Update app.py

app.py

@@ -1,4 +1,4 @@
-import streamlit as st
+import gradio as gr
 
 # --- Data Structures ---
 Inventory = [
@@ -9,49 +9,112 @@ Inventory = [
     ("Mangoes", 150),
 ]
 
-# Convert Inventory into a dictionary for easier lookup: {"Apples": 250, "Cherry": 650, ...}
-price_dict = {item[0]: item[1] for item in Inventory}
-
-# Initialize the cart in session state if not already present
-if "cart" not in st.session_state:
-    st.session_state.cart = []  # Each element will be a tuple (product_name, quantity)
-
-# --- Streamlit Layout ---
-st.title("Shopping Cart Management System")
-
-# 1. Add Products to the Shopping Cart
-st.subheader("Add Items to Your Cart")
-product_list = [item[0] for item in Inventory]  # ["Apples", "Cherry", "Chickoo", "Oranges", "Mangoes"]
-selected_product = st.selectbox("Select a product", product_list)
-selected_quantity = st.number_input("Quantity", min_value=1, value=1, step=1)
-
-if st.button("Add to Cart"):
-    # Append (product, quantity) to the cart
-    st.session_state.cart.append((selected_product, selected_quantity))
-    st.success(f"Added {selected_quantity} {selected_product}(s) to your cart!")
-
-st.write("---")
-
-# 2. Display and Remove Items from the Shopping Cart
-st.subheader("Items in Your Cart")
-if len(st.session_state.cart) == 0:
-    st.info("Your cart is empty. Add some items!")
-else:
-    # List each item along with remove button
-    for i, (product, quantity) in enumerate(st.session_state.cart):
-        col1, col2, col3 = st.columns([3, 2, 1])
-        with col1:
-            st.write(f"**{product}** x {quantity} @ {price_dict[product]} each")
-        with col2:
-            st.write(f"Subtotal: {price_dict[product] * quantity}")
-        with col3:
-            # Create a dynamic remove button
-            remove_button_label = f"Remove-{i}"
-            if st.button("Remove", key=remove_button_label):
-                st.session_state.cart.pop(i)
-                st.experimental_rerun()  # Refresh the app so the item disappears immediately
-
-    # 3. Calculate the Total Bill
-    total_bill = sum(price_dict[p] * q for p, q in st.session_state.cart)
-    st.write("---")
-    st.subheader(f"**Total Bill: {total_bill}**")
+# Create a price lookup dictionary for convenience.
+price_dict = {name: price for name, price in Inventory}
+
+def format_cart(cart):
+    """Return a formatted string of the cart contents and total bill."""
+    if not cart:
+        return "Your cart is empty."
+    summary = ""
+    total = 0
+    for i, (product, quantity) in enumerate(cart):
+        price = price_dict[product]
+        subtotal = price * quantity
+        summary += f"{i+1}. **{product}** x {quantity} @ {price} each = {subtotal}\n"
+        total += subtotal
+    summary += f"\n**Total Bill:** {total}"
+    return summary
+
+def generate_remove_options(cart):
+    """Generate options for the removal dropdown from the cart list."""
+    options = []
+    for i, (product, quantity) in enumerate(cart):
+        price = price_dict[product]
+        subtotal = price * quantity
+        options.append(f"{i}: {product} x {quantity} (Subtotal: {subtotal})")
+    return options
+
+def add_to_cart(product, quantity, cart):
+    """
+    Add the selected product and quantity to the cart.
+    Returns the updated cart state, a message, the cart summary,
+    and updated removal dropdown options.
+    """
+    # Ensure the cart exists.
+    if cart is None:
+        cart = []
+    cart.append((product, int(quantity)))
+    message = f"Added {int(quantity)} **{product}**(s) to your cart!"
+    summary = format_cart(cart)
+    remove_options = generate_remove_options(cart)
+    # Use gr.Dropdown.update to update the choices for removal.
+    return cart, message, summary, gr.Dropdown.update(choices=remove_options)
+
+def remove_from_cart(selected_option, cart):
+    """
+    Remove the selected item from the cart.
+    Returns the updated cart state, a message, the cart summary,
+    and updated removal dropdown options.
+    """
+    if not cart:
+        message = "Cart is empty."
+        return cart, message, format_cart(cart), gr.Dropdown.update(choices=[])
+    # Extract the index from the selected option.
+    index = int(selected_option.split(":")[0])
+    removed_item = cart.pop(index)
+    message = f"Removed {removed_item[1]} **{removed_item[0]}**(s) from your cart."
+    summary = format_cart(cart)
+    remove_options = generate_remove_options(cart)
+    return cart, message, summary, gr.Dropdown.update(choices=remove_options)
+
+# --- Build the Gradio Interface ---
+with gr.Blocks() as demo:
+    # Initialize an empty cart in state.
+    cart_state = gr.State([])
+
+    gr.Markdown("# Gradio Shopping Cart")
+
+    with gr.Row():
+        product_input = gr.Dropdown(
+            label="Select Product",
+            choices=[name for name, _ in Inventory],
+            value=Inventory[0][0]
+        )
+        quantity_input = gr.Number(
+            label="Quantity",
+            value=1,
+            precision=0
+        )
+        add_button = gr.Button("Add to Cart")
+
+    add_message = gr.Markdown("")  # To display add-to-cart messages.
+    cart_display = gr.Textbox(
+        label="Cart Summary",
+        interactive=False,
+        lines=10,
+        value="Your cart is empty."
+    )
+
+    gr.Markdown("## Remove Items from Cart")
+    with gr.Row():
+        remove_dropdown = gr.Dropdown(
+            label="Select Item to Remove",
+            choices=[]  # Updated dynamically after adding items.
+        )
+        remove_button = gr.Button("Remove Selected Item")
+    remove_message = gr.Markdown("")  # To display removal messages.
+
+    # Set up interactions:
+    add_button.click(
+        fn=add_to_cart,
+        inputs=[product_input, quantity_input, cart_state],
+        outputs=[cart_state, add_message, cart_display, remove_dropdown]
+    )
+    remove_button.click(
+        fn=remove_from_cart,
+        inputs=[remove_dropdown, cart_state],
+        outputs=[cart_state, remove_message, cart_display, remove_dropdown]
+    )
+
+demo.launch()