Implement balance alerts feature

rore · rore · commit 198b6d8f82c3 · 2026-03-08T15:22:06.000+02:00
diff --git a/bear-ir/account.bear.yaml b/bear-ir/account.bear.yaml
@@ -68,6 +68,9 @@ block:
           - port: accountStore
             kind: external
             ops: [get, put]
+          - port: alertLog
+            kind: block
+            targetOps: [AppendAlert]
           - port: transactionLog
             kind: block
             targetOps: [AppendTransaction]
@@ -107,6 +110,10 @@ block:
         kind: block
         targetBlock: transaction-log
         targetOps: [AppendTransaction]
+      - port: alertLog
+        kind: block
+        targetBlock: alert-log
+        targetOps: [AppendAlert]
       - port: idempotency
         kind: external
         ops: [get, put]
@@ -119,4 +126,4 @@ block:
     - kind: non_negative
       field: balanceCents
     - kind: non_negative
-      field: txSeq
+      field: txSeq
diff --git a/bear-ir/alert-log.bear.yaml b/bear-ir/alert-log.bear.yaml
@@ -0,0 +1,48 @@
+version: v1
+block:
+  name: AlertLog
+  kind: logic
+  operations:
+    - name: AppendAlert
+      contract:
+        inputs:
+          - name: accountId
+            type: string
+          - name: alertType
+            type: string
+          - name: requestId
+            type: string
+          - name: message
+            type: string
+        outputs:
+          - name: alertSeq
+            type: int
+      uses:
+        allow:
+          - port: alertStore
+            kind: external
+            ops: [append]
+      invariants:
+        - kind: non_negative
+          field: alertSeq
+    - name: GetAlerts
+      contract:
+        inputs:
+          - name: accountId
+            type: string
+        outputs:
+          - name: alertsJson
+            type: string
+      uses:
+        allow:
+          - port: alertStore
+            kind: external
+            ops: [list]
+  effects:
+    allow:
+      - port: alertStore
+        kind: external
+        ops: [append, list]
+  invariants:
+    - kind: non_negative
+      field: alertSeq
diff --git a/bear.blocks.yaml b/bear.blocks.yaml
@@ -7,4 +7,8 @@ blocks:
   - name: transaction-log
     ir: bear-ir/transaction-log.bear.yaml
     projectRoot: .
-    enabled: true
+    enabled: true
+  - name: alert-log
+    ir: bear-ir/alert-log.bear.yaml
+    projectRoot: .
+    enabled: true
diff --git a/src/main/java/blocks/account/impl/AccountImpl.java b/src/main/java/blocks/account/impl/AccountImpl.java
@@ -12,10 +12,13 @@
 import com.bear.generated.account.Account_GetBalanceResult;
 import com.bear.generated.account.Account_WithdrawRequest;
 import com.bear.generated.account.Account_WithdrawResult;
+import com.bear.generated.account.AlertLogPort;
 import com.bear.generated.account.BearValue;
 import com.bear.generated.account.TransactionLogPort;
 
 public final class AccountImpl implements AccountLogic {
+    private static final String INSUFFICIENT_FUNDS_ALERT = "INSUFFICIENT_FUNDS_ATTEMPT";
+
     @Override
     public Account_CreateAccountResult executeCreateAccount(Account_CreateAccountRequest request, AccountStorePort accountStorePort) {
         requireNonBlank(request.getOwnerId(), "ownerId");
@@ -48,11 +51,21 @@ public Account_GetBalanceResult executeGetBalance(Account_GetBalanceRequest requ
     }
 
     @Override
-    public Account_WithdrawResult executeWithdraw(Account_WithdrawRequest request, AccountStorePort accountStorePort, TransactionLogPort transactionLogPort) {
+    public Account_WithdrawResult executeWithdraw(
+        Account_WithdrawRequest request,
+        AccountStorePort accountStorePort,
+        AlertLogPort alertLogPort,
+        TransactionLogPort transactionLogPort
+    ) {
         int amountCents = requirePositiveAmount(request.getAmountCents());
         requireNonBlank(request.getRequestId(), "requestId");
         AccountState account = loadAccount(request.getAccountId(), accountStorePort);
         if (account.balanceCents() < amountCents) {
+            appendAlert(
+                alertLogPort,
+                account.accountId(),
+                request.getRequestId(),
+                "Insufficient funds for withdrawal attempt of " + amountCents + " cents");
             throw new InsufficientFundsException(account.accountId());
         }
 
@@ -82,6 +95,16 @@ private static BearValue toAccountValue(String accountId, String ownerId, int ba
             .build();
     }
 
+    private static void appendAlert(AlertLogPort alertLogPort, String accountId, String requestId, String message) {
+        alertLogPort.call(BearValue.builder()
+            .put("op", "AppendAlert")
+            .put("accountId", accountId)
+            .put("alertType", INSUFFICIENT_FUNDS_ALERT)
+            .put("requestId", requestId)
+            .put("message", message)
+            .build());
+    }
+
     private static int appendTransaction(
         TransactionLogPort transactionLogPort,
         String accountId,
@@ -123,4 +146,4 @@ private static int parseInt(String raw, String field) {
 
     private record AccountState(String accountId, String ownerId, int balanceCents) {
     }
-}
+}
diff --git a/src/main/java/blocks/alert/log/adapter/InMemoryAlertStorePort.java b/src/main/java/blocks/alert/log/adapter/InMemoryAlertStorePort.java
@@ -0,0 +1,65 @@
+package blocks.alert.log.adapter;
+
+import java.util.ArrayList;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+
+import com.bear.generated.alert.log.AlertStorePort;
+import com.bear.generated.alert.log.BearValue;
+
+public final class InMemoryAlertStorePort implements AlertStorePort {
+    private final Map<String, List<AlertRecord>> alertsByAccount = new LinkedHashMap<>();
+
+    @Override
+    public BearValue append(BearValue input) {
+        String accountId = required(input, "accountId");
+        List<AlertRecord> alerts = alertsByAccount.computeIfAbsent(accountId, ignored -> new ArrayList<>());
+        int nextSeq = alerts.size() + 1;
+        alerts.add(new AlertRecord(
+            nextSeq,
+            accountId,
+            required(input, "alertType"),
+            required(input, "requestId"),
+            required(input, "message")));
+        return BearValue.builder().put("alertSeq", Integer.toString(nextSeq)).build();
+    }
+
+    @Override
+    public BearValue list(BearValue input) {
+        String accountId = required(input, "accountId");
+        List<AlertRecord> alerts = alertsByAccount.getOrDefault(accountId, List.of());
+        StringBuilder json = new StringBuilder("[");
+        boolean first = true;
+        for (AlertRecord alert : alerts) {
+            if (!first) {
+                json.append(',');
+            }
+            first = false;
+            json.append('{')
+                .append("\"alertSeq\":").append(alert.alertSeq())
+                .append(",\"accountId\":\"").append(escape(alert.accountId())).append('\"')
+                .append(",\"alertType\":\"").append(escape(alert.alertType())).append('\"')
+                .append(",\"requestId\":\"").append(escape(alert.requestId())).append('\"')
+                .append(",\"message\":\"").append(escape(alert.message())).append('\"')
+                .append('}');
+        }
+        json.append(']');
+        return BearValue.builder().put("alertsJson", json.toString()).build();
+    }
+
+    private static String required(BearValue input, String field) {
+        String value = input == null ? null : input.get(field);
+        if (value == null || value.isBlank()) {
+            throw new IllegalArgumentException(field + " is required");
+        }
+        return value;
+    }
+
+    private static String escape(String value) {
+        return value.replace("\\", "\\\\").replace("\"", "\\\"");
+    }
+
+    private record AlertRecord(int alertSeq, String accountId, String alertType, String requestId, String message) {
+    }
+}
diff --git a/src/main/java/blocks/alert/log/impl/AlertLogImpl.java b/src/main/java/blocks/alert/log/impl/AlertLogImpl.java
@@ -0,0 +1,53 @@
+package blocks.alert.log.impl;
+
+import com.bear.generated.alert.log.AlertLogLogic;
+import com.bear.generated.alert.log.AlertLog_AppendAlertRequest;
+import com.bear.generated.alert.log.AlertLog_AppendAlertResult;
+import com.bear.generated.alert.log.AlertLog_GetAlertsRequest;
+import com.bear.generated.alert.log.AlertLog_GetAlertsResult;
+import com.bear.generated.alert.log.AlertStorePort;
+import com.bear.generated.alert.log.BearValue;
+
+public final class AlertLogImpl implements AlertLogLogic {
+    @Override
+    public AlertLog_AppendAlertResult executeAppendAlert(AlertLog_AppendAlertRequest request, AlertStorePort alertStorePort) {
+        requireNonBlank(request.getAccountId(), "accountId");
+        requireNonBlank(request.getAlertType(), "alertType");
+        requireNonBlank(request.getRequestId(), "requestId");
+        requireNonBlank(request.getMessage(), "message");
+
+        BearValue stored = alertStorePort.append(BearValue.builder()
+            .put("accountId", request.getAccountId())
+            .put("alertType", request.getAlertType())
+            .put("requestId", request.getRequestId())
+            .put("message", request.getMessage())
+            .build());
+        return new AlertLog_AppendAlertResult(parseInt(stored.get("alertSeq"), "alertSeq"));
+    }
+
+    @Override
+    public AlertLog_GetAlertsResult executeGetAlerts(AlertLog_GetAlertsRequest request, AlertStorePort alertStorePort) {
+        requireNonBlank(request.getAccountId(), "accountId");
+        BearValue listed = alertStorePort.list(BearValue.builder()
+            .put("accountId", request.getAccountId())
+            .build());
+        return new AlertLog_GetAlertsResult(defaultJson(listed.get("alertsJson")));
+    }
+
+    private static void requireNonBlank(String value, String field) {
+        if (value == null || value.isBlank()) {
+            throw new IllegalArgumentException(field + " is required");
+        }
+    }
+
+    private static int parseInt(String raw, String field) {
+        if (raw == null || raw.isBlank()) {
+            throw new IllegalStateException(field + " is missing");
+        }
+        return Integer.parseInt(raw);
+    }
+
+    private static String defaultJson(String json) {
+        return json == null ? "[]" : json;
+    }
+}
diff --git a/src/main/java/com/bear/account/demo/AccountApplication.java b/src/main/java/com/bear/account/demo/AccountApplication.java
@@ -2,10 +2,8 @@
 
 import blocks.account.adapter.InMemoryAccountStorePort;
 import blocks.account.adapter.InMemoryIdempotencyPort;
-import blocks.account.impl.AccountNotFoundException;
-import blocks.account.impl.InsufficientFundsException;
-import blocks.transaction.log.adapter.InMemoryTransactionStorePort;
-
+import blocks.alert.log.adapter.InMemoryAlertStorePort;
+import com.bear.generated.account.Account_AlertLogBlockClient;
 import com.bear.generated.account.Account_CreateAccount;
 import com.bear.generated.account.Account_CreateAccountRequest;
 import com.bear.generated.account.Account_Deposit;
@@ -15,30 +13,40 @@
 import com.bear.generated.account.Account_TransactionLogBlockClient;
 import com.bear.generated.account.Account_Withdraw;
 import com.bear.generated.account.Account_WithdrawRequest;
+import com.bear.generated.account.AlertLogPort;
 import com.bear.generated.account.TransactionLogPort;
+import com.bear.generated.alert.log.AlertLog_AppendAlert;
+import com.bear.generated.alert.log.AlertLog_GetAlerts;
+import com.bear.generated.alert.log.AlertLog_GetAlertsRequest;
 import com.bear.generated.transaction.log.TransactionLog_AppendTransaction;
 import com.bear.generated.transaction.log.TransactionLog_GetTransactions;
 import com.bear.generated.transaction.log.TransactionLog_GetTransactionsRequest;
+import blocks.transaction.log.adapter.InMemoryTransactionStorePort;
 
 public final class AccountApplication {
     private final Account_CreateAccount createAccount;
     private final Account_Deposit deposit;
     private final Account_Withdraw withdraw;
     private final Account_GetBalance getBalance;
     private final TransactionLog_GetTransactions getTransactions;
+    private final AlertLog_GetAlerts getAlerts;
 
     public AccountApplication() {
         InMemoryAccountStorePort accountStorePort = new InMemoryAccountStorePort();
         InMemoryIdempotencyPort idempotencyPort = new InMemoryIdempotencyPort();
         InMemoryTransactionStorePort transactionStorePort = new InMemoryTransactionStorePort();
+        InMemoryAlertStorePort alertStorePort = new InMemoryAlertStorePort();
         TransactionLog_AppendTransaction appendTransaction = TransactionLog_AppendTransaction.of(transactionStorePort);
+        AlertLog_AppendAlert appendAlert = AlertLog_AppendAlert.of(alertStorePort);
         TransactionLogPort transactionLogPort = new Account_TransactionLogBlockClient(appendTransaction);
+        AlertLogPort alertLogPort = new Account_AlertLogBlockClient(appendAlert);
 
-        this.createAccount = Account_CreateAccount.of(accountStorePort, idempotencyPort, transactionLogPort);
-        this.deposit = Account_Deposit.of(accountStorePort, idempotencyPort, transactionLogPort);
-        this.withdraw = Account_Withdraw.of(accountStorePort, idempotencyPort, transactionLogPort);
-        this.getBalance = Account_GetBalance.of(accountStorePort, idempotencyPort, transactionLogPort);
+        this.createAccount = Account_CreateAccount.of(accountStorePort, alertLogPort, idempotencyPort, transactionLogPort);
+        this.deposit = Account_Deposit.of(accountStorePort, alertLogPort, idempotencyPort, transactionLogPort);
+        this.withdraw = Account_Withdraw.of(accountStorePort, alertLogPort, idempotencyPort, transactionLogPort);
+        this.getBalance = Account_GetBalance.of(accountStorePort, alertLogPort, idempotencyPort, transactionLogPort);
         this.getTransactions = TransactionLog_GetTransactions.of(transactionStorePort);
+        this.getAlerts = AlertLog_GetAlerts.of(alertStorePort);
     }
 
     public String createAccount(String ownerId) {
@@ -62,6 +70,11 @@ public String getTransactionsJson(String accountId, Integer sinceSeq) {
         return getTransactions.execute(new TransactionLog_GetTransactionsRequest(accountId, sinceSeq)).getTransactionsJson();
     }
 
+    public String getAlertsJson(String accountId) {
+        getBalance(accountId);
+        return getAlerts.execute(new AlertLog_GetAlertsRequest(accountId)).getAlertsJson();
+    }
+
     private static OperationResult toOperationResult(com.bear.generated.account.Account_DepositResult result) {
         return new OperationResult(result.getBalanceCents(), result.getTxSeq());
     }
@@ -72,4 +85,4 @@ private static OperationResult toOperationResult(com.bear.generated.account.Acco
 
     public record OperationResult(int balanceCents, int txSeq) {
     }
-}
+}
diff --git a/src/main/java/com/bear/account/demo/App.java b/src/main/java/com/bear/account/demo/App.java
@@ -56,6 +56,10 @@ private void handle(HttpExchange exchange) throws IOException {
                 handleGetTransactions(exchange, segments[2]);
                 return;
             }
+            if (segments.length == 4 && "accounts".equals(segments[1]) && "alerts".equals(segments[3]) && "GET".equals(method)) {
+                handleGetAlerts(exchange, segments[2]);
+                return;
+            }
 
             sendJson(exchange, 404, "{\"error\":\"not found\"}");
         } catch (AccountNotFoundException e) {
@@ -101,6 +105,11 @@ private void handleGetTransactions(HttpExchange exchange, String accountId) thro
         sendJson(exchange, 200, "{\"transactions\":" + transactionsJson + "}");
     }
 
+    private void handleGetAlerts(HttpExchange exchange, String accountId) throws IOException {
+        String alertsJson = application.getAlertsJson(accountId);
+        sendJson(exchange, 200, "{\"alerts\":" + alertsJson + "}");
+    }
+
     private static int readSinceSeq(String rawQuery) {
         if (rawQuery == null || rawQuery.isBlank()) {
             return 0;
@@ -148,4 +157,4 @@ private static Integer requireInt(String body, String field) {
     private static String escape(String value) {
         return value.replace("\\", "\\\\").replace("\"", "\\\"");
     }
-}
+}
diff --git a/src/test/java/com/bear/account/demo/AppTest.java b/src/test/java/com/bear/account/demo/AppTest.java
