import java.security.SecureRandom;

public class PasswordGenerator {

    final String lowercaseCharacters = "abcdefghjkmnpqrstuvwxyz";
    final String uppercaseCharacters = "ABCDEFGHJKMNPQRSTUVWXYZ";
    final String digits = "0123456789";
    final String specialCharacters = ".!?=@#$()%^&/*_-+";
    final SecureRandom rand = new SecureRandom();

    private int length = 12;
    private boolean useUppercase = true;
    private boolean useLowercase = true;
    private boolean useDigits = true;
    private boolean useSpecialCharacters = true;
    private boolean requireEveryConfiguredCharacterType = true;


    public String generateRandomPassword() {
        StringBuilder generatedPassword = new StringBuilder();
        String characterPool = "";

        if (isUseLowercase()) {
            characterPool += lowercaseCharacters;
        }
        if (isUseUppercase()) {
            characterPool += uppercaseCharacters;
        }
        if (isUseDigits()) {
            characterPool += digits;
        }
        if (isUseSpecialCharacters()) {
            characterPool += specialCharacters;
        }

        for (int generatorPosition = 0; generatorPosition < getLength(); generatorPosition++) {
            String customCharacterPool = characterPool;

            if (isRequireEveryConfiguredCharacterType()) {
                if (generatorPosition == 0 && isUseLowercase()) {
                    customCharacterPool = lowercaseCharacters;
                } else if (generatorPosition == 1 && isUseUppercase()) {
                    customCharacterPool = uppercaseCharacters;
                } else if (generatorPosition == 2 && isUseDigits()) {
                    customCharacterPool = digits;
                } else if (generatorPosition == 3 && isUseSpecialCharacters()) {
                    customCharacterPool = specialCharacters;
                } else {
                    customCharacterPool = characterPool;
                }
            }

            generatedPassword.append(customCharacterPool.charAt(rand.nextInt(customCharacterPool.length())));
        }
        return generatedPassword.toString();
    }

    public String shufflePassword(String password) {
        StringBuilder shuffledPassword = new StringBuilder();
        StringBuilder passwordCopy = new StringBuilder(password);

        while (passwordCopy.length() != 0) {
            int index = rand.nextInt(passwordCopy.length());
            char c = passwordCopy.charAt(index);
            shuffledPassword.append(c);
            passwordCopy.deleteCharAt(index);
        }
        return shuffledPassword.toString();
    }

    public boolean isUseUppercase() {
        return useUppercase;
    }

    public void setUseUppercase(boolean useUppercase) {
        this.useUppercase = useUppercase;
    }

    public boolean isUseLowercase() {
        return useLowercase;
    }

    public void setUseLowercase(boolean useLowercase) {
        this.useLowercase = useLowercase;
    }

    public boolean isUseDigits() {
        return useDigits;
    }

    public void setUseDigits(boolean useDigits) {
        this.useDigits = useDigits;
    }

    public boolean isUseSpecialCharacters() {
        return useSpecialCharacters;
    }

    public void setUseSpecialCharacters(boolean useSpecialCharacters) {
        this.useSpecialCharacters = useSpecialCharacters;
    }

    public boolean isRequireEveryConfiguredCharacterType() {
        return requireEveryConfiguredCharacterType;
    }

    public void setRequireEveryConfiguredCharacterType(boolean requireEveryConfiguredCharacterType) {
        this.requireEveryConfiguredCharacterType = requireEveryConfiguredCharacterType;
    }

    public int getLength() {
        return length;
    }

    public void setLength(int length) {
        this.length = length;
    }
}