<?php
/**
 * Monitoring Library - PHP Version
 * Copyright (C) 2026 Cédric Abonnel
 * License: GNU Affero General Public License v3
 */

// --- Chemins et Constantes ---
$MONITORING_LIB_DIR  = __DIR__;
$MONITORING_BASE_DIR = dirname($MONITORING_LIB_DIR);
$MONITORING_CONF_DIR = $MONITORING_BASE_DIR . '/conf';

// États globaux
$STATUS_OK       = 0;
$STATUS_WARNING  = 1;
$STATUS_ERROR    = 2;
$STATUS_INTERNAL = 3;

$CURRENT_STATUS = $STATUS_OK;

// --- Chargement de la Config ---
$CONFIG = [
    'LOG_FILE'            => '/var/log/monitoring/events.jsonl',
    'MONITORING_LOCK_DIR' => '/var/lock/monitoring',
    'LOG_LEVEL'           => 'INFO'
];

if (file_exists($MONITORING_CONF_DIR . '/monitoring.conf.php')) {
    $global_conf = include $MONITORING_CONF_DIR . '/monitoring.conf.php';
    if (is_array($global_conf)) {
        $CONFIG = array_merge($CONFIG, $global_conf);
    }
}

// Variables d'exécution
$SCRIPT_NAME = basename($_SERVER['SCRIPT_FILENAME'] ?? $argv[0]);
$SCRIPT_PATH = realpath($_SERVER['SCRIPT_FILENAME'] ?? $argv[0]);

// --- Fonctions de Log ---

/**
 * Log un événement au format JSONL
 */
function log_event(string $level, string $event, string $message, array $extra_kv = []) {
    global $CONFIG, $SCRIPT_NAME;

    $ts = date('c'); // ISO-8601
    
    // Détection Hostname
    $host = getenv('HOSTNAME_FQDN') ?: (gethostname() ?: 'unknown');

    $log_data = [
        "ts"      => $ts,
        "host"    => $host,
        "app"     => $SCRIPT_NAME,
        "level"   => $level,
        "event"   => $event,
        "message" => $message
    ];

    // Fusion des paires clé=valeur supplémentaires
    foreach ($extra_kv as $kv) {
        if (strpos($kv, '=') !== false) {
            list($k, $v) = explode('=', $kv, 2);
            $log_data[$k] = $v;
        }
    }

    $json_line = json_encode($log_data, JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE);
    
    $log_file = $CONFIG['LOG_FILE'];
    ensure_parent_dir($log_file);
    
    file_put_contents($log_file, $json_line . "\n", FILE_APPEND | LOCK_EX);
}

function set_status(int $new_status) {
    global $CURRENT_STATUS;
    if ($new_status > $CURRENT_STATUS) {
        $CURRENT_STATUS = $new_status;
    }
}

// Helpers de logs
function log_debug($e, $m, $x = [])    { log_event("DEBUG", $e, $m, $x); }
function log_info($e, $m, $x = [])     { log_event("INFO", $e, $m, $x); }
function log_notice($e, $m, $x = [])   { log_event("NOTICE", $e, $m, $x); }
function log_warning($e, $m, $x = [])  { log_event("WARNING", $e, $m, $x); set_status(1); }
function log_error($e, $m, $x = [])    { log_event("ERROR", $e, $m, $x); set_status(2); }
function log_critical($e, $m, $x = []) { log_event("CRITICAL", $e, $m, $x); set_status(2); }

function fail_internal(string $msg) {
    log_event("ERROR", "internal_error", $msg);
    exit(3); // STATUS_INTERNAL
}

function exit_with_status() {
    global $CURRENT_STATUS;
    exit($CURRENT_STATUS);
}

// --- Utilitaires Système ---

/**
 * Vérifie la présence de commandes système
 */
function require_cmd(...$cmds) {
    foreach ($cmds as $cmd) {
        $output = [];
        $res = 0;
        exec("command -v " . escapeshellarg($cmd), $output, $res);
        if ($res !== 0) {
            fail_internal("Commande requise absente: $cmd");
        }
    }
}

/**
 * Gestion du verrouillage (Lock)
 */
function lock_or_exit(?string $lock_name = null) {
    global $CONFIG, $SCRIPT_NAME;
    $name = $lock_name ?: $SCRIPT_NAME;
    $lock_file = ($CONFIG['MONITORING_LOCK_DIR'] ?? '/var/lock/monitoring') . "/{$name}.lock";

    ensure_parent_dir($lock_file);
    $fp = fopen($lock_file, "w+");

    if (!$fp || !flock($fp, LOCK_EX | LOCK_NB)) {
        log_notice("already_running", "Une autre instance est déjà en cours", ["lock=$lock_file"]);
        exit(0);
    }
    // On garde le descripteur ouvert pour maintenir le lock
    return $fp; 
}

/**
 * Évalue un niveau selon des seuils
 */
function threshold_level($value, $warning, $critical) {
    if ($value >= $critical) return 'CRITICAL';
    if ($value >= $warning)  return 'WARNING';
    return 'INFO';
}

function ensure_parent_dir(string $file) {
    $dir = dirname($file);
    if (!is_dir($dir)) {
        if (!mkdir($dir, 0755, true)) {
            // Ici on ne peut pas appeler log_event si c'est le répertoire de log qui échoue
            error_log("Impossible de créer le répertoire : $dir");
            exit(3);
        }
    }
}

function safe_mv(string $src, string $dst) {
    if (!rename($src, $dst)) {
        fail_internal("Échec du déplacement de $src vers $dst");
    }
}