double calculateGrossPay(double *grossPay, double regularPay, double overtimePay);
void calculateFederalTax(double grossPay, double *federalTax, double *paidTax);
void calculateUnionDues(char unionCode, double *unionDues);
double calculateNetPay(double *netPay, double grossPay, double paidTax, double unionDues);
void displayEmployeeInputInfo(double employeeID, double hoursWorked, double payRate, char unionCode);
void displayEmployeeCalculationResults(double regularPay, double overtimePay, double grossPay, double federalTax, double unionDues, double netPay);
void displayPayrollSummaryInfo(int numEmployees, double totalGrossPay, double highestGrossPayEmployeeID, double highestGrossPay, double lowestGrossPayEmployeeID, double lowestGrossPay, double averageGrossPay);
void displaylowGrossID(double lowAverageID[]);
void displayTerminationMessage();

//initialize the program
int main()
{
           displayWelcomeMessage();
           // local variable declarations
           int numEmployees = 0; //number of employees processed
           double totalGrossPay = 0; //total gross pay
           double highestGrossPay = 0; //highest gross pay
           double highestGrossPayEmployeeID = 0; //counter to identify employeeID with highest gross pay
           double lowestGrossPay = std::numeric_limits<double>::infinity(); //lowest gross pay
           double lowestGrossPayEmployeeID = 0; //counter to identify employeeID with lowest gross pay
           double averageGrossPay;//average gross pay is totalgrosspay / numemployees
           double lowAverageID[4]; //Employees whose gross pay is less than average
           double employeeID[5]; // employee's ID number
           double hoursWorked[5]; // number of hours employee worked
           double payRate[5]; // employee's pay rate
           char unionCode[5]; // employee's one character union code
           char A = 'A'; // unionCode A
           char B = 'B'; //unionCode B
           char C = 'C'; //unionCode C
           double regularPay[5]; // if hoursWorked <=40 then regular pay = hoursWorked * payRate
           double overtimePay[5]; // if hoursWorked >40 then over times pay = 1.5 * (hoursWorked - 40) * payRate
           double grossPay[5]; // gross pay is hoursWorked times payRate
           double federalTax[5]; // amount of tax employee pays based on grossPay
           double paidTax[5]; // paidTax is grossPay - netPay
           double unionDues[5]; // dues paid based on unionCode
           double netPay[5]; // netPay is grossPay - (grossPay * federalTax)
           
           for (int x = 1; x <=2; x++) // loop program 2 times
           {
           //functions
           getInput(&employeeID[x], &hoursWorked[x], &payRate[x], &unionCode[x], A, B, C, &regularPay[x], &overtimePay[x]);
           calculateGrossPay(&grossPay[x], regularPay[x], overtimePay[x]);
           calculateFederalTax(grossPay[x], &federalTax[x], &paidTax[x]);
           calculateUnionDues(unionCode[x], &unionDues[x]);
           calculateNetPay(&netPay[x], grossPay[x], paidTax[x], unionDues[x]);
           displayEmployeeInputInfo(employeeID[x], hoursWorked[x], payRate[x], unionCode[x]);
           displayEmployeeCalculationResults(regularPay[x], overtimePay[x], grossPay[x], paidTax[x], unionDues[x], netPay[x]);
           
           numEmployees++; //counter for number of employees to process
           totalGrossPay += grossPay[numEmployees]; //counter for total gross pay
           averageGrossPay = totalGrossPay / numEmployees;
           //highest gross pay employee ID
           if( grossPay[x] > highestGrossPay )
               {
                   highestGrossPay = grossPay[x];
                   highestGrossPayEmployeeID = employeeID[x];
               }
           //lowest gross pay employee id    
           if( grossPay[x] < lowestGrossPay )
               {
                   lowestGrossPay = grossPay[x];
                   lowestGrossPayEmployeeID = employeeID[x];
               }
           //employees with lower than average gross pay    
           if( grossPay[x] < averageGrossPay )
               {
                   lowAverageID[x] = employeeID[x];
               } 
           }
           //display summary of results    
           displayPayrollSummaryInfo(numEmployees, totalGrossPay, highestGrossPayEmployeeID, highestGrossPay, lowestGrossPayEmployeeID, lowestGrossPay, averageGrossPay);
           //display employees with below average gross pay
           displaylowGrossID(lowAverageID);
           //display termination message
           displayTerminationMessage();
               
           system("PAUSE");
           return 0;
}
    //function definitions
    // Welcome message
    void displayWelcomeMessage()
        {
            std::cout << "My Payroll Calculator\n\n\n"; 
        }
    //get inputs from user    
    void getInput(double *EmployeeID, double *hoursWorked, double *payRate, char *unionCode, char A, char B, char C, double *regularPay, double *overtimePay)
        {
            std::cout << "EmployeeID: "; //request user input for EmployeeID    
            std::cin >> *EmployeeID;   // read input from user into employeeID
            std::cout << "Hours worked: "; // request user input for hoursWorked
            std::cin >> *hoursWorked; // read input from user into hoursWorked
            while (*hoursWorked <0 || *hoursWorked > 60) // only allow input from 0-60
                {
                    std::cout << "Error! You must enter a value between 0 and 60\n";
                    std::cout << "Hours worked: ";
                    std::cin >> *hoursWorked;
                }
            std::cout << "Pay rate: "; // request user input for payRate
            std::cin >> *payRate; // read input from user into payrate
            while (*payRate <7.50 || *payRate > 45.00) //only allow input from 7.50 - 45.00
                {
                    std::cout << "Error! You must enter a value between 7.50 and 45.00\n";
                    std::cout << "Pay rate: ";
                    std::cin >> *payRate;
                }
            std::cout << "Union code A, B, or C? "; // request user input for unionCode
            std::cin >> *unionCode; // read input from user into unionCode
            while (*unionCode !=A && *unionCode !=B && *unionCode !=C) //only allow input A, B, or C
                {
                    std::cout << "Error! Your code must be A, B, or C\n";
                    std::cout << "Union code: ";
                    std::cin >> *unionCode;
                }
            *regularPay = *hoursWorked * *payRate; // calculate regularPay
            *overtimePay = 1.5 * ( *hoursWorked - 40 ) * *payRate; // calculate overtimePay
            if ( *hoursWorked <= 40) *overtimePay = 0;//determine if there is overtime pay or not
            if ( *hoursWorked > 40) *regularPay = *payRate * 40; 
        }
    // calculate grossPay
    double calculateGrossPay(double *grossPay, double regularPay, double overtimePay)
        {
            *grossPay = regularPay + overtimePay;                        
            return *grossPay; 
        }
    // calculate paidTax
    void calculateFederalTax(double grossPay, double *federalTax, double *paidTax)
        {
            if ( grossPay > 2000 ) *federalTax = .25; // determine federal tax rate
            else if ( grossPay >= 1000 ) *federalTax = .15;
            else *federalTax = .1;
            *paidTax = grossPay * *federalTax; 
        }
        // calculate unionDues
    void calculateUnionDues(char unionCode, double *unionDues)
        {
            switch (unionCode)
                {
                    case 'A': *unionDues = 25;
                    break;
                    case 'B': *unionDues = 50;
                    break;
                    case 'C': *unionDues = 75;
                    break;
                }
        }
    // calculate netPay
    double calculateNetPay(double *netPay, double grossPay, double paidTax, double unionDues)
        {
            *netPay = grossPay - paidTax - unionDues;
            return *netPay; 
        }
    //display employee input info
    void displayEmployeeInputInfo(double employeeID, double hoursWorked, double payRate, char unionCode)
        {    
            std::cout << "\nIdentification Number: " << employeeID; //display employeeID
            std::cout << "\nHours Worked: " << hoursWorked; //display hoursWorked
            std::cout << "\nPay Rate: " << payRate; //display payRate
            std::cout << "\nUnion Code: " << unionCode; //display unionCode
        }
    //display employee calculation results
    void displayEmployeeCalculationResults(double regularPay, double overtimePay, double grossPay, double federalTax, double unionDues, double netPay)
        {
            std::cout << fixed << setprecision(2); //format output to 2 decimal places
            std::cout << "\nRegular Pay: " << regularPay; //display regularPay
            std::cout << "\nOvertime Pay: " << overtimePay; // display overtimePay
            std::cout << "\nGross Pay: " << grossPay; // display grossPay
            std::cout << "\nFederal Tax: " << federalTax; // display federalTax
            std::cout << "\nUnion Dues: " << unionDues; // display unionDues
            std::cout << "\nNet Pay: " << netPay; // display netPay
            std::cout << fixed << setprecision(0); //format output to 0 decimal places
            std::cout << "\n\n";
        }
    //display payroll summary info
    void displayPayrollSummaryInfo(int numEmployees, double totalGrossPay, double highestGrossPayEmployeeID, double highestGrossPay, double lowestGrossPayEmployeeID, double lowestGrossPay, double averageGrossPay)
        {
            std::cout << "\nEmployees Processed: " << numEmployees; //display number of employees processed
            std::cout << fixed << setprecision(2); //format output to 2 decimal places 
            std::cout << "\nTotal Gross Pay: " << totalGrossPay; //display total gross pay
            std::cout << fixed << setprecision(0); //format output to 0 decimal places
            std::cout << "\nEmployee With Highest Gross Pay: " << highestGrossPayEmployeeID; //display ID of employee with highest gross pay
            std::cout << fixed << setprecision(2); //format output to 2 decimal places 
            std::cout << "\nHighest Gross Pay: " << highestGrossPay; //display highest gross pay
            std::cout << fixed << setprecision(0); //format output to 0 decimal places
            std::cout << "\nEmployee With Lowest Gross Pay: " << lowestGrossPayEmployeeID; //display ID of employee with lowest gross pay
            std::cout << fixed << setprecision(2); //format output to 2 decimal places 
            std::cout << "\nLowest Gross Pay: " << lowestGrossPay; //display lowest gross pay
            std::cout << "\nAverage Gross Pay: " << averageGrossPay; //display average gross pay
            std::cout << "\n";
        } 
    //display employess with below average gross pay
    void displaylowGrossID(double lowAverageID[])
        {
            for (int x = 1; x <= 4; x++)
                {
                    std::cout << "\nEmployees With Below Average Gross Pay: "; 
                    std::cout << lowAverageID[x] << endl;
                }
        }      
    //display termination message
    void displayTerminationMessage()
        {
            std::cout << "\nBest payroll calculator in the whole world\n\n"; // Termination message
        }