{% extends 'django_zkp_auth/base.html' %}

{% block title %}Register — ZKP Auth{% endblock %}

{% block content %}
<div class="min-h-[70vh] flex items-center justify-center">
    <div class="glass-panel p-8 rounded-2xl w-full max-w-md border-t-4 border-brand-purple">
        <h2 class="text-3xl font-bold mb-2">New Identity</h2>
        <p class="text-gray-400 text-sm mb-6">Create a Zero-Knowledge profile.</p>

        <form id="registerForm" class="space-y-4">
            {% csrf_token %}
            <div>
                <label class="block text-xs font-mono text-brand-purple mb-1">USERNAME</label>
                <input type="text" id="username" class="glass-input w-full p-3 rounded" required>
            </div>
            <div>
                <label class="block text-xs font-mono text-brand-purple mb-1">PASSPHRASE</label>
                <input type="password" id="password" class="glass-input w-full p-3 rounded" required>
                <p class="text-[10px] text-gray-500 mt-1">Only your public key (G^x) is stored — your passphrase never leaves your device.</p>
            </div>

            <button type="submit" class="w-full bg-brand-purple text-white font-bold py-3 rounded hover:bg-white hover:text-black transition-all mt-4">
                REGISTER IDENTITY
            </button>
        </form>
    </div>
</div>
{% endblock %}

{% block extra_scripts %}
<script>
    const P = BigInt("{{ prime_p }}");
    const G = BigInt("{{ generator_g }}");

    async function hashPassword(password) {
        const msgBuffer = new TextEncoder().encode(password);
        const hashBuffer = await crypto.subtle.digest('SHA-256', msgBuffer);
        const hashArray = Array.from(new Uint8Array(hashBuffer));
        const hex = hashArray.map(b => b.toString(16).padStart(2, '0')).join('');
        return BigInt("0x" + hex);
    }

    function modPow(base, exp, mod) {
        let result = 1n;
        base = base % mod;
        while (exp > 0n) {
            if (exp % 2n === 1n) result = (result * base) % mod;
            exp = exp / 2n;
            base = (base * base) % mod;
        }
        return result;
    }

    document.getElementById('registerForm').addEventListener('submit', async (e) => {
        e.preventDefault();
        const username = document.getElementById('username').value;
        const password = document.getElementById('password').value;
        const csrfToken = document.querySelector('[name=csrfmiddlewaretoken]').value;

        const btn = e.target.querySelector('button');
        btn.innerHTML = "CALCULATING KEYS...";
        btn.classList.add('opacity-50');

        const hashInt = await hashPassword(password);
        const x = hashInt % (P - 1n);
        const y = modPow(G, x, P);

        const response = await fetch('{% url "django_zkp_auth:register" %}', {
            method: 'POST',
            headers: { 'Content-Type': 'application/json', 'X-CSRFToken': csrfToken },
            body: JSON.stringify({ username: username, public_key: y.toString() })
        });

        const data = await response.json();
        if (data.status === 'success') {
            window.location.href = data.redirect;
        } else {
            alert(data.message);
            btn.innerHTML = "TRY AGAIN";
            btn.classList.remove('opacity-50');
        }
    });
</script>
{% endblock %}