use balance to purchase

client/src/scenes/item.list.js

@@ -152,9 +152,9 @@ class ItemList extends Phaser.Scene {
         drawInventory(graphics);
         drawVbox(graphics);
 
-        this.add.text(X + WIDTH * 0.1, Y, 'Inventory', TEXT.HEADER);
+        this.add.text(X + WIDTH * 0.1, Y, 'inventory', TEXT.HEADER);
-        this.add.text(X + WIDTH * 0.47, Y, 'Combiner', TEXT.HEADER);
+        this.add.text(X + WIDTH * 0.47, Y, 'iCombinator', TEXT.HEADER);
-        this.add.text(X + WIDTH * 0.35, Y + HEIGHT / 2, 'Varibox', TEXT.HEADER);
+        this.add.text(X + WIDTH * 0.35, Y + HEIGHT / 2, `vBox - ${vbox.bits}b`, TEXT.HEADER);
 
         const reroll = this.add
             .rectangle(WIDTH * 0.01, Y + HEIGHT * 0.775, ITEM_WIDTH * 1.25, ITEM_HEIGHT * 1.25, 0x222222)

server/src/vbox.rs

@@ -96,6 +96,26 @@ impl Var {
         }
     }
 
+    fn cost(&self) -> Result<u16, Error> {
+        match self {
+            Var::Red => Ok(1),
+            Var::Green => Ok(1),
+            Var::Blue => Ok(1),
+
+            Var::Attack => Ok(2),
+            Var::Block => Ok(2),
+            Var::Buff => Ok(2),
+            Var::Debuff => Ok(2),
+            Var::Stun => Ok(2),
+
+            Var::Damage => Ok(3),
+            Var::Hp => Ok(3),
+            Var::Speed => Ok(3),
+
+            _ => Err(err_msg("var not purchasable")),
+        }
+    }
+
     fn effect(&self) -> Option<VarEffect> {
         if let Some(_skill) = self.skill() {
             return Some(VarEffect::Skill);
@@ -170,7 +190,7 @@ enum ColourCode {
 #[derive(Debug,Clone,Serialize,Deserialize)]
 pub struct Vbox {
     pub id: Uuid,
-    pub balance: u16,
+    pub bits: u16,
     pub free: Vec<Vec<Var>>,
     pub bound: Vec<Var>,
     pub instance: Uuid,
@@ -197,7 +217,7 @@ impl Vbox {
             instance: instance_id,
             free: vec![],
             bound: starting_items,
-            balance: 9,
+            bits: 9,
         };
 
         vbox.fill();
@@ -205,6 +225,21 @@ impl Vbox {
         return vbox;
     }
 
+    pub fn balance_sub(&mut self, amount: u16) -> Result<&mut Vbox, Error> {
+        let new_balance = self.bits
+            .checked_sub(amount)
+            .ok_or(format_err!("insufficient balance: {:?}", self.bits))?;
+
+        self.bits = new_balance;
+
+        Ok(self)
+    }
+
+    pub fn balance_add(&mut self, amount: u16) -> &mut Vbox {
+        self.bits = self.bits.saturating_add(amount);
+        self
+    }
+
     pub fn fill(&mut self) -> &mut Vbox {
         let colours = vec![
             (Var::Red, 1),
@@ -248,10 +283,16 @@ impl Vbox {
             return Err(err_msg("too many vars bound"));
         }
 
+        // check item exists
         self.free
             .get(i).ok_or(format_err!("no var group at index {:?}", i))?
             .get(j).ok_or(format_err!("no var at index {:?}", j))?;
 
+        // check can purchase
+        let cost = self.free[i][j].cost()?;
+        self.balance_sub(cost)?;
+
+        // actually move
         self.bound.push(self.free[i].remove(j));
 
         Ok(self)
@@ -259,8 +300,10 @@ impl Vbox {
 
     pub fn drop(&mut self, i: usize) -> Result<&mut Vbox, Error> {
         self.bound.get(i).ok_or(format_err!("no var at index {:?}", i))?;
-        self.bound.remove(i);
+        let dropped = self.bound.remove(i);
-        // balance update
+
+        // calculate total cost
+        // self.balance_add(dropped.cost()?);
         Ok(self)
     }