let metricsChart = null;

function initChart(data) {
    const container = document.getElementById('metricsChart').parentNode;
    const oldCanvas = document.getElementById('metricsChart');
    const newCanvas = document.createElement('canvas');
    newCanvas.id = 'metricsChart';
    newCanvas.height = 300;
    container.replaceChild(newCanvas, oldCanvas);
    const ctx = newCanvas.getContext('2d');
    const labels = data.map(m => {
        const d = new Date(m.created_at);
        return d.getHours().toString().padStart(2, '0') + ':' + d.getMinutes().toString().padStart(2, '0');
    });

    metricsChart = new Chart(ctx, {
        type: 'line',
        data: {
            labels: labels,
            datasets: [
                {
                    label: 'CPU',
                    data: data.map(m => m.cpu_usage),
                    borderColor: '#3b82f6',
                    backgroundColor: 'rgba(59, 130, 246, 0.1)',
                    fill: true,
                    tension: 0.3,
                    pointRadius: 1,
                },
                {
                    label: 'RAM',
                    data: data.map(m => m.ram_usage),
                    borderColor: '#22c55e',
                    backgroundColor: 'rgba(34, 197, 94, 0.1)',
                    fill: true,
                    tension: 0.3,
                    pointRadius: 1,
                },
                {
                    label: 'Disk',
                    data: data.map(m => m.disk_usage),
                    borderColor: '#8b5cf6',
                    backgroundColor: 'rgba(139, 92, 246, 0.1)',
                    fill: true,
                    tension: 0.3,
                    pointRadius: 1,
                },
            ],
        },
        options: {
            responsive: true,
            maintainAspectRatio: false,
            interaction: {
                intersect: false,
                mode: 'index',
            },
            plugins: {
                legend: {
                    labels: {
                        color: '#9ca3af',
                        font: { family: "'Inter', sans-serif" },
                        boxWidth: 12,
                        padding: 16,
                    },
                },
                tooltip: {
                    backgroundColor: '#1a1d2b',
                    borderColor: '#2a2d3d',
                    borderWidth: 1,
                    titleColor: '#e1e4ed',
                    bodyColor: '#9ca3af',
                    padding: 10,
                    cornerRadius: 8,
                    callbacks: {
                        label: function(ctx) {
                            return ctx.dataset.label + ': ' + ctx.parsed.y.toFixed(1) + '%';
                        },
                    },
                },
            },
            scales: {
                x: {
                    ticks: {
                        color: '#6b7280',
                        maxTicksLimit: 12,
                        font: { size: 11 },
                    },
                    grid: {
                        color: 'rgba(255,255,255,0.04)',
                    },
                },
                y: {
                    min: 0,
                    max: 100,
                    ticks: {
                        color: '#6b7280',
                        font: { size: 11 },
                        callback: function(v) { return v + '%'; },
                    },
                    grid: {
                        color: 'rgba(255,255,255,0.04)',
                    },
                },
            },
        },
    });
}

if (historicalData.length > 0) {
    initChart(historicalData);
}

let pendingAgentAction = null;

function showAgentModal(action) {
    pendingAgentAction = action;
    const modal = document.getElementById('agentConfirmModal');
    const title = document.getElementById('agentModalTitle');
    const msg = document.getElementById('agentModalMessage');
    const btn = document.getElementById('agentModalConfirmBtn');

    if (action === 'install') {
        title.textContent = 'Install Monitoring Agent';
        msg.innerHTML = 'This will install the monitoring agent on <strong>serverName</strong> via SSH.';
        btn.textContent = 'Install';
        btn.className = 'btn btn-primary';
    } else {
        title.textContent = 'Uninstall Monitoring Agent';
        msg.innerHTML = 'This will uninstall the monitoring agent from <strong>serverName</strong> via SSH. The service will be stopped and all agent files removed.';
        btn.textContent = 'Uninstall';
        btn.className = 'btn btn-danger';
    }

    modal.style.display = 'flex';
    modal.onclick = function(e) {
        if (e.target === modal) closeAgentModal();
    };
}

function closeAgentModal() {
    document.getElementById('agentConfirmModal').style.display = 'none';
    pendingAgentAction = null;
}

function confirmAgentAction() {
    if (!pendingAgentAction) return;

    const action = pendingAgentAction;
    const btn = document.getElementById('agentModalConfirmBtn');
    btn.disabled = true;
    btn.textContent = action === 'install' ? 'Installing...' : 'Uninstalling...';

    closeAgentModal();

    fetch('/servers/' + serverId + '/agent/' + action, {
        method: 'POST',
        headers: {
            'Accept': 'application/json',
            'Content-Type': 'application/x-www-form-urlencoded',
            'X-CSRF-Token': getCsrfToken(),
        },
        body: '_csrf_token=' + encodeURIComponent(getCsrfToken()),
    })
    .then(r => r.json())
    .then(data => {
        if (data.success) {
            showToast('success', action === 'install' ? 'Agent installed successfully.' : 'Agent uninstalled successfully.');
            setTimeout(() => location.reload(), 1500);
        } else {
            let msg = data.error || (action === 'install' ? 'Installation failed.' : 'Uninstallation failed.');
        if (data.output) msg += ' Output: ' + data.output.replace(/\n/g, ' | ');
        showToast('error', msg);
        }
    })
    .catch(err => {
        showToast('error', 'Request failed: ' + err.message);
    })
    .finally(() => {
        btn.disabled = false;
        btn.textContent = action === 'install' ? 'Install' : 'Uninstall';
    });
}

function copyAgentKey() {
    const key = document.getElementById('agentKeyFull').value;
    navigator.clipboard.writeText(key).then(() => {
        showToast('success', 'Agent key copied to clipboard.');
    }).catch(() => {
        showToast('error', 'Failed to copy agent key.');
    });
}

function regenerateAgentKey() {
    if (!confirm('Regenerate agent key? The current key will stop working immediately.')) return;

    fetch('/servers/' + serverId + '/agent/regenerate-key', {
        method: 'POST',
        headers: {
            'Accept': 'application/json',
            'Content-Type': 'application/x-www-form-urlencoded',
            'X-CSRF-Token': getCsrfToken(),
        },
        body: '_csrf_token=' + encodeURIComponent(getCsrfToken()),
    })
    .then(r => r.json())
    .then(data => {
        if (data.success) {
            showToast('success', 'Agent key regenerated.');
            setTimeout(() => location.reload(), 1500);
        } else {
            showToast('error', data.error || 'Failed to regenerate key.');
        }
    })
    .catch(err => showToast('error', 'Request failed: ' + err.message));
}

function getCsrfToken() {
    return document.querySelector('meta[name="csrf-token"]')?.content || '';
}

function serverAction(action) {
    if (action === 'shutdown' || action === 'reboot') {
        if (!confirm('Are you sure you want to ' + action + ' this server?')) return;
    }

    fetch('/servers/' + serverId + '/' + action, {
        method: 'POST',
        headers: {
            'Accept': 'application/json',
            'Content-Type': 'application/x-www-form-urlencoded',
            'X-CSRF-Token': getCsrfToken(),
        },
        body: '_csrf_token=' + encodeURIComponent(getCsrfToken()),
    })
    .then(r => r.json())
    .then(data => {
        showToast(data.success ? 'success' : 'error', data.message);
    })
    .catch(err => showToast('error', 'Request failed: ' + err.message));
}

function restartService() {
    const service = prompt('Enter service name to restart (e.g., nginx, mysql, apache2):');
    if (!service) return;

    fetch('/servers/' + serverId + '/restart-service', {
        method: 'POST',
        headers: {
            'Accept': 'application/json',
            'Content-Type': 'application/x-www-form-urlencoded',
            'X-CSRF-Token': getCsrfToken(),
        },
        body: 'service=' + encodeURIComponent(service) + '&_csrf_token=' + encodeURIComponent(getCsrfToken()),
    })
    .then(r => r.json())
    .then(data => {
        showToast(data.success ? 'success' : 'error', data.message);
    })
    .catch(err => showToast('error', 'Request failed: ' + err.message));
}

function refreshMetrics() {
    fetch('/servers/' + serverId + '/metrics', {
        headers: { 'Accept': 'application/json' },
    })
        .then(r => r.json())
        .then(data => {
            if (data.success && data.data) {
                const m = data.data;
                document.getElementById('cpuMetric').textContent = (m.cpu_usage || '-') + '%';
                document.getElementById('ramMetric').textContent = (m.ram_usage || '-') + '%';
                document.getElementById('diskMetric').textContent = (m.disk_usage || '-') + '%';
                document.getElementById('loadMetric').textContent = m.load_average || '-';
                document.getElementById('uptimeMetric').textContent = m.uptime || '-';
                if (metricsChart && metricsChart.data.labels.length > 0) {
                    const now = new Date();
                    const label = now.getHours().toString().padStart(2, '0') + ':' + now.getMinutes().toString().padStart(2, '0');
                    metricsChart.data.labels.push(label);
                    metricsChart.data.datasets[0].data.push(m.cpu_usage);
                    metricsChart.data.datasets[1].data.push(m.ram_usage);
                    metricsChart.data.datasets[2].data.push(m.disk_usage);
                    if (metricsChart.data.labels.length > 48) {
                        metricsChart.data.labels.shift();
                        metricsChart.data.datasets.forEach(ds => ds.data.shift());
                    }
                    metricsChart.update('none');
                }
            }
        });
}

setInterval(refreshMetrics, 30000);

function showThresholdModal() {
    document.getElementById('thresholdModal').style.display = 'flex';
    document.getElementById('thresholdModal').onclick = function(e) {
        if (e.target === this) closeThresholdModal();
    };
}

function closeThresholdModal() {
    document.getElementById('thresholdModal').style.display = 'none';
}

function saveThresholds() {
    const form = document.getElementById('thresholdForm');
    const data = new URLSearchParams(new FormData(form));
    data.append('_csrf_token', getCsrfToken());

    document.querySelector('#thresholdModal .btn-primary').disabled = true;

    fetch('/servers/' + serverId + '/thresholds', {
        method: 'POST',
        headers: {
            'Accept': 'application/json',
            'Content-Type': 'application/x-www-form-urlencoded',
            'X-CSRF-Token': getCsrfToken(),
        },
        body: data.toString(),
    })
    .then(r => r.json())
    .then(d => {
        showToast(d.success ? 'success' : 'error', d.message ?? d.error);
        if (d.success) closeThresholdModal();
    })
    .catch(e => showToast('error', 'Request failed: ' + e.message))
    .finally(() => {
        document.querySelector('#thresholdModal .btn-primary').disabled = false;
    });
}