Enables output of comparison as json (#78)

scripts/acceptance.sh

@@ -72,6 +72,11 @@ test_compare_baseline_with_artifact() {
     echo "$comparison"
     echo "$comparison" | grep "Your baseline file does not match the supplied artifact" >/dev/null
 
+    echo
+    echo "As json output:"
+    echo
+
+    "$aaw" compare -a "$fixtures/app-release-changed.apk" -b "$toml" --json | jq
     rm -rf "$toml"
 }
 

src/main/kotlin/io/dotanuki/aaw/Injection.kt

@@ -56,7 +56,7 @@ object Injection {
     }
 
     private val compareContext by lazy {
-        CompareContext(terminal, tomlSerializer)
+        CompareContext(terminal, tomlSerializer, jsonSerializer)
     }
 
     private val compareCommand by lazy {

src/main/kotlin/io/dotanuki/aaw/features/comparison/CompareCommand.kt

@@ -2,9 +2,11 @@ package io.dotanuki.aaw.features.comparison
 
 import arrow.core.raise.recover
 import com.github.ajalt.clikt.core.CliktCommand
+import com.github.ajalt.clikt.parameters.options.default
 import com.github.ajalt.clikt.parameters.options.flag
 import com.github.ajalt.clikt.parameters.options.option
 import com.github.ajalt.clikt.parameters.options.required
+import com.github.ajalt.clikt.parameters.options.switch
 import io.dotanuki.aaw.core.android.AndroidArtifactAnalyser
 import io.dotanuki.aaw.core.cli.ErrorReporter
 import io.dotanuki.aaw.core.cli.ExitCodes
@@ -19,10 +21,13 @@ class CompareCommand : CliktCommand(
     name = "compare"
 ) {
 
+    private val outputFormats = listOf("--json" to "json", "--console" to "console").toTypedArray()
+
     private val pathToArchive: String by option("-a", "--archive").required()
     private val pathToBaseline: String by option("-b", "--baseline").required()
     private val exitWithFailure by option("--fail").flag(default = false)
     private val withStacktraces by option("--stacktrace").flag(default = false)
+    private val format: String by option().switch(*outputFormats).default("console")
 
     override fun run() {
         ErrorReporter.printStackTraces = withStacktraces
@@ -34,7 +39,7 @@ class CompareCommand : CliktCommand(
         val current = AndroidArtifactAnalyser.analyse(ValidatedFile(pathToArchive))
         val reference = ValidatedTOML(ValidatedFile(pathToBaseline))
         val comparison = ArtifactsComparator.compare(current, reference.asBaseline())
-        ComparisonReporter.reportChanges(comparison)
+        ComparisonReporter.reportChanges(comparison, format)
 
         if (exitWithFailure && comparison.isNotEmpty()) {
             exitProcess(ExitCodes.FAILURE)

src/main/kotlin/io/dotanuki/aaw/features/comparison/CompareContext.kt

@@ -1,9 +1,11 @@
 package io.dotanuki.aaw.features.comparison
 
 import com.github.ajalt.mordant.terminal.Terminal
+import kotlinx.serialization.json.Json
 import net.peanuuutz.tomlkt.Toml
 
 data class CompareContext(
     val terminal: Terminal,
-    val tomlSerializer: Toml
+    val tomlSerializer: Toml,
+    val jsonSerializer: Json
 )

src/main/kotlin/io/dotanuki/aaw/features/comparison/ComparisonReporter.kt

@@ -6,17 +6,48 @@ import io.dotanuki.aaw.core.cli.emptyLine
 
 object ComparisonReporter {
 
+    private const val OUTCOME_NO_CHANGES = "No changes detected"
+    private const val OUTCOME_CHANGES_DETECTED = "Your baseline file does not match the supplied artifact"
+
+    context (CompareContext)
+    fun reportChanges(comparison: Set<ComparisonFinding>, format: String) {
+        when (format) {
+            "console" -> reportAsText(comparison)
+            "json" -> reportAsJson(comparison)
+        }
+    }
+
+    context (CompareContext)
+    private fun reportAsJson(comparison: Set<ComparisonFinding>) {
+        val outcome = when {
+            comparison.isEmpty() -> OUTCOME_NO_CHANGES
+            else -> OUTCOME_CHANGES_DETECTED
+        }
+
+        val results = comparison.map {
+            ComparisonResult(
+                item = it.what,
+                category = it.category.description,
+                finding = "Missing at ${it.expectation.description()}"
+            )
+        }
+
+        val serializable = SerializableComparison(outcome, results)
+        val jsonContent = jsonSerializer.encodeToString(SerializableComparison.serializer(), serializable)
+        terminal.println(jsonContent)
+    }
+
     context (CompareContext)
-    fun reportChanges(comparison: Set<ComparisonFinding>) {
+    private fun reportAsText(comparison: Set<ComparisonFinding>) {
         if (comparison.isEmpty()) {
             terminal.emptyLine()
-            terminal.println("No changes detected")
+            terminal.println(OUTCOME_NO_CHANGES)
             terminal.emptyLine()
             return
         }
 
         terminal.emptyLine()
-        terminal.println("Your baseline file does not match the supplied artifact")
+        terminal.println(OUTCOME_CHANGES_DETECTED)
         terminal.emptyLine()
 
         val changeAsTable = table {

src/main/kotlin/io/dotanuki/aaw/features/comparison/SerializableComparison.kt

@@ -0,0 +1,16 @@
+package io.dotanuki.aaw.features.comparison
+
+import kotlinx.serialization.Serializable
+
+@Serializable
+data class SerializableComparison(
+    val outcome: String,
+    val results: List<ComparisonResult>
+)
+
+@Serializable
+data class ComparisonResult(
+    val item: String,
+    val category: String,
+    val finding: String
+)