improve transaction handling

src/main/java/tech/iBeans/POSware/Lite/transact.java

@@ -0,0 +1,206 @@
+/*
+ * Click nbfs://nbhost/SystemFileSystem/Templates/Licenses/license-default.txt to change this license
+ * Click nbfs://nbhost/SystemFileSystem/Templates/Classes/Class.java to edit this template
+ */
+package tech.iBeans.POSware.Lite;
+
+// Import local modules. 
+import tech.iBeans.POSware.Lite.inventory.*;
+
+// Import global modules. 
+import java.util.*;
+
+/**
+ *
+ * @author eleven
+ */
+public class transact {
+    public static Dictionary<String, Dictionary> items = new Hashtable<>(); 
+    public static Dictionary<String, Double> price = new Hashtable<>();
+    
+    /* 
+    {item: {
+        qty: 
+        price: {
+            "tax": 
+            "subtotal": 
+            "total": 
+            "discount": 
+        }
+    }
+    }
+    */
+    
+    
+    public static void init() {
+        /* Initialize the variables, setting them with default values. 
+        */
+        
+        items = new Hashtable<>();
+        price = new Hashtable<>();
+        
+        // Set default values for prices. 
+        price.put("total", 0.00);
+        price.put("tax", 0.00);
+        price.put("subtotal", 0.00);
+        price.put("discount", 0.00);
+    };
+    
+    public static Dictionary calculate() {
+        /* Calculate the subtotal, total, and VAT. 
+        
+        Returns: (Dictionary) the contents of the price variable
+        */
+        
+        // Prepare to enumerate each item. 
+        Enumeration<String> items_list = items.keys();
+        
+        // Set default values for prices. 
+        price.put("total", 0.00);
+        price.put("subtotal", 0.00);
+        price.put("discount", 0.00);
+        price.put("tax", 0.00);
+        
+        while (items_list.hasMoreElements()) {
+            String item = items_list.nextElement();
+            
+            if (((Dictionary) items.get(item).get("price")).get("tax") != null) {
+                price.put("tax", (double) price.get("tax") + (double) ((Dictionary) items.get(item).get("price")).get("tax"));
+            };
+            if (((Dictionary) items.get(item).get("price")).get("subtotal") != null) {
+                price.put("subtotal", (double) price.get("subtotal") + (double) ((Dictionary) items.get(item).get("price")).get("subtotal"));
+            };
+            if (((Dictionary) items.get(item).get("price")).get("total") != null) {
+                price.put("total", (double) price.get("total") + (double) ((Dictionary) items.get(item).get("price")).get("total"));
+            };
+            if (((Dictionary) items.get(item).get("price")).get("discount") != null) {
+                price.put("discount", (double) price.get("discount") + (double) ((Dictionary) items.get(item).get("price")).get("discount"));
+            };
+        };
+        
+        if (price.get("tip") != null) {
+            if (Double.parseDouble(price.get("tip").toString()) >= 0) {
+                price.put("total", (double) price.get("total") + (double) price.get("tip"));
+            };
+        };
+        
+        // Return the dictionary. 
+        return(price);
+    };
+    
+    public static Dictionary<String, Double> calculate(String SKU, int QUANTITY) {
+        inventory.refresh();
+        Dictionary item_details = inventory.items.get(SKU);
+        
+        // Create an output dictionary. 
+        Dictionary<String, Double> item_pricing = new Hashtable<>();
+        
+        // Fill in with default data, especially useful when the product is not found. 
+        item_pricing.put("subtotal", 0.0);
+        item_pricing.put("total", 0.0);
+        
+        if (item_details != null) {
+            if (item_details.get("Price") != null) {
+                item_pricing.put("subtotal", Double.valueOf(item_details.get("Price").toString()) * QUANTITY);
+                item_pricing.put("total", Double.valueOf( item_pricing.get("subtotal")));
+                
+                if (item_details.get("Tax") != null) {
+                    item_pricing.put("tax", Double.valueOf(item_details.get("Tax").toString()) * QUANTITY);
+                    item_pricing.put("total", Double.valueOf(item_pricing.get("total").toString()) + Double.valueOf(item_pricing.get("tax").toString()));
+                };
+                if (item_details.get("Discount") != null) {
+                    if (Integer.parseInt(item_details.get("Discount").toString()) > 0) {
+                        item_pricing.put("discount", 
+                                QUANTITY * Double.parseDouble(item_details.get("Price").toString()) * (1 - (Double.parseDouble(item_details.get("Discount").toString()) / 100))
+                                );
+                    } else if (Integer.parseInt(item_details.get("Discount").toString()) < 0) {
+                        item_pricing.put("discount", 
+                                QUANTITY * Double.parseDouble(item_details.get("Price").toString()) * (0 - (Double.parseDouble(item_details.get("Discount").toString()) / 100))
+                                );
+                    } else {
+                        item_pricing.put("discount", (double) 0);
+                    };
+                    
+                    item_pricing.put("total", Double.valueOf(item_pricing.get("total").toString()) - Double.valueOf(item_pricing.get("discount").toString()));
+                };
+            };
+        };
+        
+        // Return the data. 
+        return item_pricing;
+        
+    };
+    
+    public static boolean add(String SKU, int QUANTITY) {
+        /* Add an item to the shopping cart. 
+        Parameters: 
+            SKU (String): the SKU of the item
+            QUANTITY (int): the quantity
+        Returns: (boolean) the calculation state
+        */
+        
+        if (QUANTITY == 0) {return(false);}
+        else if (QUANTITY < 0) {return(remove(SKU, QUANTITY));};
+        
+        // containing the current data's information
+        Dictionary ITEM_CURRENT_DATA = items.get(SKU);
+        
+        // check if the item exists
+        if (ITEM_CURRENT_DATA != null) {
+            ITEM_CURRENT_DATA.put("qty", ((int) ITEM_CURRENT_DATA.get("qty")) + QUANTITY);
+        } else {
+            // Initialize the dictionary. 
+            ITEM_CURRENT_DATA = new Hashtable<>();
+            
+            // Add the quantity. 
+            ITEM_CURRENT_DATA.put("qty", QUANTITY);
+        };
+        
+        // Calculate these items' price. 
+        ITEM_CURRENT_DATA.put("price", calculate(SKU, ((int) ITEM_CURRENT_DATA.get("qty"))));
+        
+        // Add to the shopping cart's items. 
+        items.put(SKU, ITEM_CURRENT_DATA);
+        
+        // Calculate all prices. 
+        calculate();
+        
+        // Return the success state. 
+        return((items.get(SKU) != null));
+    };
+    
+    public static boolean remove(String SKU, int QUANTITY) {
+        /* Remove an item to the shopping items. 
+        
+        Parameters: 
+            SKU (String): the SKU of the item
+            QUANTITY (int): the quantity
+        Returns: (boolean) the removal state
+        */
+        
+        if (QUANTITY == 0) {return(false);}
+        else if (QUANTITY < 0) {return(add(SKU, QUANTITY));};
+        
+        // containing the current data's information
+        Dictionary ITEM_CURRENT_DATA = items.get(SKU);
+        
+        // check if the item exists. There's no need to remove an item that's already been removed. 
+        if (ITEM_CURRENT_DATA != null) {
+            if (QUANTITY >= (int) ITEM_CURRENT_DATA.get("qty")) {
+                items.remove(SKU);
+            } else {
+                ITEM_CURRENT_DATA.put("qty", ((int) ITEM_CURRENT_DATA.get("qty")) - QUANTITY);
+                ITEM_CURRENT_DATA.put("price", calculate(SKU, ((int) ITEM_CURRENT_DATA.get("qty"))));
+                
+                // Add to the shopping cart's items. 
+                items.put(SKU, ITEM_CURRENT_DATA);
+            };
+        };
+        
+        // Calculate all prices. 
+        calculate();
+        
+        // Return the state. 
+        return(true);
+    };
+}