#!/usr/bin/env php
<?php
/**
 * Alert Engine - PHP Version
 * Copyright (C) 2026 Cédric Abonnel
 * License: GNU Affero General Public License v3
 */

require_once __DIR__ . '/../lib/monitoring-lib.php';

// --- Initialisation de la configuration spécifique ---
// On charge les fichiers de conf s'ils existent (format PHP attendu)
foreach (["/opt/monitoring/conf/alert-engine.conf.php", "/opt/monitoring/conf/alert-engine.conf.local.php"] as $conf) {
    if (file_exists($conf)) {
        $extra_conf = include $conf;
        if (is_array($extra_conf)) {
            $CONFIG = array_replace_recursive($CONFIG, $extra_conf);
        }
    }
}

// Chemins des fichiers
$LOG_SOURCE = $CONFIG['LOG_FILE'] ?? '/var/log/monitoring/events.jsonl';
$STATE_FILE = $CONFIG['ALERT_STATE_FILE'] ?? '/var/lib/monitoring/alert-engine.offset';
$DEDUP_FILE = $CONFIG['ALERT_DEDUP_FILE'] ?? '/var/lib/monitoring/alert-engine.dedup';
$DEDUP_WINDOW = $CONFIG['ALERT_DEDUP_WINDOW'] ?? 3600;

// Création des répertoires si nécessaire
ensure_parent_dir($STATE_FILE);
ensure_parent_dir($DEDUP_FILE);

/**
 * Nettoyage du fichier de déduplication (entrées expirées)
 */
function cleanup_dedup_file() {
    global $DEDUP_FILE, $DEDUP_WINDOW;
    if (!file_exists($DEDUP_FILE)) return;

    $now = time();
    $lines = file($DEDUP_FILE, FILE_IGNORE_NEW_LINES | FILE_SKIP_EMPTY_LINES);
    $kept = [];

    foreach ($lines as $line) {
        $parts = explode('|', $line);
        if (count($parts) >= 2 && ($now - (int)$parts[1]) <= $DEDUP_WINDOW) {
            $kept[] = $line;
        }
    }
    file_put_contents($DEDUP_FILE, implode("\n", $kept) . (empty($kept) ? "" : "\n"));
}

/**
 * Vérifie si une alerte doit être envoyée (Déduplication)
 */
function should_notify_dedup($key) {
    global $DEDUP_FILE, $DEDUP_WINDOW;
    if (!file_exists($DEDUP_FILE)) return true;

    $now = time();
    $last_ts = 0;
    
    $handle = fopen($DEDUP_FILE, 'r');
    while (($line = fgets($handle)) !== false) {
        $p = explode('|', trim($line));
        if (count($p) >= 5) {
            $current_key = "{$p[0]}|{$p[2]}|{$p[3]}|{$p[4]}";
            if ($current_key === $key) {
                $last_ts = (int)$p[1];
            }
        }
    }
    fclose($handle);

    return ($now - $last_ts) >= $DEDUP_WINDOW;
}

/**
 * Envoi vers ntfy
 */
function send_ntfy($title, $body, $level) {
    global $CONFIG;
    if (!($CONFIG['ALERT_NTFY_ENABLED'] ?? true)) return true;
    if (empty($CONFIG['NTFY_SERVER']) || empty($CONFIG['NTFY_TOPIC'])) return false;

    $priority = ['CRITICAL' => 'urgent', 'ERROR' => 'high', 'WARNING' => 'default'][$level] ?? 'default';
    $tags = ($CONFIG['NTFY_TAGS'][$level]) ?? 'warning';
    
    $url = rtrim($CONFIG['NTFY_SERVER'], '/') . '/' . $CONFIG['NTFY_TOPIC'];
    $headers = ["Title: $title", "Priority: $priority", "Tags: $tags"];
    
    if (!empty($CONFIG['NTFY_TOKEN'])) {
        $headers[] = "Authorization: Bearer " . $CONFIG['NTFY_TOKEN'];
    }

    $ch = curl_init($url);
    curl_setopt($ch, CURLOPT_POST, 1);
    curl_setopt($ch, CURLOPT_POSTFIELDS, $body);
    curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
    curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, 5);
    curl_exec($ch);
    $status = curl_getinfo($ch, CURLINFO_HTTP_CODE);
    curl_close($ch);

    return ($status >= 200 && $status < 300);
}

/**
 * Envoi par mail
 */
function send_mail($subject, $body) {
    global $CONFIG;
    if (!($CONFIG['ALERT_MAIL_ENABLED'] ?? true)) return true;
    if (empty($CONFIG['DEST'])) return false;

    $prefix = $CONFIG['ALERT_MAIL_SUBJECT_PREFIX'] ?? '[monitoring]';
    $headers = "From: monitoring@" . gethostname() . "\r\n" . "Content-Type: text/plain; charset=UTF-8";
    
    return mail($CONFIG['DEST'], "$prefix $subject", $body, $headers);
}

/**
 * Traitement d'une ligne de log
 */
function process_line($line) {
    global $CONFIG, $DEDUP_FILE;
    $data = json_decode($line, true);
    if (!$data || !isset($data['level'], $data['event'])) return;

    $level = strtoupper($data['level']);
    $event = $data['event'];

    if (in_array($level, ['DEBUG', 'INFO', 'NOTICE'])) return;
    if (in_array($event, ($CONFIG['ALERT_IGNORE_EVENTS'] ?? []))) return;

    // Déduplication
    $key = "{$data['host']}|{$data['app']}|{$level}|{$event}";
    if (!should_notify_dedup($key)) {
        log_debug("alert_suppressed_dedup", "Alerte dédupliquée", ["event=$event", "host={$data['host']}"]);
        return;
    }

    // Détermination des canaux (Règle spécifique puis défaut)
    $channels_str = $CONFIG['RULES'][$event] ?? $CONFIG['DEFAULT_CHANNELS'][$level] ?? '';
    if (empty($channels_str)) return;
    $channels = explode(',', $channels_str);

    $title = "{$data['host']} [{$data['app']}] $level $event";
    $body = sprintf(
        "Date: %s\nHôte: %s\nScript: %s\nNiveau: %s\nÉvénement: %s\n\nMessage:\n%s",
        $data['ts'] ?? 'N/A', $data['host'], $data['app'], $level, $event, $data['message'] ?? ''
    );

    foreach ($channels as $ch) {
        $ch = trim($ch);
        $success = false;
        if ($ch === 'ntfy') {
            $success = send_ntfy($title, $body, $level);
            $success ? log_info("alert_sent_ntfy", "Notification ntfy envoyée", ["event=$event"]) 
                    : log_error("alert_ntfy_failed", "Échec ntfy", ["event=$event"]);
        } elseif ($ch === 'mail') {
            $success = send_mail($title, $body);
            $success ? log_info("alert_sent_mail", "Mail envoyé", ["event=$event"]) 
                    : log_error("alert_mail_failed", "Échec mail", ["event=$event"]);
        }
    }

    // Enregistrement déduplication
    $entry = sprintf("%s|%s|%s|%s|%s\n", $data['host'], time(), $data['app'], $level, $event);
    file_put_contents($DEDUP_FILE, $entry, FILE_APPEND);
}

// --- Main ---

lock_or_exit("alert-engine");

if (!file_exists($LOG_SOURCE)) {
    log_notice("alert_log_missing", "Fichier de log absent", ["file=$LOG_SOURCE"]);
    exit(0);
}

$last_offset = file_exists($STATE_FILE) ? (int)file_get_contents($STATE_FILE) : 0;
$current_size = filesize($LOG_SOURCE);

// Gestion de la rotation de log
if ($last_offset > $current_size) {
    log_notice("alert_offset_reset", "Rotation détectée", ["old=$last_offset", "new=0"]);
    $last_offset = 0;
}

cleanup_dedup_file();

$fp = fopen($LOG_SOURCE, 'r');
if ($last_offset > 0) fseek($fp, $last_offset);

while (($line = fgets($fp)) !== false) {
    if (trim($line) !== '') {
        process_line($line);
    }
}
fclose($fp);

file_put_contents($STATE_FILE, $current_size);
exit_with_status();