type Mailgun = {

  api_key: string;

};

export async function main(

  resource: Mailgun,

  domain: string,

  data: {

    from: string;

    to: string;

    subject: string;

    html: string;

    recipient_variables?: string;

    template?: string;

    cc?: string;

    bcc?: string;

    text?: string;

    amp_html?: string;

    attachment?: string;

    inline?: string;

    "o:tracking-opens"?: string;

    "t:version"?: string;

    "t:text"?: string;

    "t:variables"?: string;

    "o:tag"?: string;

    "o:dkim"?: string;

    "o:deliverytime"?: string;

    "o:deliverytime-optimize-period"?: string;

    "o:time-zone-localize"?: string;

    "o:testmode"?: string;

    "o:tracking"?: string;

    "o:tracking-clicks"?: string;

    "o:require-tls"?: string;

    "o:skip-verification"?: string;

    others?: Record<string, string>;

  }

) {

  const form = new FormData();

  form.append("from", data.from);

  form.append("to", data.to);

  form.append("subject", data.subject);

  form.append("html", data.html);

  data.recipient_variables &&

    form.append("recipient-variables", data.recipient_variables);

  data.template && form.append("template", data.template);

  data.cc && form.append("cc", data.cc);

  data.bcc && form.append("bcc", data.bcc);

  data.text && form.append("text", data.text);

  data.amp_html && form.append("amp-html", data.amp_html);

  data.attachment && form.append("attachment", data.attachment);

  data.inline && form.append("inline", data.inline);

  data["o:tracking-opens"] &&

    form.append("o:tracking-opens", data["o:tracking-opens"]);

  data["t:version"] && form.append("t:version", data["t:version"]);

  data["t:text"] && form.append("t:text", data["t:text"]);

  data["t:variables"] && form.append("t:variables", data["t:variables"]);

  data["o:tag"] && form.append("o:tag", data["o:tag"]);

  data["o:dkim"] && form.append("o:dkim", data["o:dkim"]);

  data["o:deliverytime"] &&

    form.append("o:deliverytime", data["o:deliverytime"]);

  data["o:deliverytime-optimize-period"] &&

    form.append(

      "o:deliverytime-optimize-period",

      data["o:deliverytime-optimize-period"]

    );

  data["o:time-zone-localize"] &&

    form.append("o:time-zone-localize", data["o:time-zone-localize"]);

  data["o:testmode"] && form.append("o:testmode", data["o:testmode"]);

  data["o:tracking"] && form.append("o:tracking", data["o:tracking"]);

  data["o:tracking-clicks"] &&

    form.append("o:tracking-clicks", data["o:tracking-clicks"]);

  data["o:require-tls"] && form.append("o:require-tls", data["o:require-tls"]);

  data["o:skip-verification"] &&

    form.append("o:skip-verification", data["o:skip-verification"]);

  Object.entries(data.others || {}).forEach(([key, value]) =>

    form.append(key, value)

  );

  return (

    await fetch(`https://api.mailgun.net/v3/${domain}/messages`, {

      method: "POST",

      headers: {

        Authorization:

          "Basic " + Buffer.from(`api:${resource.api_key}`).toString("base64"),

      },

      body: form,

    })

  ).json();

}