aimedb: Refactor codec

src/aimedb/decoder.test.ts

@@ -1,7 +1,7 @@
 import { Decoder } from "./decoder";
 
 function decode(req) {
-  const decoder = new Decoder({});
+  const decoder = new Decoder();
 
   decoder.write(req);
 

src/aimedb/decoder.ts

@@ -1,5 +1,82 @@
 import { Transform } from "stream";
 
+import * as Request from "./request";
+
+function begin(msg: Buffer): Request.AimeRequestBase {
+  const gameId = msg.toString("ascii", 0x000a, 0x000e);
+  const keychipId = msg.toString("ascii", 0x0014, 0x001f);
+
+  return { gameId, keychipId };
+}
+
+function readerRegisterRequest(msg: Buffer): Request.RegisterRequest {
+  const luid = msg.slice(0x0020, 0x002a).toString("hex");
+
+  return {
+    ...begin(msg),
+    type: "register",
+    luid,
+  };
+}
+
+function readLogRequest(msg: Buffer): Request.LogRequest {
+  // idk what any of this stuff means yet
+  // field20 and field28 appear to be an aime id but that is all.
+
+  return {
+    ...begin(msg),
+    type: "log",
+    field20: msg.readUInt32LE(0x20),
+    field24: msg.readUInt32LE(0x24),
+    field28: msg.readUInt32LE(0x28),
+    field2C: msg.readUInt32LE(0x2c),
+    field30: msg.readUInt32LE(0x30),
+    field34: msg.readUInt32LE(0x34),
+    field38: msg.readUInt32LE(0x38),
+    field3C: msg.readUInt32LE(0x3c),
+  };
+}
+
+function readCampaignRequest(msg: Buffer): Request.CampaignRequest {
+  return {
+    ...begin(msg),
+    type: "campaign",
+  };
+}
+
+function readLookupRequest(msg: Buffer): Request.LookupRequest {
+  const luid = msg.slice(0x0020, 0x002a).toString("hex");
+
+  return {
+    ...begin(msg),
+    type: "lookup",
+    luid,
+  };
+}
+
+function readHelloRequest(msg: Buffer): Request.HelloRequest {
+  return {
+    ...begin(msg),
+    type: "hello",
+  };
+}
+
+function readGoodbyeRequest(msg: Buffer): Request.GoodbyeRequest {
+  return {
+    ...begin(msg),
+    type: "goodbye",
+  };
+}
+
+const readers = new Map<number, (msg: Buffer) => Request.AimeRequest>();
+
+readers.set(0x0005, readerRegisterRequest);
+readers.set(0x0009, readLogRequest);
+readers.set(0x000b, readCampaignRequest);
+readers.set(0x000f, readLookupRequest);
+readers.set(0x0064, readHelloRequest);
+readers.set(0x0066, readGoodbyeRequest);
+
 export class Decoder extends Transform {
   constructor() {
     super({
@@ -8,88 +85,16 @@ export class Decoder extends Transform {
     });
   }
 
-  static ident(chunk) {
-    const gameId = chunk.toString("ascii", 0x000a, 0x000e);
-    const keychipId = chunk.toString("ascii", 0x0014, 0x001f);
+  _transform(msg: Buffer, encoding, callback) {
+    const code = msg.readUInt16LE(0x04);
+    const reader = readers.get(code);
 
-    return { gameId, keychipId };
-  }
-
-  static cardId(chunk) {
-    const luid = chunk.slice(0x0020, 0x002a);
-
-    return { luid, ...Decoder.ident(chunk) };
-  }
-
-  static log(chunk) {
-    // idk what any of this stuff means yet
-    // field20 and field28 appear to be an aime id but that is all.
-
-    const field20 = chunk.readUInt32LE(0x20);
-    const field24 = chunk.readUInt32LE(0x24);
-    const field28 = chunk.readUInt32LE(0x28);
-    const field2C = chunk.readUInt32LE(0x2c);
-    const field30 = chunk.readUInt32LE(0x30);
-    const field34 = chunk.readUInt32LE(0x34);
-    const field38 = chunk.readUInt32LE(0x38);
-    const field3C = chunk.readUInt32LE(0x3c);
-
-    return {
-      field20,
-      field24,
-      field28,
-      field2C,
-      field30,
-      field34,
-      field38,
-      field3C,
-      ...Decoder.ident(chunk),
-    };
-  }
-
-  _transform(chunk, encoding, callback) {
-    const cmd = chunk.readUInt16LE(0x04);
-
-    switch (cmd) {
-      case 0x0005:
-        return callback(null, {
-          cmd: "register",
-          ...Decoder.cardId(chunk),
-        });
-
-      case 0x0009:
-        return callback(null, {
-          cmd: "log",
-          ...Decoder.log(chunk),
-        });
-
-      case 0x000b:
-        return callback(null, {
-          cmd: "campaign",
-          ...Decoder.ident(chunk),
-        });
-
-      case 0x000f:
-        return callback(null, {
-          cmd: "lookup",
-          ...Decoder.cardId(chunk),
-        });
-
-      case 0x0064:
-        return callback(null, {
-          cmd: "hello",
-          ...Decoder.ident(chunk),
-        });
-
-      case 0x0066:
-        return callback(null, {
-          cmd: "goodbye",
-        });
-
-      default:
-        return callback(null, {
-          cmd: `unknown_${cmd}`,
-        });
+    if (reader === undefined) {
+      return callback(
+        new Error(`Unknown command code 0x${code.toString(16)}`)
+      );
     }
+
+    return callback(null, reader(msg));
   }
 }

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);

src/aimedb/index.ts

@@ -1,3 +1,4 @@
+import { AimeRequest } from "./request";
 import { setup } from "./pipeline";
 
 export default async function aimedb(socket) {
@@ -6,27 +7,27 @@ export default async function aimedb(socket) {
   const { input, output } = setup(socket);
 
   try {
-    for await (const req of input) {
+    for await (const obj of input) {
+      const req = obj as AimeRequest;
+
       console.log("Aimedb: Decode", req);
 
-      const { cmd } = req;
-
-      switch (cmd) {
+      switch (req.type) {
         case "hello":
           console.log("Aimedb: Hello");
-          output.write({ cmd, status: 1 });
+          output.write({ type: req.type, status: 1 });
 
           break;
 
         case "campaign":
           console.log("Aimedb: Campaign stuff");
-          output.write({ cmd, status: 1 });
+          output.write({ type: req.type, status: 1 });
 
           break;
 
         case "lookup":
           console.log("Aimedb: Mifare lookup", req.luid);
-          output.write({ cmd, status: 1 }); // Add aimeId if desired
+          output.write({ type: req.type, status: 1 }); // Add aimeId if desired
 
           break;
 
@@ -34,13 +35,13 @@ export default async function aimedb(socket) {
           // We get sent here if lookup does not return an aimeId
 
           console.log("Aimedb: Mifare register", req.luid);
-          output.write({ cmd, status: 1, aimeId: 12345678 });
+          output.write({ type: req.type, status: 1, aimeId: 12345678 });
 
           break;
 
         case "log":
           console.log("Aimedb: Log message");
-          output.write({ cmd, status: 1 });
+          output.write({ type: req.type, status: 1 });
 
           break;
 

src/aimedb/request.ts

@@ -0,0 +1,46 @@
+export interface AimeRequestBase {
+  gameId: string;
+  keychipId: string;
+}
+
+export interface RegisterRequest extends AimeRequestBase {
+  type: "register";
+  luid: string;
+}
+
+export interface LogRequest extends AimeRequestBase {
+  type: "log";
+  field20: number;
+  field24: number;
+  field28: number;
+  field2C: number;
+  field30: number;
+  field34: number;
+  field38: number;
+  field3C: number;
+}
+
+export interface CampaignRequest extends AimeRequestBase {
+  type: "campaign";
+}
+
+export interface LookupRequest extends AimeRequestBase {
+  type: "lookup";
+  luid: string;
+}
+
+export interface HelloRequest extends AimeRequestBase {
+  type: "hello";
+}
+
+export interface GoodbyeRequest extends AimeRequestBase {
+  type: "goodbye";
+}
+
+export type AimeRequest =
+  | CampaignRequest
+  | GoodbyeRequest
+  | HelloRequest
+  | LogRequest
+  | LookupRequest
+  | RegisterRequest;

src/aimedb/response.ts

@@ -0,0 +1,35 @@
+export type RegisterLevel = "none" | "portal" | "segaid";
+
+export interface AimeResponseBase {
+  status: number;
+}
+
+export interface CampaignResponse extends AimeResponseBase {
+  type: "campaign";
+}
+
+export interface HelloResponse extends AimeResponseBase {
+  type: "hello";
+}
+
+export interface LogResponse extends AimeResponseBase {
+  type: "log";
+}
+
+export interface LookupResponse extends AimeResponseBase {
+  type: "lookup";
+  aimeId?: number;
+  registerLevel: RegisterLevel;
+}
+
+export interface RegisterResponse extends AimeResponseBase {
+  type: "register";
+  aimeId: number;
+}
+
+export type AimeResponse =
+  | CampaignResponse
+  | HelloResponse
+  | LogResponse
+  | LookupResponse
+  | RegisterResponse;