#!/dev/bash
# Name of address book
BOOK="address-book.txt"

exit=0

add() {
    # Ask the user for a name and assign to a variable
    echo -n "Name of person: " 
    read name

    # Ask the user for a phone number and assign to a variable
    echo -n "Phone number: "
    read phone

    # Echo the answers and ask for confirmation
     echo "Should I enter the values:"
     echo -e "$name ; $phone \n"
     echo -n "y/n: "
     read answer
 
    if [ "$answer" == "y" ] 
     then
     # Write the values to the address book
     echo "$name ; $phone" >>$BOOK
     else
     # Give the user a message
     echo "$name ; $phone NOT written to $BOOK"
     fi
 }
 
 list() {
     # Print the book with line numbers and paused with less
     nl --number-separator=":    " $BOOK | less 
 }
 
 find() {
     # Ask the user what to look for.
     echo -n "What person or number are you seeking: "
     read find
 
     # Print the header before the answer
     echo "Name ; Phone number"
     grep -i $find $BOOK
 }
 
 del() {
     # Ask the user which line to delete
     echo -n "Which line should I delete: "
     read number
 
     # Rename the file before deleting
     mv $BOOK boo.txt
 
     # Add line numbers and delete against that number
     nl --number-separator=":" boo.txt | grep -v $number: | awk -F: '{print $2}' |  tee $BOOK
}
 
main() {
    while [ $exit -ne 1 ]
    do
    echo "What operation do you want?"
     echo -e "add, list, find, del, exit: "
     read answer

     if [ "$answer" = "add" ]
     then
         add
     elif [ "$answer" = "list" ]
     then
         list
     elif [ "$answer" = "find" ]
     then
         find
     elif [ "$answer" = "del" ]
     then
         del
     elif [ "$answer" = "exit" ]
     then
         exit=1
     else
         echo "I do not understand the command."
     fi
     done
     exit 0
 }
main