<?php

namespace App\Services\Hosting;

use Illuminate\Support\Facades\File;
use Illuminate\Support\Facades\URL;
use Phar;
use PharData;
use RuntimeException;

class ServerAgentReleaseService
{
    public function currentVersion(): string
    {
        return (string) config('hosting.server_agent.release_version', '0.2.0');
    }

    /**
     * @return array{version: string, archive_path: string, checksum_sha256: string, filename: string}
     */
    public function ensureRelease(?string $version = null): array
    {
        $version ??= $this->currentVersion();
        $releaseDirectory = storage_path('app/server-agent/releases/'.$version);
        $packageDirectory = $releaseDirectory.'/package';
        $archiveFilename = "ladill-server-agent-{$version}.tar.gz";
        $archivePath = $releaseDirectory.'/'.$archiveFilename;
        $tarPath = $releaseDirectory."/ladill-server-agent-{$version}.tar";

        File::ensureDirectoryExists($packageDirectory);
        File::ensureDirectoryExists($releaseDirectory);

        $renderedFiles = [
            'install.sh' => $this->renderInstallScript(),
            'ladill-server-agent' => $this->renderAgentScript($version),
            'ladill-server-agent.service' => $this->renderTemplate(resource_path('server-agent/ladill-server-agent.service.tpl')),
            'manifest.json' => json_encode([
                'name' => 'ladill-server-agent',
                'version' => $version,
                'built_at' => now()->toIso8601String(),
            ], JSON_PRETTY_PRINT | JSON_UNESCAPED_SLASHES)."\n",
        ];

        foreach ($renderedFiles as $filename => $contents) {
            File::put($packageDirectory.'/'.$filename, $contents);
        }

        if (! File::exists($archivePath)) {
            if (File::exists($tarPath)) {
                File::delete($tarPath);
            }

            try {
                $phar = new PharData($tarPath);
                foreach (array_keys($renderedFiles) as $filename) {
                    $phar->addFile($packageDirectory.'/'.$filename, $filename);
                }
                $phar->compress(Phar::GZ);
                unset($phar);
            } catch (\Throwable $e) {
                throw new RuntimeException('Unable to build the server agent release archive.', previous: $e);
            } finally {
                if (File::exists($tarPath)) {
                    File::delete($tarPath);
                }
            }
        }

        if (! File::exists($archivePath)) {
            throw new RuntimeException('The server agent release archive was not created.');
        }

        return [
            'version' => $version,
            'archive_path' => $archivePath,
            'checksum_sha256' => hash_file('sha256', $archivePath),
            'filename' => $archiveFilename,
        ];
    }

    public function temporaryDownloadUrl(?string $version = null, ?\DateTimeInterface $expiresAt = null): string
    {
        $version ??= $this->currentVersion();
        $expiresAt ??= now()->addMinutes((int) config('hosting.server_agent.signed_release_ttl_minutes', 10080));

        return URL::temporarySignedRoute('server-agent.releases.download', $expiresAt, [
            'version' => $version,
        ]);
    }

    private function renderAgentScript(string $version): string
    {
        return str_replace(
            ['{{AGENT_VERSION}}', '{{HEARTBEAT_INTERVAL_SECONDS}}'],
            [
                $version,
                (string) config('hosting.server_agent.heartbeat_interval_seconds', 15),
            ],
            $this->renderTemplate(resource_path('server-agent/ladill-server-agent.sh.tpl'))
        );
    }

    private function renderInstallScript(): string
    {
        return $this->renderTemplate(resource_path('server-agent/install.sh.tpl'));
    }

    private function renderTemplate(string $path): string
    {
        $contents = @file_get_contents($path);
        if ($contents === false) {
            throw new RuntimeException("Unable to load server agent release template: {$path}");
        }

        return $contents;
    }
}