<?php
declare(strict_types=1);

namespace NeonBlog;

final class Stats
{
    private string $path;
    private Config $config;

    public function __construct(string $path, Config $config)
    {
        $this->path = $path;
        $this->config = $config;
    }

    public function record(string $routeType, string $slug, int $statusCode): void
    {
        if (!$this->config->get('stats.enabled', true) || PHP_SAPI === 'cli') {
            return;
        }
        if (($_SERVER['REQUEST_METHOD'] ?? 'GET') !== 'GET') {
            return;
        }

        $dir = dirname($this->path);
        if (!is_dir($dir)) {
            mkdir($dir, 0775, true);
        }

        $handle = fopen($this->path, 'ab');
        if (!$handle) {
            return;
        }

        flock($handle, LOCK_EX);
        clearstatcache(true, $this->path);
        if ((filesize($this->path) ?: 0) === 0) {
            fputcsv($handle, [
                'date',
                'time',
                'request_id',
                'ip_hash',
                'method',
                'path',
                'route_type',
                'slug',
                'query',
                'referrer',
                'user_agent',
                'status_code',
            ], ',', '"', '', "\n");
        }

        $query = parse_url((string) ($_SERVER['REQUEST_URI'] ?? ''), PHP_URL_QUERY) ?: '';
        fputcsv($handle, [
            date('Y-m-d'),
            date('H:i:s'),
            bin2hex(random_bytes(6)),
            $this->ipHash(),
            $_SERVER['REQUEST_METHOD'] ?? 'GET',
            parse_url((string) ($_SERVER['REQUEST_URI'] ?? '/'), PHP_URL_PATH) ?: '/',
            $routeType,
            $slug,
            $query,
            $_SERVER['HTTP_REFERER'] ?? '',
            substr((string) ($_SERVER['HTTP_USER_AGENT'] ?? ''), 0, 300),
            $statusCode,
        ], ',', '"', '', "\n");

        flock($handle, LOCK_UN);
        fclose($handle);
    }

    /** @return array<string, mixed> */
    public function summary(): array
    {
        if (!is_file($this->path)) {
            return [
                'visits' => 0,
                'routes' => [],
                'top_paths' => [],
            ];
        }

        $handle = fopen($this->path, 'rb');
        if (!$handle) {
            return ['visits' => 0, 'routes' => [], 'top_paths' => []];
        }

        $header = fgetcsv($handle, null, ',', '"', '') ?: [];
        $visits = 0;
        $routes = [];
        $paths = [];
        while (($row = fgetcsv($handle, null, ',', '"', '')) !== false) {
            if ($row === $header) {
                continue;
            }
            $record = array_combine($header, $row);
            if (!is_array($record)) {
                continue;
            }
            $visits++;
            $routes[$record['route_type']] = ($routes[$record['route_type']] ?? 0) + 1;
            $paths[$record['path']] = ($paths[$record['path']] ?? 0) + 1;
        }
        fclose($handle);
        arsort($routes);
        arsort($paths);

        return [
            'visits' => $visits,
            'routes' => $routes,
            'top_paths' => array_slice($paths, 0, 10, true),
        ];
    }

    private function ipHash(): string
    {
        $ip = (string) ($_SERVER['REMOTE_ADDR'] ?? 'cli');
        $salt = (string) $this->config->get('stats.hash_salt', 'change-me');

        return hash_hmac('sha256', $ip, $salt);
    }
}