<?php declare(strict_types = 0);
/*
** L2 Topology - persistence & configuration layer.
**
** Two tables are auto-created (portable: works on any Zabbix DB the web user
** can write to; the compose init sidecar also creates them as root):
**
**   l2_topology_history : one compressed snapshot per collection, kept 7 days
**   l2_topology_config  : single row (id=1) holding every display/collection knob
**
** Snapshots are gzip-compressed MEDIUMBLOBs so a 5-minute cadence for a week
** stays around ~100-150 MB instead of >1 GB of raw JSON.
*/

namespace Modules\WecomCenter\Lib;

use DB;
use Throwable;

class L2Store {

	public const HISTORY_TABLE = 'l2_topology_history';
	public const CONFIG_TABLE  = 'l2_topology_config';
	public const CONFIG_ID     = 1;

	/** Full default configuration. Every key can be overridden from the UI. */
	public static function defaults(): array {
		return [
			// Display page ------------------------------------------------------
			'refresh_seconds'   => 300,          // auto-refresh of the live view
			'dark_default'      => false,        // start in dark mode
			'root_label'        => 'COBCO',      // outermost frame label
			// Collection --------------------------------------------------------
			'templates'         => ['Huawei VRP by SNMP (walk)'],
			'full_interval_min' => 5,            // full topology/port collection
			'alarm_interval_min'=> 1,            // alarm-only refresh
			'history_days'      => 7,
			// Link colours (bits per second bucket) -----------------------------
			'colors' => [
				'100'     => '#F39C12', // 100M  橙色
				'1000'    => '#2ECC71', // 1G    绿色
				'10000'   => '#3498DB', // 10G   蓝色
				'20000'   => '#9B59B6', // 20G+  紫色
				'unknown' => '#E74C3C', // 未知  红色
				'down'    => '#C0392B'  // 中断  红色
			],
			// Latency thresholds (ms) applied to switch nodes (host->switch ping)
			'latency_warn'      => 3.0,
			'latency_bad'       => 5.0,
			// Grouping rules: first matching rule wins, else "Other".
			// match = contains | regex ; label may contain $1..$9 backrefs.
			'group_rules' => [
				['match' => 'contains', 'pattern' => 'DataCenter', 'label' => 'DataCenter', 'big' => true],
				['match' => 'contains', 'pattern' => 'Core',       'label' => 'Core',       'big' => true],
				['match' => 'regex',    'pattern' => 'COBCO-(\\d{4}[A-Za-z]?)', 'label' => '$1', 'big' => false],
				['match' => 'regex',    'pattern' => '^(\\d{4}[A-Za-z]?)',      'label' => '$1', 'big' => false]
			],
			'other_label'       => 'Other'
		];
	}

	/** Create tables if absent. Safe to call on every request (idempotent). */
	public static function ensureSchema(): void {
		try {
			DB::execute(
				'CREATE TABLE IF NOT EXISTS '.self::HISTORY_TABLE.' ('.
				' id BIGINT UNSIGNED NOT NULL AUTO_INCREMENT,'.
				' ts BIGINT UNSIGNED NOT NULL,'.
				' captured_at DATETIME NOT NULL,'.
				' stats TEXT NOT NULL,'.
				' snapshot MEDIUMBLOB NOT NULL,'.
				' PRIMARY KEY (id),'.
				' KEY idx_l2_ts (ts)'.
				') ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin'
			);
			DB::execute(
				'CREATE TABLE IF NOT EXISTS '.self::CONFIG_TABLE.' ('.
				' id TINYINT UNSIGNED NOT NULL,'.
				' config LONGTEXT NOT NULL,'.
				' updated DATETIME NOT NULL,'.
				' PRIMARY KEY (id)'.
				') ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin'
			);
		}
		catch (Throwable $e) {
			// Table may already exist or the DB user may lack DDL rights; the
			// compose init sidecar / install doc handles that case. Never fail a page.
		}
	}

	public static function getConfig(): array {
		self::ensureSchema();
		$cfg = self::defaults();
		try {
			$rows = DB::select('SELECT config FROM '.self::CONFIG_TABLE.' WHERE id='.self::CONFIG_ID);
			if ($rows && isset($rows[0]['config'])) {
				$saved = json_decode((string) $rows[0]['config'], true);
				if (is_array($saved)) {
					$cfg = self::mergeDeep($cfg, $saved);
				}
			}
		}
		catch (Throwable $e) {
			// fall back to defaults
		}
		// Make sure the out-of-process collectors can always read the config
		// (write it once if the mirror file is still missing).
		$mirror = dirname(__DIR__).'/assets/l2topology/config.json';
		if (!is_file($mirror)) {
			self::writeMirror($cfg);
		}
		return $cfg;
	}

	public static function saveConfig(array $cfg): void {
		self::ensureSchema();
		$cfg = self::mergeDeep(self::defaults(), $cfg);
		$json = json_encode($cfg, JSON_UNESCAPED_UNICODE | JSON_UNESCAPED_SLASHES);
		try {
			DB::execute(
				'INSERT INTO '.self::CONFIG_TABLE.' (id, config, updated) VALUES ('.self::CONFIG_ID.', ?, UTC_TIMESTAMP())'.
				' ON DUPLICATE KEY UPDATE config=VALUES(config), updated=VALUES(updated)',
				[$json]
			);
		}
		catch (Throwable $e) {
		}
		self::writeMirror($cfg);
	}

	/** Mirror config to a JSON file so the out-of-process collectors can read it. */
	public static function writeMirror(array $cfg): void {
		$file = dirname(__DIR__).'/assets/l2topology/config.json';
		try {
			$tmp = $file.'.tmp';
			file_put_contents($tmp, json_encode($cfg, JSON_UNESCAPED_UNICODE | JSON_UNESCAPED_SLASHES));
			@chmod($tmp, 0644);
			@rename($tmp, $file);
		}
		catch (Throwable $e) {
		}
	}

	/** Newest-first list of stored snapshots (for the time selector). */
	public static function listHistory(int $limit = 500): array {
		$out = [];
		try {
			$rows = DB::select(
				'SELECT ts, captured_at, stats FROM '.self::HISTORY_TABLE.' ORDER BY ts DESC LIMIT '.max(1, $limit)
			);
			foreach ($rows as $r) {
				$out[] = [
					'ts'          => (int) $r['ts'],
					'captured_at' => (string) $r['captured_at'],
					'stats'       => json_decode((string) $r['stats'], true)
				];
			}
		}
		catch (Throwable $e) {
		}
		return $out;
	}

	/**
	 * Snapshot JSON at (or just before) $ts. When $ts is null the newest stored
	 * snapshot is used, falling back to the live snapshot.json file.
	 */
	public static function snapshotAt(?int $ts): array {
		$json = null;
		$used = $ts;
		try {
			if ($ts === null) {
				$rows = DB::select('SELECT ts, snapshot FROM '.self::HISTORY_TABLE.' ORDER BY ts DESC LIMIT 1');
			}
			else {
				$rows = DB::select(
					'SELECT ts, snapshot FROM '.self::HISTORY_TABLE.' WHERE ts<=? ORDER BY ts DESC LIMIT 1',
					[$ts]
				);
				if (!$rows) {
					$rows = DB::select('SELECT ts, snapshot FROM '.self::HISTORY_TABLE.' ORDER BY ts ASC LIMIT 1');
				}
			}
			if ($rows) {
				$blob = $rows[0]['snapshot'];
				$raw = @gzdecode($blob);
				if ($raw !== false && $raw !== '') {
					$json = $raw;
					$used = (int) $rows[0]['ts'];
				}
			}
		}
		catch (Throwable $e) {
		}
		if ($json === null) {
			$file = dirname(__DIR__).'/assets/l2topology/snapshot.json';
			if (is_readable($file)) {
				$raw = file_get_contents($file);
				if ($raw !== false && $raw !== '') {
					$json = $raw;
				}
			}
		}
		return ['json' => $json, 'ts' => $used];
	}

	private static function mergeDeep(array $base, array $over): array {
		foreach ($over as $k => $v) {
			if (is_array($v) && isset($base[$k]) && is_array($base[$k]) && self::isAssoc($base[$k])) {
				$base[$k] = self::mergeDeep($base[$k], $v);
			}
			else {
				$base[$k] = $v;
			}
		}
		return $base;
	}

	private static function isAssoc(array $a): bool {
		return array_keys($a) !== range(0, count($a) - 1);
	}
}