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/*
	Scott Hernandez-Pauli

	schoolStore.cpp

	Description: An inventory system that reads inventory from a file and allows the user to view the list,
				add items to it, and calculate total cost.

	Input: Inventory file must be provided.

	Processing: 1. Prompt user with menu that is looped
					1. Add item
						Add item to inventory
					2. view inventory
						list inventory
					3. total cost
						total cost of inventory
					4. quit
						exit program
				2. Read from file
				3. Create functions
					readInData() // read in data
					createReport() // create report of inventory
					getItem() // get item to be added
					addItemToFile() // add item to inventory
					totalCost() // calculate total cost of items in inventory

	Output: Display menu driven inventory system
*/

#include <iostream>
#include <string>
#include <fstream>
#include <iomanip>

using namespace std;

struct Inventory { // Inventory struct
	int itemNumber;
	string itemName;
	int itemCount;
	double itemPrice;
};

Inventory myInventory[50]; // Array of inventory items

Inventory newItem; // Called when new item is added

int total = 0; // Amount of items in inventory at the moment

// Prototype functions
void readInData(Inventory[], int&);
void createReport(Inventory[], int);
Inventory getItem();
void addItemToFile(Inventory);
double totalCost(Inventory[], int);

int main()
{
	bool running = true; // boolean to start loop

	int option = 0; // option selected by user

	readInData(myInventory, total); // Read in data from file

	cout << "\nInventory System Management App ...\n" << endl; // Start of program

	while (running) { // Start of loop
		cout << "Please select one of the following options:" << endl // Prompt user with menu
			<< "\t1. Add New Item To Inventory" << endl
			<< "\t2. List Inventory Items" << endl
			<< "\t3. Calculate total cost of items in the inventory" << endl
			<< "\t4. Quit" << endl
			<< "option: ";
		cin >> option;

		while (!cin || option < 1 || option > 4) { // Validate option entered by user
			cout << endl << "Please select another option, selected option not valid!" << endl << endl;
			cout << "option: ";
			cin.clear();
			cin.ignore(100, '\n');
			cin >> option;
			
		}

		switch (option) { // switch for menu value
			case 1:
				addItemToFile(getItem()); // add item to a file
				break;
			case 2:
				readInData(myInventory, total); // read in data and create report.
				createReport(myInventory, total);
				break;
			case 3:
				cout << endl << fixed << showpoint << setprecision(2) << "Total Cost of All Items: " << totalCost(myInventory, total) << endl << endl; // Output total cost of items
				break;
			case 4:
				cout << endl << "Good Bye ..." << endl; // Good bye message
				exit(0); // end program
				running = false;
				break;
		}
	}

	return 0;
}

/*
	readInData(Inventory inv[], int& total)

	Reads in values from file and loads them into the inventory array

	Return Value: None
*/

void readInData(Inventory inv[], int& total) {
	total = 0; // Amount of items

	ifstream file; // input stream
	
	file.open("inventory.txt"); // file to be opened

	if (!file) { // if file does not open
		cout << "Fatal Error ... Could not open inventory.txt" << endl;
		exit(EXIT_FAILURE);
	}

	while (file >> myInventory[total].itemNumber) { // load array with items
		file >> myInventory[total].itemName;
		file >> myInventory[total].itemCount;
		file >> myInventory[total].itemPrice;
		total++;
	}

	file.close(); // close file
}

/*
	createReport(Inventory inv[], int total)

	Creates a report of all the items in the inventory

	Return Value: None
*/

void createReport(Inventory inv[], int total) {
	int pad = 12; // padding for the setw() functions
	cout << "\n******************Inventory Report******************\n" << endl;
	cout << left << setw(pad) << "Item Number" << left << setw(pad) << "Item Name" << left << setw(pad) << "Item Count" << left << setw(pad) << "Item Price" << endl;
	cout << "----------------------------------------------------\n" << endl;
	for (int i = 0; i < total; i++) {
		cout << left << setw(pad) << inv[i].itemNumber // item number
			 << left << setw(pad) << inv[i].itemName // item name
			 << left << setw(pad) << inv[i].itemCount // item count
			 << "$ " <<left << setw(pad) << fixed << showpoint << setprecision(2) << inv[i].itemPrice << endl; // item price
	}

	cout << endl;
}

/*
	Inventory getItem()

	Prompts the user for the item they want to add to the inventory

	Return value: Item to be added
*/

Inventory getItem() {
	// Prompt user for different values needed for an item
	cout << endl << "Item Number: ";
	cin >> newItem.itemNumber;

	while (!cin) { // Validate item number
		cout << endl << "Please enter a valid item number" << endl << endl
			<< "Item Number: ";
		cin.clear();
		cin.ignore(100, '\n');
		cin >> newItem.itemNumber;
		
	}

	cout << endl << "Item Name: ";
	cin >> newItem.itemName;

	cout << endl << "Item Count: ";
	cin >> newItem.itemCount;

	while (!cin || newItem.itemCount < 1) { // validate item count (>=1)
		cout << endl << "Please enter a valid item count(>=1)" << endl << endl
			<< "Item Count: ";
		cin.clear();
		cin.ignore(100, '\n');
		cin >> newItem.itemCount;
	}

	cout << endl << "Item Price: ";
	cin >> newItem.itemPrice;

	while (!cin || newItem.itemPrice < 1) { // Validate item price(>= 1)
		cout << endl << "Please enter a valid item price(>=1)" << endl << endl
			<< "Item Price: ";
		cin.clear();
		cin.ignore(100, '\n');
		cin >> newItem.itemPrice;
	}

	cout << endl;

	return newItem; // Return item to be added
}

/*
	addItemToFile(Inventory item)

	Add item supplied to the inventory

	Return Value: None
*/

void addItemToFile(Inventory item) {
	ofstream file; // output stream

	file.open("inventory.txt", ios::app); // open file and append

	if (!file) { // if file does not exist
		cout << "Fatal Error ... Could not open inventory.txt. Failed to create Item!" << endl;
	}
	else {
		file << item.itemNumber << " " << item.itemName << " " << item.itemCount << " " << item.itemPrice << endl; // Add item to file
	}
}

/*
	totalCost(Inventory inv[], int total)

	Calculate total cost of inventory

	Return Value: total value of inventory
*/

double totalCost(Inventory inv[], int total) {
	double amount = 0; // cost of inventory
	for (int i = 0; i < total; i++) { // loop through each item and add them up
		amount += inv[i].itemPrice;
	}

	return amount; // return amount
}