document.addEventListener('DOMContentLoaded', () => {
    const addForm = document.getElementById('add-form');
    const instancesList = document.getElementById('instances-list');
    const refreshBtn = document.getElementById('refresh-btn');
    const portInput = document.getElementById('port');
    const ufwCmd = document.getElementById('ufw-cmd');
    const iptablesCmd = document.getElementById('iptables-cmd');

    let config = { firewall_host_ip: null };

    const updateFirewallCmds = () => {
        const port = portInput.value || '4646';
        const hostIp = config.firewall_host_ip || window.location.hostname;
        ufwCmd.textContent = `sudo ufw allow from ${hostIp} to any port ${port} proto tcp`;
        iptablesCmd.textContent = `sudo iptables -I INPUT -p tcp -s ${hostIp} --dport ${port} -j ACCEPT`;
    };

    const fetchConfig = async () => {
        try {
            const res = await fetch('/api/config');
            if (res.ok) {
                config = await res.json();
                updateFirewallCmds();
            }
        } catch (e) {
            console.error('Failed to fetch config:', e);
        }
    };

    portInput.addEventListener('input', updateFirewallCmds);
    
    // Initial fetch of config and instances
    fetchConfig();
    updateFirewallCmds();

    const fetchInstances = async () => {
        try {
            const res = await fetch('/api/instances');
            if (res.status === 401) {
                return; // Let browser handle auth
            }
            const data = await res.json();
            renderInstances(data);
        } catch (e) {
            console.error('Failed to fetch instances:', e);
        }
    };

    const renderInstances = (instances) => {
        if (instances.length === 0) {
            instancesList.innerHTML = '<div class="empty-state">No instances configured yet.</div>';
            return;
        }

        instancesList.innerHTML = instances.map(inst => {
            let statusClass = 'status-unknown';
            if (inst.last_status === 'Sent') statusClass = 'status-sent';
            else if (inst.last_status === 'Offline') statusClass = 'status-offline';
            else if (inst.last_status.startsWith('Failed')) statusClass = 'status-offline';

            const timeAgo = inst.last_checked ? Math.round((Date.now()/1000 - inst.last_checked)) + 's ago' : 'Never';

            return `
                <div class="instance-item">
                    <div class="instance-info">
                        <h3>${escapeHtml(inst.name)}</h3>
                        <div class="instance-meta">
                            <span>${escapeHtml(inst.ip)}:${inst.port}</span>
                            <span class="status-badge ${statusClass}">${escapeHtml(inst.last_status)}</span>
                            <span>Last checked: ${timeAgo}</span>
                        </div>
                    </div>
                    <button class="delete-btn" onclick="deleteInstance(${inst.id})" title="Delete">
                        <svg width="20" height="20" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round">
                            <polyline points="3 6 5 6 21 6"></polyline>
                            <path d="M19 6v14a2 2 0 0 1-2 2H7a2 2 0 0 1-2-2V6m3 0V4a2 2 0 0 1 2-2h4a2 2 0 0 1 2 2v2"></path>
                        </svg>
                    </button>
                </div>
            `;
        }).join('');
    };

    addForm.addEventListener('submit', async (e) => {
        e.preventDefault();
        const name = document.getElementById('name').value;
        const ip = document.getElementById('ip').value;
        const port = parseInt(document.getElementById('port').value, 10);
        const secret = document.getElementById('secret').value;

        try {
            const res = await fetch('/api/instances', {
                method: 'POST',
                headers: {
                    'Content-Type': 'application/json'
                },
                body: JSON.stringify({ name, ip, port, secret })
            });

            if (res.ok) {
                addForm.reset();
                document.getElementById('port').value = "4646";
                fetchInstances();
            } else {
                alert('Failed to add instance');
            }
        } catch (e) {
            console.error('Error adding instance', e);
        }
    });

    refreshBtn.addEventListener('click', fetchInstances);

    window.deleteInstance = async (id) => {
        if (!confirm('Are you sure you want to delete this instance?')) return;
        try {
            const res = await fetch(`/api/instances/${id}`, { method: 'DELETE' });
            if (res.ok) {
                fetchInstances();
            }
        } catch (e) {
            console.error('Error deleting instance', e);
        }
    };

    function escapeHtml(unsafe) {
        if (!unsafe) return '';
        return unsafe.toString()
            .replace(/&/g, "&amp;")
            .replace(/</g, "&lt;")
            .replace(/>/g, "&gt;")
            .replace(/"/g, "&quot;")
            .replace(/'/g, "&#039;");
    }

    fetchInstances();
    setInterval(fetchInstances, 5000);
});