/*
  xsns_87_mcp2515.ino - MCP2515 CAN bus support for Tasmota

  Copyright (C) 2021  Marius Bezuidenhout

  This program is free software: you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation, either version 3 of the License, or
  (at your option) any later version.

  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/>.
*/

#ifdef USE_SPI
#ifdef USE_MCP2515
/*********************************************************************************************\
 * MCP2515 - Microchip CAN controller
 *
 * Connections:
 * MCP2515  ESP8266         Tasmota
 * -------  --------------  ----------
 *  INT     not used
 *  SCK     GPIO14          SPI CLK
 *  SI      GPIO13          SPI MOSI
 *  SO      GPIO12          SPI MISO
 *  CS      GPIO0..5,15,16  MCP2515
 *  Gnd     Gnd
 *  VCC     Vin/5V
\*********************************************************************************************/

#define XSNS_87              87

// set defaults if not defined
#ifndef MCP2515_BITRATE
  #define MCP2515_BITRATE  CAN_500KBPS
#endif

#ifndef MCP2515_CLOCK
  #define MCP2515_CLOCK  MCP_8MHZ
#endif

#ifndef MCP2515_MAX_FRAMES
  #define MCP2515_MAX_FRAMES 14
#endif

#ifndef CAN_KEEP_ALIVE_SECS
  #define CAN_KEEP_ALIVE_SECS 300
#endif

#ifndef MCP2515_TIMEOUT
  #define MCP2515_TIMEOUT 10
#endif

#ifndef MCP2515_BMS_CLIENT
  #define MCP2515_BMS_CLIENT
  // Look for Freedom Won BMS data in CAN message
  #ifndef MCP2515_BMS_FREEDWON
    #define MCP2515_BMS_FREEDWON
  #endif  // MCP2515_BMS_FREEDWON
#endif // MCP2515_BMS_CLIENT

#include "mcp2515.h"

#ifdef MCP2515_BMS_CLIENT
struct BMS_Struct {
  uint16_t  stateOfCharge;
  uint16_t  stateOfHealth;
  uint16_t  battVoltage; // Div 100
  int16_t   battAmp; // Div 10
  int16_t   battTemp; // Div 10
  char      name[17];
} bms;
#endif

int8_t mcp2515_init_status = 1;

uint32_t lastFrameRecv = 0;
struct can_frame canFrame;
MCP2515 *mcp2515 = nullptr;

char c2h(char c)
{
  return "0123456789ABCDEF"[0x0F & (unsigned char)c];
}

void MCP2515_Init(void) {
  mcp2515 = new MCP2515(5);
  if (MCP2515::ERROR_OK != mcp2515->reset()) {
    AddLog(LOG_LEVEL_ERROR, PSTR("MCP2515: Failed to reset module"));
    mcp2515_init_status = 0;
  }

  if (MCP2515::ERROR_OK != mcp2515->setBitrate(MCP2515_BITRATE, MCP2515_CLOCK)) {
    AddLog(LOG_LEVEL_ERROR, PSTR("MCP2515: Failed to set module bitrate"));
    mcp2515_init_status = 0;
  }

  if (mcp2515_init_status && MCP2515::ERROR_OK != mcp2515->setNormalMode()) {
    AddLog(LOG_LEVEL_ERROR, PSTR("MCP2515: Failed to set normal mode"));
    mcp2515_init_status = 0;
  }
#ifdef MCP2515_BMS_FREEDWON
  // TODO: Filter CAN bus messages
  //mcp2515->setFilterMask();
  //mcp2515->setFilter();
#endif
}

void MCP2515_Read() {
  uint8_t nCounter = 0;
  bool checkRcv;
  if (mcp2515_init_status) {

    checkRcv = mcp2515->checkReceive();

    while (checkRcv && nCounter <= MCP2515_MAX_FRAMES) {
      mcp2515->checkReceive();
      nCounter++;
      if (mcp2515->readMessage(&canFrame) == MCP2515::ERROR_OK) {
        lastFrameRecv = TasmotaGlobal.uptime;
#ifdef MCP2515_BMS_CLIENT
  #ifdef MCP2515_BMS_FREEDWON
      switch (canFrame.can_id) {
        // Charge/Discharge parameters
        case 0x351:
          break;
        // State of Charge/Health
        case 0x355:
          if (6 >= canFrame.can_dlc) {
            bms.stateOfCharge = (canFrame.data[1] << 8) | canFrame.data[0];
            bms.stateOfHealth = (canFrame.data[3] << 8) | canFrame.data[2];
          } else {
            AddLog(LOG_LEVEL_DEBUG, PSTR("MCP2515: Unexpected length (%d) for ID 0x355"), canFrame.can_dlc);
          }
          break;
        // Voltage/Current/Temperature
        case 0x356:
          if (6 >= canFrame.can_dlc) {
            bms.battVoltage = (canFrame.data[1] << 8) | canFrame.data[0];
            bms.battAmp = (canFrame.data[3] << 8) | canFrame.data[2];
            bms.battTemp = (canFrame.data[5] << 8) | canFrame.data[4]; // Convert to fahrenheit if SetOpion8 is set
          } else {
            AddLog(LOG_LEVEL_DEBUG, PSTR("MCP2515: Unexpected length (%d) for ID 0x356"), canFrame.can_dlc);
          }
          break;
        // Manufacturer name
        case 0x35E:
        // Battery Model / Firmware version
        case 0x35F:
          break;
        // Battery / BMS name
        case 0x370:
        case 0x371:
          for(int i = 0; i < canFrame.can_dlc; i++) {
            uint8_t nameStrPos = i + ((canFrame.can_id & 0x1) * 8); // If can_id is 0x371 then fill from byte 8 onwards
            bms.name[nameStrPos] = canFrame.data[i];
          }
          bms.name[16] = 0; // Ensure that name is null terminated
          break;
        // Modules status
        case 0x372:
        // Min/Max cell voltage/temperature
        case 0x373:
        // Min. cell voltage id string
        case 0x374:
        // Max. cell voltage id string
        case 0x375:
        // Min. cell temperature id string
        case 0x376:
        // Max. cell temperature id string
        case 0x377:
        // Installed capacity
        case 0x379:
        // Serial number
        case 0x380:
        case 0x381:
          break;
        default:
          char canMsg[17];
          canMsg[0] = 0;
          for(int i = 0; i < canFrame.can_dlc; i++) {
            canMsg[i*2] = c2h(canFrame.data[i]>>4);
            canMsg[i*2+1] = c2h(canFrame.data[i]);
          }
          if (canFrame.can_dlc > 0) {
            canMsg[(canFrame.can_dlc - 1) * 2 + 2] = 0;
          }
          AddLog(LOG_LEVEL_DEBUG, PSTR("MCP2515: Received message 0x%s from ID 0x%X"), canMsg, (uint32_t)canFrame.can_id);
          break;
      }
  #endif // MCP2515_BMS_FREEDWON
#endif // MCP2515_BMS_CLIENT
      } else if (mcp2515->checkError()) {
        uint8_t errFlags = mcp2515->getErrorFlags();
          mcp2515->clearRXnOVRFlags();
          AddLog(LOG_LEVEL_DEBUG, PSTR("MCP2515: Received error %d"), errFlags);
          break;
      }
    }

#ifdef MCP2515_BMS_FREEDWON
    if (!(TasmotaGlobal.uptime%CAN_KEEP_ALIVE_SECS) && TasmotaGlobal.uptime>60) {
      canFrame.can_id  = 0x305;
      canFrame.can_dlc = 0;
      if (MCP2515::ERROR_OK != mcp2515->sendMessage(&canFrame)) {
        AddLog(LOG_LEVEL_ERROR, PSTR("MCP2515: Failed to send keep alive frame"));
      }
    }
#endif
  }
}

void MCP2515_Show(bool Json) {
  if (Json) {
    if (lastFrameRecv > 0 && TasmotaGlobal.uptime - lastFrameRecv <= MCP2515_TIMEOUT ) {
#ifdef MCP2515_BMS_CLIENT
    ResponseAppend_P(PSTR(",\"MCP2515\":{\"SOC\":%d,\"SOH\":%d}"), \
      bms.stateOfCharge,
      bms.stateOfHealth
      );
#endif // MCP2515_BMS_CLIENT
    }
#ifdef USE_WEBSERVER
  } else {
  #ifdef MCP2515_BMS_CLIENT
    char ampStr[6];
    dtostrf((float(bms.battAmp) / 10), 5, 1, ampStr);
    WSContentSend_PD(HTTP_SNS_SOC, bms.name, bms.stateOfCharge);
    WSContentSend_PD(HTTP_SNS_SOH, bms.name, bms.stateOfHealth);
    WSContentSend_Voltage(bms.name, (float(bms.battVoltage) / 100));
    WSContentSend_PD(HTTP_SNS_CURRENT, ampStr);
    WSContentSend_Temp(bms.name, ConvertTemp(float(bms.battTemp) / 10));
  #endif // MCP2515_BMS_CLIENT
#endif  // USE_WEBSERVER
  }
}

/*********************************************************************************************\
 * Interface
\*********************************************************************************************/

bool Xsns87(uint8_t function)
{
  bool result = false;

  if (PinUsed(GPIO_MCP2515_CS, GPIO_ANY) && TasmotaGlobal.spi_enabled) {
    switch (function) {
      case FUNC_INIT:
        MCP2515_Init();
        break;
      case FUNC_EVERY_50_MSECOND:
        MCP2515_Read();
        break;
      case FUNC_JSON_APPEND:
        MCP2515_Show(1);
        break;

#ifdef USE_WEBSERVER
      case FUNC_WEB_SENSOR:
        MCP2515_Show(0);
        break;
#endif  // USE_WEBSERVER
    }
  }
  return result;
}

#endif  // USE_MCP2515
#endif // USE_SPI