aimedb: Refactor codec

src/aimedb/encoder.ts

@@ -1,10 +1,22 @@
 import { Transform } from "stream";
 
-const registerLevels = {
-  none: 0,
-  portal: 1,
-  segaid: 2,
-};
+import { AimeResponse, RegisterLevel } from "./response";
+
+const registerLevels = new Map<RegisterLevel, number>();
+
+registerLevels.set("none", 0);
+registerLevels.set("portal", 1);
+registerLevels.set("segaid", 2);
+
+function begin(length: number) {
+  const buf = Buffer.alloc(length);
+
+  buf.writeUInt16LE(0xa13e, 0x0000); // Magic?
+  buf.writeUInt16LE(0x3087, 0x0002); // ???
+  buf.writeUInt16LE(length, 0x0006);
+
+  return buf;
+}
 
 export class Encoder extends Transform {
   constructor() {
@@ -14,35 +26,25 @@ export class Encoder extends Transform {
     });
   }
 
-  static init(length) {
-    const buf = Buffer.alloc(length);
+  _transform(msg: AimeResponse, encoding, callback) {
+    console.log("Aimedb: Encode", msg);
 
-    buf.writeUInt16LE(0xa13e, 0x0000); // Magic?
-    buf.writeUInt16LE(0x3087, 0x0002); // ???
-    buf.writeUInt16LE(length, 0x0006);
+    let buf: Buffer;
 
-    return buf;
-  }
-
-  _transform(chunk, encoding, callback) {
-    console.log("Aimedb: Encode", chunk);
-
-    let buf;
-
-    switch (chunk.cmd) {
+    switch (msg.type) {
       case "hello":
-        buf = Encoder.init(0x0020);
+        buf = begin(0x0020);
         buf.writeUInt16LE(0x0065, 0x0004); // cmd code
-        buf.writeUInt16LE(chunk.status, 0x0008);
+        buf.writeUInt16LE(msg.status, 0x0008);
 
         break;
 
       case "campaign":
         // Still figuring this out...
 
-        buf = Encoder.init(0x0200);
+        buf = begin(0x0200);
         buf.writeUInt16LE(0x000c, 0x0004); // cmd code
-        buf.writeUInt16LE(chunk.status, 0x0008);
+        buf.writeUInt16LE(msg.status, 0x0008);
 
         // Campaign array starts at 0x20
         // Element size is 0xA0
@@ -53,31 +55,31 @@ export class Encoder extends Transform {
         // -1 aime id means card is not registered
         // register level does not seem to matter
 
-        buf = Encoder.init(0x0130);
+        buf = begin(0x0130);
         buf.writeUInt16LE(0x0010, 0x0004); // cmd code
-        buf.writeUInt16LE(chunk.status, 0x0008);
-        buf.writeInt32LE(chunk.aimeId || -1, 0x0020);
-        buf.writeUInt8(registerLevels[chunk.registerLevel], 0x0024);
+        buf.writeUInt16LE(msg.status, 0x0008);
+        buf.writeInt32LE(msg.aimeId || -1, 0x0020);
+        buf.writeUInt8(registerLevels[msg.registerLevel], 0x0024);
 
         break;
 
       case "register":
-        buf = Encoder.init(0x0030);
+        buf = begin(0x0030);
         buf.writeUInt16LE(0x0006, 0x0004); // cmd code
-        buf.writeUInt16LE(chunk.status, 0x0008);
-        buf.writeInt32LE(chunk.aimeId, 0x0020);
+        buf.writeUInt16LE(msg.status, 0x0008);
+        buf.writeInt32LE(msg.aimeId, 0x0020);
 
         break;
 
       case "log":
-        buf = Encoder.init(0x0020);
+        buf = begin(0x0020);
         buf.writeUInt16LE(0x000a, 0x0004); // cmd code
-        buf.writeUInt16LE(chunk.status, 0x0008);
+        buf.writeUInt16LE(msg.status, 0x0008);
 
         break;
 
       default:
-        return callback(new Error(`Unimplemented response: ${chunk.cmd}`));
+        return callback(new Error("Unimplemented response type"));
     }
 
     console.log("Aimedb: Send", buf);