/*

   bsh-dbus-logger.ino

   B/S/H/ D-Bus data logger

   (C) 2024 Hajo Noerenberg

   http://www.noerenberg.de/
   https://github.com/hn/bsh-home-appliances

   This program is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License version 3.0 as
   published by the Free Software Foundation.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License along
   with this program. If not, see <http://www.gnu.org/licenses/gpl-3.0.txt>.

*/

#include <SoftwareSerial.h>
#include "CRC16.h"
#include "CRC.h"

#define BSHDBUSRX D5
#define BSHDBUSTX D6

#define FRAMEBUFLEN 250
#define USERBUFLEN 32

SoftwareSerial dbus(BSHDBUSRX, BSHDBUSTX);

CRC16 crc(CRC16_XMODEM_POLYNOME,
          CRC16_XMODEM_INITIAL,
          CRC16_XMODEM_XOR_OUT,
          CRC16_XMODEM_REV_IN,
          CRC16_XMODEM_REV_OUT);

void setup() {
  // put your setup code here, to run once:

  dbus.begin(9600);   // 8N2 not supported, works nevertheless

  Serial.begin(115200);
  Serial.println("B/S/H/ D-Bus logger started.");

}

byte framebuf[FRAMEBUFLEN];
unsigned int framepos = 0;
unsigned int framelen = 0;

unsigned long readlast = 0;

char userbuf[USERBUFLEN];
unsigned int userlen = 0;

void loop() {
  // put your main code here, to run repeatedly:

  while (dbus.available()) {
    unsigned long readnow = millis();
    byte rawbyte = dbus.read();

    if ((readnow - readlast) > 20) {
      if ((framelen > 0) && (framepos == framelen)) {
        Serial.printf("(ack=none)\n");
      } else if (framepos > 0) {
        Serial.printf("(read=timout)\n");
      }
      framepos = framelen = 0;
      crc.restart();
    } else if ((framelen > 0) && (framepos == framelen)) {
      framepos = framelen = 0;
      crc.restart();
      // Strictly speaking, this should not be necessary here
      // if the timing is precise, so it is a kind of workaround:
      if (rawbyte == ((framebuf[1] & 0xf0) | 0x0a)) {
        Serial.printf("%02x (ack=ok)\n", rawbyte);
        continue;
      } else {
        Serial.printf("(ack=err, re-evaluate byte)\n");
      }
    }

    readlast = readnow;
    crc.add(rawbyte);
    Serial.printf("%02x", rawbyte);

    if (framepos < FRAMEBUFLEN) {
      framebuf[framepos++] = rawbyte;
    }

    if (framepos == 1) {
      framelen = 2 + 2 + (unsigned int) rawbyte;
      Serial.printf(" | ");
    } else if (framepos == 2) {
      Serial.printf(".");
    } else if (framepos == 3) {
      Serial.printf("-");
    } else if (framepos == 4) {
      Serial.printf(" | ");
    } else if (framepos == (framelen - 2)) {
      for (unsigned int p = framelen; p < 10; p++) {
        Serial.printf("   ");
      }
      Serial.printf(" | ");
    } else if (framepos == framelen) {
      if (crc.calc()) {
        Serial.printf(" (crc=err, len=%d)\n", framelen);
        framepos = framelen = 0;
        crc.restart();
      } else {
        Serial.printf(" (crc=ok) | ");
        // We only process a small sample set of data here:
        switch (framebuf[1] << 16 | framebuf[2] << 8 | framebuf[3]) {
          case 0x141004:
            Serial.printf("(Temperature=%d) ", framebuf[4]);
            break;
          case 0x141005:
            Serial.printf("(Washing program=%d) ", framebuf[6]);
            break;
          case 0x141006:
            Serial.printf("(Spin speed=%d) ", framebuf[4]);
            break;
          case 0x2a1600:
            Serial.printf("(Remaining time=%d) ", framebuf[4]);
            break;
        }
      }
    } else {
      Serial.printf(" ");
    }
  }

  // Dirty way to write to the D-Bus: No silence / collision / anything detection, just fire and forget
  // Input via terminal: DS.CC-CC MM MM (no length prefix, no crc)

  while (Serial.available()) {
    byte c = Serial.read();
    if (((c >= '0' && c <= '9') || (c >= 'A' && c <= 'F') || (c >= 'a' && c <= 'f')) && userlen < USERBUFLEN) {
      userbuf[userlen++] = c;
    }
    if (c != '\r' && c != '\n') continue;
    if (userlen < 6 || userlen % 2) {
      Serial.println("Error: Invalid input length");
      userlen = 0;
      continue;
    }
    CRC16 outcrc(CRC16_XMODEM_POLYNOME, CRC16_XMODEM_INITIAL, CRC16_XMODEM_XOR_OUT, CRC16_XMODEM_REV_IN, CRC16_XMODEM_REV_OUT);
    byte outbyte = userlen / 2 - 1;
    outcrc.add(outbyte);
    dbus.write(outbyte);
    for (unsigned int i = 0; i < userlen; i += 2) {
      outbyte = (userbuf[i] % 32 + 9) % 25 * 16 + (userbuf[i + 1] % 32 + 9) % 25;
      outcrc.add(outbyte);
      dbus.write(outbyte);
    }
    uint16_t outcc = outcrc.calc();
    dbus.write(outcc >> 8);
    dbus.write(outcc);
    userlen = 0;
  }
}