Update app.py

app.py

@@ -1222,547 +1222,183 @@ def visualize_reorganization(df_items, df_loc, df_pairs, df_recs, coords, id_to_
     return img
 
 # =============================================================================
-# GRADIO INTERFACE
+# GRADIO INTERFACE LAYOUT
 # =============================================================================
 
-with gr.Blocks(title="Makerspace Inventory System", css=CUSTOM_CSS) as demo:
-    
-    # State variables
-    matched_items_state = gr.State(None)
-    proposals_state = gr.State([])
-    
-    # Main menu
-    with gr.Group(visible=True, elem_id="main-menu-container") as main_menu:
-        gr.Markdown("# 🔧 Makerspace Inventory System", elem_id="main-menu-title")
-        gr.Markdown("*Smart inventory management powered by AI*", elem_id="main-menu-subtitle")
-        
+# --- Navigation Handler ---
+def change_page(page_name):
+    """
+    Returns visibility updates (True/False) for the four main containers.
+    The order must match the 'outputs' list in the .click() methods.
+    """
+    is_main = page_name == 'main'
+    is_checkout = page_name == 'checkout'
+    is_add_items = page_name == 'add_items'
+    is_analysis = page_name == 'analysis'
+
+    return gr.update(visible=is_main), gr.update(visible=is_checkout), gr.update(visible=is_add_items), gr.update(visible=is_analysis)
+
+
+# --- Gradio Blocks UI Definition ---
+with gr.Blocks(css=CUSTOM_CSS, title="Makerspace Inventory Management System") as demo:
+
+    # 1. Define Page Containers (Visibility controlled via the .click() method)
+    # The initial page (main menu) is visible=True, all others are visible=False.
+    main_menu_container = gr.Box(elem_id="main-menu-container")
+    checkout_page = gr.Box(visible=False, elem_classes="module-page")
+    add_items_page = gr.Box(visible=False, elem_classes="module-page")
+    analysis_page = gr.Box(visible=False, elem_classes="module-page")
+
+    # The list of outputs used by all navigation buttons
+    page_outputs = [main_menu_container, checkout_page, add_items_page, analysis_page]
+
+    # --- MAIN MENU (Always Visible Initially) ---
+    with main_menu_container:
+        gr.Markdown("# <span id='main-menu-title'>Integrated Makerspace Inventory</span>")
+        gr.Markdown("## <span id='main-menu-subtitle'>Smart inventory management powered by AI</span>")
         with gr.Row():
-            checkout_btn = gr.Button("🛒 Check Out Items", size="lg", elem_classes=["module-button"], scale=1)
-            add_items_btn = gr.Button("📦 Add Items", size="lg", elem_classes=["module-button"], scale=1)
-            analysis_btn = gr.Button("📊 Inventory Analysis", size="lg", elem_classes=["module-button"], scale=1)
-    
-    # CHECK OUT MODULE
-    with gr.Group(visible=False, elem_classes=["module-page"]) as checkout_module:
-        gr.Markdown("# 🛒 Check Out Items", elem_classes=["section-header"])
-        
-        with gr.Accordion("📖 How to Use", open=False):
-            gr.Markdown("""
-            **Step 1:** Upload a photo of items or type item names manually (comma-separated)
-            
-            **Step 2:** Review detected items and adjust quantities
-            
-            **Step 3:** Confirm checkout with optional user ID
-            
-            💡 **Tip:** The AI automatically matches items to inventory using smart search!
-            """)
-        
-        with gr.Group(visible=True) as checkout_screen1:
-            gr.Markdown("### 📸 Scan Items", elem_classes=["subsection-header"])
-            
-            with gr.Row():
-                with gr.Column(scale=2):
-                    checkout_image = gr.Image(
-                        type="pil", 
-                        label="Upload Image of Items", 
-                        sources=["upload", "webcam"],
-                        height=400
-                    )
-                    
-                    if EXAMPLE_CHECKOUT_IMAGE:
-                        load_example_checkout_btn = gr.Button("📸 Load Example", size="sm", variant="secondary", scale=0)
-                
-                with gr.Column(scale=1):
-                    gr.Markdown("""
-                    ### Quick Guide
-                    
-                    **Upload:** Click the upload icon to select an image from your device
-                    
-                    **Webcam:** Click the camera icon to take a photo with your webcam
-                    
-                    💡 Make sure items are clearly visible and well-lit
-                    """)
-            
-            checkout_manual = gr.Textbox(
-                label="Or Enter Item Names Manually",
-                placeholder="e.g., drill, safety glasses, Arduino",
-                info="Separate multiple items with commas"
-            )
-            
-            checkout_status = gr.Markdown("")
-            checkout_scan_btn = gr.Button("🔍 Scan & Match Items", variant="primary", size="lg")
-        
-        with gr.Group(visible=False) as checkout_screen2:
-            gr.Markdown("### ✅ Review Items", elem_classes=["subsection-header"])
-            gr.Markdown("*Adjust quantities or remove items before checkout*")
-            
-            checkout_item_controls = []
-            for i in range(10):
-                with gr.Row(visible=False) as item_row:
-                    with gr.Column(scale=3):
-                        item_info = gr.Markdown("")
-                    with gr.Column(scale=1):
-                        item_qty = gr.Number(value=1, minimum=1, label="Qty")
-                    with gr.Column(scale=1):
-                        item_remove = gr.Button("🗑️ Remove", size="sm", variant="stop")
-                
-                checkout_item_controls.append({
-                    'row': item_row,
-                    'info': item_info,
-                    'qty': item_qty,
-                    'remove': item_remove
-                })
-            
-            with gr.Row():
-                checkout_rescan_btn = gr.Button("↩️ Rescan", variant="secondary")
-                checkout_confirm_btn = gr.Button("✅ Proceed to Checkout", variant="primary", size="lg")
-        
-        with gr.Group(visible=False) as checkout_screen3:
-            gr.Markdown("### 🎫 Confirm Checkout", elem_classes=["subsection-header"])
-            
-            checkout_preview = gr.Markdown("")
-            
-            checkout_user_id = gr.Textbox(
-                label="User ID (Optional)",
-                placeholder="Enter your ID or leave blank",
-                info="Leave blank for auto-generated ID"
-            )
-            
-            checkout_processing = gr.Markdown("")
-            
-            with gr.Row():
-                checkout_cancel_btn = gr.Button("❌ Cancel", variant="secondary")
-                checkout_final_btn = gr.Button("✅ Complete Checkout", variant="primary", size="lg")
-        
+            checkout_btn = gr.Button("🛒 Check Out Items", elem_classes="module-button primary-button")
+            add_items_btn = gr.Button("➕ Add Items to Inventory", elem_classes="module-button primary-button")
+            analysis_btn = gr.Button("📊 Inventory Analysis", elem_classes="module-button primary-button")
+
+    # --- CHECK OUT MODULE ---
+    with checkout_page:
+        back_to_main_btn_c = gr.Button("← Back to Main Menu")
+        gr.Markdown("<div class='section-header'>🛒 Check Out Items</div>")
+
+        # Your existing CHECK OUT UI components go here:
+        with gr.Row(variant="panel", elem_classes="gap"):
+            with gr.Column(min_width=400):
+                gr.Markdown("### 📸 Scan Item(s) with Image or Webcam")
+                image_input = gr.Image(type="filepath", label="Upload Item Image", sources=["upload", "webcam"], elem_classes="image-upload-container")
+                manual_text_input = gr.Textbox(label="Manual Item Entry (Optional)", placeholder="e.g., drill bit, digital multimeter, 1/4 inch wrench", info="Enter comma-separated items if image detection fails.")
+
+            with gr.Column():
+                scan_btn = gr.Button("🔍 Scan & Match Items", variant="primary", elem_classes="primary-button")
+                match_status = gr.Markdown("Ready to scan.", elem_classes="instructions-box")
+                matched_items_state = gr.State(value=[])  # To hold the matched items data
+
+        gr.Markdown("### 📝 Review & Confirm Checkout")
+        checkout_preview = gr.Markdown("No items scanned yet.")
+        user_id_input = gr.Textbox(label="Your ID (Optional)", placeholder="Enter your student/staff ID for tracking.")
+        confirm_checkout_btn = gr.Button("✅ Confirm Checkout", variant="primary", elem_classes="primary-button")
         checkout_result = gr.Markdown("")
-        
-        with gr.Row():
-            checkout_return_btn = gr.Button("🏠 Return to Main Menu", variant="secondary")
-            checkout_another_btn = gr.Button("🛒 Check Out More Items", variant="primary", visible=False)
-    
-    # ADD ITEMS MODULE
-    with gr.Group(visible=False, elem_classes=["module-page"]) as add_items_module:
-        gr.Markdown("# 📦 Add Items to Inventory", elem_classes=["section-header"])
-        
-        with gr.Accordion("📖 How to Use", open=False):
-            gr.Markdown("""
-            **Receipt Upload:**
-            1. Upload receipt image or PDF → AI extracts items
-            2. Review and edit detected items (check/uncheck, edit quantities)
-            3. Click "Apply Updates" to add to inventory
-            
-            **Manual Entry:**
-            - Enter item name and quantity for quick updates
-            - System uses fuzzy matching to find items
-            
-            **View & History:**
-            - Browse inventory with category filters
-            - Track all changes with timestamps
-            """)
-        
-        with gr.Tab("📄 Receipt Upload"):
-            gr.Markdown("### Upload Receipt", elem_classes=["subsection-header"])
-            
-            receipt_file = gr.File(label="Upload Receipt (PDF or Image)", file_types=[".pdf", ".png", ".jpg", ".jpeg"])
-            
-            if EXAMPLE_RECEIPT_PDF:
-                load_example_receipt_btn = gr.Button("📄 Load Example", size="sm", variant="secondary", scale=0)
-            
-            receipt_status = gr.Markdown("")
-            
-            gr.Markdown("### Review Detected Items", elem_classes=["subsection-header"])
-            gr.Markdown("*Check items to include, edit quantities, then apply*")
-            
-            add_items_table = gr.Dataframe(
-                headers=["Include", "Item Name", "Quantity", "Match Confidence"],
-                label="Detected Items",
-                datatype=["bool", "str", "number", "str"],
-                interactive=True,
-                col_count=(4, "fixed")
-            )
-            
-            add_items_status = gr.Markdown("")
-            
-            with gr.Row():
-                add_items_reject_btn = gr.Button("❌ Clear All", variant="secondary")
-                add_items_confirm_btn = gr.Button("✅ Apply Updates", variant="primary", interactive=False)
-        
-        with gr.Tab("✍️ Manual Entry"):
-            gr.Markdown("### Manually Add Items", elem_classes=["subsection-header"])
-            
-            with gr.Row():
-                manual_item = gr.Textbox(
-                    label="Item Name",
-                    placeholder="e.g., Arduino Uno",
-                    info="Fuzzy matching will find similar items"
-                )
-                manual_qty = gr.Number(
-                    label="Quantity to Add",
-                    value=1,
-                    minimum=1
-                )
-            
-            manual_apply_btn = gr.Button("➕ Add to Inventory", variant="primary")
-            manual_status = gr.Markdown("")
-            manual_inventory_display = gr.Dataframe(label="Updated Inventory", visible=False)
-        
-        with gr.Tab("📊 View & History"):
-            gr.Markdown("### Current Inventory", elem_classes=["subsection-header"])
-            
-            with gr.Row():
-                inventory_category_filter = gr.Dropdown(
-                    choices=["All"] + get_categories(),
-                    value="All",
-                    label="Filter by Category"
-                )
-                view_inventory_btn = gr.Button("🔄 Refresh Inventory")
-            
-            inventory_display = gr.Dataframe(label="Current Inventory", visible=False)
-            
-            gr.Markdown("### Update History", elem_classes=["subsection-header"])
-            
-            view_history_btn = gr.Button("📜 View Update Log")
-            history_display = gr.Textbox(label="Update History", lines=10, visible=False)
-        
-        add_items_return_btn = gr.Button("🏠 Return to Main Menu", variant="secondary")
-    
-    # INVENTORY ANALYSIS MODULE
-    with gr.Group(visible=False, elem_classes=["module-page"]) as analysis_module:
-        gr.Markdown("# 📊 Inventory Layout Analysis", elem_classes=["section-header"])
-        
-        with gr.Accordion("📖 Understanding the Analysis", open=True):
-            gr.Markdown("""
-            This module analyzes checkout patterns to optimize item placement and minimize walking distance.
-            
-            ### 📈 Key Metrics:
-            
-            **Support** - Frequency of co-occurrence (e.g., 0.10 = 10% of checkouts)
-            
-            **Lift** - Correlation strength (Lift > 1 = items checked out together more than random)
-            
-            **Confidence** - Conditional probability (e.g., 0.80 = 80% chance of B when checking A)
-            
-            **Distance Saved** - Walking distance reduction in grid units
-            
-            ### 🎯 Goal:
-            Items frequently checked together should be placed closer to reduce travel time!
-            """)
-        
-        with gr.Row():
-            with gr.Column(scale=1):
-                gr.Markdown("### ⚙️ Parameters", elem_classes=["subsection-header"])
-                
-                min_support = gr.Slider(
-                    minimum=0.01,
-                    maximum=0.2,
-                    value=0.02,
-                    step=0.01,
-                    label="Minimum Support",
-                    info="Lower = more patterns (less significant)"
+
+        # Link CHECKOUT button actions to functions
+        scan_btn.click(
+            scan_items_checkout,
+            inputs=[image_input, manual_text_input],
+            outputs=[matched_items_state, match_status]
+        ).then(
+            confirm_checkout_preview,
+            inputs=[matched_items_state],
+            outputs=[checkout_preview]
+        )
+
+        confirm_checkout_btn.click(
+            process_checkout,
+            inputs=[matched_items_state, user_id_input],
+            outputs=[checkout_result]
+        ).then(
+            lambda: (gr.update(value=None), gr.update(value="Ready to scan.", visible=True)),
+            inputs=None,
+            outputs=[image_input, match_status]
+        )
+
+
+    # --- ADD ITEMS MODULE ---
+    with add_items_page:
+        back_to_main_btn_a = gr.Button("← Back to Main Menu")
+        gr.Markdown("<div class='section-header'>➕ Add Items to Inventory</div>")
+
+        # Your existing ADD ITEMS UI components go here:
+        with gr.Tabs():
+            with gr.TabItem("Receipt/Invoice Upload"):
+                gr.Markdown("Upload a PDF or image of a receipt/invoice to automatically add new inventory items.")
+                receipt_file = gr.File(label="Upload Receipt (PDF or Image)")
+                process_receipt_btn = gr.Button("Extract & Propose Updates", variant="primary", elem_classes="primary-button")
+                receipt_updates_table = gr.Dataframe(
+                    headers=["Include", "Item Name", "Quantity", "Match Type"],
+                    datatype=["checkbox", "str", "number", "str"],
+                    row_count=0,
+                    col_count=4,
+                    interactive=True,
+                    label="Proposed Inventory Updates"
                 )
-                
-                top_k_pairs = gr.Slider(
-                    minimum=5,
-                    maximum=50,
-                    value=25,
-                    step=5,
-                    label="Top K Pairs",
-                    info="Number of frequent pairs to optimize"
+                apply_updates_btn = gr.Button("Apply Selected Updates", variant="primary", elem_classes="primary-button")
+                receipt_summary = gr.Markdown("")
+
+                process_receipt_btn.click(
+                    extract_text_from_receipt,
+                    inputs=[receipt_file],
+                    outputs=[receipt_updates_table, gr.State(value=[])] # Note: The proposals state is not fully used here but kept for completeness
                 )
-                
-                max_moves = gr.Slider(
-                    minimum=5,
-                    maximum=30,
-                    value=10,
-                    step=1,
-                    label="Maximum Moves",
-                    info="Limit on relocations"
+                apply_updates_btn.click(
+                    apply_updates_from_table,
+                    inputs=[receipt_updates_table],
+                    outputs=[receipt_summary, gr.State(value=None)] # Outputting to a dummy State to avoid confusion
                 )
-                
-                min_gain = gr.Slider(
-                    minimum=0.0,
-                    maximum=1.0,
-                    value=0.05,
-                    step=0.01,
-                    label="Minimum Distance Gain",
-                    info="Threshold for suggestions"
+
+            with gr.TabItem("Manual Single Update"):
+                gr.Markdown("Manually update the quantity of a single item. Use a positive number to add, or a negative number to remove.")
+                manual_item_name = gr.Textbox(label="Item Name", placeholder="e.g., Arduino Uno, 3D Printer Filament (White)")
+                manual_quantity = gr.Number(label="Quantity Change (+ or -)", value=1)
+                manual_update_btn = gr.Button("Apply Manual Update", variant="primary", elem_classes="primary-button")
+                manual_update_summary = gr.Markdown("")
+
+                manual_update_btn.click(
+                    manual_update,
+                    inputs=[manual_item_name, manual_quantity],
+                    outputs=[manual_update_summary, gr.State(value=None)]
                 )
-                
-                run_analysis_btn = gr.Button("🔍 Run Analysis", variant="primary", size="lg")
-            
-            with gr.Column(scale=2):
-                gr.Markdown("### 📊 Summary", elem_classes=["subsection-header"])
-                analysis_summary = gr.Textbox(label="", lines=14, show_label=False)
-        
-        gr.Markdown("### 🗺️ Visual Layout Comparison", elem_classes=["subsection-header"])
-        analysis_viz = gr.Image(label="", type="numpy", show_label=False)
-        
-        with gr.Row():
-            with gr.Column():
-                gr.Markdown("### 🔗 Frequent Pairs", elem_classes=["subsection-header"])
-                pairs_table = gr.Dataframe(label="", show_label=False)
-            
-            with gr.Column():
-                gr.Markdown("### 📍 Recommendations", elem_classes=["subsection-header"])
-                recs_table = gr.Dataframe(label="", show_label=False)
-        
-        analysis_return_btn = gr.Button("🏠 Return to Main Menu", variant="secondary")
-    
-    # EVENT HANDLERS - Navigation
-    def show_checkout():
-        return (gr.update(visible=False), gr.update(visible=True), 
-                gr.update(visible=False), gr.update(visible=False))
-    
-    def show_add_items():
-        return (gr.update(visible=False), gr.update(visible=False),
-                gr.update(visible=True), gr.update(visible=False))
-    
-    def show_analysis():
-        return (gr.update(visible=False), gr.update(visible=False),
-                gr.update(visible=False), gr.update(visible=True))
-    
-    def return_to_menu():
-        return (gr.update(visible=True), gr.update(visible=False),
-                gr.update(visible=False), gr.update(visible=False))
-    
-    checkout_btn.click(fn=show_checkout, outputs=[main_menu, checkout_module, add_items_module, analysis_module])
-    add_items_btn.click(fn=show_add_items, outputs=[main_menu, checkout_module, add_items_module, analysis_module])
-    analysis_btn.click(fn=show_analysis, outputs=[main_menu, checkout_module, add_items_module, analysis_module])
-    
-    checkout_return_btn.click(fn=return_to_menu, outputs=[main_menu, checkout_module, add_items_module, analysis_module])
-    add_items_return_btn.click(fn=return_to_menu, outputs=[main_menu, checkout_module, add_items_module, analysis_module])
-    analysis_return_btn.click(fn=return_to_menu, outputs=[main_menu, checkout_module, add_items_module, analysis_module])
-    
-    # EVENT HANDLERS - Checkout
-    def update_checkout_screen2(matched_items):
-        updates = []
-        
-        if not matched_items:
-            for i in range(10):
-                updates.extend([gr.update(visible=False), gr.update(value=""), gr.update(value=1)])
-            return updates
-        
-        for i in range(10):
-            if i < len(matched_items):
-                item_data = matched_items[i]
-                updates.extend([
-                    gr.update(visible=True),
-                    gr.update(value=create_checkout_item_display(item_data, i)),
-                    gr.update(value=item_data['quantity'], maximum=item_data['item']['Quantity']),
-                ])
-            else:
-                updates.extend([gr.update(visible=False), gr.update(value=""), gr.update(value=1)])
-        
-        return updates
-    
-    def remove_checkout_item(matched_items, item_idx):
-        if matched_items and 0 <= item_idx < len(matched_items):
-            matched_items.pop(item_idx)
-        return matched_items
-    
-    def set_checkout_quantity(matched_items, item_idx, new_qty):
-        if matched_items and 0 <= item_idx < len(matched_items):
-            max_qty = matched_items[item_idx]['item']['Quantity']
-            matched_items[item_idx]['quantity'] = max(1, min(int(new_qty), max_qty))
-        return matched_items
-    
-    def reset_checkout():
-        return (
-            gr.update(visible=True), gr.update(visible=False), gr.update(visible=False),
-            None, "", None, "", "", gr.update(visible=False)
-        )
-    
-    def show_checkout_complete_options():
-        return gr.update(visible=False), gr.update(visible=True)
-    
-    checkout_scan_btn.click(
-        fn=lambda: (gr.update(value="⏳ Scanning...", interactive=False), "🔍 **Processing...** AI is analyzing your image..."),
-        outputs=[checkout_scan_btn, checkout_status]
-    ).then(
-        fn=scan_items_checkout,
-        inputs=[checkout_image, checkout_manual],
-        outputs=[matched_items_state, checkout_status]
-    ).then(
-        fn=lambda: gr.update(value="🔍 Scan & Match Items", interactive=True),
-        outputs=[checkout_scan_btn]
-    ).then(
-        fn=lambda items: (
-            gr.update(visible=False) if items else gr.update(),
-            gr.update(visible=True) if items else gr.update(),
-            gr.update(visible=False)
-        ),
-        inputs=[matched_items_state],
-        outputs=[checkout_screen1, checkout_screen2, checkout_screen3]
-    ).then(
-        fn=update_checkout_screen2,
-        inputs=[matched_items_state],
-        outputs=[checkout_item_controls[i][key] for i in range(10) for key in ['row', 'info', 'qty']]
-    )
-    
-    for i in range(10):
-        checkout_item_controls[i]['qty'].change(
-            fn=lambda items, new_qty, idx=i: set_checkout_quantity(items, idx, new_qty),
-            inputs=[matched_items_state, checkout_item_controls[i]['qty']],
-            outputs=[matched_items_state]
-        )
-        
-        checkout_item_controls[i]['remove'].click(
-            fn=lambda items, idx=i: remove_checkout_item(items, idx),
-            inputs=[matched_items_state],
-            outputs=[matched_items_state]
-        ).then(
-            fn=update_checkout_screen2,
-            inputs=[matched_items_state],
-            outputs=[checkout_item_controls[j][key] for j in range(10) for key in ['row', 'info', 'qty']]
-        )
-    
-    checkout_confirm_btn.click(
-        fn=confirm_checkout_preview,
-        inputs=[matched_items_state],
-        outputs=[checkout_preview]
-    ).then(
-        fn=lambda: (gr.update(visible=False), gr.update(visible=False), gr.update(visible=True)),
-        outputs=[checkout_screen1, checkout_screen2, checkout_screen3]
-    )
-    
-    checkout_rescan_btn.click(
-        fn=reset_checkout,
-        outputs=[checkout_screen1, checkout_screen2, checkout_screen3, matched_items_state,
-                checkout_status, checkout_image, checkout_manual, checkout_result, checkout_another_btn]
-    )
-    
-    checkout_cancel_btn.click(
-        fn=reset_checkout,
-        outputs=[checkout_screen1, checkout_screen2, checkout_screen3, matched_items_state,
-                checkout_status, checkout_image, checkout_manual, checkout_result, checkout_another_btn]
-    )
-    
-    checkout_final_btn.click(
-        fn=lambda: (gr.update(value="⏳ Processing...", interactive=False), "⏳ **Processing checkout...** Updating inventory..."),
-        outputs=[checkout_final_btn, checkout_processing]
-    ).then(
-        fn=process_checkout,
-        inputs=[matched_items_state, checkout_user_id],
-        outputs=[checkout_result]
-    ).then(
-        fn=lambda: (gr.update(value="✅ Complete Checkout", interactive=True), ""),
-        outputs=[checkout_final_btn, checkout_processing]
-    ).then(
-        fn=lambda: (gr.update(visible=False), gr.update(visible=False), gr.update(visible=False)),
-        outputs=[checkout_screen1, checkout_screen2, checkout_screen3]
-    ).then(
-        fn=show_checkout_complete_options,
-        outputs=[checkout_return_btn, checkout_another_btn]
-    )
-    
-    checkout_another_btn.click(
-        fn=reset_checkout,
-        outputs=[checkout_screen1, checkout_screen2, checkout_screen3, matched_items_state,
-                checkout_status, checkout_image, checkout_manual, checkout_result, checkout_another_btn]
-    ).then(
-        fn=lambda: (gr.update(visible=True), gr.update(visible=False)),
-        outputs=[checkout_return_btn, checkout_another_btn]
-    )
-    
-    # EVENT HANDLERS - Add Items
-    receipt_file.change(
-        fn=lambda: "📄 **Processing receipt...** Extracting text with OCR...",
-        outputs=[receipt_status]
-    ).then(
-        fn=extract_text_from_receipt,
-        inputs=[receipt_file],
-        outputs=[add_items_table, proposals_state]
-    ).then(
-        fn=lambda proposals: (gr.update(interactive=len(proposals) > 0), "✅ Items detected! Review and edit the table below."),
-        inputs=[proposals_state],
-        outputs=[add_items_confirm_btn, receipt_status]
-    )
-    
-    add_items_confirm_btn.click(
-        fn=lambda: (gr.update(value="⏳ Applying...", interactive=False), "⏳ **Updating inventory...**"),
-        outputs=[add_items_confirm_btn, add_items_status]
-    ).then(
-        fn=apply_updates_from_table,
-        inputs=[add_items_table],
-        outputs=[add_items_status, inventory_display]
-    ).then(
-        fn=lambda: (gr.update(value="✅ Apply Updates", interactive=False), gr.update(visible=True)),
-        outputs=[add_items_confirm_btn, inventory_display]
-    )
-    
-    add_items_reject_btn.click(
-        fn=lambda: ([["No items", "", "", ""]], "❌ Cleared all items.", []),
-        outputs=[add_items_table, add_items_status, proposals_state]
-    ).then(
-        fn=lambda: gr.update(interactive=False),
-        outputs=[add_items_confirm_btn]
-    )
-    
-    manual_apply_btn.click(
-        fn=lambda: gr.update(value="⏳ Adding...", interactive=False),
-        outputs=[manual_apply_btn]
-    ).then(
-        fn=manual_update,
-        inputs=[manual_item, manual_qty],
-        outputs=[manual_status, manual_inventory_display]
-    ).then(
-        fn=lambda: (gr.update(value="➕ Add to Inventory", interactive=True), gr.update(visible=True)),
-        outputs=[manual_apply_btn, manual_inventory_display]
-    )
-    
-    view_inventory_btn.click(
-        fn=view_inventory_table,
-        inputs=[inventory_category_filter],
-        outputs=[inventory_display]
-    ).then(
-        fn=lambda: gr.update(visible=True),
-        outputs=[inventory_display]
-    )
-    
-    inventory_category_filter.change(
-        fn=view_inventory_table,
-        inputs=[inventory_category_filter],
-        outputs=[inventory_display]
-    )
-    
-    view_history_btn.click(
-        fn=view_update_history,
-        outputs=[history_display]
-    ).then(
-        fn=lambda: gr.update(visible=True),
-        outputs=[history_display]
-    )
-    
-    # EVENT HANDLERS - Analysis
-    run_analysis_btn.click(
-        fn=run_analysis,
-        inputs=[min_support, top_k_pairs, max_moves, min_gain],
-        outputs=[pairs_table, recs_table, analysis_summary, analysis_viz]
-    )
-    
-    # EXAMPLE INPUTS
-    if EXAMPLE_CHECKOUT_IMAGE:
-        def load_checkout_example():
-            try:
-                return Image.open(EXAMPLE_CHECKOUT_IMAGE)
-            except:
-                return None
-        
-        load_example_checkout_btn.click(
-            fn=load_checkout_example,
-            outputs=[checkout_image]
+
+
+    # --- INVENTORY ANALYSIS MODULE ---
+    with analysis_page:
+        back_to_main_btn_n = gr.Button("← Back to Main Menu")
+        gr.Markdown("<div class='section-header'>📊 Inventory Analysis</div>")
+
+        # Your existing ANALYSIS UI components go here:
+        with gr.Accordion("Analysis Configuration", open=False):
+            min_support_slider = gr.Slider(minimum=0.01, maximum=0.1, step=0.005, value=0.02, label="Min Support for Item Pairs")
+            top_k_pairs_slider = gr.Slider(minimum=10, maximum=100, step=5, value=30, label="Top K Pairs for Relocation")
+            max_moves_slider = gr.Slider(minimum=5, maximum=50, step=5, value=15, label="Max Relocation Moves")
+            min_gain_slider = gr.Slider(minimum=0.01, maximum=1.0, step=0.01, value=0.05, label="Minimum Gain for a Move")
+
+        run_analysis_btn = gr.Button("🚀 Run Inventory Optimization Analysis", variant="primary", elem_classes="primary-button")
+        analysis_status = gr.Markdown("Press 'Run Inventory Optimization Analysis' to start.")
+
+        with gr.Tabs():
+            with gr.TabItem("Frequent Item Pairs (Recommendations)"):
+                item_pairs_df = gr.Dataframe(interactive=False, label="Frequent Item Pairs", height=300)
+
+            with gr.TabItem("Location Relocation Recommendations"):
+                relocation_df = gr.Dataframe(interactive=False, label="Optimized Relocation Moves", height=300)
+
+            with gr.TabItem("Current Inventory"):
+                category_dropdown = gr.Dropdown(choices=["All"] + get_categories(), value="All", label="Filter by Category")
+                inventory_df = gr.Dataframe(view_inventory_table(), interactive=False, label="Current Inventory Status", height=500)
+                category_dropdown.change(view_inventory_table, inputs=category_dropdown, outputs=inventory_df)
+
+            with gr.TabItem("Update History"):
+                update_history_text = gr.Textbox(view_update_history(), label="Inventory Update Log", interactive=False)
+
+        run_analysis_btn.click(
+            run_analysis,
+            inputs=[min_support_slider, top_k_pairs_slider, max_moves_slider, min_gain_slider],
+            outputs=[item_pairs_df, relocation_df, analysis_status, inventory_df]
         )
-    
-    if EXAMPLE_RECEIPT_PDF:
-        def load_receipt_example():
-            try:
-                return EXAMPLE_RECEIPT_PDF
-            except:
-                return None
         
-        load_example_receipt_btn.click(
-            fn=load_receipt_example,
-            outputs=[receipt_file]
-        )
 
-if __name__ == "__main__":
-    demo.launch()
+    # 3. Add the click events for general navigation (The fix for "No API Found")
+    checkout_btn.click(lambda: change_page('checkout'), outputs=page_outputs)
+    add_items_btn.click(lambda: change_page('add_items'), outputs=page_outputs)
+    analysis_btn.click(lambda: change_page('analysis'), outputs=page_outputs)
+
+    # Back button logic
+    for btn in [back_to_main_btn_c, back_to_main_btn_a, back_to_main_btn_n]:
+        btn.click(lambda: change_page('main'), outputs=page_outputs)
+
+
+# Launch the Gradio App
+demo.launch()