From 6a8e00cc852af59f11ab189913f1b60dc708b257 Mon Sep 17 00:00:00 2001
From: Tau <tau@nowhere>
Date: Mon, 26 Nov 2018 17:07:51 -0500
Subject: [PATCH] Add encoder layer to aimedb

---
 src/aimedb.js | 86 ++++++++++++++++++++++++++++++++++++++++++++-------
 1 file changed, 75 insertions(+), 11 deletions(-)

diff --git a/src/aimedb.js b/src/aimedb.js
index 4cca1fc..5c63f93 100644
--- a/src/aimedb.js
+++ b/src/aimedb.js
@@ -3,7 +3,7 @@ const { Transform, pipeline } = require('stream')
 
 const K = Buffer.from('Copyright(C)SEGA', 'utf8')
 
-class Decoder extends Transform {
+class Deframer extends Transform {
   constructor(options) {
     super({
       readableObjectMode: true,
@@ -43,7 +43,71 @@ class Decoder extends Transform {
   }
 }
 
+class Decoder extends Transform {
+  constructor(options) {
+    super({
+      readableObjectMode: true,
+      writableObjectMode: true,
+      ...options,
+    })
+  }
+
+  static ident(payload) {
+    const gameId = payload.toString('ascii', 2, 6)
+    const keychipId = payload.toString('ascii', 12, 23)
+
+    return { gameId, keychipId }
+  }
+
+  _transform(chunk, encoding, callback) {
+    const { cmd, payload } = chunk
+
+    switch (cmd) {
+      case 0x0064:
+        return callback(null, {
+          cmd: 'hello',
+          ...Decoder.ident(payload)
+        })
+
+      case 0x0066:
+        return callback(null, {
+          cmd: 'goodbye',
+        })
+
+      default:
+        return callback(new Error(`Unknown AimeDB command ${cmd}`))
+    }
+  }
+}
+
 class Encoder extends Transform {
+  constructor(options) {
+    super({
+      readableObjectMode: true,
+      writableObjectMode: true,
+      ...options,
+    })
+  }
+
+  _transform(chunk, encoding, callback) {
+    console.log('Aimedb: Encode', chunk)
+
+    let payload
+
+    switch (chunk.cmd) {
+      case 'hello':
+        payload = Buffer.alloc(24)
+        payload.writeInt16LE(chunk.status)
+
+        return callback(null, { cmd: 0x0065, payload })
+
+      default:
+        return callback(newError(`Unimplemented response: ${cmd}`))
+    }
+  }
+}
+
+class Framer extends Transform {
   constructor(options) {
     super({
       writableObjectMode: true,
@@ -79,14 +143,15 @@ async function dispatch(socket) {
     crypto
       .createDecipheriv('aes-128-ecb', K, null)
       .setAutoPadding(false),
+    new Deframer(),
     new Decoder(),
   )
 
-
   const output = new Encoder()
 
   pipeline(
     output,
+    new Framer(),
     crypto
       .createCipheriv('aes-128-ecb', K, null)
       .setAutoPadding(false),
@@ -95,26 +160,25 @@ async function dispatch(socket) {
 
   try {
     for await (const req of input) {
+      console.log('Aimedb: Decode', req)
+
+      const { cmd } = req
       let payload
 
-      switch (req.cmd) {
-      case 0x0064:
+      switch (cmd) {
+      case 'hello':
         console.log('Aimedb: Hello')
-
-        payload = Buffer.alloc(24)
-        payload.writeInt16LE(0x0001, 0)
-
-        output.write({ cmd: 0x0065, payload })
+        output.write({ cmd, status: 1 })
 
         break
 
-      case 0x0066:
+      case 'goodbye':
         console.log('Aimedb: Goodbye')
 
         break
 
       default:
-        console.log('Aimedb: Unknown command', req.cmd)
+        console.log('Aimedb: Handler not implemented!')
 
         break
       }