import os, json
from google.oauth2.service_account import Credentials
from googleapiclient.discovery import build
from googleapiclient.http import MediaFileUpload

SCOPES = ["https://www.googleapis.com/auth/drive.file"]

def _get_env(name: str) -> str:
    v = os.getenv(name, "").strip()
    if not v:
        raise RuntimeError(f"Missing env secret: {name}")
    return v

def _get_drive_service():
    creds_json = _get_env("GOOGLE_SERVICE_ACCOUNT_JSON")
    info = json.loads(creds_json)
    creds = Credentials.from_service_account_info(info, scopes=SCOPES)
    return build("drive", "v3", credentials=creds, cache_discovery=False)

def upload_file(local_path: str, filename: str, mime_type: str):
    folder_id = _get_env("DRIVE_FOLDER_ID")
    service = _get_drive_service()

    file_metadata = {"name": filename, "parents": [folder_id]}
    media = MediaFileUpload(local_path, mimetype=mime_type, resumable=True)

    created = service.files().create(
        body=file_metadata,
        media_body=media,
        fields="id, webViewLink"
    ).execute()

    file_id = created["id"]
    return {
        "driveFileId": file_id,
        "webViewLink": created.get("webViewLink"),
        "directDownloadLink": f"https://drive.google.com/uc?id={file_id}"
    }