<?php

declare(strict_types=1);

namespace Box\Mod\Mailgateway;

use FOSSBilling\InformationException;

class DependencyInstaller
{
    public function status(): array
    {
        return ['installed' => $this->installed(), 'available' => function_exists('proc_open')
            && $this->php() !== null && $this->composer() !== null && is_writable(__DIR__),
            'request_timeout_ms' => (RuntimeConfig::get('composer_timeout_seconds') + 30) * 1000];
    }

    public function install(bool $force = false): array
    {
        if (!$force && $this->installed()) {
            return ['installed' => true];
        }
        $php = $this->php();
        $composer = $this->composer();
        if (!function_exists('proc_open') || $php === null || $composer === null || !is_writable(__DIR__)) {
            throw new InformationException('Web installation is unavailable. Run composer install from the Mailgateway directory using SSH.');
        }
        if (!is_file(__DIR__ . '/composer.lock')) {
            throw new InformationException('The module composer.lock is missing. Restore it before installing dependencies.');
        }
        $command = [$php, $composer, 'install', '--no-dev', '--prefer-dist', '--no-interaction',
            '--no-progress', '--no-scripts', '--no-plugins', '--optimize-autoloader'];
        $result = $this->run($command);
        if ($result['timeout']) {
            throw new InformationException('Dependency installation exceeded its configured timeout. Run composer install from the Mailgateway directory using SSH.');
        }
        if ($result['exit'] !== 0 || !$this->installed()) {
            throw new InformationException('Composer installation failed. Run composer install from the Mailgateway directory using SSH to see the detailed error.');
        }
        return ['installed' => true];
    }

    private function installed(): bool
    {
        return is_file(__DIR__ . '/vendor/autoload.php')
            && is_file(__DIR__ . '/vendor/webklex/php-imap/src/ClientManager.php');
    }

    private function php(): ?string
    {
        foreach (RuntimeConfig::get('php_cli_paths') as $path) {
            if (is_file($path) && is_executable($path)) {
                return $path;
            }
        }
        return null;
    }

    private function composer(): ?string
    {
        foreach (RuntimeConfig::get('composer_paths') as $path) {
            if (is_file($path) && is_readable($path)) {
                return $path;
            }
        }
        return null;
    }

    protected function run(array $command): array
    {
        // PHP may terminate a web request before Composer completes otherwise.
        @set_time_limit(RuntimeConfig::get('composer_timeout_seconds') + 15);
        $process = proc_open($command, [['pipe', 'r'], ['pipe', 'w'], ['pipe', 'w']], $pipes, __DIR__);
        if (!is_resource($process)) {
            throw new InformationException('Composer could not be started. Run composer install using SSH.');
        }
        fclose($pipes[0]);
        stream_set_blocking($pipes[1], false);
        stream_set_blocking($pipes[2], false);
        $deadline = microtime(true) + RuntimeConfig::get('composer_timeout_seconds');
        $exit = -1;
        $timeout = false;
        try {
            while (true) {
                // Drain both pipes to avoid deadlock. Never expose Composer output:
                // repository authentication and environment details can appear there.
                stream_get_contents($pipes[1]);
                stream_get_contents($pipes[2]);
                $status = proc_get_status($process);
                if (!$status['running']) {
                    $exit = $status['exitcode'];
                    break;
                }
                if (microtime(true) >= $deadline) {
                    $timeout = true;
                    proc_terminate($process, 9);
                    break;
                }
                usleep(100000);
            }
        } finally {
            fclose($pipes[1]);
            fclose($pipes[2]);
            $closed = proc_close($process);
            if ($exit === -1) {
                $exit = $closed;
            }
        }
        return ['exit' => $exit, 'timeout' => $timeout];
    }
}