1 files changed, 138 insertions, 0 deletions
diff --git a/web/protocol.js b/web/protocol.js
new file mode 100644
index 0000000..9c93f8e
--- /dev/null
+++ b/web/protocol.js
@@ -0,0 +1,138 @@
+export const ADDR = {
+  CTRL: 0xdb96,
+  OVEN: 0xaa55,
+};
+
+export const FUNC = {
+  // used by oven
+  O_CONNECT: 0x01,
+  O_TEMPS: 0x02,
+  O_READ: 0x03,
+  O_ACK_WRITE: 0x06,
+
+  // used by CTRL
+  C_PWM_HEAT: 0x08,
+  C_PWM_COOL: 0x0d,
+  C_STARTSTOP: 0x10,
+  C_REQ_READ: 0x11,
+  C_WRITE: 0x20,
+  C_ACK_CONNECT: 0xf1,
+  C_ACK_READ: 0xf2,
+};
+
+export const ARG = {
+  // for STARSTOP, REQUEST_READ
+  STARTSTOP_START: 0x11,
+  STARTSTOP_STOP: 0x22,
+  REQUEST_READ: 0x11,
+
+  // for CONNECT / ACK_CONNECT
+  CONNECT_CONNECTING: 0x0100,
+  CONNECT_CONNECTED: 0x0200,
+
+  // for *_PWM
+  PWM_ON: 0x44,
+  PWM_OFF: 0x88,
+};
+
+const lookup = (tbl, val) => Object.keys(tbl).find(key => tbl[key] === val); 
+
+export class Message {
+  constructor(buffer) {
+    this.buf = buffer;
+    this.view = new DataView(this.buf);
+    this.data = new DataView(this.buf, 4, this.buf.byteLength - 6);
+  }
+
+  get16(i) { return this.data.getUint16(i, false); }
+  set16(i, v) { this.data.setUint16(i, v, false); }
+
+  get address() { return this.view.getUint16(0, false); }
+  set address(val) { this.view.setUint16(0, val, false); }
+
+  get func() { return this.view.getUint8(2); }
+  set func(val) { this.view.setUint8(2, val)}
+
+  get data_len() { return this.view.getUint8(3); }
+  set data_len(val) { this.view.setUint8(3, val); }
+
+  get length() { return this.buf.byteLength; }
+
+  get checksum() { return this.view.getUint16(this.buf.byteLength-2, false); }
+  set checksum(val) { this.view.setUint16(this.buf.byteLength-2, val, false); }
+
+  calculateSum() {
+    let sum = 0;
+    for (let i = 0; i < this.length - 2; i++) {
+      sum += this.view.getUint8(i);
+    }
+    return sum & 0xffff;
+  }
+
+  getDataArray() {
+	  return new Uint8Array(this.buf, 4, this.buf.byteLength - 6);
+  }
+
+  toString() {
+	  const address = lookup(ADDR, this.address) ?? "????";
+	  const func = lookup(FUNC, this.func) ?? "?_??";
+	  const data = this.getDataArray();
+	  return `to ${address}: ${func.substr(2)} [${data}]`;
+  }
+
+  static from8(addr, func, data) {
+    const len = 2 + 2 + data.length + 2;
+
+    const msg = new Message(new ArrayBuffer(len));
+    msg.address = addr;
+    msg.func = func;
+    msg.data_len = data.length;
+
+    for (let i = 0; i < data.length; i++) {
+      msg.data.setUint8(i, data[i]);
+    }
+
+    msg.checksum = msg.calculateSum();
+    return msg;
+  }
+
+  static from16(addr, func, data) {
+    const len = 2 + 2 + 2*data.length + 2;
+
+    const msg = new Message(new ArrayBuffer(len));
+    msg.address = addr;
+    msg.func = func;
+    msg.data_len = 2*data.length;
+
+    for (let i = 0; i < data.length; i++) {
+      msg.data.setUint16(2*i, data[i], false);
+    }
+
+    msg.checksum = msg.calculateSum();
+    return msg;
+  }
+
+  static empty(addr, func, data_len) {
+    const len = 2 + 2 + 2*data_len + 2;
+
+    const msg = new Message(new ArrayBuffer(len));
+    msg.address = addr;
+    msg.func = func;
+    msg.data_len = data_len;
+
+    return msg;
+  }
+
+  static tryParse(buffer) {
+    if (buffer.length < 4 + 2) return;
+
+    const data_len = buffer[3];
+    if (buffer.length < 4 + data_len + 2) return;
+
+    const msg = new Message(buffer.slice(0, 4 + data_len + 2).buffer);
+    if (msg.calculateSum() !== msg.checksum) {
+      throw new Error(`checksum mismatch: expected ${hex(msg.checksum)} but calculated ${hex(msg.calculateSum())}`);
+    }
+    return msg;
+  };
+}