/**
 * ClassName: Programming 1
 *
 * @author Sebastian Lawe
 * @version 05.11.2014
 *
 * Assignment: 5
 * Course: ADEV-1000
 * Section: 2
 * Date Created: 05/11/2014
 * Last Updated: 05/11/2014
 */
import java.util.Scanner;
public class JavaMart
{
    public static void main(String[] args)
    {
        // Declare and initialize variable.
        int productsCounted = 0;
        double totalInventoryCost = 0;

        // Output header.
        System.out.println("Java Mart Inventory System\n--------------------------");

        // Get name.
        String name = getName();

        // Do once and repeat while anotherEntry is true.
        do {
            // Get SKU.
            String sku = getSKU();

            // Get description.
            String description = getDescription();

            // Add to totalInventoryCost
            totalInventoryCost += getQuantityOnHand() * getCostPerUnit();

            // Increment Count.
            productsCounted++;
        }while(anotherEntry());

        // Output report
        System.out.println("\nInventory Report\n--------------------------");
        System.out.println("Inventory performed by: " + name);
        System.out.println("Number of products counted: " + productsCounted);
        System.out.println("Total Inventory Cost: $" +  totalInventoryCost);

    }

    /**
     * Gets a name from the user.
     *
     * @return - the name of the user.
     */
    private static String getName()
    {
         //Declare and initialize name variable.
         String name = "";

         //Loop if the received name is invalid. Set name to the users entered value.
         while(!validName(name = promptAndInput("Employee Name: ")));

         // Return the name.
         return name;
    }

    /**
     * Gets an SKU from the user.
     *
     * @return - the SKU.
     */
    private static String getSKU()
    {
        // Declare and initialize sku variable.
        String sku = "";

        // Loop if the received SKU is invalid. Set sku to the users entered value.
        while(!validSKU(sku = promptAndInput("\nEnter SKU number: ")));

        // Return sku.
        return sku;
    }

    /**
     * Gets a description from a user.
     *
     * @return
     */
    private static String getDescription()
    {
        // Declare and initialize description variable.
        String description = "";

        // Loop if the received description is invalid.  Set description to the users entered value.
        while(!validDescription(description = promptAndInput("Enter description: ")));

        // Return description.
        return description;
    }

    /**
     * Gets the quantity on hand from the user.
     *
     * @return - the quantity on hand entered by user.
     */
    private static int getQuantityOnHand()
    {
        // Declare and initialize quantityOnHand variable.
        int quantityOnHand = 0;

        // Loop if the received number is invalid. Set quantityOnHand to the users entered value.
        while(!validNumber(quantityOnHand = Integer.parseInt(promptAndInput("Enter quantity on hand: "))));

        // Return result.
        return quantityOnHand;
    }

    /**
     * Gets the cost per unit from the user
     *
     * @return - the cost per unit entered by the user.
     */
    private static double getCostPerUnit()
    {
        // Declare and initialize variables
        double costPerUnit = 0;

        // Loop if the received number is invalid. Set costPerUnit to the users entered value.
        while(!validCostPerUnit(costPerUnit = Double.parseDouble(promptAndInput("Enter unit cost: "))));

        // Return result
        return costPerUnit;
    }

    /**
     * Checks to see if the name is valid.
     *
     * @param name - the name to validate.
     * @return - whether or not the name was valid.
     */
    private static boolean validName(String name){
        // Declare and initlialize boolean.
        boolean validEntry = false;

        // Check if length is greater than 0.
        if(name.length() > 0)
        {
            // Set valid entry to true.
            validEntry = true;
        }
        else
        {
            // Output error.
            System.out.println("\n**Error 01** - You must enter your name\n");
        }

        // Return result.
        return validEntry;
    }

    /**
     * Checks to see if the sku is valid.
     *
     * @param sku - the sku to validate.
     * @return  - whether or not the sku was valid.
     */
    private static boolean validSKU(String sku)
    {
        // Declare and initialize boolean.
        boolean validEntry = false;

        // Check to see if sku length is equal to 5
        if(sku.length() == 5)
        {
            // Set valid entry to true.
            validEntry = true;
        }
        else
        {
            // Output error.
            System.out.println("\n**Error 02** - SKU number must be five characters");
        }

        // Return result;
        return validEntry;
    }

    /**
     * Checks to see if the description is valid.
     *
     * @param description - the description to validate.
     * @return - whether or not the description was valid.
     */
    private static boolean validDescription(String description)
    {
        // Declare and initialize boolean.
        boolean validEntry = true;

        // Check if description is less than or equal to 0.
        if(description.length() <= 0){
            // Output error.
            System.out.println("\n**Error 03** - Product description is required\n");

            // Set validEntry to false.
            validEntry = false;
        }
        else if(description.length() > 20)
        {
            //Output error.
            System.out.println("\n**Error 04** - Product description is more than 20 characters\n");

            // Set valid entry to false
            validEntry = false;
        }

        // Return result.
        return validEntry;
    }

    /**
     * Checks to see if the number is not negative
     *
     * @return - whether or not the number was negative.
     */
    private static boolean validNumber(int number)
    {
        // Declare and initialize boolean.
        boolean validEntry = false;

        // Check if number is greater or equal to 0
        if(number >= 0)
        {
            // Set validEntry to true.
            validEntry = true;
        }
        else
        {
            // Output error.
            System.out.println("\n**Error 05** - Quantity on hand is a negative value\n");
        }

        // Return validEntry.
        return validEntry;
    }

    /**
     * Checks if the entered value is a valid coat per unit.
     *
     * @param costPerUnit - the cost per unit.
     * @return - whether or not the cost per unit was valid.
     */
    private static boolean validCostPerUnit(double costPerUnit)
    {
        // Declare an initialize boolean.
        boolean validEntry = false;

        // Check if cost per unit is between 0.01 - 5000.00
        if(costPerUnit >= 0.01 && costPerUnit <= 5000.00)
        {
            // Set valid entry to true.
            validEntry = true;
        }
        else
        {
            // Output error.
            System.out.println("\n**Error 06** - Unit cost must be a value between .01 - 5000.00\n");
        }
        return validEntry;
    }

    /**
     * Checks to see if the response is a valid y/n response.
     *
     * @param response - the yes or no response.
     * @return - whether or not the response was a valid y/n answer
     */
    private static boolean validResponse(String response)
    {
        // Declare and initialize boolean.
        boolean validEntry = false;

        // Check if response is 'y' or 'n'
        if(response.toLowerCase().equals("y") || response.toLowerCase().equals("n"))
        {
            // Set validEntry to true.
            validEntry = true;
        }
        else
        {
            // Output error.
            System.out.println("\n**Error** - Invalid response");
        }

        // Return result.
        return validEntry;
    }
    /**
     * Prompts user and returns the users entry.
     *
     * @param prompt - what is being asked of the user.
     * @return - the users entry.
     */
    private static String promptAndInput(String prompt)
    {
        // Declare and initialize scanner object.
        Scanner scanner = new Scanner(System.in);

        // Output prompt.
        System.out.print(prompt);

        // Return users input.
        return scanner.nextLine();
    }

    /**
     * Asks the user if another entry is required.
     *
     * @return - the users reponse. True is yes, false is no.
     */
    private static boolean anotherEntry()
    {
        // Declare and initialize string.
        String yesOrNo = "";

        // Loop if the received response is invalid. Set yesOrNo to user input.
        while(!validResponse(yesOrNo = promptAndInput("\nEnter another item? (y/n): ")));

        // Return result.
        return yesOrNo.equals("y");
    }
}