from __future__ import annotations

import base64
from email.mime.text import MIMEText

from google.auth.transport.requests import Request
from google.oauth2.credentials import Credentials
from googleapiclient.discovery import build

from scripts.edoxid_calendar_config import GoogleConfig


class GmailService:
    """Kirim email reminder H-1/1-jam sebagai tu@informatika.untan.ac.id
    langsung (scope gmail.send, akun OAuth yang sama dengan Calendar)."""

    def __init__(self, config: GoogleConfig):
        # Sengaja TIDAK set `scopes=` di sini: refresh_token sudah membawa scope
        # gabungan (calendar + gmail.send) dari OAuth consent aslinya. Meminta
        # scope yang lebih sempit secara eksplisit saat refresh terbukti bisa
        # ditolak Google dengan `invalid_scope` tergantung versi google-auth
        # yang jalan (dites 2026-07-27: lolos di lokal, gagal di container
        # Airflow karena google-auth versi lain via apache-airflow-providers-google).
        creds = Credentials(
            token=None,
            refresh_token=config.refresh_token,
            token_uri="https://oauth2.googleapis.com/token",
            client_id=config.client_id,
            client_secret=config.client_secret,
        )
        creds.refresh(Request())

        self._service = build("gmail", "v1", credentials=creds, cache_discovery=False)

    def send(self, to: list[str], subject: str, body_text: str) -> str:
        message = MIMEText(body_text, "plain", "utf-8")
        message["to"] = ", ".join(to)
        message["subject"] = subject

        raw = base64.urlsafe_b64encode(message.as_bytes()).decode("utf-8")
        result = self._service.users().messages().send(userId="me", body={"raw": raw}).execute()
        return result["id"]