# File: backend/drive_test.py
import os.path
from google.auth.transport.requests import Request
from google.oauth2.credentials import Credentials
from google_auth_oauthlib.flow import InstalledAppFlow
from googleapiclient.discovery import build

# If modifying these scopes, delete the file token.json.
# We ONLY ask for read-only access to metadata (Project constraint: No content storage)
SCOPES = ["https://www.googleapis.com/auth/drive.metadata.readonly"]

def connect_to_drive():
    """Shows basic usage of the Drive v3 API."""
    creds = None
    
    # The file token.json stores the user's access and refresh tokens, and is
    # created automatically when the authorization flow completes for the first time.
    if os.path.exists("backend/token.json"):
        creds = Credentials.from_authorized_user_file("backend/token.json", SCOPES)
    
    # If there are no (valid) credentials available, let the user log in.
    if not creds or not creds.valid:
        if creds and creds.expired and creds.refresh_token:
            print("Refreshing Expired Token...")
            creds.refresh(Request())
        else:
            print("Initiating New Login...")
            # We look for credentials.json in the backend folder
            flow = InstalledAppFlow.from_client_secrets_file(
                "backend/credentials.json", SCOPES
            )
            # This opens a local browser for you to sign in
            creds = flow.run_local_server(port=0)
        
        # Save the credentials for the next run
        with open("backend/token.json", "w") as token:
            token.write(creds.to_json())

    try:
        service = build("drive", "v3", credentials=creds)

        # Call the Drive v3 API
        print("\nSuccessfully connected! Fetching top 10 files...\n")
        
        # We only ask for specific fields: id, name, mimeType (file type)
        results = (
            service.files()
            .list(pageSize=10, fields="nextPageToken, files(id, name, mimeType)")
            .execute()
        )
        items = results.get("files", [])

        if not items:
            print("No files found.")
            return

        print(f"{'FILE NAME':<40} | {'TYPE'}")
        print("-" * 60)
        for item in items:
            # Simple truncation for display
            name = (item["name"][:35] + '..') if len(item["name"]) > 35 else item["name"]
            print(f"{name:<40} | {item['mimeType']}")

    except Exception as error:
        print(f"An error occurred: {error}")

if __name__ == "__main__":
    # Ensure we are running from the root folder context roughly
    if not os.path.exists("backend/credentials.json"):
        print("ERROR: backend/credentials.json not found!")
        print("Please make sure you are running this from the DocuSort root folder.")
    else:
        connect_to_drive()