<?php
/**
 * JARVIS Agent API
 * Handles registration, heartbeats, metrics, HA state pushes, and command polling
 * from remote jarvis-agent clients on external networks.
 *
 * Auth:  POST /api/agent/register  → uses AGENT_REGISTRATION_KEY
 *        All other actions         → uses X-Agent-Key header (per-agent key)
 */

header('Content-Type: application/json');

$agentAction = $action ?? ($parts[1] ?? '');

// ── Helpers ───────────────────────────────────────────────────────────────────

function agent_error(int $code, string $msg): void {
    http_response_code($code);
    echo json_encode(['error' => $msg]);
    exit;
}

function agent_ok(array $payload = []): void {
    echo json_encode(array_merge(['ok' => true], $payload));
    exit;
}

function generate_api_key(): string {
    return bin2hex(random_bytes(24));
}

function get_agent_by_key(string $key): ?array {
    $rows = JarvisDB::query(
        'SELECT * FROM registered_agents WHERE api_key = ? LIMIT 1',
        [$key]
    );
    return $rows[0] ?? null;
}

function update_agent_seen(string $agentId, string $status = 'online'): void {
    JarvisDB::query(
        'UPDATE registered_agents SET last_seen = NOW(), status = ? WHERE agent_id = ?',
        [$status, $agentId]
    );
}

// ── Auth (all actions except register) ───────────────────────────────────────

$agentKey       = $_SERVER['HTTP_X_AGENT_KEY'] ?? '';
$browserActions = ['list', 'status', 'myip'];

if ($agentAction !== 'register') {
    if (in_array($agentAction, $browserActions)) {
        $token   = $_SESSION['jarvis_token'] ?? '';
        $localIP = $_SERVER['REMOTE_ADDR'] ?? '';
        if (empty($token) && !in_array($localIP, ['127.0.0.1', '::1'])) {
            agent_error(401, 'Unauthorized');
        }
        $agent = null;
    } else {
        if (empty($agentKey)) agent_error(401, 'X-Agent-Key header required');
        $agent = get_agent_by_key($agentKey);
        if (!$agent) agent_error(401, 'Invalid agent key');
    }
}

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

switch ($agentAction) {

    // ── REGISTER ─────────────────────────────────────────────────────────────
    case 'register':
        if ($method !== 'POST') agent_error(405, 'POST only');
        $regKey = $_SERVER['HTTP_X_REGISTRATION_KEY'] ?? ($data['registration_key'] ?? '');
        if (!hash_equals(AGENT_REGISTRATION_KEY, $regKey)) agent_error(403, 'Invalid registration key');

        $hostname     = trim($data['hostname'] ?? '');
        $agentType    = $data['agent_type'] ?? 'linux';
        $ipAddress    = $data['ip_address'] ?? ($_SERVER['REMOTE_ADDR'] ?? '');
        $capabilities = $data['capabilities'] ?? [];
        $agentId      = $data['agent_id'] ?? ($hostname . '_' . substr(md5($hostname . $ipAddress), 0, 8));

        if (!$hostname) agent_error(400, 'hostname required');
        if (!in_array($agentType, ['linux', 'homeassistant', 'proxmox', 'windows'])) agent_error(400, 'Invalid agent_type');

        // Upsert agent
        $existing = JarvisDB::query('SELECT api_key FROM registered_agents WHERE agent_id = ?', [$agentId]);
        if ($existing) {
            $apiKey = $existing[0]['api_key'];
            JarvisDB::query(
                'UPDATE registered_agents SET hostname=?, agent_type=?, ip_address=?, capabilities=?, last_seen=NOW(), status="online" WHERE agent_id=?',
                [$hostname, $agentType, $ipAddress, json_encode($capabilities), $agentId]
            );
        } else {
            $apiKey = generate_api_key();
            JarvisDB::query(
                'INSERT INTO registered_agents (agent_id, hostname, agent_type, ip_address, api_key, capabilities, last_seen, status) VALUES (?,?,?,?,?,?,NOW(),"online")',
                [$agentId, $hostname, $agentType, $ipAddress, $apiKey, json_encode($capabilities)]
            );
        }

        agent_ok(['agent_id' => $agentId, 'api_key' => $apiKey]);

    // ── HEARTBEAT ────────────────────────────────────────────────────────────
    case 'heartbeat':
        update_agent_seen($agent['agent_id']);

        // Return any pending commands for this agent
        $commands = JarvisDB::query(
            'SELECT id, command_type, command_data FROM agent_commands WHERE agent_id = ? AND status = "pending" ORDER BY created_at ASC LIMIT 10',
            [$agent['agent_id']]
        );

        // Mark as delivered
        if ($commands) {
            $cmdIds = array_column($commands, 'id');
            $placeholders = implode(',', array_fill(0, count($cmdIds), '?'));
            JarvisDB::query("UPDATE agent_commands SET status='delivered', delivered_at=NOW() WHERE id IN ($placeholders)", $cmdIds);
            foreach ($commands as &$cmd) {
                $cmd['command_data'] = json_decode($cmd['command_data'] ?? '{}', true);
            }
        }

        agent_ok(['commands' => $commands ?: []]);

    // ── METRICS ──────────────────────────────────────────────────────────────
    case 'metrics':
        if ($method !== 'POST') agent_error(405, 'POST only');
        update_agent_seen($agent['agent_id']);

        $metricType = $data['type'] ?? 'system';
        $metricData = $data['data'] ?? [];

        JarvisDB::query(
            'INSERT INTO agent_metrics (agent_id, metric_type, metric_data) VALUES (?,?,?)',
            [$agent['agent_id'], $metricType, json_encode($metricData)]
        );

        // Prune old metrics (keep 24h)
        JarvisDB::query(
            'DELETE FROM agent_metrics WHERE agent_id = ? AND recorded_at < DATE_SUB(NOW(), INTERVAL 24 HOUR)',
            [$agent['agent_id']]
        );

        agent_ok();

    // ── HA STATE PUSH ────────────────────────────────────────────────────────
    case 'ha_state':
        if ($method !== 'POST') agent_error(405, 'POST only');
        update_agent_seen($agent['agent_id']);

        $entities = $data['entities'] ?? [];
        if (empty($entities)) agent_error(400, 'entities array required');

        foreach ($entities as $e) {
            $entityId   = $e['entity_id'] ?? '';
            $entityName = $e['name'] ?? $e['friendly_name'] ?? $entityId;
            $domain     = explode('.', $entityId)[0] ?? 'unknown';
            $state      = $e['state'] ?? '';
            $attrs      = $e['attributes'] ?? [];
            $lastChanged = $e['last_changed'] ?? date('Y-m-d H:i:s');

            if (!$entityId) continue;

            JarvisDB::query(
                'INSERT INTO ha_entities (agent_id, entity_id, entity_name, domain, state, attributes, last_changed, updated_at)
                 VALUES (?,?,?,?,?,?,?,NOW())
                 ON DUPLICATE KEY UPDATE entity_name=VALUES(entity_name), state=VALUES(state), attributes=VALUES(attributes), last_changed=VALUES(last_changed), updated_at=NOW()',
                [$agent['agent_id'], $entityId, $entityName, $domain, $state, json_encode($attrs), $lastChanged]
            );
        }

        // Also update kb_facts for compatibility with existing KB engine
        $entityMap = [];
        $all = JarvisDB::query('SELECT entity_id, entity_name, domain, state, attributes FROM ha_entities WHERE agent_id = ?', [$agent['agent_id']]);
        foreach ($all as $row) {
            $entityMap[$row['entity_id']] = [
                'entity_id' => $row['entity_id'],
                'name'      => $row['entity_name'],
                'domain'    => $row['domain'],
                'state'     => $row['state'],
                'attributes'=> json_decode($row['attributes'] ?? '{}', true),
            ];
        }
        JarvisDB::query(
            'INSERT INTO kb_facts (fact_key, fact_value, fact_type) VALUES ("ha/entity_map", ?, "json")
             ON DUPLICATE KEY UPDATE fact_value=VALUES(fact_value), updated_at=NOW()',
            [json_encode($entityMap)]
        );

        agent_ok(['accepted' => count($entities)]);

    // ── COMMAND RESULT ───────────────────────────────────────────────────────
    case 'command_result':
        if ($method !== 'POST') agent_error(405, 'POST only');
        $cmdId  = (int)($data['command_id'] ?? 0);
        $result = $data['result'] ?? [];
        $status = ($data['success'] ?? true) ? 'executed' : 'failed';

        JarvisDB::query(
            'UPDATE agent_commands SET status=?, executed_at=NOW(), result=? WHERE id=? AND agent_id=?',
            [$status, json_encode($result), $cmdId, $agent['agent_id']]
        );
        agent_ok();

    // ── LIST (admin: get all agents status) ──────────────────────────────────
    case 'list':
        // Mark agents offline if last_seen > 2 minutes ago
        JarvisDB::query(
            'UPDATE registered_agents SET status="offline" WHERE last_seen < DATE_SUB(NOW(), INTERVAL 2 MINUTE) AND status = "online"'
        );
        $agents = JarvisDB::query('SELECT agent_id, hostname, agent_type, ip_address, status, last_seen, capabilities FROM registered_agents ORDER BY agent_type, hostname');
        foreach ($agents as &$a) {
            $a['capabilities'] = json_decode($a['capabilities'] ?? '[]', true);
        }
        $realIp = $_SERVER['HTTP_CF_CONNECTING_IP'] ?? $_SERVER['HTTP_X_FORWARDED_FOR'] ?? $_SERVER['REMOTE_ADDR'] ?? '';
        $realIp = trim(explode(',', $realIp)[0]);
        agent_ok(['agents' => $agents, 'my_ip' => $realIp]);

    // ── LATEST METRICS (for dashboard display) ───────────────────────────────
    case 'status':
        $agentIdReq = $data['agent_id'] ?? ($parts[2] ?? '');
        $whereAgent = $agentIdReq ? 'AND agent_id = ?' : '';
        $params     = $agentIdReq ? [$agentIdReq] : [];

        $latest = JarvisDB::query(
            "SELECT agent_id, metric_type, metric_data, recorded_at
             FROM agent_metrics
             WHERE (agent_id, metric_type, recorded_at) IN (
               SELECT agent_id, metric_type, MAX(recorded_at)
               FROM agent_metrics $whereAgent
               GROUP BY agent_id, metric_type
             )
             ORDER BY agent_id, metric_type",
            $params
        );

        $grouped = [];
        foreach ($latest as $row) {
            $grouped[$row['agent_id']][$row['metric_type']] = json_decode($row['metric_data'], true);
            $grouped[$row['agent_id']]['recorded_at'] = $row['recorded_at'];
        }

        agent_ok(['metrics' => $grouped]);

    // ── MY IP (browser client IP detection) ──────────────────────────────────
    case 'myip':
        agent_ok(['ip' => $_SERVER['REMOTE_ADDR'] ?? '']);

    default:
        agent_error(404, 'Unknown agent action: ' . $agentAction);
}