#include "system.h"
#include "i2cmaster.h"
#include "print.h"

I2CMaster::I2CMaster() noexcept {
  RCC.APB1PCENR.B.I2C1EN = SET;
  RCC.APB2PCENR.B.IOPCEN = SET;
  
  // GPIO Alternate Config - default SCL/PC2, SDA/PC1
  GPIOC.CFGLR.modify([](GPIOA_Type::CFGLR_DEF & r) -> auto {
    r.B.CNF1  = 3u;
    r.B.MODE1 = 1u;
    r.B.CNF2  = 3u;
    r.B.MODE2 = 1u;
    return r.R;
  });
  
  RCC.APB1PRSTR.B.I2C1RST = SET;
  RCC.APB1PRSTR.B.I2C1RST = RESET;
  
  I2C1.CTLR2.B.FREQ = 48u;
  I2C1.CKCFGR.B.CCR = 480u;
  I2C1.CTLR1.B.PE   = SET;
}
bool I2CMaster::Send(const unsigned char addr, const unsigned char * data, const unsigned int len) {
  bool result = false;
  do {
    if (! send_address(addr & ~1u)) break;
    
    if (data == nullptr) { return stop_condition(); }
    
    for (unsigned n=0u; n<len; n++) {
      const unsigned char to_send = data [n];
      if (! wait_for([]() -> bool { return I2C1.STAR1.B.TxE == RESET; })) break;
      I2C1.DATAR.B.DATAR = to_send;
    }
    if (! wait_for([]()   -> bool { return I2C1.STAR1.B.BTF == RESET; })) break;
    result = true;
  } while (false);
  return result and stop_condition();
}
bool I2CMaster::Receive (const unsigned char addr, unsigned char * data, const unsigned int len) {
  bool result = false;
  do {
    if (! send_address(addr |  1u)) break;
    
    I2C1.CTLR1.B.ACK = SET;
    for (unsigned n=0u; n<len-1; n++) {
      if (! wait_for([]() -> bool { return I2C1.STAR1.B.RxNE == RESET; })) break;
      data [n] = I2C1.DATAR.B.DATAR;
    }
    I2C1.CTLR1.B.ACK = RESET;
    if (! wait_for([]()   -> bool { return I2C1.STAR1.B.RxNE == RESET; })) break;
    data [len-1] = I2C1.DATAR.B.DATAR;
    result = true;
  } while (false);
  return result and stop_condition();
}
bool I2CMaster::send_address(const unsigned char addr) {
  I2C1.CTLR1.B.START = SET;
  if (! wait_for([]() -> bool { return I2C1.STAR1.B.SB   == RESET; })) return false;
  I2C1.DATAR.B.DATAR = addr;
  if (! wait_for([]() -> bool { return I2C1.STAR1.B.ADDR == RESET; })) return false;
  volatile unsigned x = I2C1.STAR2.R;  (void) x;
  return true;
}
bool I2CMaster::stop_condition() {
  I2C1.CTLR1.B.STOP = SET;
  return wait_for([]() -> bool { return I2C1.CTLR1.B.STOP == SET; });
}

void I2CMaster::FindActive(Print& print) {
  const char * blank = "               \r";
  for (unsigned addr = 0u; addr < 0xFF; addr += 2u) {
    print << "addr = " << (int) addr;
    if (send_address(addr & ~1u)) {
      print << " ... OK\r\n";
    } else {
      print << blank;
    }
    stop_condition();
  }
  print << blank;
}