/**
 * RFC 5322 message builder for draft creation.
 *
 * Drafts go out as a single `text/html` part carrying the rendered `--body`
 * markdown. Gmail's composer adopts exactly one part of a draft as its editing
 * surface and discards the rest, so a message offering only HTML leaves it no
 * choice — the composer opens in rich text, our markup survives the human's
 * edits, and Gmail generates the `text/plain` alternative itself on send.
 *
 * Both alternatives were tried and rejected against live sends:
 *
 * - Single-part `text/plain` (the original bug) drops the composer into
 *   plain-text mode. On send Gmail hard-wraps at ~70 columns with real CRLFs
 *   and ships no HTML alternative, so recipients get ragged columns nothing
 *   can reflow — while the compose window still shows the original unwrapped
 *   paragraphs, hiding the damage until the message is gone.
 * - `multipart/alternative` (plain + HTML) fixes the wrapping but is a coin
 *   flip: two identically-built drafts behaved differently, one keeping our
 *   rendered markup and one adopting the plain part and delivering the raw
 *   markdown source to the reader — `**bold**` and `[text](url)` and all.
 *
 * See specs/commands/gmail-draft.md ("Message structure", "Body rendering").
 */
export interface ComposeFields {
    /** Sender — the authenticated account's address. */
    from: string;
    to: string[];
    cc?: string[];
    bcc?: string[];
    subject: string;
    /** Markdown source, rendered to the HTML body — unless `plain` is set. */
    body: string;
    /**
     * Treat `body` as literal text rather than markdown. Still sends a single
     * `text/html` part (reverting to `text/plain` is the original defect); the
     * HTML is built structurally instead of through the markdown renderer.
     */
    plain?: boolean;
}
/** Split a comma-separated recipient flag into trimmed, non-empty addresses. */
export declare function parseRecipients(value: string): string[];
/**
 * Render the body markdown to an HTML document.
 *
 * `breaks: true` is deliberate: email bodies carry meaningful single-line
 * breaks (signature blocks, addresses, value lists), and markdown's default of
 * collapsing them into spaces would silently reflow content the author laid
 * out. The flip side — a pre-wrapped body keeps its wrapping — is why
 * DRAFT_HELP tells callers not to hard-wrap.
 */
export declare function renderMarkdown(body: string): string;
/**
 * Render the body as literal text: no markdown, so `*`, `_`, `#` and friends
 * reach the reader exactly as written. Blank line starts a paragraph, a single
 * newline is a line break — the same block semantics as the markdown path, so
 * `--plain` changes how the body is interpreted, not how it is laid out.
 */
export declare function renderPlainText(body: string): string;
/**
 * Build a base64url-encoded RFC 5322 message suitable for
 * `users.drafts.create` / `users.messages.send` `raw` fields.
 */
export declare function buildRawMessage(fields: ComposeFields): string;