#!/bin/bash

echo "GPG Encrypted Message Utility"
echo "1) Write (Encrypt & Sign a message)"
echo "2) Read (Decrypt a message)"
echo "3) Import someone's public key"
read -p "Select an option (1, 2, or 3): " option

echo ""

if [ "$option" == "1" ]; then
    # WRITING / ENCRYPTING
    read -p "Enter the recipient's email address: " email
    read -p "Enter the name for the output file (e.g., secret.asc): " outfile
    
    echo "----------------------------------------"
    echo "Type your secret message below."
    echo "When you are finished, press [Enter] to go to a new line, then press [Ctrl+D]."
    echo "----------------------------------------"
    
    # This reads directly from the terminal input and feeds it to GPG
    gpg --encrypt --sign --armor --recipient "$email" > "$outfile"
    
    if [ $? -eq 0 ]; then
        echo ""
        echo "Success! Message encrypted and saved to '$outfile'."
        echo "You can now safely send this file to $email."
    else
        echo ""
        echo "Error: Encryption failed. Are you sure you imported their public key?"
    fi

elif [ "$option" == "2" ]; then
    # READING / DECRYPTING
    read -p "Enter the path to the encrypted file (e.g., secret.asc): " infile
    
    if [ -f "$infile" ]; then
        echo ""
        echo "Decrypting message..."
        echo "----------------------------------------"
        # GPG automatically knows to use your private key to decrypt
        gpg --decrypt "$infile"
        echo ""
        echo "----------------------------------------"
    else
        echo "Error: File '$infile' does not exist in this directory."
    fi

elif [ "$option" == "3" ]; then
    # IMPORTING PUBLIC KEY
    read -p "Enter the path to the public key file you want to import (e.g., friend_key.asc): " keyfile
    
    if [ -f "$keyfile" ]; then
        echo ""
        echo "Importing public key from '$keyfile'..."
        echo "----------------------------------------"
        
        gpg --import "$keyfile"
        
        if [ $? -eq 0 ]; then
            echo "----------------------------------------"
            echo "Success! The public key has been added to your keychain."
            echo "You can now use Option 1 to send encrypted messages to this person."
        else
            echo "----------------------------------------"
            echo "Error: Failed to import the key. Make sure it is a valid GPG public key file."
        fi
    else
        echo "Error: File '$keyfile' does not exist in this directory."
    fi

else
    echo "Invalid option selected. Exiting."
fi