const EMAIL_ELEMENT = 'input[name="email"]';
const EMAIL_HASH_ELEMENT = 'input[name="email_hash"]';
const GA_ID_ELEMENT = 'input[name="ga_id"]';

function getCookie(name, encodingType = 'raw') {
    const cookie = document.cookie
        .split('; ')
        .find((row) => row.startsWith(`${name}=`))
        ?.split('=')[1];
    if (!cookie) return '';
    if (encodingType === 'base64') {
        const cookieValue = decodeURIComponent(cookie.toString('utf8'));
        const decodedBytes = Uint8Array.from(atob(cookieValue), (char) => char.charCodeAt(0));
        const decoder = new TextDecoder('utf-8');
        return decoder.decode(decodedBytes);
    }
    return cookie;
}

async function sha256(message) {
    const msgBuffer = new TextEncoder().encode(message);
    const hashBuffer = await crypto.subtle.digest('SHA-256', msgBuffer);
    const hashArray = Array.from(new Uint8Array(hashBuffer));
    const hashHex = hashArray
        .map((b) => b.toString(16).padStart(2, '0'))
        .join('');
    return hashHex;
}

function addEmailHashListener(emailElement, emailHashElement) {
    emailElement.addEventListener('blur', () => {
        if (!emailElement.value) return;
        sha256(emailElement.value).then((hashValue) => {
            emailHashElement.value = hashValue;
            emailHashElement.dispatchEvent(new Event('input', { bubbles: true }));
        });
    });
}

function setGaIdValue(gidElement) {
    gidElement.value = getCookie('_gid');
    gidElement.dispatchEvent(new Event('input', { bubbles: true }));
}

function handlePrefill() {
    const form = document.querySelector('form');
    console.log(form);
    if (!form) return;
    const emailElement = form.querySelector(EMAIL_ELEMENT);
    const emailHashElement = form.querySelector(EMAIL_HASH_ELEMENT);
    const gidElement = form.querySelector(GA_ID_ELEMENT);
    
    console.log(emailElement, emailHashElement, gidElement);
    
    if (gidElement) setGaIdValue(gidElement);
    
    if (emailElement && emailHashElement) addEmailHashListener(emailElement, emailHashElement);    
}

document.addEventListener('readystatechange', event => {
    console.log(event.target.readyState); 
    if (event.target.readyState === "complete") handlePrefill();
});