feat: added exceptions

server/src/main/kotlin/org/ccoin/exceptions/CCoinException.kt

@@ -0,0 +1,8 @@
+package org.ccoin.exceptions
+
+/** Base exception class for all CCoin-related exceptions */
+open class CCoinException(
+    message: String,
+    cause: Throwable? = null,
+    val errorCode: String? = null
+) : Exception(message, cause)

server/src/main/kotlin/org/ccoin/exceptions/InsufficientFundsException.kt

@@ -0,0 +1,10 @@
+package org.ccoin.exceptions
+
+class InsufficientFundsException(
+    val address: String,
+    val requestedAmount: Double,
+    val availableBalance: Double
+) : CCoinException(
+    message = "Insufficient funds in wallet $address. Requested: $requestedAmount, Available: $availableBalance",
+    errorCode = "INSUFFICIENT_FUNDS"
+)

server/src/main/kotlin/org/ccoin/exceptions/InvalidTransactionException.kt

@@ -0,0 +1,9 @@
+package org.ccoin.exceptions
+
+class InvalidTransactionException(
+    message: String,
+    val transactionHash: String? = null
+) : CCoinException(
+    message = message,
+    errorCode = "INVALID_TRANSACTION"
+)

server/src/main/kotlin/org/ccoin/exceptions/WalletNotFoundException.kt

@@ -0,0 +1,8 @@
+package org.ccoin.exceptions
+
+class WalletNotFoundException(
+    val address: String
+) : CCoinException(
+    message = "Wallet with address '$address' not found",
+    errorCode = "WALLET_NOT_FOUND"
+)