app.py

import re
from urllib.parse import quote

import pandas as pd
import streamlit as st
import tabulate
from plotly import graph_objects as go

SITE_URL = "tidbitstatistics.com/venmo-splitter/"


def splitter(data):
    """parse data from string to df"""
    lines = data.split("\n")

    totals = []
    for line in lines:
        nums = list(filter(None, re.split(r"(?:[^\d\.])", line)))
        all_splits = list(filter(None, re.split(r"(?: |:|,)+", line)))

        name = " ".join(all_splits[: len(all_splits) - len(nums)])
        total = sum(float(num) for num in nums)

        totals.append((name, round(total, 2)))

    return pd.DataFrame(totals, columns=["Person", "Subtotals"]).set_index("Person")


def final_calc(df, fees, discounts, tax, tip, total):
    """do final calcs"""
    df["pct_total"] = df["Subtotals"] / round(df["Subtotals"].sum(), 2)

    df["Fees"] = fees / len(df)
    df["Discounts"] = discounts / len(df)

    df["Taxes"] = round(df["pct_total"] * tax, 2)
    df["Tip"] = round(df["pct_total"] * tip, 2)

    def total_check(x, total):
        remainder = round(total - x.sum(), 2)
        if remainder == 0:
            return x
        x.iloc[-1] = x.iloc[-1] + remainder
        return x

    df["Fees"] = total_check(df["Fees"], fees)
    df["Discounts"] = total_check(df["Discounts"], discounts)
    df["Taxes"] = total_check(df["Taxes"], tax)
    df["Tip"] = total_check(df["Tip"], tip)

    df["Total"] = round(
        df["Subtotals"] + df["Fees"] - df["Discounts"] + df["Taxes"] + df["Tip"], 2
    )

    return df["Total"].sum() if round(df["Total"].sum(), 2) != total else df


def show_title():
    """Show title and description at top of dashboard"""

    st.title("Venmo Splitter")
    st.write(
        "Enter in each persons items line by line, as well as a discount, fees, tax and tip "
        + "(if available).\n\n I'll split up the payments and give you some venmo request links!"
    )


def get_desc():
    st.header("What is this for?")

    desc = st.text_input("Name of restaraunt, bar, etc.")
    desc = (
        f"{desc} - calculated with {SITE_URL}"
        if desc
        else f"Calculated with {SITE_URL}"
    )
    return quote(desc)


def get_transactions():
    st.header("Input your transactions here")

    with st.expander(label="Accepted Formats"):
        st.write(
            """
            On each line, provide the name of the person and each
            associated cost separated by a number of spaces,
            with a ':' or a ',' if you'd like.
            
            ```
            Michael 8.99  10.99   5.99
            Mitchell:    14.50    13.50
            Cole 12.99,   1.09
            Ethan: 1.99 3.50
            ```
            """
        )

    data = st.text_area("Input the items here", height=180)

    return splitter(data)


def main():
    """Display all elements for the dashboard"""
    show_title()

    desc = get_desc()

    totals = get_transactions()

    st.markdown(totals.to_markdown())

    subtotal = totals["Subtotals"].sum()

    st.write(f"Subtotal: {subtotal}")

    st.header("Any discounts, fees, tip or tax?")
    col1, col2 = st.columns(2)

    discounts = col1.number_input(
        "Discounts (subtracted equally)", step=1.0, min_value=0.0
    )
    fees = col2.number_input("Fees (added equally)", step=1.0, min_value=0.0)
    tax = col1.number_input(
        "Tax (distributed relative to subtotal)", step=1.0, min_value=0.0
    )
    tip = col2.number_input(
        "Tip (distributed relative to subtotal)", step=1.0, min_value=0.0
    )

    st.header("Give me the total so I know I did my math correctly!")
    total = st.number_input("Put the total here")

    final_df = final_calc(
        totals, discounts=discounts, fees=fees, tax=tax, tip=tip, total=total
    )

    def format_radio_1(x):
        return "Request" if x == "charge" else "Pay"

    def format_radio_2(x):
        return (
            "Private"
            if x == "private"
            else ("Just friends" if x == "friends" else "Public")
        )

    venmo_type = st.radio(
        "Do you want links to request or send money?",
        ["charge", "pay"],
        format_func=format_radio_1,
    )
    audience = st.radio(
        "Who do you want to see the request?",
        ["private", "friends", "public"],
        format_func=format_radio_2,
    )

    if st.button("Calculate my totals!"):
        if not isinstance(final_df, pd.core.frame.DataFrame):
            st.write(
                f'Whoops! Your inputted total was {"${:,.2f}".format(total)}, '
                + f'but I calculated your total as {"${:,.2f}".format(final_df)}.'
            )
            st.write(
                "Double check all your inputs "
                + "(or if you don't care just change the total to what I calculated)"
            )
        else:
            st.header(
                "Here are your totals, complete with links to charge your friends on venmo!"
            )

            final_df["URL"] = (
                "https://venmo.com/?txn="
                + venmo_type
                + "&audience="
                + audience
                + "&amount="
                + final_df["Total"].astype(str)
                + "&note="
                + desc
            )

            final_df["Link"] = final_df["URL"]

            final_df = final_df.reset_index()

            final_df["Total NF"] = final_df["Total"]
            final_df["Subtotals"] = final_df["Subtotals"].apply("${:,.2f}".format)
            final_df["Fees"] = final_df["Fees"].apply("${:,.2f}".format)
            final_df["Discounts"] = final_df["Discounts"].apply("${:,.2f}".format)
            final_df["Taxes"] = final_df["Taxes"].apply("${:,.2f}".format)
            final_df["Tip"] = final_df["Tip"].apply("${:,.2f}".format)
            final_df["Total"] = final_df["Total"].apply("${:,.2f}".format)

            display_cols = [
                "Person",
                "Subtotals",
                "Fees",
                "Discounts",
                "Taxes",
                "Tip",
                "Total",
                "Link",
            ]
            st.markdown(final_df[display_cols].to_markdown(index=False))

            if tip > 0:
                bef_tax_tip = (tip / subtotal) * 100
                tip_str = f"Your tip was {bef_tax_tip:.2f}%"

                if tax > 0:
                    aft_tax_tip = (tip / (subtotal + tax)) * 100
                    tip_str = tip_str + f" before tax and {aft_tax_tip:.2f}% after tax"

                st.write(tip_str)

            if tax > 0:
                tax_pct = (tax / subtotal) * 100
                st.write(f"The tax rate was {tax_pct:.2f}%")

            if discounts > 0:
                discount_pct = (discounts / subtotal) * 100
                st.write(f"You saved {discount_pct:.2f}% with your discount")

            if fees > 0:
                fee_pct = (fees / subtotal) * 100
                st.write(f"Your fees added an extra {fee_pct:.2f}% to your subtotal")

            fig = go.Figure(
                data=[
                    go.Pie(
                        labels=final_df["Person"],
                        values=final_df["Total NF"],
                        text=final_df["Total"],
                        hovertemplate="%{label}: <br>%{text}<br>%{percent}<extra></extra>",
                    )
                ]
            )

            st.plotly_chart(fig, use_container_width=True)


if __name__ == "__main__":
    main()