zabbix-deploy/web-modules/WecomCenter/lib/Helper.php

<?php declare(strict_types = 0);
/*
** WeCom Center - business logic helpers.
** Works through the official Zabbix API so every setting is stored in the
** Zabbix database itself -> survives image upgrades and is portable.
*/

namespace Modules\WecomCenter\Lib;

use API;
use Exception;

class Helper {

	// Zabbix trigger severity index => media severity bit (1 << index).
	public const SEVERITY_BITS = [1, 2, 4, 8, 16, 32];

	// Built-in alert schemes: name => [severity_mask, active(0=enabled,1=disabled)]
	public const SCHEMES = [
		'standard' => [48, 0],   // High + Disaster (recommended)
		'warnplus' => [56, 0],   // Average + High + Disaster
		'all'      => [63, 0],   // everything
		'quiet'    => [32, 0],   // Disaster only
		'off'      => [63, 1]    // alerting disabled
	];

	/* ------------------------------------------------------------------ */
	/*  Media types / robot                                               */
	/* ------------------------------------------------------------------ */

	/**
	 * All webhook media types (type == 4).
	 */
	public static function webhookMediatypes(): array {
		try {
			$res = API::Mediatype()->get([
				'output'           => ['mediatypeid', 'name', 'type', 'status'],
				'selectParameters' => 'extend',
				'filter'           => ['type' => 4]
			]);
			return is_array($res) ? $res : [];
		}
		catch (\Throwable $e) {
			return [];
		}
	}

	public static function getMediatype(string $mediatypeid): ?array {
		try {
			$res = API::Mediatype()->get([
				'output'           => ['mediatypeid', 'name', 'type', 'status'],
				'selectParameters' => 'extend',
				'mediatypeids'     => [$mediatypeid]
			]);
			return (is_array($res) && $res) ? $res[0] : null;
		}
		catch (\Throwable $e) {
			return null;
		}
	}

	// Fixed WeCom group-robot endpoint; the per-bot secret lives in {$WECOM_KEY}.
	public const WECOM_BASE = 'https://qyapi.weixin.qq.com/cgi-bin/webhook/send?key=';
	public const KEY_MACRO  = '{$WECOM_KEY}';

	/** Read a global macro value; null when missing. */
	public static function getGlobalMacro(string $name): ?string {
		try {
			$res = API::UserMacro()->get([
				'globalmacro' => true,
				'output'      => ['globalmacroid', 'macro', 'value'],
				'filter'      => ['macro' => $name]
			]);
			return ($res && isset($res[0])) ? (string) $res[0]['value'] : null;
		}
		catch (\Throwable $e) {
			return null;
		}
	}

	/** Create or update a global macro. */
	public static function setGlobalMacro(string $name, string $value): void {
		$res = API::UserMacro()->get([
			'globalmacro' => true,
			'output'      => ['globalmacroid', 'macro'],
			'filter'      => ['macro' => $name]
		]);
		if ($res && isset($res[0])) {
			API::UserMacro()->updateGlobal([
				['globalmacroid' => $res[0]['globalmacroid'], 'value' => $value]
			]);
		}
		else {
			API::UserMacro()->createGlobal([
				['macro' => $name, 'value' => $value]
			]);
		}
	}

	/**
	 * Current robot key: {$WECOM_KEY} global macro, falling back to any legacy
	 * value still stored in the media type parameters.
	 */
	public static function webhookKey(?array $mediatype = null): string {
		$v = self::getGlobalMacro(self::KEY_MACRO);
		if ($v !== null && $v !== '') {
			return $v;
		}
		foreach (($mediatype['parameters'] ?? []) as $p) {
			$n = strtolower($p['name']);
			$val = (string) $p['value'];
			if ($n === 'key' && strpos($val, '{') === false) {
				return $val;
			}
			if (in_array($n, ['webhook_url', 'url', 'webhook'], true)) {
				if (strpos($val, 'key=') !== false) {
					return substr($val, strpos($val, 'key=') + 4);
				}
				if (strpos($val, 'http') !== 0) {
					return $val;
				}
			}
		}
		return '';
	}

	/** Persist the robot key into the {$WECOM_KEY} global macro (managed here, not in the media type). */
	public static function setWebhookKey(string $key): void {
		self::setGlobalMacro(self::KEY_MACRO, $key);
	}

	/** Full webhook URL for this bot = fixed base + {$WECOM_KEY}. */
	public static function webhookUrl(?array $mediatype = null): string {
		$key = self::webhookKey($mediatype);
		return $key === '' ? '' : self::WECOM_BASE.$key;
	}

	/* ------------------------------------------------------------------ */
	/*  Robot user + media (severity / active)                            */
	/* ------------------------------------------------------------------ */

	/**
	 * Find the dedicated robot user with its media.
	 */
	public static function robotUser(string $username = 'wecomrobot'): ?array {
		$res = API::User()->get([
			'output'        => ['userid', 'username'],
			'selectMedias'  => 'extend',
			'filter'        => ['username' => $username]
		]);
		return $res ? $res[0] : null;
	}

	/**
	 * Current severity mask + active flag of a user's media for a media type.
	 * Returns ['active'=>int, 'severity'=>int] or null when media absent.
	 */
	public static function currentMedia(?array $user, string $mediatypeid): ?array {
		if (!$user || empty($user['medias'])) {
			return null;
		}
		foreach ($user['medias'] as $m) {
			if ((string) $m['mediatypeid'] === (string) $mediatypeid) {
				return [
					'active'   => (int) $m['active'],
					'severity' => (int) $m['severity'],
					'period'   => $m['period'] ?? '1-7,00:00-24:00',
					'sendto'   => $m['sendto'] ?? ''
				];
			}
		}
		return null;
	}

	/**
	 * Ensure a robot user exists; create one (no frontend access) if missing.
	 */
	public static function ensureRobotUser(string $username): array {
		$user = self::robotUser($username);
		if ($user) {
			return $user;
		}

		// best-effort group / role for a non-login notification account
		$grp = API::UserGroup()->get([
			'output' => ['usrgrpid', 'name'],
			'filter' => ['name' => 'No access to the frontend'],
			'limit'  => 1
		]);
		$usrgrpid = $grp ? $grp[0]['usrgrpid'] : null;
		if ($usrgrpid === null) {
			$all = API::UserGroup()->get(['output' => ['usrgrpid'], 'limit' => 1]);
			$usrgrpid = $all ? $all[0]['usrgrpid'] : null;
		}

		$role = API::Role()->get([
			'output' => ['roleid', 'name'],
			'filter' => ['name' => 'User role'],
			'limit'  => 1
		]);
		$roleid = $role ? $role[0]['roleid'] : null;

		$create = [
			'username' => $username,
			'passwd'   => bin2hex(random_bytes(16)).'Aa1!',
			'usrgrps'  => [['usrgrpid' => $usrgrpid]]
		];
		if ($roleid !== null) {
			$create['roleid'] = $roleid;
		}

		$res = API::User()->create($create);
		return self::robotUser($username);
	}

	/**
	 * Apply severity mask + active flag to a user's media for a media type.
	 * Rebuilds the whole media list (API user.update replaces medias).
	 */
	public static function applyMedia(string $userid, string $mediatypeid, int $severity, int $active,
			string $sendto = 'WeCom') {
		$res = API::User()->get([
			'output'       => ['userid'],
			'selectMedias' => 'extend',
			'userids'      => [$userid]
		]);
		$medias = [];
		if ($res) {
			foreach (($res[0]['medias'] ?? []) as $m) {
				$medias[] = [
					'mediatypeid' => $m['mediatypeid'],
					'sendto'      => $m['sendto'],
					'severity'    => (string) $m['severity'],
					'active'      => (string) $m['active'],
					'period'      => $m['period'] ?: '1-7,00:00-24:00'
				];
			}
		}

		$hit = false;
		foreach ($medias as &$m) {
			if ((string) $m['mediatypeid'] === (string) $mediatypeid) {
				$m['severity'] = (string) $severity;
				$m['active']   = (string) $active;
				if ($sendto !== '') {
					$m['sendto'] = $sendto;
				}
				$hit = true;
			}
		}
		unset($m);
		if (!$hit) {
			$medias[] = [
				'mediatypeid' => $mediatypeid,
				'sendto'      => $sendto !== '' ? $sendto : 'WeCom',
				'severity'    => (string) $severity,
				'active'      => (string) $active,
				'period'      => '1-7,00:00-24:00'
			];
		}

		API::User()->update(['userid' => $userid, 'medias' => $medias]);
	}

	/* ------------------------------------------------------------------ */
	/*  Send test message                                                 */
	/* ------------------------------------------------------------------ */

	public static function testWebhook(string $url, string $text): array {
		$payload = json_encode(['msgtype' => 'text', 'text' => ['content' => $text]], JSON_UNESCAPED_UNICODE);
		$ch = curl_init($url);
		curl_setopt_array($ch, [
			CURLOPT_RETURNTRANSFER => true,
			CURLOPT_POST           => true,
			CURLOPT_POSTFIELDS     => $payload,
			CURLOPT_HTTPHEADER     => ['Content-Type: application/json'],
			CURLOPT_TIMEOUT        => 15,
			CURLOPT_SSL_VERIFYPEER => false,
			CURLOPT_SSL_VERIFYHOST => 0
		]);
		$body = curl_exec($ch);
		$status = curl_getinfo($ch, CURLINFO_HTTP_CODE);
		$err = curl_error($ch);
		curl_close($ch);
		return ['status' => $status, 'body' => $body !== false ? $body : $err];
	}

	/* ------------------------------------------------------------------ */
	/*  Templates                                                         */
	/* ------------------------------------------------------------------ */

	/**
	 * Bundled templates shipped inside modules/WecomCenter/templates/.
	 */
	public static function bundledTemplates(string $module_dir): array {
		$dir = rtrim($module_dir, '/').'/templates';
		$out = [];
		if (!is_dir($dir)) {
			return $out;
		}
		foreach (scandir($dir) as $f) {
			if ($f === '.' || $f === '..') {
				continue;
			}
			$ext = strtolower(pathinfo($f, PATHINFO_EXTENSION));
			if (in_array($ext, ['xml', 'yaml', 'yml', 'json'], true)) {
				$out[] = ['file' => $f, 'name' => pathinfo($f, PATHINFO_FILENAME)];
			}
		}
		return $out;
	}

	public static function importTemplate(string $module_dir, string $file): array {
		$dir = rtrim($module_dir, '/').'/templates';
		$file = basename($file);
		$path = $dir.'/'.$file;
		if (!is_file($path)) {
			throw new Exception('Template file not found: '.$file);
		}
		$ext = strtolower(pathinfo($file, PATHINFO_EXTENSION));
		$format = ['xml' => 'xml', 'json' => 'json', 'yaml' => 'yaml', 'yml' => 'yaml'][$ext] ?? 'yaml';
		$source = file_get_contents($path);
		$result = API::Configuration()->import([
			'format' => $format,
			'source' => $source,
			'rules'  => [
				'template_groups' => ['createMissing' => true, 'updateExisting' => true],
				'templates'       => ['createMissing' => true, 'updateExisting' => true],
				'items'           => ['createMissing' => true, 'updateExisting' => true],
				'triggers'        => ['createMissing' => true, 'updateExisting' => true]
			]
		]);
		return is_array($result) ? $result : [];
	}

	/* ------------------------------------------------------------------ */
	/*  Map coordinates                                                   */
	/* ------------------------------------------------------------------ */

	public static function hosts(): array {
		return API::Host()->get([
			'output'    => ['hostid', 'name'],
			'sortfield' => 'name',
			'limit'     => 1000
		]);
	}

	public static function setHostLocation(string $hostid, string $lat, string $lon): void {
		API::Host()->update([
			'hostid'         => $hostid,
			'inventory_mode' => 0, // manual
			'inventory'      => [
				'location_lat' => $lat,
				'location_lon' => $lon
			]
		]);
	}

	public static function hostLocation(string $hostid): array {
		$res = API::Host()->get([
			'output'           => ['hostid', 'name'],
			'selectInventory'  => ['location_lat', 'location_lon'],
			'hostids'          => [$hostid]
		]);
		return $res ? $res[0] : [];
	}

	/* ------------------------------------------------------------------ */
	/*  Helpers                                                           */
	/* ------------------------------------------------------------------ */

	public static function severityMask(array $indices): int {
		$mask = 0;
		foreach ($indices as $i) {
			$i = (int) $i;
			if ($i >= 1 && $i <= 6) {
				$mask |= self::SEVERITY_BITS[$i - 1];
			}
		}
		return $mask;
	}

	/* ------------------------------------------------------------------ */
	/*  Triggers (per-trigger alerting switch)                            */
	/* ------------------------------------------------------------------ */

	/**
	 * Search triggers by description. An empty search returns nothing on
	 * purpose - the instance has tens of thousands of triggers, listing all
	 * is pointless. Results are capped.
	 */
	public static function triggers(string $search, int $limit = 200): array {
		$search = trim($search);
		if ($search === '') {
			return [];
		}
		try {
			$res = API::Trigger()->get([
				'output'      => ['triggerid', 'description', 'status', 'priority'],
				'selectHosts' => ['host'],
				'search'      => ['description' => $search],
				'limit'       => $limit
			]);
			return is_array($res) ? $res : [];
		}
		catch (\Throwable $e) {
			return [];
		}
	}

	public static function triggerCount(): int {
		try {
			$n = API::Trigger()->get(['countOutput' => true]);
			return (int) $n;
		}
		catch (\Throwable $e) {
			return 0;
		}
	}

	/**
	 * Set trigger status. $map = [triggerid => status(0 enabled,1 disabled)].
	 * NB: this Zabbix version's trigger.update does NOT accept a "triggers"
	 * array, so we update one trigger at a time.
	 */
	public static function setTriggersStatus(array $map): int {
		$changed = 0;
		foreach ($map as $tid => $status) {
			$res = API::Trigger()->update([
				'triggerid' => (string) $tid,
				'status'    => (string) ((int) $status)
			]);
			if ($res === false) {
				throw new Exception('trigger.update failed for '.$tid);
			}
			$changed++;
		}
		return $changed;
	}

	/* ================================================================== */
	/*  ALERT STRATEGY ENGINE                                             */
	/*  Classify triggers by name keyword, map to severity, apply to the  */
	/*  template triggers + prototypes (API) and discovered triggers (SQL)*/
	/* ================================================================== */

	public const TEMPLATE_NAME  = 'Huawei VRP by SNMP walk';
	public const STRATEGY_MACRO = '{$WECOM_STRATEGY}';

	// Ordered classes - first match wins (highest priority first).
	public const CLASSES = [
		'device_down' => [
			'label' => 'cls.device_down',
			'kw'    => ['unavailable by icmp', 'icmp ping loss', 'no snmp data', 'no data', 'unreachable']
		],
		'hw_fault' => [
			'label' => 'cls.hw_fault',
			'kw'    => ['fan is in critical', 'power supply', 'temperature is above critical',
				'temperature is too low', 'is in critical state', 'psu']
		],
		'restarted' => [
			'label' => 'cls.restarted',
			'kw'    => ['has been restarted', 'has been rebooted']
		],
		'core_link' => [
			'label' => 'cls.core_link',
			'kw'    => ['link down'],
			'core'  => ['to:', 'dist', 'core', 'csw', 'uplink', 'aggregat', '汇聚', 'trunk']
		],
		'interface_down' => [
			'label' => 'cls.interface_down',
			'kw'    => ['link down']
		],
		'perf' => [
			'label' => 'cls.perf',
			'kw'    => ['high bandwidth usage', 'high error rate', 'high cpu', 'high memory', 'utilization',
				'high icmp ping response time', 'changed to lower speed', 'temperature is above warning']
		],
		'other' => ['label' => 'cls.other', 'kw' => []]
	];

	// Selectable alert strategies. min = lowest severity index that still notifies.
	public const STRATEGY_PRESETS = [
		'steady' => [
			'label' => 'preset.steady', 'desc' => 'preset.steady.desc', 'min' => 4,
			'targets' => ['device_down' => 5, 'hw_fault' => 5, 'restarted' => 5, 'core_link' => 5,
				'interface_down' => 3, 'perf' => 2]
		],
		'core' => [
			'label' => 'preset.core', 'desc' => 'preset.core.desc', 'min' => 5,
			'targets' => ['device_down' => 5, 'hw_fault' => 5, 'restarted' => 5, 'core_link' => 5,
				'interface_down' => 2, 'perf' => 1]
		],
		'observe' => [
			'label' => 'preset.observe', 'desc' => 'preset.observe.desc', 'min' => 2,
			'targets' => ['device_down' => 5, 'hw_fault' => 5, 'restarted' => 5, 'core_link' => 5,
				'interface_down' => 3, 'perf' => 2]
		],
		'night' => [
			'label' => 'preset.night', 'desc' => 'preset.night.desc', 'min' => 5,
			'targets' => ['device_down' => 5, 'hw_fault' => 5, 'restarted' => 5, 'core_link' => 5,
				'interface_down' => 2, 'perf' => 1]
		],
		'balanced' => [
			'label' => 'preset.balanced', 'desc' => 'preset.balanced.desc', 'min' => 3,
			'targets' => ['device_down' => 5, 'hw_fault' => 5, 'restarted' => 5, 'core_link' => 5,
				'interface_down' => 3, 'perf' => 2]
		]
	];

	/** Classify one trigger description into a class key. */
	public static function classifyRaw(string $desc): string {
		$d = strtolower($desc);
		foreach (self::CLASSES as $key => $def) {
			if (empty($def['kw'])) {
				continue;
			}
			$hit = false;
			foreach ($def['kw'] as $k) {
				if (strpos($d, $k) !== false) {
					$hit = true;
					break;
				}
			}
			if (!$hit) {
				continue;
			}
			if ($key === 'core_link') {
				if (self::hasCoreToken($d)) {
					return 'core_link';
				}
				continue; // non-core link-down -> interface_down
			}
			return $key;
		}
		return 'other';
	}

	private static function hasCoreToken(string $d): bool {
		foreach ((self::CLASSES['core_link']['core'] ?? []) as $t) {
			if (strpos($d, $t) !== false) {
				return true;
			}
		}
		return false;
	}

	public static function templateHostid(): ?string {
		try {
			$res = API::Template()->get([
				'output' => ['templateid', 'host'],
				'filter' => ['host' => self::TEMPLATE_NAME],
				'limit'  => 1
			]);
			if ($res) {
				return (string) $res[0]['templateid'];
			}
			$res = API::Host()->get([
				'output' => ['hostid', 'host'],
				'filter' => ['host' => self::TEMPLATE_NAME],
				'limit'  => 1
			]);
			return $res ? (string) $res[0]['hostid'] : null;
		}
		catch (\Throwable $e) {
			return null;
		}
	}

	public static function severityMaskFromMin(int $min): int {
		$mask = 0;
		for ($i = max(1, $min); $i <= 6; $i++) {
			$mask |= (1 << ($i - 1));
		}
		return $mask;
	}

	public static function currentStrategy(): string {
		$v = self::getGlobalMacro(self::STRATEGY_MACRO);
		return $v === null ? '' : (string) $v;
	}

	public static function saveStrategyKey(string $key): void {
		self::setGlobalMacro(self::STRATEGY_MACRO, $key);
	}

	private static function sqlEsc(string $s): string {
		return str_replace(["\\", "'"], ["\\\\", "''"], $s);
	}

	private static function classCondSql(string $key): string {
		$def = self::CLASSES[$key] ?? null;
		if (!$def || empty($def['kw'])) {
			return '1=0';
		}
		$parts = [];
		foreach ($def['kw'] as $k) {
			$parts[] = "LOCATE('".self::sqlEsc($k)."', LOWER(t.description)) > 0";
		}
		$cond = '('.implode(' OR ', $parts).')';
		if ($key === 'core_link') {
			$cp = [];
			foreach (($def['core'] ?? []) as $t) {
				$cp[] = "LOCATE('".self::sqlEsc($t)."', LOWER(t.description)) > 0";
			}
			$cond .= ' AND ('.implode(' OR ', $cp).')';
		}
		elseif ($key === 'interface_down') {
			$cp = [];
			foreach ((self::CLASSES['core_link']['core'] ?? []) as $t) {
				$cp[] = "LOCATE('".self::sqlEsc($t)."', LOWER(t.description)) > 0";
			}
			$cond .= ' AND NOT ('.implode(' OR ', $cp).')';
		}
		return $cond;
	}

	private static function scopeSql(string $tid): string {
		return 'EXISTS (SELECT 1 FROM functions f JOIN items i ON i.itemid=f.itemid '
			.'JOIN hosts_templates ht ON ht.hostid=i.hostid '
			.'WHERE f.triggerid=t.triggerid AND ht.templateid='.(int) $tid.')';
	}

	/** Dry-run: per-class {count, changes, target} over hosted (discovered) triggers. */
	public static function previewStrategy(string $tid, array $targets): array {
		$out = ['total' => 0, 'changes' => 0, 'classes' => []];
		$scope = self::scopeSql($tid);
		foreach ($targets as $key => $target) {
			if ($key === 'other') {
				continue;
			}
			$cond = self::classCondSql($key);
			$row = DBfetch(DBselect(
				'SELECT COUNT(*) AS c, SUM(CASE WHEN t.priority<>'.(int) $target.' THEN 1 ELSE 0 END) AS ch '
				.'FROM triggers t WHERE t.flags=4 AND '.$scope.' AND '.$cond
			));
			$c = $row ? (int) $row['c'] : 0;
			$ch = $row ? (int) $row['ch'] : 0;
			$out['classes'][$key] = ['count' => $c, 'changes' => $ch, 'target' => (int) $target];
			$out['total'] += $c;
			$out['changes'] += $ch;
		}
		return $out;
	}

	/**
	 * Apply a strategy:
	 *  - template triggers  -> API trigger.update (instant propagation)
	 *  - trigger prototypes -> API triggerprototype.update (future re-discovery)
	 *  - discovered triggers -> SQL priority update (takes effect immediately)
	 */
	public static function applyStrategy(string $tid, array $targets): array {
		$res = ['trigger' => 0, 'prototype' => 0, 'discovered' => 0];

		$trs = API::Trigger()->get(['hostids' => $tid, 'output' => ['triggerid', 'description', 'priority']]);
		foreach ($trs as $t) {
			$c = self::classifyRaw((string) $t['description']);
			if (!isset($targets[$c]) || $c === 'other') {
				continue;
			}
			$tg = (int) $targets[$c];
			if ((int) $t['priority'] !== $tg) {
				API::Trigger()->update(['triggerid' => $t['triggerid'], 'priority' => $tg]);
				$res['trigger']++;
			}
		}

		$prs = API::TriggerPrototype()->get(['hostids' => $tid, 'output' => ['triggerid', 'description', 'priority']]);
		foreach ($prs as $p) {
			$c = self::classifyRaw((string) $p['description']);
			if (!isset($targets[$c]) || $c === 'other') {
				continue;
			}
			$tg = (int) $targets[$c];
			if ((int) $p['priority'] !== $tg) {
				API::TriggerPrototype()->update(['triggerid' => $p['triggerid'], 'priority' => $tg]);
				$res['prototype']++;
			}
		}

		// Discovered triggers: low priority classes first so higher priority wins on overlap.
		$order = ['perf', 'interface_down', 'core_link', 'restarted', 'hw_fault', 'device_down'];
		$scope = self::scopeSql($tid);
		foreach ($order as $key) {
			if (!isset($targets[$key])) {
				continue;
			}
			$tg = (int) $targets[$key];
			$cond = self::classCondSql($key);
			$cnt = DBfetch(DBselect(
				'SELECT COUNT(*) AS c FROM triggers t WHERE t.flags=4 AND '.$scope
				.' AND '.$cond.' AND t.priority<>'.$tg
			));
			$n = $cnt ? (int) $cnt['c'] : 0;
			if ($n > 0) {
				$ok = DBexecute('UPDATE triggers AS t SET t.priority='.$tg
					.' WHERE t.flags=4 AND '.$scope.' AND '.$cond.' AND t.priority<>'.$tg);
				if ($ok === false) {
					throw new Exception('DB update failed for class '.$key);
				}
				$res['discovered'] += $n;
			}
		}
		return $res;
	}

	/* ================================================================== */
	/*  SERVER TUNING GENERATOR (Zabbix server process / cache settings)  */
	/*  Produces a copy-paste env block + restart command. Nothing is     */
	/*  written here - the operator applies it on the host (zero risk).   */
	/* ================================================================== */

	public const TUNING_PROFILES = [
		'small' => [
			'StartSNMPPollers' => 10, 'StartPollers' => 10, 'StartLLDWorkers' => 5,
			'StartPreprocessors' => 3, 'CacheSize' => '256M', 'ValueCacheSize' => '64M',
			'HistoryCacheSize' => '32M', 'HistoryIndexCacheSize' => '8M', 'TrendCacheSize' => '32M'
		],
		'medium' => [
			'StartSNMPPollers' => 30, 'StartPollers' => 20, 'StartLLDWorkers' => 10,
			'StartPreprocessors' => 5, 'CacheSize' => '512M', 'ValueCacheSize' => '128M',
			'HistoryCacheSize' => '64M', 'HistoryIndexCacheSize' => '16M', 'TrendCacheSize' => '64M'
		],
		'large' => [
			'StartSNMPPollers' => 60, 'StartPollers' => 40, 'StartLLDWorkers' => 20,
			'StartPreprocessors' => 10, 'CacheSize' => '1G', 'ValueCacheSize' => '256M',
			'HistoryCacheSize' => '128M', 'HistoryIndexCacheSize' => '32M', 'TrendCacheSize' => '128M'
		]
	];

	/**
	 * Build a compose .env / environment snippet for the chosen profile, plus
	 * the command to recreate the server container.
	 * @return array{env:string, cmd:string}
	 */
	public static function tuningSnippet(string $profile): array {
		$vals = self::TUNING_PROFILES[$profile] ?? self::TUNING_PROFILES['medium'];
		$lines = [];
		foreach ($vals as $k => $v) {
			$lines[] = 'ZBX_'.$k.'='.$v;
		}
		$env = implode("\n", $lines);
		$cmd = "# paste the ZBX_* lines into /opt/zabbix/.env (or docker-compose environment)\n"
			."cd /opt/zabbix && docker compose up -d zabbix-server";
		return ['env' => $env, 'cmd' => $cmd];
	}

	/* ================================================================== */
	/*  TEMPLATE SWITCH / MIGRATION (old template -> new template)        */
	/* ================================================================== */

	/** Huawei-related templates available on this server (source/target candidates). */
	public static function huaweiTemplates(): array {
		try {
			$res = API::Template()->get([
				'output'    => ['templateid', 'host', 'name'],
				'search'    => ['host' => 'Huawei'],
				'sortfield' => 'host'
			]);
			return $res ?: [];
		}
		catch (\Throwable $e) {
			return [];
		}
	}

	/** Hosts currently linked to the given template. */
	public static function hostsOnTemplate(string $tid): array {
		$res = API::Host()->get([
			'output'                => ['hostid', 'host', 'name'],
			'templateids'           => [$tid],
			'selectParentTemplates' => ['templateid'],
			'sortfield'             => 'name'
		]);
		return $res ?: [];
	}

	public static function templateNames(array $ids): array {
		$out = [];
		if (!$ids) {
			return $out;
		}
		$res = API::Template()->get(['output' => ['templateid', 'host'], 'templateids' => $ids]);
		foreach ($res as $t) {
			$out[$t['templateid']] = $t['host'];
		}
		return $out;
	}

	/** Dry-run: which hosts would move from $src to $dst. */
	public static function switchPreview(string $src, string $dst): array {
		$hosts = self::hostsOnTemplate($src);
		$names = [];
		foreach ($hosts as $h) {
			$names[] = ($h['name'] !== '') ? $h['name'] : $h['host'];
		}
		$tn = self::templateNames([$src, $dst]);
		return [
			'src'      => $src,
			'dst'      => $dst,
			'src_name' => $tn[$src] ?? $src,
			'dst_name' => $tn[$dst] ?? $dst,
			'count'    => count($hosts),
			'hosts'    => array_slice($names, 0, 300)
		];
	}

	/** Replace the source template link with the target for every host on source. */
	public static function switchApply(string $src, string $dst): int {
		if ($src === $dst) {
			throw new Exception('Source and target template are the same.');
		}
		$hosts = self::hostsOnTemplate($src);
		$n = 0;
		foreach ($hosts as $h) {
			$new = [];
			$has_dst = false;
			foreach (($h['parentTemplates'] ?? []) as $pt) {
				if ((string) $pt['templateid'] === $src) {
					continue;
				}
				if ((string) $pt['templateid'] === $dst) {
					$has_dst = true;
				}
				$new[] = ['templateid' => $pt['templateid']];
			}
			if (!$has_dst) {
				$new[] = ['templateid' => $dst];
			}
			API::Host()->update(['hostid' => $h['hostid'], 'templates' => $new]);
			$n++;
		}
		return $n;
	}
}