import streamlit as st
import pandas as pd
from datetime import date

st.set_page_config(page_title="Family Expense Manager", page_icon="💰", layout="wide")

# ----------------------------
# UI styling
# ----------------------------
st.markdown(
    '''
    <style>
    div[data-testid="stDataEditor"] button {
        background: #1f6feb !important;
        color: white !important;
        border: 1px solid #1f6feb !important;
        opacity: 1 !important;
    }
    div[data-testid="stDataEditor"] button:hover {
        background: #1557b0 !important;
        color: white !important;
    }
    div[data-testid="stDataEditor"] [role="gridcell"]:focus,
    div[data-testid="stDataEditor"] [role="gridcell"]:focus-within {
        background-color: rgba(31, 111, 235, 0.08) !important;
        outline: 2px solid #1f6feb !important;
    }
    </style>
    ''',
    unsafe_allow_html=True
)

# ----------------------------
# Session state initialization
# ----------------------------
if "member_df" not in st.session_state:
    st.session_state.member_df = pd.DataFrame([
        {"Name": "Abbas", "Family Position": "Father"},
        {"Name": "Sara", "Family Position": "Mother"},
        {"Name": "Bilal", "Family Position": "Son"},
        {"Name": "Ayesha", "Family Position": "Daughter"},
    ])

if "income_sources" not in st.session_state:
    st.session_state.income_sources = ["Salary", "Business", "Freelance", "Bonus", "Rent Income", "Other"]

if "category_map" not in st.session_state:
    st.session_state.category_map = {
        "Groceries": ["Vegetables", "Meat", "General Store"],
        "Utilities": ["Electricity", "Gas", "Internet", "Water"],
        "Rent": ["House Rent"],
        "School Fees": ["Tuition Fee", "Books", "Transport Fee"],
        "Transport": ["Fuel", "Ride Fare", "Maintenance"],
        "Medical": ["Medicine", "Doctor", "Lab Tests"],
        "Entertainment": ["Family Dinner", "Movies", "Outing"],
        "Household": ["Cleaning", "Maintenance", "Furniture"],
        "Other": ["Miscellaneous"],
    }

if "income_df" not in st.session_state:
    st.session_state.income_df = pd.DataFrame(columns=["ID", "Date", "Member", "Source", "Amount", "Notes"])

if "expense_df" not in st.session_state:
    st.session_state.expense_df = pd.DataFrame(columns=[
        "ID", "Date", "Expense Type", "Paid By", "Participants",
        "Category", "Subcategory", "Amount", "Description", "Month"
    ])

if "budget_df" not in st.session_state:
    st.session_state.budget_df = pd.DataFrame([
        {"Category": "Groceries", "Monthly Budget": 30000},
        {"Category": "Utilities", "Monthly Budget": 15000},
        {"Category": "Rent", "Monthly Budget": 50000},
        {"Category": "School Fees", "Monthly Budget": 20000},
        {"Category": "Transport", "Monthly Budget": 10000},
        {"Category": "Medical", "Monthly Budget": 10000},
        {"Category": "Entertainment", "Monthly Budget": 8000},
        {"Category": "Household", "Monthly Budget": 12000},
        {"Category": "Other", "Monthly Budget": 10000},
    ])

if "dev_notes_df" not in st.session_state:
    st.session_state.dev_notes_df = pd.DataFrame(columns=["ID", "Date", "Type", "Title", "Details", "Status"])

if "next_income_id" not in st.session_state:
    st.session_state.next_income_id = 1
if "next_expense_id" not in st.session_state:
    st.session_state.next_expense_id = 1
if "next_note_id" not in st.session_state:
    st.session_state.next_note_id = 1


# ----------------------------
# Helpers
# ----------------------------
def normalize_month(d):
    return pd.to_datetime(d).strftime("%Y-%m")


def get_member_names():
    if st.session_state.member_df.empty:
        return []
    return st.session_state.member_df["Name"].tolist()


def add_member(name, family_position):
    name = name.strip()
    family_position = family_position.strip()

    if not name or not family_position:
        return False, "Enter both name and family position."

    if name in get_member_names():
        return False, "This member already exists."

    new_row = pd.DataFrame([{
        "Name": name,
        "Family Position": family_position
    }])

    st.session_state.member_df = pd.concat(
        [st.session_state.member_df, new_row],
        ignore_index=True
    )
    return True, f"{name} added successfully."


def dataframe_to_csv_download(df):
    return df.to_csv(index=False).encode("utf-8")


def load_uploaded_csv(uploaded_file, expected_cols):
    df = pd.read_csv(uploaded_file)
    missing = [c for c in expected_cols if c not in df.columns]
    if missing:
        raise ValueError(f"Missing columns: {', '.join(missing)}")
    return df[expected_cols]


def format_df(df):
    config = {}
    if "Amount" in df.columns:
        config["Amount"] = st.column_config.NumberColumn(format="%,d")
    if "Monthly Budget" in df.columns:
        config["Monthly Budget"] = st.column_config.NumberColumn(format="%,d")
    if "Spent" in df.columns:
        config["Spent"] = st.column_config.NumberColumn(format="%,d")
    if "Remaining" in df.columns:
        config["Remaining"] = st.column_config.NumberColumn(format="%,d")
    return config


# ----------------------------
# Sidebar
# ----------------------------
st.sidebar.title("💰 Family Expense Manager")
page = st.sidebar.radio(
    "Go to",
    ["Dashboard", "Add Income", "Add Expense", "Monthly Budget", "Masters", "Reports", "Development Notes", "Data Backup"]
)

st.sidebar.markdown("---")
new_member_name = st.sidebar.text_input("Member Name")
new_member_position = st.sidebar.selectbox(
    "Family Position",
    ["Father", "Mother", "Son", "Daughter", "Brother", "Sister", "Grandfather", "Grandmother", "Other"]
)

if st.sidebar.button("Add Member"):
    success, message = add_member(new_member_name, new_member_position)
    if success:
        st.sidebar.success(message)
    else:
        st.sidebar.warning(message)

st.sidebar.write("**Members:**")
if not st.session_state.member_df.empty:
    for _, row in st.session_state.member_df.iterrows():
        st.sidebar.write(f"• {row['Name']} ({row['Family Position']})")
else:
    st.sidebar.write("No members added yet.")

# ----------------------------
# Dashboard
# ----------------------------
if page == "Dashboard":
    st.title("🏠 Family Expense Dashboard")

    income_df = st.session_state.income_df.copy()
    expense_df = st.session_state.expense_df.copy()
    budget_df = st.session_state.budget_df.copy()

    total_income = int(income_df["Amount"].sum()) if not income_df.empty else 0
    total_expense = int(expense_df["Amount"].sum()) if not expense_df.empty else 0
    balance = total_income - total_expense

    c1, c2, c3 = st.columns(3)
    c1.metric("Total Income", f"Rs. {total_income:,}")
    c2.metric("Total Expenses", f"Rs. {total_expense:,}")
    c3.metric("Net Balance", f"Rs. {balance:,}")

    st.markdown("### This Month Snapshot")
    current_month = date.today().strftime("%Y-%m")

    month_income = int(income_df[income_df["Date"].astype(str).str[:7] == current_month]["Amount"].sum()) if not income_df.empty else 0
    month_expense = int(expense_df[expense_df["Month"] == current_month]["Amount"].sum()) if not expense_df.empty else 0
    month_budget = int(budget_df["Monthly Budget"].sum()) if not budget_df.empty else 0

    c4, c5, c6 = st.columns(3)
    c4.metric("This Month Income", f"Rs. {month_income:,}")
    c5.metric("This Month Expense", f"Rs. {month_expense:,}")
    c6.metric("Monthly Budget", f"Rs. {month_budget:,}")

    st.markdown("### Family Members")
    st.dataframe(st.session_state.member_df, use_container_width=True, hide_index=True)

    st.markdown("### Category Wise Expense")
    if not expense_df.empty:
        by_category = expense_df.groupby("Category", as_index=False)["Amount"].sum().sort_values("Amount", ascending=False)
        st.bar_chart(by_category.set_index("Category"))
        st.dataframe(by_category, use_container_width=True, hide_index=True, column_config=format_df(by_category))
    else:
        st.info("No expenses added yet.")

    st.markdown("### Expense by Family Member")
    if not expense_df.empty:
        by_member = expense_df.groupby("Paid By", as_index=False)["Amount"].sum().sort_values("Amount", ascending=False)
        st.bar_chart(by_member.set_index("Paid By"))
        st.dataframe(by_member, use_container_width=True, hide_index=True, column_config=format_df(by_member))
    else:
        st.info("No member expense data yet.")

    st.markdown("### Combined vs Individual Expense")
    if not expense_df.empty:
        by_type = expense_df.groupby("Expense Type", as_index=False)["Amount"].sum()
        st.bar_chart(by_type.set_index("Expense Type"))
        st.dataframe(by_type, use_container_width=True, hide_index=True, column_config=format_df(by_type))

# ----------------------------
# Add Income
# ----------------------------
elif page == "Add Income":
    st.title("➕ Add Income")

    with st.form("income_form", clear_on_submit=True):
        income_date = st.date_input("Date", value=date.today())
        member = st.selectbox("Member", get_member_names())
        source = st.selectbox("Income Source", st.session_state.income_sources)
        amount = st.number_input("Amount", min_value=0, step=100, format="%d")
        notes = st.text_area("Notes")
        submit_income = st.form_submit_button("Save Income")

    if submit_income:
        if amount <= 0:
            st.error("Amount must be greater than zero.")
        else:
            new_row = pd.DataFrame([{
                "ID": st.session_state.next_income_id,
                "Date": str(income_date),
                "Member": member,
                "Source": source,
                "Amount": int(amount),
                "Notes": notes
            }])
            st.session_state.income_df = pd.concat([st.session_state.income_df, new_row], ignore_index=True)
            st.session_state.next_income_id += 1
            st.success("Income added successfully.")

    st.markdown("### Income Records")
    st.dataframe(st.session_state.income_df, use_container_width=True, hide_index=True, column_config=format_df(st.session_state.income_df))

    if not st.session_state.income_df.empty:
        st.markdown("### Edit or Delete Income")
        selected_income_id = st.selectbox("Select Income Record", st.session_state.income_df["ID"].tolist())
        selected_income = st.session_state.income_df[st.session_state.income_df["ID"] == selected_income_id].iloc[0]

        col1, col2 = st.columns([3, 1])
        with col1:
            with st.form("edit_income_form"):
                edit_income_date = st.date_input("Edit Date", value=pd.to_datetime(selected_income["Date"]).date())
                member_names = get_member_names()
                member_index = member_names.index(selected_income["Member"]) if selected_income["Member"] in member_names else 0
                edit_member = st.selectbox("Edit Member", member_names, index=member_index)
                source_index = st.session_state.income_sources.index(selected_income["Source"]) if selected_income["Source"] in st.session_state.income_sources else 0
                edit_source = st.selectbox("Edit Income Source", st.session_state.income_sources, index=source_index)
                edit_amount = st.number_input("Edit Amount", min_value=0, step=100, format="%d", value=int(selected_income["Amount"]))
                edit_notes = st.text_area("Edit Notes", value=selected_income["Notes"])
                update_income = st.form_submit_button("Update Income")

            if update_income:
                idx = st.session_state.income_df.index[st.session_state.income_df["ID"] == selected_income_id][0]
                st.session_state.income_df.at[idx, "Date"] = str(edit_income_date)
                st.session_state.income_df.at[idx, "Member"] = edit_member
                st.session_state.income_df.at[idx, "Source"] = edit_source
                st.session_state.income_df.at[idx, "Amount"] = int(edit_amount)
                st.session_state.income_df.at[idx, "Notes"] = edit_notes
                st.success("Income updated successfully.")

        with col2:
            st.write("")
            st.write("")
            if st.button("Delete Income", type="primary"):
                st.session_state.income_df = st.session_state.income_df[st.session_state.income_df["ID"] != selected_income_id].reset_index(drop=True)
                st.success("Income deleted successfully.")
                st.rerun()

# ----------------------------
# Add Expense
# ----------------------------
elif page == "Add Expense":
    st.title("🧾 Add Expense")

    categories = list(st.session_state.category_map.keys())
    member_names = get_member_names()

    with st.form("expense_form", clear_on_submit=True):
        exp_date = st.date_input("Date", value=date.today())
        expense_type = st.radio("Expense Type", ["Individual", "Combined"], horizontal=True)
        paid_by = st.selectbox("Paid By", member_names)
        default_participants = [paid_by] if expense_type == "Individual" else member_names
        participants = st.multiselect("Participants", member_names, default=default_participants)
        category = st.selectbox("Category", categories)
        subcategory = st.selectbox("Subcategory", st.session_state.category_map.get(category, ["Miscellaneous"]))
        amount = st.number_input("Amount", min_value=0, step=100, format="%d")
        description = st.text_area("Description")
        submit_expense = st.form_submit_button("Save Expense")

    if submit_expense:
        if amount <= 0:
            st.error("Amount must be greater than zero.")
        elif expense_type == "Combined" and not participants:
            st.error("Please select at least one participant for combined expense.")
        else:
            if expense_type == "Individual":
                participants = [paid_by]

            new_row = pd.DataFrame([{
                "ID": st.session_state.next_expense_id,
                "Date": str(exp_date),
                "Expense Type": expense_type,
                "Paid By": paid_by,
                "Participants": ", ".join(participants),
                "Category": category,
                "Subcategory": subcategory,
                "Amount": int(amount),
                "Description": description,
                "Month": normalize_month(exp_date)
            }])
            st.session_state.expense_df = pd.concat([st.session_state.expense_df, new_row], ignore_index=True)
            st.session_state.next_expense_id += 1
            st.success("Expense added successfully.")

    st.markdown("### Expense Records")
    st.dataframe(st.session_state.expense_df, use_container_width=True, hide_index=True, column_config=format_df(st.session_state.expense_df))

    if not st.session_state.expense_df.empty:
        st.markdown("### Edit or Delete Expense")
        selected_expense_id = st.selectbox("Select Expense Record", st.session_state.expense_df["ID"].tolist())
        selected_expense = st.session_state.expense_df[st.session_state.expense_df["ID"] == selected_expense_id].iloc[0]

        existing_participants = [p.strip() for p in str(selected_expense["Participants"]).split(",") if p.strip()]
        category_index = categories.index(selected_expense["Category"]) if selected_expense["Category"] in categories else 0

        col1, col2 = st.columns([3, 1])
        with col1:
            with st.form("edit_expense_form"):
                edit_exp_date = st.date_input("Edit Date", value=pd.to_datetime(selected_expense["Date"]).date())
                edit_expense_type = st.radio(
                    "Edit Expense Type",
                    ["Individual", "Combined"],
                    index=0 if selected_expense["Expense Type"] == "Individual" else 1,
                    horizontal=True
                )
                paid_by_index = member_names.index(selected_expense["Paid By"]) if selected_expense["Paid By"] in member_names else 0
                edit_paid_by = st.selectbox("Edit Paid By", member_names, index=paid_by_index)
                edit_participants = st.multiselect("Edit Participants", member_names, default=existing_participants)
                edit_category = st.selectbox("Edit Category", categories, index=category_index)
                subcategory_options = st.session_state.category_map.get(edit_category, ["Miscellaneous"])
                sub_index = subcategory_options.index(selected_expense["Subcategory"]) if selected_expense["Subcategory"] in subcategory_options else 0
                edit_subcategory = st.selectbox("Edit Subcategory", subcategory_options, index=sub_index)
                edit_amount = st.number_input("Edit Amount", min_value=0, step=100, format="%d", value=int(selected_expense["Amount"]))
                edit_description = st.text_area("Edit Description", value=selected_expense["Description"])
                update_expense = st.form_submit_button("Update Expense")

            if update_expense:
                if edit_expense_type == "Combined" and not edit_participants:
                    st.error("Please select at least one participant for combined expense.")
                else:
                    if edit_expense_type == "Individual":
                        edit_participants = [edit_paid_by]

                    idx = st.session_state.expense_df.index[st.session_state.expense_df["ID"] == selected_expense_id][0]
                    st.session_state.expense_df.at[idx, "Date"] = str(edit_exp_date)
                    st.session_state.expense_df.at[idx, "Expense Type"] = edit_expense_type
                    st.session_state.expense_df.at[idx, "Paid By"] = edit_paid_by
                    st.session_state.expense_df.at[idx, "Participants"] = ", ".join(edit_participants)
                    st.session_state.expense_df.at[idx, "Category"] = edit_category
                    st.session_state.expense_df.at[idx, "Subcategory"] = edit_subcategory
                    st.session_state.expense_df.at[idx, "Amount"] = int(edit_amount)
                    st.session_state.expense_df.at[idx, "Description"] = edit_description
                    st.session_state.expense_df.at[idx, "Month"] = normalize_month(edit_exp_date)
                    st.success("Expense updated successfully.")

        with col2:
            st.write("")
            st.write("")
            if st.button("Delete Expense", type="primary"):
                st.session_state.expense_df = st.session_state.expense_df[st.session_state.expense_df["ID"] != selected_expense_id].reset_index(drop=True)
                st.success("Expense deleted successfully.")
                st.rerun()

# ----------------------------
# Monthly Budget
# ----------------------------
elif page == "Monthly Budget":
    st.title("📅 Monthly Budget")

    budget_df = st.session_state.budget_df.copy()
    edited_budget = st.data_editor(
        budget_df,
        num_rows="dynamic",
        use_container_width=True,
        key="budget_editor",
        hide_index=True,
        column_config={
            "Monthly Budget": st.column_config.NumberColumn(format="%,d")
        }
    )

    col1, col2 = st.columns([1, 1])

    with col1:
        if st.button("Save Budget"):
            edited_budget["Monthly Budget"] = pd.to_numeric(edited_budget["Monthly Budget"], errors="coerce").fillna(0).astype(int)
            st.session_state.budget_df = edited_budget
            st.success("Budget updated successfully.")

    with col2:
        if not st.session_state.budget_df.empty:
            delete_budget_category = st.selectbox("Delete Budget Row", st.session_state.budget_df["Category"].tolist())
            if st.button("Delete Budget Category"):
                st.session_state.budget_df = st.session_state.budget_df[
                    st.session_state.budget_df["Category"] != delete_budget_category
                ].reset_index(drop=True)
                st.success("Budget row deleted successfully.")
                st.rerun()

    st.markdown("### Budget vs Expense")
    expense_df = st.session_state.expense_df.copy()
    current_month = date.today().strftime("%Y-%m")
    if not expense_df.empty:
        this_month_expense = expense_df[expense_df["Month"] == current_month].groupby("Category", as_index=False)["Amount"].sum()
    else:
        this_month_expense = pd.DataFrame(columns=["Category", "Amount"])

    merged = st.session_state.budget_df.merge(this_month_expense, on="Category", how="left")
    merged["Amount"] = merged["Amount"].fillna(0).astype(int)
    merged["Remaining"] = (merged["Monthly Budget"] - merged["Amount"]).astype(int)
    merged = merged.rename(columns={"Amount": "Spent"})
    st.dataframe(merged, use_container_width=True, hide_index=True, column_config=format_df(merged))

# ----------------------------
# Masters
# ----------------------------
elif page == "Masters":
    st.title("🛠️ Masters")

    tab1, tab2, tab3 = st.tabs(["Family Members", "Income Sources", "Categories & Subcategories"])

    with tab1:
        st.subheader("Family Members")
        st.caption("At least one family member is compulsory.")

        col1, col2 = st.columns(2)
        with col1:
            new_name = st.text_input("New Family Member Name")
            new_position = st.selectbox(
                "New Family Position",
                ["Father", "Mother", "Son", "Daughter", "Brother", "Sister", "Grandfather", "Grandmother", "Other"],
                key="masters_new_position"
            )
            if st.button("Add Family Member"):
                success, message = add_member(new_name, new_position)
                if success:
                    st.success(message)
                    st.rerun()
                else:
                    st.warning(message)

        with col2:
            member_names = get_member_names()
            selected_member_name = st.selectbox("Delete Family Member", member_names)
            if st.button("Delete Family Member"):
                if len(st.session_state.member_df) <= 1:
                    st.error("At least one family member must remain.")
                else:
                    st.session_state.member_df = st.session_state.member_df[
                        st.session_state.member_df["Name"] != selected_member_name
                    ].reset_index(drop=True)
                    st.success("Family member deleted successfully.")
                    st.rerun()

        st.markdown("### Rename / Update Family Position")
        member_names = get_member_names()
        selected_edit_member = st.selectbox("Select Family Member", member_names, key="edit_family_member")

        selected_row = st.session_state.member_df[
            st.session_state.member_df["Name"] == selected_edit_member
        ].iloc[0]

        edit_name = st.text_input("Edit Name", value=selected_row["Name"])
        family_positions = ["Father", "Mother", "Son", "Daughter", "Brother", "Sister", "Grandfather", "Grandmother", "Other"]
        edit_position = st.selectbox(
            "Edit Family Position",
            family_positions,
            index=family_positions.index(selected_row["Family Position"]) if selected_row["Family Position"] in family_positions else 0,
            key="edit_family_position"
        )

        if st.button("Update Family Member"):
            edit_name = edit_name.strip()
            if not edit_name:
                st.warning("Name cannot be empty.")
            else:
                old_name = selected_row["Name"]

                duplicate_name = st.session_state.member_df[
                    (st.session_state.member_df["Name"] == edit_name) &
                    (st.session_state.member_df["Name"] != old_name)
                ]

                if not duplicate_name.empty:
                    st.warning("Another family member already has this name.")
                else:
                    idx = st.session_state.member_df.index[
                        st.session_state.member_df["Name"] == old_name
                    ][0]
                    st.session_state.member_df.at[idx, "Name"] = edit_name
                    st.session_state.member_df.at[idx, "Family Position"] = edit_position

                    if not st.session_state.income_df.empty:
                        st.session_state.income_df.loc[
                            st.session_state.income_df["Member"] == old_name, "Member"
                        ] = edit_name

                    if not st.session_state.expense_df.empty:
                        st.session_state.expense_df.loc[
                            st.session_state.expense_df["Paid By"] == old_name, "Paid By"
                        ] = edit_name

                        st.session_state.expense_df["Participants"] = st.session_state.expense_df["Participants"].astype(str).str.replace(
                            old_name, edit_name, regex=False
                        )

                    st.success("Family member updated successfully.")
                    st.rerun()

        st.dataframe(st.session_state.member_df, use_container_width=True, hide_index=True)

    with tab2:
        st.subheader("Income Sources")

        col1, col2 = st.columns(2)
        with col1:
            new_income_source = st.text_input("New Income Source")
            if st.button("Add Income Source"):
                if not new_income_source.strip():
                    st.warning("Enter a valid income source.")
                elif new_income_source.strip() in st.session_state.income_sources:
                    st.warning("This income source already exists.")
                else:
                    st.session_state.income_sources.append(new_income_source.strip())
                    st.success("Income source added successfully.")
                    st.rerun()

        with col2:
            selected_source = st.selectbox("Delete Income Source", st.session_state.income_sources)
            if st.button("Delete Income Source"):
                if len(st.session_state.income_sources) <= 1:
                    st.error("At least one income source must remain.")
                else:
                    st.session_state.income_sources.remove(selected_source)
                    st.success("Income source deleted successfully.")
                    st.rerun()

        rename_source = st.selectbox("Rename Income Source", st.session_state.income_sources)
        renamed_value = st.text_input("New Name for Selected Source")
        if st.button("Update Income Source Name"):
            if not renamed_value.strip():
                st.warning("Enter a valid new name.")
            elif renamed_value.strip() in st.session_state.income_sources:
                st.warning("This income source already exists.")
            else:
                idx = st.session_state.income_sources.index(rename_source)
                st.session_state.income_sources[idx] = renamed_value.strip()
                st.success("Income source renamed successfully.")
                st.rerun()

        st.dataframe(pd.DataFrame({"Income Source": st.session_state.income_sources}), use_container_width=True, hide_index=True)

    with tab3:
        st.subheader("Categories & Subcategories")

        categories = list(st.session_state.category_map.keys())

        col1, col2 = st.columns(2)
        with col1:
            new_category = st.text_input("New Category")
            if st.button("Add Category"):
                if not new_category.strip():
                    st.warning("Enter a valid category.")
                elif new_category.strip() in st.session_state.category_map:
                    st.warning("This category already exists.")
                else:
                    st.session_state.category_map[new_category.strip()] = ["Miscellaneous"]
                    st.success("Category added successfully.")
                    st.rerun()

        with col2:
            delete_category = st.selectbox("Delete Category", categories)
            if st.button("Delete Category"):
                if len(st.session_state.category_map) <= 1:
                    st.error("At least one category must remain.")
                else:
                    del st.session_state.category_map[delete_category]
                    st.success("Category deleted successfully.")
                    st.rerun()

        rename_category = st.selectbox("Rename Category", categories)
        renamed_category_value = st.text_input("New Category Name")
        if st.button("Update Category Name"):
            if not renamed_category_value.strip():
                st.warning("Enter a valid category name.")
            elif renamed_category_value.strip() in st.session_state.category_map:
                st.warning("This category already exists.")
            else:
                st.session_state.category_map[renamed_category_value.strip()] = st.session_state.category_map.pop(rename_category)
                st.success("Category renamed successfully.")
                st.rerun()

        st.markdown("---")
        current_category = st.selectbox("Manage Subcategories For", list(st.session_state.category_map.keys()))
        current_subcategories = st.session_state.category_map[current_category]

        sub1, sub2 = st.columns(2)
        with sub1:
            new_subcategory = st.text_input("New Subcategory")
            if st.button("Add Subcategory"):
                if not new_subcategory.strip():
                    st.warning("Enter a valid subcategory.")
                elif new_subcategory.strip() in st.session_state.category_map[current_category]:
                    st.warning("This subcategory already exists.")
                else:
                    st.session_state.category_map[current_category].append(new_subcategory.strip())
                    st.success("Subcategory added successfully.")
                    st.rerun()

        with sub2:
            delete_subcategory = st.selectbox("Delete Subcategory", current_subcategories)
            if st.button("Delete Subcategory"):
                if len(st.session_state.category_map[current_category]) <= 1:
                    st.error("At least one subcategory must remain in a category.")
                else:
                    st.session_state.category_map[current_category].remove(delete_subcategory)
                    st.success("Subcategory deleted successfully.")
                    st.rerun()

        rename_subcategory = st.selectbox("Rename Subcategory", current_subcategories)
        renamed_subcategory_value = st.text_input("New Subcategory Name")
        if st.button("Update Subcategory Name"):
            if not renamed_subcategory_value.strip():
                st.warning("Enter a valid subcategory name.")
            elif renamed_subcategory_value.strip() in st.session_state.category_map[current_category]:
                st.warning("This subcategory already exists.")
            else:
                idx = st.session_state.category_map[current_category].index(rename_subcategory)
                st.session_state.category_map[current_category][idx] = renamed_subcategory_value.strip()
                st.success("Subcategory renamed successfully.")
                st.rerun()

        flat_rows = []
        for cat, subs in st.session_state.category_map.items():
            for sub in subs:
                flat_rows.append({"Category": cat, "Subcategory": sub})

        st.dataframe(pd.DataFrame(flat_rows), use_container_width=True, hide_index=True)

# ----------------------------
# Reports
# ----------------------------
elif page == "Reports":
    st.title("📊 Reports")

    expense_df = st.session_state.expense_df.copy()
    income_df = st.session_state.income_df.copy()

    if expense_df.empty and income_df.empty:
        st.info("No data available yet.")
    else:
        st.markdown("### Filter Reports")
        col1, col2, col3 = st.columns(3)

        with col1:
            report_month = st.text_input("Month (YYYY-MM)", value=date.today().strftime("%Y-%m"))
        with col2:
            member_filter = st.selectbox("Member", ["All"] + get_member_names())
        with col3:
            category_filter = st.selectbox("Category", ["All"] + list(st.session_state.category_map.keys()))

        filtered_expense = expense_df.copy()
        filtered_income = income_df.copy()

        if not filtered_expense.empty:
            filtered_expense = filtered_expense[filtered_expense["Month"] == report_month]

        if not filtered_income.empty:
            filtered_income = filtered_income[filtered_income["Date"].astype(str).str[:7] == report_month]

        if member_filter != "All":
            if not filtered_expense.empty:
                filtered_expense = filtered_expense[filtered_expense["Paid By"] == member_filter]
            if not filtered_income.empty:
                filtered_income = filtered_income[filtered_income["Member"] == member_filter]

        if category_filter != "All" and not filtered_expense.empty:
            filtered_expense = filtered_expense[filtered_expense["Category"] == category_filter]

        total_income = int(filtered_income["Amount"].sum()) if not filtered_income.empty else 0
        total_expense = int(filtered_expense["Amount"].sum()) if not filtered_expense.empty else 0
        savings = total_income - total_expense

        r1, r2, r3 = st.columns(3)
        r1.metric("Report Income", f"Rs. {total_income:,}")
        r2.metric("Report Expense", f"Rs. {total_expense:,}")
        r3.metric("Savings", f"Rs. {savings:,}")

        st.markdown("### Expense Table")
        st.dataframe(filtered_expense, use_container_width=True, hide_index=True, column_config=format_df(filtered_expense))

        st.markdown("### Income Table")
        st.dataframe(filtered_income, use_container_width=True, hide_index=True, column_config=format_df(filtered_income))

        if not filtered_expense.empty:
            st.markdown("### Category Summary")
            summary = filtered_expense.groupby("Category", as_index=False)["Amount"].sum().sort_values("Amount", ascending=False)
            st.dataframe(summary, use_container_width=True, hide_index=True, column_config=format_df(summary))
            st.bar_chart(summary.set_index("Category"))

            st.markdown("### Expense Type Summary")
            type_summary = filtered_expense.groupby("Expense Type", as_index=False)["Amount"].sum()
            st.dataframe(type_summary, use_container_width=True, hide_index=True, column_config=format_df(type_summary))
            st.bar_chart(type_summary.set_index("Expense Type"))

# ----------------------------
# Development Notes
# ----------------------------
elif page == "Development Notes":
    st.title("📝 Development Notes")

    with st.form("dev_note_form", clear_on_submit=True):
        note_date = st.date_input("Date", value=date.today())
        note_type = st.selectbox("Type", ["Requirement", "Bug", "Improvement", "Idea", "Task"])
        title = st.text_input("Title")
        details = st.text_area("Details")
        status = st.selectbox("Status", ["Open", "In Progress", "Completed", "Hold"])
        submit_note = st.form_submit_button("Add Note")

    if submit_note:
        if not title.strip():
            st.error("Title is required.")
        else:
            new_row = pd.DataFrame([{
                "ID": st.session_state.next_note_id,
                "Date": str(note_date),
                "Type": note_type,
                "Title": title.strip(),
                "Details": details.strip(),
                "Status": status
            }])
            st.session_state.dev_notes_df = pd.concat([st.session_state.dev_notes_df, new_row], ignore_index=True)
            st.session_state.next_note_id += 1
            st.success("Development note added successfully.")

    st.markdown("### Notes List")
    st.dataframe(st.session_state.dev_notes_df, use_container_width=True, hide_index=True)

    if not st.session_state.dev_notes_df.empty:
        st.markdown("### Edit or Delete Note")
        selected_note_id = st.selectbox("Select Note", st.session_state.dev_notes_df["ID"].tolist())
        selected_note = st.session_state.dev_notes_df[st.session_state.dev_notes_df["ID"] == selected_note_id].iloc[0]

        type_options = ["Requirement", "Bug", "Improvement", "Idea", "Task"]
        status_options = ["Open", "In Progress", "Completed", "Hold"]

        col1, col2 = st.columns([3, 1])
        with col1:
            with st.form("edit_note_form"):
                edit_note_date = st.date_input("Edit Date", value=pd.to_datetime(selected_note["Date"]).date())
                edit_note_type = st.selectbox("Edit Type", type_options, index=type_options.index(selected_note["Type"]))
                edit_title = st.text_input("Edit Title", value=selected_note["Title"])
                edit_details = st.text_area("Edit Details", value=selected_note["Details"])
                edit_status = st.selectbox("Edit Status", status_options, index=status_options.index(selected_note["Status"]))
                update_note = st.form_submit_button("Update Note")

            if update_note:
                if not edit_title.strip():
                    st.error("Title is required.")
                else:
                    idx = st.session_state.dev_notes_df.index[st.session_state.dev_notes_df["ID"] == selected_note_id][0]
                    st.session_state.dev_notes_df.at[idx, "Date"] = str(edit_note_date)
                    st.session_state.dev_notes_df.at[idx, "Type"] = edit_note_type
                    st.session_state.dev_notes_df.at[idx, "Title"] = edit_title.strip()
                    st.session_state.dev_notes_df.at[idx, "Details"] = edit_details.strip()
                    st.session_state.dev_notes_df.at[idx, "Status"] = edit_status
                    st.success("Development note updated successfully.")

        with col2:
            st.write("")
            st.write("")
            if st.button("Delete Note", type="primary"):
                st.session_state.dev_notes_df = st.session_state.dev_notes_df[st.session_state.dev_notes_df["ID"] != selected_note_id].reset_index(drop=True)
                st.success("Development note deleted successfully.")
                st.rerun()

# ----------------------------
# Data Backup
# ----------------------------
elif page == "Data Backup":
    st.title("💾 Data Backup")

    st.markdown("### Download Current Data")
    st.download_button(
        "Download Family Members CSV",
        data=dataframe_to_csv_download(st.session_state.member_df),
        file_name="family_members.csv",
        mime="text/csv"
    )
    st.download_button(
        "Download Income CSV",
        data=dataframe_to_csv_download(st.session_state.income_df),
        file_name="income_data.csv",
        mime="text/csv"
    )
    st.download_button(
        "Download Expense CSV",
        data=dataframe_to_csv_download(st.session_state.expense_df),
        file_name="expense_data.csv",
        mime="text/csv"
    )
    st.download_button(
        "Download Budget CSV",
        data=dataframe_to_csv_download(st.session_state.budget_df),
        file_name="budget_data.csv",
        mime="text/csv"
    )
    st.download_button(
        "Download Development Notes CSV",
        data=dataframe_to_csv_download(st.session_state.dev_notes_df),
        file_name="development_notes.csv",
        mime="text/csv"
    )

    st.markdown("### Restore from CSV")
    uploaded_members = st.file_uploader("Upload Family Members CSV", type=["csv"], key="members_upload")
    uploaded_income = st.file_uploader("Upload Income CSV", type=["csv"], key="income_upload")
    uploaded_expense = st.file_uploader("Upload Expense CSV", type=["csv"], key="expense_upload")
    uploaded_budget = st.file_uploader("Upload Budget CSV", type=["csv"], key="budget_upload")
    uploaded_notes = st.file_uploader("Upload Development Notes CSV", type=["csv"], key="notes_upload")

    if st.button("Restore Uploaded Data"):
        try:
            if uploaded_members is not None:
                st.session_state.member_df = load_uploaded_csv(uploaded_members, ["Name", "Family Position"])
            if uploaded_income is not None:
                st.session_state.income_df = load_uploaded_csv(uploaded_income, ["ID", "Date", "Member", "Source", "Amount", "Notes"])
            if uploaded_expense is not None:
                st.session_state.expense_df = load_uploaded_csv(
                    uploaded_expense,
                    ["ID", "Date", "Expense Type", "Paid By", "Participants", "Category", "Subcategory", "Amount", "Description", "Month"]
                )
            if uploaded_budget is not None:
                st.session_state.budget_df = load_uploaded_csv(uploaded_budget, ["Category", "Monthly Budget"])
            if uploaded_notes is not None:
                st.session_state.dev_notes_df = load_uploaded_csv(uploaded_notes, ["ID", "Date", "Type", "Title", "Details", "Status"])

            if not st.session_state.income_df.empty:
                st.session_state.next_income_id = int(pd.to_numeric(st.session_state.income_df["ID"], errors="coerce").fillna(0).max()) + 1
            if not st.session_state.expense_df.empty:
                st.session_state.next_expense_id = int(pd.to_numeric(st.session_state.expense_df["ID"], errors="coerce").fillna(0).max()) + 1
            if not st.session_state.dev_notes_df.empty:
                st.session_state.next_note_id = int(pd.to_numeric(st.session_state.dev_notes_df["ID"], errors="coerce").fillna(0).max()) + 1

            st.success("Data restored successfully.")
        except Exception as e:
            st.error(f"Restore failed: {e}")