<?php

namespace Controllers;

use Libs\ExecLib;
use Libs\ResponseLib;
use Psr\Http\Message\ServerRequestInterface;
use function React\Async\await;

class MailSendController
{
    public function __invoke(ServerRequestInterface $request)
    {
        $body = json_decode((string) $request->getBody(), true);
        if (!is_array($body)) {
            return ResponseLib::sendFail('Invalid JSON body', [], 'E_VALIDATE')->withStatus(400);
        }

        $templateName = trim((string)($body['mail_template'] ?? ''));
        $config       = $body['mail_config'] ?? null;
        if ($templateName === '' || !is_array($config)) {
            return ResponseLib::sendFail('Missing mail_template or mail_config', [], 'E_VALIDATE')->withStatus(400);
        }

        // Required fields for sending
        $toEmail = trim((string)($config['to_email'] ?? ''));
        $toName  = trim((string)($config['to_name']  ?? ''));
        $subject = trim((string)($config['subject']  ?? ''));
        if ($toEmail === '' || $subject === '') {
            return ResponseLib::sendFail('Missing to_email or subject', [], 'E_VALIDATE')->withStatus(400);
        }

        $fromEmail = trim((string)($_ENV['MAIL_FROM'] ?? 'no-reply@example.com'));
        $fromName  = trim((string)($_ENV['MAIL_FROM_NAME'] ?? 'No Reply'));

        // Load template file from templates/{name}.tpl
        $tplPath = dirname(__DIR__) . DIRECTORY_SEPARATOR . 'templates' . DIRECTORY_SEPARATOR . $templateName . '.tpl';
        if (!is_file($tplPath)) {
            return ResponseLib::sendFail('Template not found', ['template' => $templateName], 'E_NOT_FOUND')->withStatus(404);
        }
        $tpl = file_get_contents($tplPath);
        if ($tpl === false) {
            return ResponseLib::sendFail('Failed to load template', ['template' => $templateName], 'E_IO')->withStatus(500);
        }

        // Simple placeholder substitution: {{key}}
        $replacements = [];
        foreach ($config as $k => $v) {
            if (is_scalar($v)) {
                $replacements['{{' . $k . '}}'] = (string)$v;
            }
        }
        $bodyText = strtr($tpl, $replacements);

        // Build RFC 5322 message
        $headers = [];
        $headers[] = sprintf('From: %s <%s>', $fromName !== '' ? $fromName : $fromEmail, $fromEmail);
        $headers[] = sprintf('To: %s <%s>', $toName !== '' ? $toName : $toEmail, $toEmail);
        $headers[] = sprintf('Subject: %s', $subject);
        $headers[] = 'MIME-Version: 1.0';
        $headers[] = 'Content-Type: text/plain; charset=UTF-8';
        $headers[] = 'Content-Transfer-Encoding: 8bit';

        $message = implode("\r\n", $headers) . "\r\n\r\n" . $bodyText . "\r\n";

        // Write to temp file
        $tmpFile = tempnam(sys_get_temp_dir(), 'mail_');
        if ($tmpFile === false) {
            return ResponseLib::sendFail('Failed to create temp file', [], 'E_IO')->withStatus(500);
        }
        file_put_contents($tmpFile, $message);

        // Execute sendmail (postfix)
        $sendmail = $_ENV['SENDMAIL_PATH'] ?? '/usr/sbin/sendmail';
        $cmd = sprintf("%s -t -i < %s", escapeshellcmd($sendmail), escapeshellarg($tmpFile));

        try {
            [$code, $output] = await(ExecLib::exec($cmd, (float)($_ENV['SENDMAIL_TIMEOUT'] ?? 10)));
        } catch (\Throwable $e) {
            @unlink($tmpFile);
            return ResponseLib::sendFail('Sendmail failed', ['error' => $e->getMessage()], 'E_SENDMAIL')->withStatus(500);
        } finally {
            @unlink($tmpFile);
        }

        if ($code !== 0) {
            return ResponseLib::sendFail('Sendmail exited with non-zero', ['code' => $code, 'output' => $output], 'E_SENDMAIL')->withStatus(500);
        }

        return ResponseLib::sendOk([
            'status' => 'sent',
            'to' => $toEmail,
            'template' => $templateName,
            'code' => $code,
        ]);
    }
}