//
// hello.broadhop-LED.t1624.ino
//    broad-hop LED tiny1624 hello-world
//
// Neil Gershenfeld 11/14/23
//
// This work may be reproduced, modified, distributed,
// performed, and displayed for any purpose, but must
// acknowledge this project. Copyright is retained and
// must be preserved. The work is provided as is; no
// warranty is provided, and users accept all liability.
//
#define LED1 21 

// Downstream Pins (Connect these to Node 1)
#define RxOut D7  // Connect to Node 1's TX (Pin 21 on C3)
#define TxOut D6  // Connect to Node 1's RX (Pin 20 on C3)

// Upstream Port: Uses the USB-C cable to talk to Laptop
#define PortIn Serial 

// Downstream Port: Talks to the chain of nodes
HardwareSerial PortOut(1); 

// Global Variables (Keep these the same)
char cmd;
uint8_t arg, addr, address;

void setup() {
   delay(2000); // Give USB time to wake up

   // 1. Setup LED
   pinMode(LED1, OUTPUT);
   digitalWrite(LED1, HIGH); // OFF

   // 2. Start Upstream (USB)
   PortIn.begin(921600);
   // Wait for Python script to connect (Optional, prevents missed packets)
   // while(!PortIn); 

   // 3. Start Downstream (Pins D7/D6)
   PortOut.begin(921600, SERIAL_8N1, RxOut, TxOut);
   
   // 4. Set Sensor Pin
   pinMode(RxOut, INPUT);
}

void loop() {
  //
  // wait for a command
  //
  while (PortIn.available() == 0);
  cmd = PortIn.read();
  //
  // all LED command?
  //
  if (cmd == 'L') {
    PortOut.write(cmd);
    while (PortIn.available() == 0);
    arg = PortIn.read();
    if (arg & 0b1)
      digitalWrite(LED1,HIGH);
    else
      digitalWrite(LED1,LOW);
    }
  //
  // individual LED command?
  //
  else if (cmd == 'l') {

    PortOut.write(cmd);

    while (PortIn.available() == 0);
    addr = PortIn.read();
    PortOut.write(addr);
    
    while (PortIn.available() == 0);
    arg = PortIn.read();
    PortOut.write(arg);

    if (addr == address) {
      if (arg & 0b1)
        digitalWrite(LED1,HIGH);
      else
        digitalWrite(LED1,LOW);
      
      }
    }
  //
  // address assignment command?
  //
  else if (cmd == 'a') {
    PortOut.end();
    pinMode(RxOut, INPUT);
    delay(2);
    if (digitalRead(RxOut) == LOW) {
      //
      // nothing connected, last node
      //
      address = 0;
      PortIn.write(0);

      PortOut.begin(921600, SERIAL_8N1, RxOut, TxOut);
      }
    else {
      //
      // something connected, wait for hop count
      //
      PortOut.begin(921600, SERIAL_8N1, RxOut, TxOut);
      PortOut.write('a');
      
      while (PortOut.available() == 0);
      arg = PortOut.read();
      address = arg+1;
      PortIn.write(address);
      }
    }
  }