fix: update error messages for empty and blank input validation

Author: marc0der

prompts/12-sdkman_bash_cli_download-todo.md

@@ -21,7 +21,7 @@ Consider the following rules during execution of the tasks:
 
 ### Task 2: Improve Error Messages for Empty/Blank Input Validation
 
-- [ ] Update error messages for empty and blank input validation to use "[empty/blank]" format
+- [X] Update error messages for empty and blank input validation to use "[empty/blank]" format
 
 **Description**: The test cases for empty and blank input validation currently use the actual empty/blank values as error messages. The TODO comments suggest these should be changed to a more descriptive "[empty/blank]" format for better error reporting and consistency.
 

src/main/kotlin/io/sdkman/broker/application/service/SdkmanCliDownloadServiceImpl.kt

@@ -34,12 +34,16 @@ class SdkmanCliDownloadServiceImpl : SdkmanCliDownloadService {
         if (version.isNotBlank()) {
             version.right()
         } else {
-            VersionError.InvalidVersion(version).left()
+            VersionError.InvalidVersion("[empty/blank]").left()
         }
 
     private fun validatePlatform(platformCode: String): Either<VersionError, Platform> =
-        Platform.fromCode(platformCode)
-            .toEither { VersionError.InvalidPlatform(platformCode) }
+        if (platformCode.isBlank()) {
+            VersionError.InvalidPlatform("[empty/blank]").left()
+        } else {
+            Platform.fromCode(platformCode)
+                .toEither { VersionError.InvalidPlatform(platformCode) }
+        }
 
     private fun constructDownloadInfo(version: String): SdkmanCliDownloadInfo {
         val tag = if (version.startsWith("latest+")) "latest" else version

src/test/kotlin/io/sdkman/broker/application/service/SdkmanCliDownloadServiceSpec.kt

@@ -77,15 +77,13 @@ class SdkmanCliDownloadServiceSpec : ShouldSpec({
             should("return InvalidVersion error for empty version") {
                 val result = underTest.downloadSdkmanCli("install", "", "linuxx64")
 
-                // TODO: change error message to [empty/blank]
-                result shouldBeLeft VersionError.InvalidVersion("")
+                result shouldBeLeft VersionError.InvalidVersion("[empty/blank]")
             }
 
             should("return InvalidVersion error for blank version") {
                 val result = underTest.downloadSdkmanCli("install", "   ", "linuxx64")
 
-                // TODO: change error message to [empty/blank]
-                result shouldBeLeft VersionError.InvalidVersion("   ")
+                result shouldBeLeft VersionError.InvalidVersion("[empty/blank]")
             }
         }
 
@@ -99,8 +97,7 @@ class SdkmanCliDownloadServiceSpec : ShouldSpec({
             should("return InvalidPlatform error for empty platform") {
                 val result = underTest.downloadSdkmanCli("install", "5.19.0", "")
 
-                // TODO: change error message to [empty/blank]
-                result shouldBeLeft VersionError.InvalidPlatform("")
+                result shouldBeLeft VersionError.InvalidPlatform("[empty/blank]")
             }
         }