import streamlit as st
import requests
from pydantic import BaseModel
from typing import Optional, List

# Define the Customer model, mirroring the one in main.py
class Customer(BaseModel):
    name: str
    email: str
    phone: Optional[int] = None
    address: Optional[str] = None
    id: int

# FastAPI backend URL
BASE_URL = "https://vishnugupta-enrollmentapi.hf.space"

def get_customers():
    """Fetches all customers from the backend."""
    try:
        response = requests.get(f"{BASE_URL}/customers")
        response.raise_for_status()  # Raise an exception for bad status codes
        return response.json()
    except requests.exceptions.RequestException as e:
        st.error(f"Error fetching customers: {e}")
        return []

def create_customer(customer: Customer):
    """Creates a new customer."""
    try:
        response = requests.post(f"{BASE_URL}/customers", json=customer.dict())
        response.raise_for_status()
        st.success("Customer created successfully!")
        return response.json()
    except requests.exceptions.RequestException as e:
        st.error(f"Error creating customer: {e}")
        return None

def update_customer(customer_id: int, customer: Customer):
    """Updates an existing customer."""
    try:
        response = requests.put(f"{BASE_URL}/customer/{customer_id}", json=customer.dict())
        response.raise_for_status()
        st.success("Customer updated successfully!")
        return response.json()
    except requests.exceptions.RequestException as e:
        st.error(f"Error updating customer: {e}")
        return None

def delete_customer(customer_id: int):
    """Deletes a customer."""
    try:
        response = requests.delete(f"{BASE_URL}/customer/{customer_id}")
        response.raise_for_status()
        st.success("Customer deleted successfully!")
        return response.json()
    except requests.exceptions.RequestException as e:
        st.error(f"Error deleting customer: {e}")
        return None

def main():
    """Main function to run the Streamlit app."""
    st.set_page_config(page_title="CRM Dashboard", layout="wide")

    st.title("Customer Relationship Management (CRM)")

    menu = ["View Customers", "Add Customer", "Update Customer", "Delete Customer"]
    choice = st.sidebar.selectbox("Menu", menu)

    if choice == "View Customers":
        st.subheader("All Customers")
        customers = get_customers()
        if customers:
            st.table(customers)
        else:
            st.info("No customers found.")

    elif choice == "Add Customer":
        st.subheader("Add a New Customer")
        with st.form("add_customer_form"):
            name = st.text_input("Name")
            email = st.text_input("Email")
            phone = st.number_input("Phone", value=0, format="%d")
            address = st.text_area("Address")
            customer_id = len(requests.get(f"{BASE_URL}/customers").json())+1

            submitted = st.form_submit_button("Add Customer")
            if submitted:
                new_customer = Customer(name=name, email=email, phone=phone, address=address, id=customer_id)
                create_customer(new_customer)

    elif choice == "Update Customer":
        st.subheader("Update a Customer")
        customers = get_customers()
        if customers:
            customer_ids = [c["id"] for c in customers]
            selected_id = st.selectbox("Select Customer ID to Update", customer_ids)
            
            selected_customer = next((c for c in customers if c["id"] == selected_id), None)

            if selected_customer:
                with st.form("update_customer_form"):
                    name = st.text_input("Name", value=selected_customer["name"])
                    email = st.text_input("Email", value=selected_customer["email"])
                    phone = st.number_input("Phone", value=selected_customer.get("phone") or 0, format="%d")
                    address = st.text_area("Address", value=selected_customer.get("address", ""))
                    
                    updated = st.form_submit_button("Update Customer")
                    if updated:
                        updated_customer = Customer(name=name, email=email, phone=phone, address=address, id=selected_id)
                        update_customer(selected_id, updated_customer)
            else:
                st.warning("Selected customer not found.")
        else:
            st.info("No customers to update.")

    elif choice == "Delete Customer":
        st.subheader("Delete a Customer")
        customers = get_customers()
        if customers:
            customer_ids = [c["id"] for c in customers]
            selected_id = st.selectbox("Select Customer ID to Delete", customer_ids)
            selected_customer = next((c for c in customers if c["id"] == selected_id), None)
            
            if st.button("Delete Customer"):
                delete_customer(selected_id)
        else:
            st.info("No customers to delete.")

if __name__ == "__main__":
    main()