import gradio as gr

# -----------------------------
# Core data and logic
# -----------------------------

# Same inventory as in the notebook
Inventory = [
    [1, "Apples", 250],
    [2, "Cherry", 650],
    [3, "Chickoo", 50],
    [4, "Grapes", 90],
    [5, "Mangoes", 150],
]

# Global cart (Space will run single-process)
YourCart = []  # each item is [product_id, name, price_per_kg]

def add_item_to_cart(item_id: int):
    """Add one unit of the given product ID to the cart."""
    try:
        item = Inventory[item_id - 1]
    except IndexError:
        return "Invalid item ID. Please enter a valid Product ID."

    YourCart.append(item)
    return f"The item {item[1]} has been added to the cart, and your shopping cart has been updated."

def remove_item_from_cart(cart_index: int):
    """Remove item by 1-based index from the cart."""
    if not YourCart:
        return "Invalid cart index or cart is empty."

    try:
        removed_item = YourCart.pop(cart_index - 1)
        return f"The item {removed_item[1]} has been removed from the cart, and your shopping cart has been updated."
    except IndexError:
        return "Invalid cart index or cart is empty."

def display_cart(cart):
    """Return a formatted string of the cart contents."""
    if not cart:
        return "Your cart is empty!!!\nWhy not buy Fruits from us ..."

    lines = []
    lines.append("Your Cart\n")
    lines.append("Index   Name           Quantity   Price (Total)\n")
    lines.append("--------------------------------------------------")

    unique_items = list({tuple(i) for i in cart})
    total_cost = 0

    for idx, item in enumerate(unique_items, start=1):
        quantity = cart.count(list(item))
        name = item[1]
        price_per_kg = item[2]
        price_total = price_per_kg * quantity
        total_cost += price_total
        lines.append(
            f"{idx:<7} {name:<14} {quantity:<9} {price_total:>10.2f}"
        )

    lines.append("--------------------------------------------------")
    lines.append(f"Total Cost: {total_cost:.2f}")
    return "\n".join(lines)

def total_cost(cart):
    """Compute total cost as plain string."""
    if not cart:
        return "Total cost: 0.00"
    s = sum(item[2] for item in cart)
    return f"Total cost: {s:.2f}"

# -----------------------------
# Gradio interface wrapper
# -----------------------------

def gradio_interface(item_id, cart_index):
    """
    Wrapper matching your notebook logic:
    - If item_id is provided, add that product.
    - If cart_index is provided, remove that entry.
    - Always return: cart_display, add_message, remove_message, total_cost_message.
    """
    add_msg = ""
    remove_msg = ""

    # Normalize None to 0 (Gradio Number can return None)
    if item_id is not None and item_id > 0:
        add_msg = add_item_to_cart(int(item_id))

    if cart_index is not None and cart_index > 0:
        remove_msg = remove_item_from_cart(int(cart_index))

    cart_display = display_cart(YourCart)
    cost_msg = total_cost(YourCart)

    return cart_display, add_msg, remove_msg, cost_msg

# -----------------------------
# Build Gradio Blocks UI
# -----------------------------

with gr.Blocks() as demo:
    gr.Markdown("# Fruit Shopping Cart System")

    with gr.Row():
        itemid_input = gr.Number(
            label="Enter Product ID to Add to Cart",
            interactive=True
        )
        cartindex_input = gr.Number(
            label="Enter Index ID to Remove from Cart",
            interactive=True
        )

    with gr.Row():
        add_button = gr.Button("Add to Cart")
        remove_button = gr.Button("Remove from Cart")

    cart_display_output = gr.Textbox(
        label="Your Cart",
        interactive=False,
        lines=12
    )
    add_message_output = gr.Textbox(
        label="Add Item Message",
        interactive=False,
        lines=3
    )
    remove_message_output = gr.Textbox(
        label="Remove Item Message",
        interactive=False,
        lines=3
    )
    total_cost_output = gr.Textbox(
        label="Total Cost",
        interactive=False,
        lines=2
    )

    # Add item: pass itemid_input and a dummy 0 for cart_index
    add_button.click(
        fn=gradio_interface,
        inputs=[itemid_input, gr.Number(visible=False, value=0)],
        outputs=[
            cart_display_output,
            add_message_output,
            remove_message_output,
            total_cost_output,
        ],
    )

    # Remove item: pass a dummy 0 for item_id and cartindex_input
    remove_button.click(
        fn=gradio_interface,
        inputs=[gr.Number(visible=False, value=0), cartindex_input],
        outputs=[
            cart_display_output,
            add_message_output,
            remove_message_output,
            total_cost_output,
        ],
    )

# This is the entrypoint Hugging Face Spaces expects
if __name__ == "__main__":
    demo.launch()