Create Draft

//native

/**

 * Create Draft

 * Save an unsent draft in the connected Gmail account. Set `is_html` to send `body` as HTML. To draft a reply, pass the original's `thread_id` and its `Message-ID` header as `in_reply_to` and keep the same subject.

 */

export async function main(

  auth: RT.Gmail,

  to: string,

  subject: string,

  body: string,

  cc: string | undefined,

  bcc: string | undefined,

  is_html: boolean = false,

  thread_id: string | undefined,

  in_reply_to: string | undefined

) {

  const headers = [

    `To: ${to}`,

    cc ? `Cc: ${cc}` : undefined,

    bcc ? `Bcc: ${bcc}` : undefined,

    `Subject: =?UTF-8?B?${base64(subject)}?=`,

    in_reply_to ? `In-Reply-To: ${in_reply_to}` : undefined,

    in_reply_to ? `References: ${in_reply_to}` : undefined,

    "MIME-Version: 1.0",

    `Content-Type: text/${is_html ? "html" : "plain"}; charset="UTF-8"`,

    "Content-Transfer-Encoding: base64",

  ].filter((h) => h !== undefined)

  const mime = `${headers.join("\r\n")}\r\n\r\n${base64(body)}`

  const raw = base64(mime).replace(/\+/g, "-").replace(/\//g, "_")

  const response = await fetch(

    "https://gmail.googleapis.com/gmail/v1/users/me/drafts",

    {

      method: "POST",

      headers: {

        Authorization: `Bearer ${auth.token}`,

        "Content-Type": "application/json",

        Accept: "application/json",

      },

      body: JSON.stringify({

        message: { raw, threadId: thread_id || undefined },

      }),

    }

  )

  if (!response.ok) {

    throw new Error(`${response.status} ${await response.text()}`)

  }

  return await response.json()

}

function base64(s: string) {

  const bytes = new TextEncoder().encode(s)

  let binary = ""

  for (const b of bytes) binary += String.fromCharCode(b)

  return btoa(binary)

}