app.py

import streamlit as st

for k, v in st.session_state.items():
    st.session_state[k] = v

# --- SHARED ON ALL PAGES ---
#st.logo(image=":material/medical_information:")
#st.logo(image="images/medical_information_24dp_1F1F1F_FILL0_wght400_GRAD0_opsz24.png") 
st.logo(image="images/menu_book_60dp_75FBFD.png")

# --- PAGE SETUP ---
start_page = st.Page(
    page="pages/chapter_index.py",
    title="Saudi Billing System Chapter Index",
    icon=":material/home:",
    default=True,)

type_text_page = st.Page(
    page="pages/type_text.py",
    title="DEMO type text",
    icon=":material/keyboard:",
    default=False,)

upload_file_page = st.Page(
    page="pages/upload_file.py",
    title="DEMO upload file (not yet active)",
    icon=":material/file_upload:",
    default=False,)

about_page = st.Page(
    page="pages/about.py",
    title="About the app",
    icon=":material/info:",
    default=False)

#PAGES = {
#    "Chapter Index": "pages/chapter_index.py" ,
#    "DEMO type_text": "pages/type_text.py",
#    "DEMO upload file (not yet active)": "pages/upload_file.py",
#    "About": "pages/about.py",
#}

#selection = st.sidebar.radio("Pages", list(PAGES.keys()))
#selection = st.sidebar.radio("Pages", [start_page, type_text_page, upload_file_page, about_page])
#page = PAGES[selection]

# --- NAVIGATION SETUP ---
pg = st.navigation(pages=[start_page, type_text_page, upload_file_page, about_page]) # WITHOUT SECTIONS
#pg = st.navigation({"Chapter_Index": [start_page], "Demo": [type_text_page, upload_file_page], "About": [about_page]}) # WITH SECTIONS
pg.run() 

st.sidebar.text("Project by JA-RAD")

def filter_chapters_env(df, chapter_column_name):
    chapter_names = st.sidebar.multiselect(
        label="Chapter Name", options=df[chapter_column_name].unique(), default=st.session_state.get("chapter_names"), key='filter_chapters', on_change=update_chapters
    )
    st.session_state["chapter_names"] = chapter_names

    if chapter_names:
        df = df[df["chapter_name"].isin(chapter_names)]
    return df

def update_chapters():
   st.session_state["chapter_names"] = st.session_state.filter_chapters