feat(mail): add SMTP mailer and order confirmation mail builder

src/Mail/OrderMailer.php

@@ -0,0 +1,71 @@
+<?php
+
+namespace Bazaar\Mail;
+
+final class OrderMailer
+{
+    public function __construct(
+        private readonly Mailer $mailer,
+        private readonly string $currency = 'usd',
+        private readonly string $appName = 'Bazaar'
+    ) {
+    }
+
+    public function orderConfirmation(string $recipient, array $order, array $items): void
+    {
+        $this->mailer->send(new Email(
+            $recipient,
+            sprintf('%s order #%d confirmed', $this->appName, (int) $order['id']),
+            $this->confirmationBody($order, $items)
+        ));
+    }
+
+    public function statusUpdate(string $recipient, array $order): void
+    {
+        $this->mailer->send(new Email(
+            $recipient,
+            sprintf('%s order #%d is now %s', $this->appName, (int) $order['id'], $order['status']),
+            $this->statusBody($order)
+        ));
+    }
+
+    private function confirmationBody(array $order, array $items): string
+    {
+        $lines = [
+            'Thank you for your order.',
+            '',
+            'Order #' . (int) $order['id'],
+            '',
+        ];
+        foreach ($items as $item) {
+            $label = $item['productName'];
+            if (($item['variantLabel'] ?? '') !== '') {
+                $label .= ' (' . $item['variantLabel'] . ')';
+            }
+            $lines[] = sprintf(
+                '  %d x %s - %s',
+                (int) $item['quantity'],
+                $label,
+                formatMoney((int) $item['unitPriceCents'] * (int) $item['quantity'], $order['currency'])
+            );
+        }
+        $lines[] = '';
+        if ((int) ($order['discountCents'] ?? 0) > 0) {
+            $lines[] = 'Discount (' . ($order['couponCode'] ?? '') . '): -'
+                . formatMoney((int) $order['discountCents'], $order['currency']);
+        }
+        $lines[] = 'Total: ' . formatMoney((int) $order['totalCents'], $order['currency']);
+
+        return implode("\n", $lines);
+    }
+
+    private function statusBody(array $order): string
+    {
+        return implode("\n", [
+            'Your order status has changed.',
+            '',
+            'Order #' . (int) $order['id'],
+            'New status: ' . $order['status'],
+        ]);
+    }
+}

src/Mail/SmtpMailer.php

@@ -0,0 +1,73 @@
+<?php
+
+namespace Bazaar\Mail;
+
+final class SmtpMailer implements Mailer
+{
+    private array $sent = [];
+
+    public function __construct(
+        private readonly string $host,
+        private readonly int $port = 587,
+        private readonly ?string $username = null,
+        private readonly ?string $password = null,
+        private readonly int $timeout = 10
+    ) {
+    }
+
+    public function send(Email $email): void
+    {
+        $socket = fsockopen($this->host, $this->port, $errno, $error, $this->timeout);
+        if ($socket === false) {
+            throw new \RuntimeException("SMTP connection failed: {$error} ({$errno})");
+        }
+
+        $this->expect($socket, 220);
+        $this->command($socket, 'EHLO bazaar', 250);
+
+        if ($this->username !== null && $this->password !== null) {
+            $this->command($socket, 'AUTH LOGIN', 334);
+            $this->command($socket, base64_encode($this->username), 334);
+            $this->command($socket, base64_encode($this->password), 235);
+        }
+
+        $this->command($socket, 'MAIL FROM:<' . $email->from . '>', 250);
+        $this->command($socket, 'RCPT TO:<' . $email->to . '>', 250);
+        $this->command($socket, 'DATA', 354);
+
+        $headers = implode("\r\n", [
+            'From: ' . $email->from,
+            'To: ' . $email->to,
+            'Subject: ' . $email->subject,
+            'MIME-Version: 1.0',
+            'Content-Type: text/plain; charset=UTF-8',
+        ]);
+        fwrite($socket, $headers . "\r\n\r\n" . $email->body . "\r\n.\r\n");
+        $this->expect($socket, 250);
+
+        $this->command($socket, 'QUIT', 221);
+        fclose($socket);
+
+        $this->sent[] = $email;
+    }
+
+    public function sent(): array
+    {
+        return $this->sent;
+    }
+
+    private function command($socket, string $line, int $expected): void
+    {
+        fwrite($socket, $line . "\r\n");
+        $this->expect($socket, $expected);
+    }
+
+    private function expect($socket, int $expected): void
+    {
+        $response = (string) fgets($socket, 512);
+        $code = (int) substr($response, 0, 3);
+        if ($code !== $expected) {
+            throw new \RuntimeException("SMTP expected {$expected}, got: " . trim($response));
+        }
+    }
+}