<?php

namespace App\Services\Ssl;

use App\Models\Domain;
use App\Models\HostedSite;
use Carbon\CarbonInterface;
use Illuminate\Support\Facades\Log;

class SslProvisioner
{
    public function __construct(
        private readonly SslCertificateExpiryParser $expiryParser = new SslCertificateExpiryParser(),
    ) {
    }

    public function isConfigured(): bool
    {
        $host = config('mailinfra.web_ssh_host');
        $keyPath = config('mailinfra.web_ssh_key_path');
        $email = config('mailinfra.ssl_email');

        return ! empty($host) && ! empty($keyPath) && ! empty($email);
    }

    public function provisionCertificate(Domain $domain): bool
    {
        $domainName = rtrim($domain->host, '.');
        $webroot = config('mailinfra.ssl_webroot');
        $email = config('mailinfra.ssl_email');

        $domains = escapeshellarg($domainName);
        $wwwDomain = 'www.' . $domainName;

        if ($this->domainResolvesToServer($wwwDomain)) {
            $domains .= ' -d ' . escapeshellarg($wwwDomain);
        } else {
            Log::info('SslProvisioner: www subdomain does not resolve, skipping', ['domain' => $wwwDomain]);
        }

        $commands = [
            sprintf(
                'certbot certonly --webroot -w %s -d %s --non-interactive --agree-tos -m %s',
                escapeshellarg($webroot),
                $domains,
                escapeshellarg($email)
            ),
        ];

        [$success, $output] = $this->sshExec($commands);

        if (! $success) {
            Log::error('SslProvisioner: certbot failed', [
                'domain' => $domainName,
                'output' => $output,
            ]);

            return false;
        }

        Log::info('SslProvisioner: certificate issued', ['domain' => $domainName]);

        return true;
    }

    /**
     * @return array{success: bool, output: string, exit_code: int}
     */
    public function renewCertificates(bool $force = false): array
    {
        $command = 'certbot renew --quiet --no-random-sleep-on-renew';
        if ($force) {
            $command .= ' --force-renewal';
        }

        [$success, $output, $exitCode] = $this->sshExecWithExitCode([$command]);

        if (! $success) {
            Log::warning('SslProvisioner: certbot renew completed with errors', [
                'output' => $output,
                'exit_code' => $exitCode,
            ]);
        } else {
            Log::info('SslProvisioner: certbot renew completed');
        }

        return [
            'success' => $success,
            'output' => $output,
            'exit_code' => $exitCode,
        ];
    }

    public function readCertificateExpiry(string $domainName): ?CarbonInterface
    {
        $domainName = rtrim($domainName, '.');
        $certPath = "/etc/letsencrypt/live/{$domainName}/fullchain.pem";
        $command = sprintf(
            'openssl x509 -in %s -noout -enddate 2>/dev/null',
            escapeshellarg($certPath)
        );

        [$success, $output] = $this->sshExec([$command]);

        if (! $success) {
            return null;
        }

        return $this->expiryParser->parseOpenSslEndDate($output);
    }

    private function domainResolvesToServer(string $hostname): bool
    {
        if (! function_exists('dns_get_record')) {
            return false;
        }

        $records = @dns_get_record($hostname, DNS_A);
        if (! is_array($records) || $records === []) {
            $cname = @dns_get_record($hostname, DNS_CNAME);

            return is_array($cname) && $cname !== [];
        }

        return true;
    }

    public function generateNginxConfig(Domain $domain): bool
    {
        $domainName = rtrim($domain->host, '.');
        $confDir = config('mailinfra.ssl_nginx_conf_dir', '/etc/nginx/sites-enabled');
        $confPath = "{$confDir}/{$domainName}.conf";

        // Check if this domain has a hosted site - use its document root instead of default
        $hostedSite = HostedSite::where('domain', $domainName)->first();
        if ($hostedSite) {
            $includeWww = $this->domainResolvesToServer('www.' . $domainName);
            $config = $this->buildHostedSiteNginxServerBlock($hostedSite, $includeWww);
        } else {
            $webroot = config('mailinfra.ssl_webroot');
            $includeWww = $this->domainResolvesToServer('www.' . $domainName);
            $config = $this->buildNginxServerBlock($domainName, $webroot, $includeWww);
        }

        $escapedConfig = str_replace("'", "'\\''", $config);

        $commands = [
            "echo '{$escapedConfig}' > {$confPath}",
        ];

        [$success, $output] = $this->sshExec($commands);

        if (! $success) {
            Log::error('SslProvisioner: Nginx config generation failed', [
                'domain' => $domainName,
                'output' => $output,
            ]);

            return false;
        }

        Log::info('SslProvisioner: Nginx config written', ['domain' => $domainName, 'path' => $confPath]);

        return true;
    }

    public function reloadNginx(): bool
    {
        [$success, $output] = $this->sshExec(['nginx -t && systemctl reload nginx']);

        if (! $success) {
            Log::error('SslProvisioner: Nginx reload failed', ['output' => $output]);

            return false;
        }

        return true;
    }

    private function buildNginxServerBlock(string $domainName, string $webroot, bool $includeWww = true): string
    {
        $certPath = "/etc/letsencrypt/live/{$domainName}/fullchain.pem";
        $keyPath = "/etc/letsencrypt/live/{$domainName}/privkey.pem";
        $serverNames = $includeWww ? "{$domainName} www.{$domainName}" : $domainName;

        return <<<NGINX
server {
    listen 443 ssl http2;
    listen [::]:443 ssl http2;
    server_name {$serverNames};

    ssl_certificate {$certPath};
    ssl_certificate_key {$keyPath};
    ssl_protocols TLSv1.2 TLSv1.3;
    ssl_ciphers HIGH:!aNULL:!MD5;

    root {$webroot};
    index index.php;

    charset utf-8;

    location / {
        try_files \$uri \$uri/ /index.php?\$query_string;
    }

    location = /favicon.ico { access_log off; log_not_found off; }
    location = /robots.txt  { access_log off; log_not_found off; }

    error_page 404 /index.php;

    location ~ \.php$ {
        fastcgi_pass unix:/run/php/php8.4-fpm.sock;
        fastcgi_param SCRIPT_FILENAME \$realpath_root\$fastcgi_script_name;
        include fastcgi_params;
    }

    location ~ /\.(?!well-known).* {
        deny all;
    }
}
NGINX;
    }

    private function buildHostedSiteNginxServerBlock(HostedSite $site, bool $includeWww = true): string
    {
        $domainName = $site->domain;
        $docRoot = $site->document_root;
        $username = $site->account?->username ?? 'www-data';
        $phpVersion = $site->php_version ?? '8.3';
        $certPath = "/etc/letsencrypt/live/{$domainName}/fullchain.pem";
        $keyPath = "/etc/letsencrypt/live/{$domainName}/privkey.pem";
        $serverNames = $includeWww ? "{$domainName} www.{$domainName}" : $domainName;

        return <<<NGINX
server {
    listen 443 ssl http2;
    listen [::]:443 ssl http2;
    server_name {$serverNames};

    ssl_certificate {$certPath};
    ssl_certificate_key {$keyPath};
    ssl_protocols TLSv1.2 TLSv1.3;
    ssl_ciphers HIGH:!aNULL:!MD5;

    root {$docRoot};
    index index.php index.html index.htm;

    charset utf-8;

    access_log /home/{$username}/logs/{$domainName}-access.log;
    error_log /home/{$username}/logs/{$domainName}-error.log;

    location / {
        try_files \$uri \$uri/ /index.php?\$args;
    }

    location = /favicon.ico { access_log off; log_not_found off; }
    location = /robots.txt  { access_log off; log_not_found off; }

    location ~ \.php\$ {
        fastcgi_pass unix:/run/php/php{$phpVersion}-fpm.sock;
        fastcgi_param SCRIPT_FILENAME \$document_root\$fastcgi_script_name;
        include fastcgi_params;
        fastcgi_read_timeout 300;
    }

    location ~ /\.(?!well-known).* {
        deny all;
    }

    location ~* \.(jpg|jpeg|png|gif|ico|css|js|woff|woff2|ttf|svg|eot)\$ {
        expires 30d;
        add_header Cache-Control "public, immutable";
    }

    # Security: prevent PHP execution in upload directories
    location ~* /(?:uploads|files|media)/.*\.php\$ {
        deny all;
    }

    client_max_body_size 64M;
}

server {
    listen 80;
    listen [::]:80;
    server_name {$serverNames};
    return 301 https://\$host\$request_uri;
}
NGINX;
    }

    /**
     * @return array{0: bool, 1: string}
     */
    private function sshExec(array $commands): array
    {
        [$success, $output] = $this->sshExecWithExitCode($commands);

        return [$success, $output];
    }

    /**
     * @return array{0: bool, 1: string, 2: int}
     */
    private function sshExecWithExitCode(array $commands): array
    {
        $sshHost = config('mailinfra.web_ssh_host');
        $sshUser = config('mailinfra.web_ssh_user', 'root');
        $sshKeyPath = config('mailinfra.web_ssh_key_path');

        if (empty($sshHost) || empty($sshKeyPath)) {
            return [false, 'SSH not configured', 1];
        }

        $sshBase = sprintf(
            'ssh -i %s -o StrictHostKeyChecking=no %s@%s',
            escapeshellarg($sshKeyPath),
            escapeshellarg($sshUser),
            escapeshellarg($sshHost)
        );

        $fullCommand = $sshBase . ' ' . escapeshellarg(implode(' && ', $commands));

        $output = [];
        $exitCode = 0;
        exec($fullCommand . ' 2>&1', $output, $exitCode);

        return [$exitCode === 0, implode("\n", $output), $exitCode];
    }
}