Add applet viewer config parser

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

archive/src/main/kotlin/org/openrs2/archive/jav/JavConfig.kt

@@ -0,0 +1,66 @@
+package org.openrs2.archive.jav
+
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.future.await
+import kotlinx.coroutines.withContext
+import org.openrs2.http.checkStatusCode
+import java.io.BufferedReader
+import java.net.URI
+import java.net.http.HttpClient
+import java.net.http.HttpRequest
+import java.net.http.HttpResponse
+
+public data class JavConfig(
+    public val config: Map<String, String>,
+    public val params: Map<String, String>,
+    public val messages: Map<String, String>
+) {
+    public companion object {
+        public suspend fun download(client: HttpClient, url: String): JavConfig {
+            val request = HttpRequest.newBuilder(URI(url))
+                .GET()
+                .build()
+
+            val response = client.sendAsync(request, HttpResponse.BodyHandlers.ofInputStream()).await()
+            response.checkStatusCode()
+
+            return withContext(Dispatchers.IO) {
+                response.body().bufferedReader().use { reader ->
+                    read(reader)
+                }
+            }
+        }
+
+        public fun read(reader: BufferedReader): JavConfig {
+            val config = mutableMapOf<String, String>()
+            val params = mutableMapOf<String, String>()
+            val messages = mutableMapOf<String, String>()
+
+            reader.lineSequence().map(String::trim).forEach { line ->
+                when {
+                    line.startsWith("//") || line.startsWith("#") -> Unit
+                    line.startsWith("msg=") -> {
+                        val parts = line.substring("msg=".length).split("=", limit = 2)
+                        if (parts.size == 2) {
+                            messages[parts[0]] = parts[1]
+                        }
+                    }
+                    line.startsWith("param=") -> {
+                        val parts = line.substring("param=".length).split("=", limit = 2)
+                        if (parts.size == 2) {
+                            params[parts[0]] = parts[1]
+                        }
+                    }
+                    else -> {
+                        val parts = line.split("=", limit = 2)
+                        if (parts.size == 2) {
+                            config[parts[0]] = parts[1]
+                        }
+                    }
+                }
+            }
+
+            return JavConfig(config, params, messages)
+        }
+    }
+}