#include "PZEMSensor.h"

#include <stdio.h>

#define REG_VOLTAGE 0x0000
#define REG_CURRENT_L 0x0001
#define REG_CURRENT_H 0X0002
#define REG_POWER_L 0x0003
#define REG_POWER_H 0x0004
#define REG_ENERGY_L 0x0005
#define REG_ENERGY_H 0x0006
#define REG_FREQUENCY 0x0007
#define REG_PF 0x0008
#define REG_ALARM 0x0009
#define CMD_RHR 0x03
#define CMD_RIR 0X04
#define CMD_WSR 0x06
#define CMD_CAL 0x41
#define CMD_REST 0x42
#define WREG_ALARM_THR 0x0001
#define WREG_ADDR 0x0002
#define UPDATE_TIME 200
#define RESPONSE_SIZE 32
#define READ_TIMEOUT 100
#define PZEM_BAUD_RATE 9600

#define DEBUG
// Debugging function;
void printBuf(uint8_t *buffer, uint16_t len) {
#ifdef DEBUG
    for (uint16_t i = 0; i < len; i++) {
        char temp[6];
        sprintf(temp, "%.2x ", buffer[i]);
        Serial.print(temp);
    }
    Serial.println();
#endif
}

PZEMSensor::PZEMSensor(SoftwareSerial *port, uint16_t addr) {
    _serial = port;
    _addr = addr;
}

PZEM_Info *PZEMSensor::values() {
    // Update vales if necessary
    if (!refresh()) {
        _values = PZEM_Info();
    }
    return &_values;
}

/*!
 * PZEM004Tv30::sendCmd8
 *
 * Prepares the 8 byte command buffer and sends
 *
 * @param[in] cmd - Command to send (position 1)
 * @param[in] rAddr - Register address (postion 2-3)
 * @param[in] val - Register value to write (positon 4-5)
 * @param[in] check - perform a simple read check after write
 *
 * @return success
*/
bool PZEMSensor::sendCmd8(uint8_t cmd, uint16_t rAddr, uint16_t val, bool check, uint16_t slave_addr) {
    uint8_t sendBuffer[8];  // Send buffer
    uint8_t respBuffer[8];  // Response buffer (only used when check is true)

    if ((slave_addr == 0xFFFF) ||
        (slave_addr < 0x01) ||
        (slave_addr > 0xF7)) {
        slave_addr = _addr;
    }

    sendBuffer[0] = slave_addr;  // Set slave address
    sendBuffer[1] = cmd;         // Set command

    sendBuffer[2] = (rAddr >> 8) & 0xFF;  // Set high byte of register address
    sendBuffer[3] = (rAddr)&0xFF;         // Set low byte =//=

    sendBuffer[4] = (val >> 8) & 0xFF;  // Set high byte of register value
    sendBuffer[5] = (val)&0xFF;         // Set low byte =//=

    setCRC(sendBuffer, 8);  // Set CRC of frame

    _serial->write(sendBuffer, 8);  // send frame

    if (check) {
        if (!recieve(respBuffer, 8)) {  // if check enabled, read the response
            return false;
        }

        // Check if response is same as send
        for (uint8_t i = 0; i < 8; i++) {
            if (sendBuffer[i] != respBuffer[i])
                return false;
        }
    }
    return true;
}

bool PZEMSensor::setAddress(uint8_t addr) {
    if (addr < 0x01 || addr > 0xF7)  // sanity check
        return false;

    // Write the new address to the address register
    if (!sendCmd8(CMD_WSR, WREG_ADDR, addr, true))
        return false;

    _addr = addr;  // If successful, update the current slave address

    return true;
}

uint8_t PZEMSensor::getAddress() {
    return _addr;
}

bool PZEMSensor::setPowerAlarm(uint16_t watts) {
    if (watts > 25000) {  // Sanitych check
        watts = 25000;
    }

    // Write the watts threshold to the Alarm register
    if (!sendCmd8(CMD_WSR, WREG_ALARM_THR, watts, true))
        return false;

    return true;
}

bool PZEMSensor::getPowerAlarm() {
    if (!refresh())  // Update vales if necessary
        return NAN;  // Update did not work, return NAN

    return _values.alarms != 0x0000;
}

void PZEMSensor::init() {
    if (_addr < 0x01 || _addr > 0xF8) {
        // Sanity check of address
        _addr = PZEM_DEFAULT_ADDR;
    }
    // Set initial lastRed time so that we read right away
    _lastRead = 0;
    _lastRead -= UPDATE_TIME;
}

bool PZEMSensor::refresh() {
    static uint8_t response[25];
    if (_lastRead + UPDATE_TIME > millis()) {
        return true;
    }
    // Read 10 registers starting at 0x00 (no check)
    sendCmd8(CMD_RIR, 0x00, 0x0A, false);
    if (recieve(response, 25) != 25) {  // Something went wrong
        return false;
    }
    // Update the current values
    _values.voltage = ((uint32_t)response[3] << 8 |  // Raw voltage in 0.1V
                       (uint32_t)response[4]) /
                      10.0;

    _values.current = ((uint32_t)response[5] << 8 |  // Raw current in 0.001A
                       (uint32_t)response[6] |
                       (uint32_t)response[7] << 24 |
                       (uint32_t)response[8] << 16) /
                      1000.0;

    _values.power = ((uint32_t)response[9] << 8 |  // Raw power in 0.1W
                     (uint32_t)response[10] |
                     (uint32_t)response[11] << 24 |
                     (uint32_t)response[12] << 16) /
                    10.0;

    _values.energy = ((uint32_t)response[13] << 8 |  // Raw Energy in 1Wh
                      (uint32_t)response[14] |
                      (uint32_t)response[15] << 24 |
                      (uint32_t)response[16] << 16) /
                     1000.0;

    _values.freq = ((uint32_t)response[17] << 8 |  // Raw Frequency in 0.1Hz
                    (uint32_t)response[18]) /
                   10.0;

    _values.pf = ((uint32_t)response[19] << 8 |  // Raw pf in 0.01
                  (uint32_t)response[20]) /
                 100.0;

    _values.alarms = ((uint32_t)response[21] << 8 |  // Raw alarm value
                      (uint32_t)response[22]);

    // Record current time as _lastRead
    _lastRead = millis();
    return true;
}

bool PZEMSensor::reset() {
    uint8_t buffer[] = {0x00, CMD_REST, 0x00, 0x00};
    uint8_t reply[5];
    buffer[0] = _addr;

    setCRC(buffer, 4);
    _serial->write(buffer, 4);

    uint16_t length = recieve(reply, 5);

    if (length == 0 || length == 5) {
        return false;
    }

    return true;
}

uint16_t PZEMSensor::recieve(uint8_t *resp, uint16_t len) {
    ((SoftwareSerial *)_serial)->listen();  // Start software serial listen
    unsigned long startTime = millis();     // Start time for Timeout
    uint8_t index = 0;                      // Bytes we have read
    while ((index < len) && (millis() - startTime < READ_TIMEOUT)) {
        if (_serial->available() > 0) {
            uint8_t c = (uint8_t)_serial->read();
            resp[index++] = c;
        }
    }
    // Check CRC with the number of bytes read
    if (!checkCRC(resp, index)) {
        return 0;
    }
    return index;
}

bool PZEMSensor::checkCRC(const uint8_t *buf, uint16_t len) {
    if (len <= 2)  // Sanity check
        return false;

    uint16_t crc = CRC16(buf, len - 2);  // Compute CRC of data
    return ((uint16_t)buf[len - 2] | (uint16_t)buf[len - 1] << 8) == crc;
}

void PZEMSensor::setCRC(uint8_t *buf, uint16_t len) {
    if (len <= 2)  // Sanity check
        return;

    uint16_t crc = CRC16(buf, len - 2);  // CRC of data

    // Write high and low byte to last two positions
    buf[len - 2] = crc & 0xFF;         // Low byte first
    buf[len - 1] = (crc >> 8) & 0xFF;  // High byte second
}

// Pre computed CRC table
static const uint16_t crcTable[] PROGMEM = {
    0X0000, 0XC0C1, 0XC181, 0X0140, 0XC301, 0X03C0, 0X0280, 0XC241,
    0XC601, 0X06C0, 0X0780, 0XC741, 0X0500, 0XC5C1, 0XC481, 0X0440,
    0XCC01, 0X0CC0, 0X0D80, 0XCD41, 0X0F00, 0XCFC1, 0XCE81, 0X0E40,
    0X0A00, 0XCAC1, 0XCB81, 0X0B40, 0XC901, 0X09C0, 0X0880, 0XC841,
    0XD801, 0X18C0, 0X1980, 0XD941, 0X1B00, 0XDBC1, 0XDA81, 0X1A40,
    0X1E00, 0XDEC1, 0XDF81, 0X1F40, 0XDD01, 0X1DC0, 0X1C80, 0XDC41,
    0X1400, 0XD4C1, 0XD581, 0X1540, 0XD701, 0X17C0, 0X1680, 0XD641,
    0XD201, 0X12C0, 0X1380, 0XD341, 0X1100, 0XD1C1, 0XD081, 0X1040,
    0XF001, 0X30C0, 0X3180, 0XF141, 0X3300, 0XF3C1, 0XF281, 0X3240,
    0X3600, 0XF6C1, 0XF781, 0X3740, 0XF501, 0X35C0, 0X3480, 0XF441,
    0X3C00, 0XFCC1, 0XFD81, 0X3D40, 0XFF01, 0X3FC0, 0X3E80, 0XFE41,
    0XFA01, 0X3AC0, 0X3B80, 0XFB41, 0X3900, 0XF9C1, 0XF881, 0X3840,
    0X2800, 0XE8C1, 0XE981, 0X2940, 0XEB01, 0X2BC0, 0X2A80, 0XEA41,
    0XEE01, 0X2EC0, 0X2F80, 0XEF41, 0X2D00, 0XEDC1, 0XEC81, 0X2C40,
    0XE401, 0X24C0, 0X2580, 0XE541, 0X2700, 0XE7C1, 0XE681, 0X2640,
    0X2200, 0XE2C1, 0XE381, 0X2340, 0XE101, 0X21C0, 0X2080, 0XE041,
    0XA001, 0X60C0, 0X6180, 0XA141, 0X6300, 0XA3C1, 0XA281, 0X6240,
    0X6600, 0XA6C1, 0XA781, 0X6740, 0XA501, 0X65C0, 0X6480, 0XA441,
    0X6C00, 0XACC1, 0XAD81, 0X6D40, 0XAF01, 0X6FC0, 0X6E80, 0XAE41,
    0XAA01, 0X6AC0, 0X6B80, 0XAB41, 0X6900, 0XA9C1, 0XA881, 0X6840,
    0X7800, 0XB8C1, 0XB981, 0X7940, 0XBB01, 0X7BC0, 0X7A80, 0XBA41,
    0XBE01, 0X7EC0, 0X7F80, 0XBF41, 0X7D00, 0XBDC1, 0XBC81, 0X7C40,
    0XB401, 0X74C0, 0X7580, 0XB541, 0X7700, 0XB7C1, 0XB681, 0X7640,
    0X7200, 0XB2C1, 0XB381, 0X7340, 0XB101, 0X71C0, 0X7080, 0XB041,
    0X5000, 0X90C1, 0X9181, 0X5140, 0X9301, 0X53C0, 0X5280, 0X9241,
    0X9601, 0X56C0, 0X5780, 0X9741, 0X5500, 0X95C1, 0X9481, 0X5440,
    0X9C01, 0X5CC0, 0X5D80, 0X9D41, 0X5F00, 0X9FC1, 0X9E81, 0X5E40,
    0X5A00, 0X9AC1, 0X9B81, 0X5B40, 0X9901, 0X59C0, 0X5880, 0X9841,
    0X8801, 0X48C0, 0X4980, 0X8941, 0X4B00, 0X8BC1, 0X8A81, 0X4A40,
    0X4E00, 0X8EC1, 0X8F81, 0X4F40, 0X8D01, 0X4DC0, 0X4C80, 0X8C41,
    0X4400, 0X84C1, 0X8581, 0X4540, 0X8701, 0X47C0, 0X4680, 0X8641,
    0X8201, 0X42C0, 0X4380, 0X8341, 0X4100, 0X81C1, 0X8081, 0X4040};

uint16_t PZEMSensor::CRC16(const uint8_t *data, uint16_t len) {
    uint8_t nTemp;          // CRC table index
    uint16_t crc = 0xFFFF;  // Default value

    while (len--) {
        nTemp = *data++ ^ crc;
        crc >>= 8;
        crc ^= (uint16_t)pgm_read_word(&crcTable[nTemp]);
    }
    return crc;
}

void PZEMSensor::search() {
    static uint8_t response[7];
    for (uint16_t addr = 0x01; addr <= 0xF8; addr++) {
        sendCmd8(CMD_RIR, 0x00, 0x01, false, addr);
        if (recieve(response, 7) != 7) {
            // Something went wrong
            continue;
        } else {
            Serial.print("Device on addr: ");
            Serial.print(addr);
        }
    }
}