import crypto from "node:crypto";
// Helper function to convert strings to Uint8Array (binary)
function encode(input) {
    return new TextEncoder().encode(input);
}
// Helper function to convert Uint8Array (binary) to base64
function toBase64(arr) {
    return btoa(String.fromCharCode(...arr));
}
// Helper function to convert base64 to Uint8Array (binary)
function fromBase64(base64) {
    return new Uint8Array(atob(base64)
        .split("")
        .map((char) => char.charCodeAt(0)));
}
// Function to derive a 256-bit key from any input string using SHA-256
async function deriveKey(keyString) {
    const keyMaterial = encode(keyString);
    const keyHash = await crypto.subtle.digest("SHA-256", keyMaterial); // Generate SHA-256 hash
    // Import the hash as a CryptoKey for AES-GCM
    return crypto.subtle.importKey("raw", keyHash, { name: "AES-GCM" }, false, [
        "encrypt",
        "decrypt",
    ]);
}
// Encrypt function
export async function encrypt(plaintext, keyString) {
    const key = await deriveKey(keyString); // Derive a 256-bit AES key from any input string
    const iv = crypto.getRandomValues(new Uint8Array(12)); // AES-GCM needs a 12-byte IV
    const encrypted = await crypto.subtle.encrypt({
        name: "AES-GCM",
        iv,
        tagLength: 128,
    }, key, encode(plaintext) // convert plaintext to binary
    );
    // Concatenate IV and encrypted data
    const combined = new Uint8Array(iv.length + encrypted.byteLength);
    combined.set(iv, 0); // first part is the IV
    combined.set(new Uint8Array(encrypted), iv.length); // second part is the ciphertext
    // Convert to base64 for storage/transmission
    return toBase64(combined);
}
// Decrypt function
export async function decrypt(combinedCiphertext, keyString) {
    const key = await deriveKey(keyString); // Derive the same 256-bit AES key from the input string
    const combined = fromBase64(combinedCiphertext); // decode base64 to binary
    // Split the IV and the ciphertext
    const iv = combined.slice(0, 12); // First 12 bytes are the IV
    const ciphertext = combined.slice(12); // The rest is the encrypted data
    console.log();
    // log.info({keyString, key, ciphertext})
    // Perform decryption
    const decrypted = await crypto.subtle.decrypt({
        name: "AES-GCM",
        iv,
        tagLength: 128,
    }, key, ciphertext);
    // Convert decrypted data from binary to string
    return new TextDecoder().decode(decrypted);
}
//   // Example usage:
//   const key = "any-length-key-you-want"; // Now can be any length
//   const message = "This is a secret message.";
//   encrypt(message, key).then((combinedCiphertext) => {
//     console.log("Encrypted message:", combinedCiphertext);
//     // Now decrypt it
//     decrypt(combinedCiphertext, key).then((decryptedMessage) => {
//       console.log("Decrypted message:", decryptedMessage);
//     });
//   });
