"""SMTP sender using smtplib.

Sends messages to the submission port (587) of docker-mailserver.
"""
import mimetypes
import smtplib
from email.mime.base import MIMEBase
from email.mime.multipart import MIMEMultipart
from email.mime.text import MIMEText
from email.utils import formatdate, make_msgid
from email import encoders

from flask import current_app


def send_message(
    from_email: str,
    password: str,
    to_emails: list[str],
    cc_emails: list[str],
    bcc_emails: list[str],
    subject: str,
    body_html: str,
    body_text: str = "",
    important: bool = False,
    attachments: list | None = None,
) -> bytes:
    host = current_app.config["SMTP_HOST"]
    port = int(current_app.config.get("SMTP_PORT", 587))

    body_msg = MIMEMultipart("alternative")
    if body_text:
        body_msg.attach(MIMEText(body_text, "plain", "utf-8"))
    body_msg.attach(MIMEText(body_html, "html", "utf-8"))

    if attachments:
        msg = MIMEMultipart("mixed")
        msg.attach(body_msg)
        for att in attachments:
            filename = att["filename"]
            data = att["data"]
            ctype, _ = mimetypes.guess_type(filename)
            if ctype is None:
                ctype = "application/octet-stream"
            maintype, subtype = ctype.split("/", 1)
            part = MIMEBase(maintype, subtype)
            part.set_payload(data)
            encoders.encode_base64(part)
            part.add_header("Content-Disposition", "attachment", filename=filename)
            msg.attach(part)
    else:
        msg = body_msg
    msg["From"] = from_email
    msg["To"] = ", ".join(to_emails)
    if cc_emails:
        msg["Cc"] = ", ".join(cc_emails)
    msg["Subject"] = subject
    msg["Date"] = formatdate()
    msg["Message-ID"] = make_msgid()
    if important:
        msg["X-Priority"] = "1"
        msg["Importance"] = "high"

    all_recipients = to_emails + cc_emails + bcc_emails

    raw = msg.as_bytes()

    smtp = smtplib.SMTP(host, port, timeout=15)
    try:
        smtp.ehlo()
        smtp.login(from_email, password)
        smtp.sendmail(from_email, all_recipients, raw)
    finally:
        smtp.quit()

    return raw