Add custom JSON pretty printer

This produces identical output to the Firefox pretty printer.

Signed-off-by: Graham <gpe@openrs2.org>

json/src/main/kotlin/org/openrs2/json/JsonPrettyPrinter.kt

@@ -0,0 +1,24 @@
+package org.openrs2.json
+
+import com.fasterxml.jackson.core.JsonGenerator
+import com.fasterxml.jackson.core.util.DefaultIndenter
+import com.fasterxml.jackson.core.util.DefaultPrettyPrinter
+
+public class JsonPrettyPrinter : DefaultPrettyPrinter() {
+    init {
+        indentArraysWith(UNIX_INDENT)
+        indentObjectsWith(UNIX_INDENT)
+    }
+
+    override fun createInstance(): DefaultPrettyPrinter {
+        return JsonPrettyPrinter()
+    }
+
+    override fun writeObjectFieldValueSeparator(g: JsonGenerator) {
+        g.writeRaw(": ")
+    }
+
+    private companion object {
+        private val UNIX_INDENT = DefaultIndenter("  ", "\n")
+    }
+}

json/src/main/kotlin/org/openrs2/json/ObjectMapperProvider.kt

@@ -3,6 +3,7 @@ package org.openrs2.json
 import com.fasterxml.jackson.databind.Module
 import com.fasterxml.jackson.databind.ObjectMapper
 import com.fasterxml.jackson.databind.PropertyNamingStrategies
+import com.fasterxml.jackson.databind.SerializationFeature
 import com.fasterxml.jackson.module.kotlin.registerKotlinModule
 import javax.inject.Inject
 import javax.inject.Provider
@@ -14,6 +15,8 @@ public class ObjectMapperProvider @Inject constructor(
         return ObjectMapper()
             .registerKotlinModule()
             .registerModules(modules)
+            .enable(SerializationFeature.INDENT_OUTPUT)
+            .setDefaultPrettyPrinter(JsonPrettyPrinter())
             .setPropertyNamingStrategy(PropertyNamingStrategies.SNAKE_CASE)
     }
 }