from google.oauth2.credentials import Credentials
from google_auth_oauthlib.flow import InstalledAppFlow
from googleapiclient.discovery import build
import base64, os
from dotenv import load_dotenv
load_dotenv()

SCOPES = ['https://www.googleapis.com/auth/gmail.modify']

def get_gmail_service():
    creds = None
    if os.path.exists(os.getenv("GOOGLE_TOKEN_FILE")):
        creds = Credentials.from_authorized_user_file(os.getenv("GOOGLE_TOKEN_FILE"), SCOPES)
    if not creds or not creds.valid:
        flow = InstalledAppFlow.from_client_secrets_file(os.getenv("GOOGLE_CREDENTIALS_FILE"), SCOPES)
        creds = flow.run_local_server(port=0)
        with open(os.getenv("GOOGLE_TOKEN_FILE"), 'w') as f:
            f.write(creds.to_json())
    return build('gmail', 'v1', credentials=creds)

def fetch_unread_emails(max_results=10):
    service = get_gmail_service()
    results = service.users().messages().list(
        userId='me', labelIds=['INBOX', 'UNREAD'], maxResults=max_results
    ).execute()
    messages = results.get('messages', [])
    emails = []
    for msg in messages:
        full = service.users().messages().get(userId='me', id=msg['id'], format='full').execute()
        headers = {h['name']: h['value'] for h in full['payload']['headers']}
        body = ''
        if 'parts' in full['payload']:
            for part in full['payload']['parts']:
                if part['mimeType'] == 'text/plain':
                    body = base64.urlsafe_b64decode(part['body']['data']).decode('utf-8')
        emails.append({
            'id': msg['id'],
            'from': headers.get('From', ''),
            'subject': headers.get('Subject', ''),
            'body': body[:1000]  # truncate for LLM context
        })
    return emails

def send_reply(service, original_msg_id, to, subject, body_text):
    import email.mime.text, email.mime.multipart
    msg = email.mime.multipart.MIMEMultipart()
    msg['To'] = to
    msg['Subject'] = f"Re: {subject}"
    msg.attach(email.mime.text.MIMEText(body_text, 'plain'))
    raw = base64.urlsafe_b64encode(msg.as_bytes()).decode()
    service.users().messages().send(userId='me', body={'raw': raw}).execute()