//=========================================================================
#define PROGRAMMER "SOLUTIONS, Nofrills"
#define PROG_CODE  "soln"
#define COURSE     "ECE-1021"
#define YEAR       (2004)
#define TERM       "Spring"
#define SECTION    (0)
#define ASSIGNMENT "HW5B"
#define REVISION   (0)
#define TITLE      "How much did that REALLY cost? (modularized)"
#define SUBTITLE   "Last modified on 12 MAR 04"
#define EMAIL      "ece1021@eas.uccs.edu"
#define FILENAME   "05b0soln.c"
//=========================================================================

// NOTE: This file was prepared using the new template.c

//=========================================================================
// PROBLEM
//=========================================================================

// Generate an amortization table for a credit card on which a single
// purchase is made and which is paid back according to the minimum payment
// terms of the card.

//=========================================================================
// PSEUDOCODE (top levels only)
//=========================================================================

// 1. TASK: Get Input Data from User.
//
// 2. TASK: Generate a Month-by-Month Table until item is paid off.
// 2.1. TASK: Output Table Header (first row of table)
// 2.2. TASK: Initialize variables for first month
// 2.3. TASK: Initialize variable for running totals
// 2.4. WHILE (balance > 0)
// 2.4.1. TASK: Update variables for that month's activity
// 2.4.2. TASK: Update running totals
// 2.4.3. TASK: Print out activity for that month
//
// 3. TASK: Generate a Final Summary after the item is paid off.

//=========================================================================
// DEVIATIONS FROM SUBMITTED PSEUDOCODE
//=========================================================================
//
// Change: (See pseudocode task 2.2.2)
// Was SET: new_balance = 0.0
// Now SET: new_balance = purchase
//
// Reason For Change:
// Careless mistake in typing pseudocode.
//
// Change: (See pseudocode task 2.4)
// The main loop test was (balance > 0)
// It has been changed to (balance > 0.005)
//
// Reason For Change:
// The account is considered paid off once less than one cent is owed.
// Otherwise, the program keeps expecting payments until the balance
// finally underflows (i.e., gets smaller than ~1e-308).

//=========================================================================
// WAIVED COMPILER WARNINGS
//=========================================================================
//
// Linker Warning: No module definition file specified: using defaults
// Reason for Waiver: Can't suppress. Does not have adverse impact.

//=========================================================================
// CODE SECTION
//=========================================================================

//== INCLUDE FILES ========================================================
#include <stdio.h> // printf()

//== MACRO DEFINITIONS ====================================================
#define FALSE (0)
#define TRUE (!FALSE)
#define BLANKLINE printf("\n")

//== FUNCTION PROTOTYPES (for Primary Functions) ==========================
void PrintHeader(void);
void GetInputData(double *price, double *apr,
						double *min_percentage, double *abs_minimum_pmt);
int  MonthByMonthTable(double price, double apr,
							  double min_percentage, double abs_minimum_pmt,
							  double *TotalFinanceCost, double *TotalCost);
void FinalSummary(double price, int months,
						double TotalFinanceCost, double TotalCost);

//== MAIN FUNCTION ========================================================
void GetInputData(double *price, double *apr,
						double *fraction, double *minimum);
int  MonthByMonthTable(double price, double apr,
							  double fraction, double minimum,
							  double *TotalFinance, double *TotalCost);
void FinalSummary(double price, int months,
						double TotalFinance, double TotalCost);

int main(void)
{
	int months;
	double purchase;
	double apr, fraction, abs_minimum_pmt;
	double TotalFinance, TotalCost;

	PrintHeader();
	BLANKLINE;

	GetInputData(&purchase, &apr, &fraction, &abs_minimum_pmt);
	months = MonthByMonthTable(purchase, apr, fraction, abs_minimum_pmt,
										 &TotalFinance, &TotalCost);
	FinalSummary(purchase, months, TotalFinance, TotalCost);

	return(0);
}

//=========================================================================
// PRIMARY FUNCTIONS (functions called directly by main() )
//=========================================================================

//== FUNCTION PROTOTYPES (for Support Functions) ==========================
int printc(char c, int n);
void PrintMonthlyHeader(void);
void PrintMonthlyInfo(int month, double old_bal, double interest,
							 double pmt, double new_bal, double min_due);
double MonthlyInterest(double balance, double apr);
double MinDue(double balance, double percentage, double abs_min);
double MontlyInterest(double balance, double apr);

//== PRIMARY FUNCTIONS ====================================================
void PrintHeader(void)
{
	printc('=', 79); printf("\n");
	printf("Course....... %s-%i (%s %i)\n", COURSE, SECTION, TERM, YEAR);
	printf("Programmer... %s (%s)\n", PROGRAMMER, PROG_CODE);
	printf("Assignment... %s (Rev %i) (Source Code in %s)\n",
		ASSIGNMENT, REVISION, FILENAME);
	printf("Description.. %s\n", TITLE);
	printf("              %s\n", SUBTITLE);
	printc('=', 79); printf("\n");

	return;
}

void GetInputData(double *price, double *apr,
						double *min_percentage, double *abs_minimum_pmt)
{
	//-----------------------------------------------------------------
	// TASK: Get Input Data from User.
	//-----------------------------------------------------------------
	printf("Enter the purchase price (in $): ");
	scanf("%lf", price);
	printf("Enter the Annual Percentage Rage (in %): ");
	scanf("%lf", apr);
	printf("Enter the Minimum Payment Percentage (in %): ");
	scanf("%lf", min_percentage);
	printf("Enter the Minimum Payment (in $): ");
	scanf("%lf", abs_minimum_pmt);

	return;
}

int  MonthByMonthTable(double price, double apr,
							  double min_percentage, double abs_minimum_pmt,
							  double *TotalFinanceCost, double *TotalCost)
{
	//-----------------------------------------------------------------
	// TASK: Generate a Month-by-Month Table until item is paid off.
	//-----------------------------------------------------------------

	int month;
	double interest, payment, minimum_due;
	double old_balance, new_balance;

	// 2.1. TASK: Output Table Header (first row of table)
	PrintMonthlyHeader();

	// 2.2. TASK: Initialize variables for first month
	month = -1;
	new_balance = price;
	minimum_due = 0.0;

	// 2.3. TASK: Initialize variable for running totals
	*TotalFinanceCost = 0.0;
	*TotalCost = 0.0;

	while (new_balance > 0.005)
	{
		// 2.4.1. TASK: Update variables for that month's activity
		month++;

		old_balance = new_balance;  // new_balance from previous month
		payment = minimum_due;      // minimum_due from previous month

		interest = MonthlyInterest(old_balance, apr);
		new_balance = old_balance + interest - payment;

		// 2.4.1.6. TASK: Set Minimum Payment
		minimum_due = MinDue(new_balance, min_percentage, abs_minimum_pmt);

		// 2.4.2. TASK: Update running totals
		*TotalFinanceCost += interest;
		*TotalCost += payment;

		// 2.4.3. TASK: Print out activity for that month
		PrintMonthlyInfo(month, old_balance, interest,
							  payment, new_balance, minimum_due);
	}

	return(month);
}

void FinalSummary(double price, int months,
						double TotalFinanceCost, double TotalCost)
{
	//-----------------------------------------------------------------
	// TASK: Generate a Final Summary after the item is paid off.
	//-----------------------------------------------------------------

	BLANKLINE;
	BLANKLINE;
	printf("SUMMARY\n");
	BLANKLINE;
	printf("Number of Months required to pay off: %5i\n", months);
	printf("Original Purchase Price: ....    $%9.2f\n", price);
	printf("Total Finance Charges: ...... +   %9.2f\n", TotalFinanceCost);
	printf("Total Cost of Item: ......... =  $%9.2f\n", TotalCost);

	return;
}

//=========================================================================
// SUPPORT FUNCTIONS (functions not called directly by main() )
//=========================================================================

int printc(char c, int n)
{
	while(0 < n--)
		printf("%c", c);

	return(n);
}

// Support Functions for TASK #2

void PrintMonthlyHeader(void)
{
	BLANKLINE;
	BLANKLINE;
	printf("MONTH BY MONTH ACTIVITY\n");
	BLANKLINE;
	printf(" MONTH ");
	printf(" OLD BAL ");
	printf(" FIN CHG ");
	printf(" PAYMENT ");
	printf(" NEW BAL ");
	printf(" MIN DUE ");
	printf("\n");

	return;
}

void PrintMonthlyInfo(int month, double old_bal, double interest,
							 double pmt, double new_bal, double min_due)
{
		printf(" %4i ", month);
		printf(" %8.2f", old_bal);
		printf(" %8.2f", interest);
		printf(" %8.2f", pmt);
		printf(" %8.2f", new_bal);
		printf(" %8.2f", min_due);
		printf("\n");

		return;
}

double MonthlyInterest(double balance, double apr)
{
	return(balance * ((0.01 * apr)/12.0)); // apr -> monthly fraction
}

double MinDue(double balance, double percentage, double abs_min)
{
	double minimum_due;

	if(balance > abs_min)
	{
		minimum_due = balance * (0.01 * percentage);
		if(minimum_due < abs_min)
			minimum_due = abs_min;
	}
	else
		minimum_due = balance;

	return(minimum_due);
}