import streamlit as st

from backend.adapters.snowflake import get_current_user_name, get_session, resolve_env
from backend.actions.ccpa_upload import upload_ccpa_emails_from_csv
from backend.permissions import require_access

session = get_session()
require_access(session, "CCPA")

st.title("CCPA Email Upload")

st.markdown(
    """
Upload a CSV file containing emails and requested dates to the CCPA Fan List.
Emails will be validated, lowercased, and stored in the database.

**CSV format:** Must contain columns `email` and `requested_date`.
Date format should be `MM/DD/YY`.

If the same email appears multiple times, only the oldest date is kept.
Existing entries are only updated if the new date is older.
"""
)

uploaded_file = st.file_uploader("Choose a CSV file", type=["csv"])

if st.button("Upload"):
    if uploaded_file is None:
        st.warning("Please upload a CSV file first.")
    else:
        session = get_session()
        user = get_current_user_name(session)

        schema = resolve_env(session)

        result = upload_ccpa_emails_from_csv(session, uploaded_file, user, schema)

        if result.errors:
            st.error(
                f"Upload rejected — {len(result.errors)} validation error(s). "
                "Fix all errors and re-upload."
            )
            st.dataframe(
                {"Validation Errors": result.errors},
                width="content",
            )
        else:
            total_processed = result.inserted_count + result.updated_count
            st.success(f"Successfully processed {total_processed} email(s)")

            col1, col2, col3 = st.columns(3)
            with col1:
                st.metric("New emails inserted", result.inserted_count)
            with col2:
                st.metric("Existing emails updated", result.updated_count)
            with col3:
                st.metric("Skipped (date already older)", result.skipped_count)