import { google } from "googleapis";

// the main function is the entrypoint.
export function main({ config }) {
    const oauth2Client = new google.auth.OAuth2();
    oauth2Client.setCredentials({ access_token: config["Google Gmail"].accessToken });
    const gmail = google.gmail({ version: "v1", auth: oauth2Client });

    return (async function () {
        let inbox = null;
        let foundThreadId = null;

        try {
            inbox = await gmail.users.messages.list({
                userId: "me",
                q: `from:${config["Email Address"]} subject:${config["Subject"]}`
            });

            if (inbox && inbox.data && inbox.data.messages && inbox.data.messages[0]) {
                foundThreadId = inbox.data.messages[0].threadId
            }
        } catch (err) { }

        const rawEmail = `To: ${config["Email Address"]}\r\nSubject: ${config["Subject"]}\r\n
${config["Email Text And Signature"]}`

        const newMessage = {
            raw: Buffer.from(rawEmail).toString("base64")
        }

        if (foundThreadId) {
            newMessage.threadId = foundThreadId;
        }

        try {
            const res = await gmail.users.messages.send({
                userId: "me",
                requestBody: newMessage
            });

            if (foundThreadId) {
                return {
                    response: `Email reply to ${config["Email Address"]} successfully sent.`
                };
            } else {
                return {
                    response: `Email to ${config["Email Address"]} successfully sent.`
                };
            }
        } catch (err) {
            return {
                response: JSON.stringify(`Error: ${err}`)
            };
        }
    })();
}