/*
Convert  an ArrayBuffer into a string
from https://developers.google.com/web/updates/2012/06/How-to-convert-ArrayBuffer-to-and-from-String
*/
export function ab2str(buf) {
    return String.fromCharCode.apply(null, new Uint8Array(buf));
}

/*
Convert a string into an ArrayBuffer
from https://developers.google.com/web/updates/2012/06/How-to-convert-ArrayBuffer-to-and-from-String
*/
export function str2ab(str) {
    const buf = new ArrayBuffer(str.length);
    const bufView = new Uint8Array(buf);
    for (let i = 0, strLen = str.length; i < strLen; i++) {
        bufView[i] = str.charCodeAt(i);
    }
    return buf;
}

export function exportedKeyToPem(key, type) {
    let exportedAsString = ab2str(key);
    let exportedAsBase64 = window.btoa(exportedAsString);
    return `-----BEGIN ${type.toUpperCase()} KEY-----\n${exportedAsBase64}\n-----END ${type.toUpperCase()} KEY-----`;
}

export function pemToKey(pemKey, type) {
    const base64 = pemKey.replace(`-----BEGIN ${type.toUpperCase()} KEY-----`, '').replace(`-----END ${type.toUpperCase()} KEY-----`, '').trim();
    const binaryDerString = window.atob(base64);
    const binaryDer = str2ab(binaryDerString);
    return window.crypto.subtle.importKey(
        "pkcs8",
        binaryDer,
        {
            name: "Ed25519",
        },
        true,
        ["sign"],
    );
}

export async function genKey() {
  // Generate keys
    const { publicKey, privateKey } = await crypto.subtle.generateKey(
      {
        name: "Ed25519",
      },
      true,
      ["sign", "verify"],
    );
    const exportedPubkey = await crypto.subtle.exportKey("spki", publicKey);
    const exportedPrivkey = await crypto.subtle.exportKey("pkcs8", privateKey);
    // const privkey = await crypto.subtle.wrapKey("pkcs8", privateKey, wrapkey, { name: "AES-KW" });
    const key = {
        privateKey: exportedPrivkey,
        publicKey: exportedPubkey
    }
    return key;
}