#!/bin/sh

echo "###############################"
echo " Welcome to password generator "
echo "###############################"


# i) feature to show the strength of the password generated. For example, week, strong, very strong, etc.
# ii) to give choices to users to include either letters (upper/lower case) or digits or symbols in the password
# iii) to only generate password that is not previously generated to other users
# iv) feature to generate bulk of N passwords according to user's input size of N.
# v) send the generated password to the clipboard on both Unix and Mac OSx so that user can copy and
# store the password.
# vi) implement a feature to generate another password if 
# previously generated password is forgotten
# by a specific user.
# vii) to write the script so that it can be run in both Linux and Mac OSx.


#  display the menu

echo "1. Generate a password"
echo "2. Generate bulk of passwords"
echo "3. Generate a password for a specific user"
echo "4. Show password strength"
echo "Q. Exit"


# read the input from the keyboard and assign it to a variable
read -p "Enter your choice: " choice


#  validate the input
case $choice in
    1)
        echo "Generating a password"

        # generate a password
        # ask user to enter the password length
        read -p "Enter the password length: " length

        #  ask user to add lowercase letters or uppercase letters or digits or symbols to the password
        read -p "Do you want to add lowercase letters? (y/n): " lowercase
        read -p "Do you want to add uppercase letters? (y/n): " uppercase
        read -p "Do you want to add digits? (y/n): " digits
        read -p "Do you want to add symbols? (y/n): " symbols

        #  generate the password
        password=""
        while [ ${#password} -lt $length ]
        do
            if [ $lowercase = "y" ]
            then
                password=$password$(echo $RANDOM | tr '[0-9]' 'a-z')
            fi
            if [ $uppercase = "y" ]
            then
                password=$password$(echo $RANDOM | tr '[0-9]' 'A-Z')
            fi
            if [ $digits = "y" ]
            then
                password=$password$(echo $RANDOM | tr '[0-9]' '0-9')
            fi
            if [ $symbols = "y" ]
            then
                password=$password$(echo $RANDOM | tr '[0-9]' '!@#$%^&*()')
            fi
        done

        #  display the password and copy it to the clipboard
        echo "Your password is: $password"
        echo $password | pbcopy
        echo "Password copied to clipboard"
        exit
        ;;
    2)
        echo "Generating bulk of passwords"

        #  ask user to enter the number of passwords to be generated
        read -p "Enter the number of passwords to be generated: " number

        #  ask user to enter the password length
        read -p "Enter the password length: " length

        #  ask user to add lowercase letters or uppercase letters or digits or symbols to the password
        read -p "Do you want to add lowercase letters? (y/n): " lowercase
        read -p "Do you want to add uppercase letters? (y/n): " uppercase
        read -p "Do you want to add digits? (y/n): " digits
        read -p "Do you want to add symbols? (y/n): " symbols

        #  generate the passwords
        for (( i=1; i<=$number; i++ ))
        do
            password=""
            while [ ${#password} -lt $length ]
            do
                if [ $lowercase = "y" ]
                then
                    password=$password$(echo $RANDOM | tr '[0-9]' 'a-z')
                fi
                if [ $uppercase = "y" ]
                then
                    password=$password$(echo $RANDOM | tr '[0-9]' 'A-Z')
                fi
                if [ $digits = "y" ]
                then
                    password=$password$(echo $RANDOM | tr '[0-9]' '0-9')
                fi
                if [ $symbols = "y" ]
                then
                    password=$password$(echo $RANDOM | tr '[0-9]' '!@#$%^&*()')
                fi
            done
            echo "Password $i: $password"
            # save the password to a file to a passwords.txt
            echo "Password $i: $password" >> passwords.txt
            
            
        done    
        echo "Done! Passwords have been saved in a file passwords.txt"
        exit

        ;;
    3)
        echo "Generating a password for a specific user"

        #  ask user to enter the user name
        read -p "Enter the user name: " username

        #  ask user to enter the password length
        read -p "Enter the password length: " length

        #  ask user to add lowercase letters or uppercase letters or digits or symbols to the password
        read -p "Do you want to add lowercase letters? (y/n): " lowercase
        read -p "Do you want to add uppercase letters? (y/n): " uppercase
        read -p "Do you want to add digits? (y/n): " digits
        read -p "Do you want to add symbols? (y/n): " symbols

        #  generate the password
        password=""
        while [ ${#password} -lt $length ]
        do
            if [ $lowercase = "y" ]
            then
                password=$password$(echo $RANDOM | tr '[0-9]' 'a-z')
            fi
            if [ $uppercase = "y" ]
            then
                password=$password$(echo $RANDOM | tr '[0-9]' 'A-Z')
            fi
            if [ $digits = "y" ]
            then
                password=$password$(echo $RANDOM | tr '[0-9]' '0-9')
            fi
            if [ $symbols = "y" ]
            then
                password=$password$(echo $RANDOM | tr '[0-9]' '!@#$%^&*()')
            fi
        done

        #  display the password and user name and copy it to the clipboard
        echo "Your user name is: $username"
        echo "Your password is: $password"
        echo "$username:$password" | pbcopy
        echo "Password copied to clipboard"
        exit
        ;;
    4)
        echo "Show password strength"
        #  ask user to enter the password
        read -p "Enter the password: " password

        #  calculate the strength of the password
        #  a strong password should have at least one lowercase letter, one uppercase letter, one digit and one symbol
        #  a weak password should have  no lowercase letter, no uppercase letter, no digit and one symbol
        #  a medium password should have at least one lowercase letter or one uppercase letter or one digit and one symbol
        #  the passwords should be categorized as weak, strong, very strong,

        #  calculate the number of lowercase letters
        lowercase_count=$(echo $password | grep -o -E '[a-z]' | wc -l)

        #  calculate the number of uppercase letters
        uppercase_count=$(echo $password | grep -o -E '[A-Z]' | wc -l)

        #  calculate the number of digits
        digits_count=$(echo $password | grep -o -E '[0-9]' | wc -l)

        #  calculate the number of symbols
        symbols_count=$(echo $password | grep -o -E '[!@#$%^&*()]' | wc -l)

        #  calculate the strength of the password
        if [ $lowercase_count -eq 0 ] && [ $uppercase_count -eq 0 ] && [ $digits_count -eq 0 ] && [ $symbols_count -eq 0 ]
        then
            strength="weak"
        elif [ $lowercase_count -gt 0 ] && [ $uppercase_count -gt 0 ] && [ $digits_count -gt 0 ] && [ $symbols_count -gt 0 ]
        then
            strength="strong"
        else
            strength="very strong"
        fi


        ;;
    Q)
        echo "Exiting..."
        exit
        ;;
    *)
        echo "Error: Invalid option"

        exit
        ;;
esac