from langchain.agents import Tool
from langchain_community.utilities import GoogleSerperAPIWrapper
from src.config.env import SERPER_API_KEY
from langchain_google_community import GmailToolkit
from langchain_google_community.gmail.utils import (
    build_resource_service,
    get_gmail_credentials,
)
from google.oauth2.credentials import Credentials
from google.auth.transport.requests import Request
import os


def get_gmail_tool():
    creds = Credentials(
        token=None,
        refresh_token=os.getenv("GMAIL_REFRESH_TOKEN"),
        token_uri="https://oauth2.googleapis.com/token",
        client_id=os.getenv("GMAIL_CLIENT_ID"),
        client_secret=os.getenv("GMAIL_CLIENT_SECRET"),
        scopes=["https://mail.google.com/"]
    )
    creds.refresh(Request())
    service = build_resource_service(credentials=creds)
    return GmailToolkit(api_resource=service)
    
def get_tools(rag_chain):
    tools = []

    # === RAG Tool ===
    tools.append(
        Tool(
            name="RAG",
            func=lambda x: rag_chain.invoke({"input": x}),
            description="Use this for questions about UWF, using the Student Handbook as context."
        )
    )

    # === Google Search Tool ===
    search = GoogleSerperAPIWrapper(serper_api_key=SERPER_API_KEY)
    tools.append(
        Tool(
            name="Google Search",
            func=search.run,
            description="Fallback when RAG does not contain the information."
        )
    )

    # === Gmail Tool via Hugging Face Secrets ===
    try:
        toolkit = get_gmail_tool()
        gmail_send_tool = next(
            (tool for tool in toolkit.get_tools() if tool.__class__.__name__ == "GmailSendMessage"),
            None
        )
        if gmail_send_tool:
            # Gmail Send Helper

            def send_email_function(input_data):
                if isinstance(input_data, str):
                    input_data = {"message": input_data}
            
                input_data.setdefault("to", "default_advisor@gmail.com")
                input_data.setdefault("subject", "Meeting Request")
                input_data.setdefault("message", "Dear Advisor, the student would like to book a meeting with you.")
            
                return gmail_send_tool(input_data)
                
            tools.append(
                Tool(
                    name="Gmail",
                    func=send_email_function,
                    description="Send email to the advisor if the student requests it."
                )
            )
    except Exception as e:
        print(f"[Warning] Gmail tool could not be initialized: {e}")

    return tools