import {z} from 'zod';
const safeHeaderString = z.string().regex(/^[^\r\n]*$/, 'Must not contain newline characters');
export const attachmentSchema = z.object({
filename: safeHeaderString.transform((s) => s.replaceAll('"', '')).describe('Attachment filename'),
mimeType: safeHeaderString.describe('MIME type (e.g., application/pdf)'),
content: z.string().describe('Base64-encoded file data'),
});
export type Attachment = z.output<typeof attachmentSchema>;
/**
* Appends MIME multipart body with attachments to an array of RFC 2822 header lines.
* If no attachments, appends a plain text body.
*/
export function appendMimeBody(lines: string[], body: string, attachments?: Attachment[]): void {
if (attachments && attachments.length > 0) {
const boundary = `boundary_${Date.now()}_${Math.random().toString(36).substring(2)}`;
lines.push(`Content-Type: multipart/mixed; boundary="${boundary}"`);
lines.push('');
// Text body part
lines.push(`--${boundary}`);
lines.push('Content-Type: text/plain; charset=utf-8');
lines.push('');
lines.push(body);
lines.push('');
// Attachment parts
for (const attachment of attachments) {
lines.push(`--${boundary}`);
lines.push(`Content-Type: ${attachment.mimeType}`);
lines.push('Content-Transfer-Encoding: base64');
lines.push(`Content-Disposition: attachment; filename="${attachment.filename}"`);
lines.push('');
lines.push(attachment.content);
lines.push('');
}
lines.push(`--${boundary}--`);
} else {
lines.push('Content-Type: text/plain; charset=utf-8');
lines.push('');
lines.push(body);
}
}
