import pandas as pd
import streamlit as st
from geopy.distance import geodesic
from st_aggrid import AgGrid


class DataFrames:
    Dframe = pd.DataFrame()


st.title("Distance Calculator")

st.write(
    """This app allows you to calculate the distance between two points in a dataframe.
    Please choose a file containing the latitude and longitude columns for the 2 points.
                      """
)

distance_sample_file_path = "samples/distance.xlsx"

# Create a download button
st.download_button(
    label="Download Distance Calculator Sample File",
    data=open(distance_sample_file_path, "rb").read(),
    file_name="distance.xlsx",
    mime="application/vnd.openxmlformats-officedocument.spreadsheetml.sheet",
)

uploaded_file = st.file_uploader(
    "Upload Excel file",
    type=["xlsx"],
    accept_multiple_files=False,
    help="Upload the Excel file containing the latitude and longitude columns for the 2 points",
)

if uploaded_file:
    DataFrames.Dframe = pd.read_excel(uploaded_file, keep_default_na=False)

    col1_list = DataFrames.Dframe.columns.tolist()
    latitude1_dd = st.selectbox(
        "Choose Latitude of point 1", col1_list, key="latitude1"
    )
    longitude1_dd = st.selectbox(
        "Choose Longitude of point 1", col1_list, key="longitude1"
    )
    latitude2_dd = st.selectbox(
        "Choose Latitude of point 2", col1_list, key="latitude2"
    )
    longitude2_dd = st.selectbox(
        "Choose Longitude of point 2", col1_list, key="longitude2"
    )

    def calculate_distance(row):
        coord1 = (row[latitude1_dd], row[longitude1_dd])
        coord2 = (row[latitude2_dd], row[longitude2_dd])
        return geodesic(coord1, coord2).meters

    if st.button("CALCULATE DISTANCE", type="primary"):
        try:
            df = DataFrames.Dframe.copy()
            df["distance_meters"] = df.apply(calculate_distance, axis=1)
            st.success("The distances are calculated successfully")
            DataFrames.Dframe = df

            @st.fragment
            def table_data():
                if DataFrames.Dframe is not None:
                    AgGrid(
                        DataFrames.Dframe,
                        fit_columns_on_grid_load=True,
                        theme="streamlit",
                        enable_enterprise_modules=True,
                        filter=True,
                    )

            table_data()

        except Exception as e:
            st.error(
                f"An error occurred. Make sure the file contains the latitudes and longitudes columns. Error: {e}"
            )

else:
    st.info(
        "Please choose a file containing the latitude and longitude columns for the 2 points"
    )