<?php
/**
 * JARVIS Alerts API
 * GET  /api/alerts         — return active alerts (auto-generates agent alerts first)
 * POST /api/alerts/resolve — resolve an alert by id
 * POST /api/alerts         — manually create an alert
 */

// ── Auto-generate alerts from agent data ─────────────────────────────────────

function refresh_agent_alerts(): void {
    // Thresholds
    $CPU_WARN    = 85;
    $MEM_WARN    = 85;
    $DISK_WARN   = 88;
    $DISK_CRIT   = 95;

    // ── Mark auto-resolve alerts whose condition cleared ──────────────────────
    // We'll re-evaluate below and upsert; first collect keys that are still active
    $still_active = [];

    // ── Offline agents ────────────────────────────────────────────────────────
    $offline = JarvisDB::query(
        "SELECT agent_id, hostname FROM registered_agents
         WHERE status='offline' OR last_seen < DATE_SUB(NOW(), INTERVAL 3 MINUTE)"
    );
    foreach ($offline as $ag) {
        $key = 'agent:' . $ag['agent_id'] . ':offline';
        upsert_alert($key, 'critical', 'Agent Offline: ' . $ag['hostname'],
            'JARVIS Agent on ' . $ag['hostname'] . ' is not responding. Last contact was more than 3 minutes ago.');
        $still_active[$key] = true;
    }

    // ── Metric-based alerts ───────────────────────────────────────────────────
    // Get latest system metrics for each agent
    $latest = JarvisDB::query(
        "SELECT m.agent_id, m.metric_data, a.hostname
         FROM agent_metrics m
         JOIN registered_agents a ON a.agent_id = m.agent_id
         WHERE m.metric_type = 'system'
           AND (m.agent_id, m.recorded_at) IN (
               SELECT agent_id, MAX(recorded_at) FROM agent_metrics
               WHERE metric_type = 'system'
               GROUP BY agent_id
           )
           AND m.recorded_at > DATE_SUB(NOW(), INTERVAL 5 MINUTE)"
    );

    foreach ($latest as $row) {
        $d  = json_decode($row['metric_data'] ?? '{}', true);
        $hn = $row['hostname'];
        $id = $row['agent_id'];

        // CPU
        $cpu = (float)($d['cpu_percent'] ?? 0);
        if ($cpu >= $CPU_WARN) {
            $key = 'agent:' . $id . ':cpu_high';
            $sev = $cpu >= 95 ? 'critical' : 'warning';
            upsert_alert($key, $sev, 'High CPU: ' . $hn,
                round($cpu, 1) . '% CPU utilization on ' . $hn . '. Sustained high load detected.');
            $still_active[$key] = true;
        }

        // Memory
        $mem_pct = (float)($d['memory']['percent'] ?? 0);
        if ($mem_pct >= $MEM_WARN) {
            $key = 'agent:' . $id . ':mem_high';
            $sev = $mem_pct >= 95 ? 'critical' : 'warning';
            upsert_alert($key, $sev, 'High Memory: ' . $hn,
                round($mem_pct, 1) . '% memory used on ' . $hn .
                ' (' . round($d['memory']['used_mb'] ?? 0) . '/' .
                round($d['memory']['total_mb'] ?? 0) . ' MB).');
            $still_active[$key] = true;
        }

        // Disk
        foreach (($d['disk'] ?? []) as $disk) {
            $pct = (int)($disk['percent'] ?? 0);
            if ($pct >= $DISK_WARN) {
                $mount = $disk['mount'] ?? '/';
                $key   = 'agent:' . $id . ':disk:' . str_replace('/', '_', $mount);
                $sev   = $pct >= $DISK_CRIT ? 'critical' : 'warning';
                upsert_alert($key, $sev, 'Disk Full: ' . $hn . ' ' . $mount,
                    $mount . ' is ' . $pct . '% full on ' . $hn .
                    ' (' . ($disk['used'] ?? '?') . ' of ' . ($disk['size'] ?? '?') . ' used).');
                $still_active[$key] = true;
            }
        }

        // Services down
        foreach (($d['services'] ?? []) as $svc) {
            if (($svc['status'] ?? '') === 'active') continue;
            if (($svc['status'] ?? '') === 'unknown') continue; // not watched/installed
            $svcName = $svc['service'] ?? '';
            $key = 'agent:' . $id . ':svc:' . $svcName;
            upsert_alert($key, 'warning', 'Service Down: ' . $svcName . ' on ' . $hn,
                $svcName . ' is ' . ($svc['status'] ?? 'inactive') . ' on ' . $hn . '.');
            $still_active[$key] = true;
        }
    }

    // ── Auto-resolve alerts whose condition has cleared ────────────────────────
    if (!empty($still_active)) {
        $active_keys = array_keys($still_active);
        // Get all auto-resolvable alerts that are unresolved
        $open_auto = JarvisDB::query(
            "SELECT id, source_key FROM alerts WHERE resolved=0 AND auto_resolve=1 AND source_key IS NOT NULL"
        );
        foreach ($open_auto as $row) {
            if (!isset($still_active[$row['source_key']])) {
                JarvisDB::query(
                    'UPDATE alerts SET resolved=1, resolved_at=NOW() WHERE id=?',
                    [$row['id']]
                );
            }
        }
    } else {
        // Nothing active — resolve all auto alerts
        JarvisDB::query(
            "UPDATE alerts SET resolved=1, resolved_at=NOW()
             WHERE resolved=0 AND auto_resolve=1"
        );
    }
}

function upsert_alert(string $key, string $sev, string $title, string $msg): void {
    $existing = JarvisDB::query(
        'SELECT id, severity FROM alerts WHERE source_key=? AND resolved=0 LIMIT 1',
        [$key]
    );
    if ($existing) {
        // Update severity/message if changed (e.g., warning → critical)
        if ($existing[0]['severity'] !== $sev) {
            JarvisDB::query(
                'UPDATE alerts SET severity=?, title=?, message=?, created_at=NOW() WHERE id=?',
                [$sev, $title, $msg, $existing[0]['id']]
            );
        }
    } else {
        JarvisDB::query(
            'INSERT INTO alerts (alert_type, title, message, severity, source_key, auto_resolve) VALUES (?,?,?,?,?,1)',
            ['agent', $title, $msg, $sev, $key]
        );
    }
}

// ── Route ─────────────────────────────────────────────────────────────────────

if ($method === 'GET') {
    // Rate-limit agent alert refresh to once per 60 seconds via kb_facts lock
    $last_refresh = JarvisDB::query("SELECT fact_value FROM kb_facts WHERE category='agent' AND fact_key='alert_refresh' LIMIT 1");
    $last_ts = !empty($last_refresh) ? (int)$last_refresh[0]['fact_value'] : 0;
    if (time() - $last_ts >= 60) {
        JarvisDB::query(
            "INSERT INTO kb_facts (category, fact_key, fact_value, host) VALUES ('agent', 'alert_refresh', ?, 'local')
             ON DUPLICATE KEY UPDATE fact_value=VALUES(fact_value), updated_at=NOW()",
            [time()]
        );
        refresh_agent_alerts();
    }
    $alerts = JarvisDB::query(
        'SELECT * FROM alerts WHERE resolved=0 ORDER BY severity DESC, created_at DESC LIMIT 30'
    );
    echo json_encode(['alerts' => $alerts ?: [], 'count' => count($alerts ?: [])]);

} elseif ($method === 'POST' && ($action === 'resolve' || ($data['action'] ?? '') === 'resolve')) {
    $id = (int)($data['id'] ?? 0);
    JarvisDB::query('UPDATE alerts SET resolved=1, resolved_at=NOW() WHERE id=?', [$id]);
    echo json_encode(['success' => true]);

} elseif ($method === 'POST') {
    JarvisDB::query(
        'INSERT INTO alerts (alert_type, title, message, severity) VALUES (?,?,?,?)',
        [$data['type'] ?? 'system', $data['title'] ?? 'Alert', $data['message'] ?? '', $data['severity'] ?? 'info']
    );
    echo json_encode(['success' => true]);
}