Add file upload support

server/src/main/kotlin/Main.kt

@@ -2,6 +2,8 @@ package xyz.maxwellj.chookchat
 
 import io.javalin.Javalin
 import io.javalin.websocket.WsContext
+import io.javalin.http.UploadedFile
+
 import java.util.concurrent.ConcurrentHashMap
 import java.util.UUID
 
@@ -359,6 +361,33 @@ fun main(args: Array<String>) {
             ctx.redirect("/index.html") 
         }
         .get("/api/createaccount/{content}") { ctx -> ctx.result(createAccount(ctx.pathParam("content")))}
+        .post("/api/upload") { ctx ->
+            val uploadedFiles = ctx.uploadedFiles()
+            if (uploadedFiles.isEmpty()) {
+                ctx.status(400).result("No files uploaded")
+                return@post
+            }
+            val uploadedFile = uploadedFiles[0]
+            val originalFilename = uploadedFile.filename()
+            val uuid = UUID.randomUUID().toString()
+            val fileExtension = originalFilename.substringAfterLast(".", "")
+            val baseFilename = originalFilename.substringBeforeLast(".")
+            val newFilename = "${baseFilename}_${uuid}${if (fileExtension.isNotEmpty()) ".$fileExtension" else ""}"
+            val filePath = Paths.get("uploads", newFilename)
+            Files.copy(uploadedFile.content(), filePath)
+            val processedData = JSONObject().apply {
+                put("type", "fileStatus")
+                put("username", "system")
+                put("content", "success")
+            }
+            ctx.result(processedData.toString())
+            val processedData2 = JSONObject().apply {
+                put("type", "file")
+                put("username", "system")
+                put("content", "https://maxwellj.xyz/chookchat/uploads/$newFilename")
+            }
+            WsSessionManager.broadcast(processedData2.toString())
+        }
         .ws("/api/websocket") { ws -> 
             ws.onConnect { ctx -> 
                 WsSessionManager.addSession(ctx)