<?php

declare(strict_types=1);

class SearchLogParser
{
    private string $logDir;
    private string $vhostBase;
    private string $cacheFile;
    private int    $cacheTtl;

    public function __construct(
        string $logDir    = '/var/log/apache2',
        string $vhostBase = '*-access.log',
        string $cacheFile = '',
        int    $cacheTtl  = 600
    ) {
        $this->logDir    = rtrim($logDir, '/');
        $this->vhostBase = $vhostBase;
        $this->cacheFile = $cacheFile !== ''
            ? $cacheFile
            : dirname(__DIR__) . '/_cache/search_terms.json';
        $this->cacheTtl  = $cacheTtl;
    }

    /** @return array<string,int> terme => nombre d'occurrences, trié desc */
    public function topTerms(int $limit = 100): array
    {
        if ($this->cacheValid()) {
            $data = json_decode((string) file_get_contents($this->cacheFile), true);
            if (is_array($data)) {
                return array_slice($data, 0, $limit, true);
            }
        }

        $counts = [];
        foreach ($this->logFiles() as $file) {
            $this->parseFile($file, $counts);
        }
        arsort($counts);

        @mkdir(dirname($this->cacheFile), 0755, true);
        file_put_contents($this->cacheFile, json_encode($counts, JSON_UNESCAPED_UNICODE));

        return array_slice($counts, 0, $limit, true);
    }

    public function isReadable(): bool
    {
        return count($this->logFiles()) > 0;
    }

    private function cacheValid(): bool
    {
        return file_exists($this->cacheFile)
            && (time() - filemtime($this->cacheFile)) < $this->cacheTtl;
    }

    /** @return list<array{path:string,type:string}> type: plain|gz|tgz */
    private function logFiles(): array
    {
        $pattern = $this->logDir . '/' . $this->vhostBase;
        $files   = [];

        // Fichiers correspondant au pattern de base (courants + rotations incluses si glob)
        $bases = glob($pattern) ?: [];
        // Ajouter aussi les rotations (.N, .N.gz, .N.tar.gz) pour chaque base trouvée
        foreach ($bases as $base) {
            // Exclure les rotations déjà capturées par le pattern glob
            if (str_ends_with($base, '.gz') || preg_match('/\.\d+$/', $base)) {
                continue;
            }
            $candidates = array_merge([$base], glob($base . '.*') ?: []);
            foreach ($candidates as $path) {
                if (!is_readable($path)) {
                    continue;
                }
                if (str_ends_with($path, '.tar.gz')) {
                    $files[] = ['path' => $path, 'type' => 'tgz'];
                } elseif (str_ends_with($path, '.gz')) {
                    $files[] = ['path' => $path, 'type' => 'gz'];
                } else {
                    $files[] = ['path' => $path, 'type' => 'plain'];
                }
            }
        }

        return $files;
    }

    private function parseFile(array $file, array &$counts): void
    {
        if ($file['type'] === 'tgz') {
            try {
                $phar = new PharData($file['path']);
                foreach ($phar as $entry) {
                    $content = @file_get_contents('phar://' . $file['path'] . '/' . $entry->getFilename());
                    if ($content === false) {
                        continue;
                    }
                    foreach (explode("\n", $content) as $line) {
                        $this->parseLine($line, $counts);
                    }
                }
            } catch (\Exception $e) {
                // archive illisible, on ignore
            }
        } elseif ($file['type'] === 'gz') {
            $h = @gzopen($file['path'], 'rb');
            if (!$h) {
                return;
            }
            while (!gzeof($h)) {
                $line = gzgets($h, 8192);
                if ($line !== false) {
                    $this->parseLine($line, $counts);
                }
            }
            gzclose($h);
        } else {
            $h = @fopen($file['path'], 'rb');
            if (!$h) {
                return;
            }
            while (($line = fgets($h)) !== false) {
                $this->parseLine($line, $counts);
            }
            fclose($h);
        }
    }

    private function parseLine(string $line, array &$counts): void
    {
        if (!str_contains($line, 'GET /search?')) {
            return;
        }
        if (!preg_match('/"GET \/search\?([^"]*) HTTP\//', $line, $m)) {
            return;
        }

        parse_str($m[1], $params);
        $q = trim(urldecode($params['q'] ?? ''));

        if ($q === '' || mb_strlen($q) > 200) {
            return;
        }
        $q = mb_strtolower($q);
        $counts[$q] = ($counts[$q] ?? 0) + 1;
    }
}