Code Editor for app.py

from enum import Enum
import streamlit as st

class Step(Enum):
    INITIAL = 1
    PLACEHOLDER_SELECTION = 2
    PROCESSING = 3

    @classmethod
    def next_value(cls, current_value):
        next_value = (current_value.value % len(cls)) + 1
        return Step(next_value)


if "step" not in st.session_state:
    st.session_state.step = Step.INITIAL

cols = st.columns([1, 1, 1, 1, 1])

def handle_placeholder_click(message=None):
    if st.session_state.step == Step.PROCESSING:
        st.session_state.step = Step.INITIAL
    else:
        st.session_state.step = Step.next_value(st.session_state.step)

    st.write(f"Message: {message}")


if st.session_state.step.value == Step.INITIAL.value:
    st.button(
        "Click here to display placeholder messages",
        on_click=handle_placeholder_click,
        args=("Display placeholders",),
    )
elif st.session_state.step.value == Step.PLACEHOLDER_SELECTION.value:
    with cols[1]:
        st.button(
            "Placeholder 1", on_click=handle_placeholder_click, args=("Placeholder 1",)
        )
    with cols[2]:
        st.button(
            "Placeholder 2", on_click=handle_placeholder_click, args=("Placeholder 2",)
        )
    with cols[3]:
        st.button(
            "Placeholder 3", on_click=handle_placeholder_click, args=("Placeholder 3",)
        )
else:
    st.write("The message has been sent and is being processed.")
    st.button("RESET", on_click=handle_placeholder_click, args=("RESET BUTTON",))