RemCust

#!/bin/bash
# Kevin Fan (26/4/17)
# Description: This script searches and removes all of a customer's information
# from the Address Book based on a particular customers name or alias

# Clear the terminal
clear

# This function reads in the search input from the user
function readInput 
{
	# Ask user for search name
	printf "\nPlease enter name or alias of customer you wish to remove:  "

	# Reads in search name as parameter
	read input

	# Converts the entered input from user to all lowercase to perform a case insensitive search 
	# (all customers added by the AddCust script are converted to all lower case on addition to file)
	lowerCaseInput=${input,,}

	# Performs an awk search on the lowerCaseInput on the name and alias. Count the number of lines and assign to variable
	searchCount=$(awk -v search="$lowerCaseInput" '$2 ~ search || $3 ~ search' CustomerDetails | wc -l)

	# Calls the checkInput function to check is the input a valid one
	checkInput
}


# This function checks the search input to see if its valid.
function checkInput
{
	# If search input is blank, error message is displayed and calls the readInput function to ask user to re-enter search name/alias
	if [ -z $lowerCaseInput ]; then
		printf "\n\tNo entry detected. Please re-enter search term"
		readInput
	# If search count of input is not 0, display the number of matches found and call the actionAfterSearch function
	elif [[ $searchCount -ne 0 ]]; then
		printf "\n$searchCount match(s) were found:\n"
		# Awk functions that search on the lowerCaseInput on the name and alias and displays the matching lines
		awk -v search="$lowerCaseInput" '$2 ~ search || $3 ~ search' CustomerDetails
		actionAfterSearch
	# If search count of input is 0, display message and call the actionAfterSearch function
	elif [[ $searchCount -eq 0 ]]; then
		printf "\nNo matches were found\n"
		actionAfterSearch
	fi
}


# This function serves as a secondary menu that gives options to the user after the search
# Users can remove all the matching entries, perfom another seach or return to the main menu
function actionAfterSearch
{
	# Local variable to control while loop
	validChoice=false;
	while [[ $validChoice = false ]]; do
		printf "\n\t1) Remove all matching entries found\n"
		printf "\n\t2) Perform another search\n"
		printf "\n\t=========================================\n"
		printf "\n\t0) Return to Main Menu\n"
		printf "\nEnter choice: "
		read choice
		clear
			# If entered choice is not a number, display error message and loop back
			if ! [[ $choice =~ ^-?[0-9]+$ ]]; then
				printf "\nInvalid (String) entry, only integers shown are allowed. Please re-renter option\n"
			# If entered choice is a number greater than or less than the options available, display error message and loop back
			elif [ $choice -le -1 ] || [ $choice -ge 3 ]; then
				printf "\nInvalid number entered\n"
			# If entered choice is 1, set the validChoice variable to valid and call the removeInput function
			elif [[ $choice -eq 1 ]]; then
				validChoice=valid
				removeInput
			# If the eneted choice is 2, set the validChoice variable to valid and call the readInput function to search again
			elif [[ $choice -eq 2 ]]; then
				validChoice=valid
				readInput
			# In all other cases, set the validChoice variable to value, and the script will end and return back to menu script
			else
				validChoice=valid
			fi
	done
}

#This function removes the searched customer(s), an additional confirmation is asked from the user to delete the Customers or not
function removeInput
{
	# Until loop that read user choice until the upperCase of choice variable is either Y or N
	until [[ ${choice^^} = 'Y' || ${choice^^} = 'N' ]]; do
		printf "\nRemove customers (Y/N):"
		read choice
	done

	# User choice to converted to upper case, and if its Y then remove the searched Customer(s) and return to menu script
	if [[ ${choice^^} = 'Y' ]]; then
		# Inverted awk search - moves all Customers whos names and alias that do not have the search term to another tempoary file
		awk -v search="$lowerCaseInput" '!($2 ~ search) && !($3 ~ search)' CustomerDetails > /tmp/CustomerDetails

		#Temp file is moved back to the same directory replacing the old file
		mv /tmp/CustomerDetails CustomerDetails
		printf "\nCustomer Details successfully removed\n"
		sleep 1
	# User choice to converted to upper case, and if its N and return to menu script
	elif [[ ${choice^^} = 'N' ]]; then
		printf "\nNo customer(s) removed"
		sleep 1
	fi
}

# Calls the readInput function that begins the script
readInput