Baranov_A_E_task_atm

src/main/java/hse/java/lectures/lecture3/tasks/atm/Atm.java

@@ -4,11 +4,11 @@
 
 public class Atm {
     public enum Denomination {
-        D50(50),
-        D100(100),
-        D500(500),
+        D5000(5000),
         D1000(1000),
-        D5000(5000);
+        D500(500),
+        D100(100),
+        D50(50);
 
         private final int value;
 
@@ -32,14 +32,59 @@ public static Denomination fromInt(int value) {
     public Atm() {
     }
 
-    public void deposit(Map<Denomination, Integer> banknotes){}
+    public void deposit(Map<Denomination, Integer> banknotes) {
+        if (banknotes == null || banknotes.isEmpty()) {
+            throw new InvalidDepositException("Deposit has to be non-empty");
+        }
+
+        for (Map.Entry<Denomination, Integer> entry : banknotes.entrySet()) {
+            if (entry.getValue() <= 0) {
+                throw new InvalidDepositException("Denomination has to be positive value");
+            }
+
+            this.banknotes.merge(entry.getKey(), entry.getValue(), Integer::sum);
+        }
+    }
 
     public Map<Denomination, Integer> withdraw(int amount) {
-        return Map.of();
+        if (amount <= 0) {
+            throw new InvalidAmountException("Amount has to be positive value");
+        } else if (amount > getBalance()) {
+            throw new InsufficientFundsException("Not enough funds in ATM");
+        }
+
+        Map<Denomination, Integer> change = new EnumMap<>(Denomination.class);
+
+        for (Map.Entry<Denomination, Integer> entry : banknotes.entrySet()) {
+            if (amount == 0) break;
+
+            Denomination denomination = entry.getKey();
+            Integer denominationAmount = entry.getValue();
+
+            int times = Integer.min(amount / denomination.value, denominationAmount);
+
+            amount -= denomination.value * times;
+            change.put(denomination, times);
+        }
+
+        if (amount > 0) {
+            throw new CannotDispenseException("Cannot dispense");
+        }
+
+        for (Map.Entry<Denomination, Integer> entry : change.entrySet()) {
+            int times = banknotes.get(entry.getKey());
+            banknotes.put(entry.getKey(), times - entry.getValue());
+        }
+
+        return change;
     }
 
     public int getBalance() {
-        return 0;
+        int sum = 0;
+        for (Map.Entry<Denomination, Integer> entry : banknotes.entrySet()) {
+            sum += entry.getKey().value * entry.getValue();
+        }
+        return sum;
     }
 
 }