import os.path
import base64
import json
import pickle
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
from googleapiclient.errors import HttpError

# If modifying these SCOPES, delete the file token.json.
SCOPES = ['https://www.googleapis.com/auth/gmail.readonly']

def authenticate_gmail():
    """Shows basic usage of the Gmail API.
    Lists the user's Gmail labels.
    """
    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('token.json'):
        creds = Credentials.from_authorized_user_file('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:
            creds.refresh(Request())
        else:
            flow = InstalledAppFlow.from_client_secrets_file(
                'Credentials.json', SCOPES)
            creds = flow.run_local_server(port=0)
        # Save the credentials for the next run
        with open('token.json', 'w') as token:
            token.write(creds.to_json())

    try:
        # Call the Gmail API
        service = build('gmail', 'v1', credentials=creds)
        return service
    except HttpError as error:
        print(f'An error occurred: {error}')
        return None

def get_latest_email(service):
    """Get the latest email from the inbox"""
    try:
        # Retrieve a list of messages
        results = service.users().messages().list(userId='me', maxResults=1).execute()
        messages = results.get('messages', [])
        
        if not messages:
            print('No messages found.')
            return

        # Get the message ID
        message_id = messages[0]['id']

        # Fetch the email content by message ID
        message = service.users().messages().get(userId='me', id=message_id, format='full').execute()

        # Get the email payload
        payload = message['payload']
        headers = payload.get('headers', [])
        
        # Print the sender, subject, and body of the email
        for header in headers:
            if header['name'] == 'From':
                print(f"From: {header['value']}")
            if header['name'] == 'Subject':
                print(f"Subject: {header['value']}")

        # Extract the body
        parts = payload.get('parts', [])
        for part in parts:
            if part.get('mimeType') == 'text/plain':
                body = part.get('body', {}).get('data', '')
                body_decoded = base64.urlsafe_b64decode(body).decode('utf-8')
                print(f"Body: {body_decoded}")

    except HttpError as error:
        print(f'An error occurred: {error}')

if __name__ == '__main__':
    service = authenticate_gmail()
    print(service)
    if service:
        get_latest_email(service)