#include "util.h"
#include "legato.h"
#include <termios.h>

le_result_t readFromFile(const char* path,
                         void* value,
                         int (*scanCallback)(FILE* f, void* val)) {
  FILE* f = fopen(path, "r");
  if (f == NULL) {
    LE_WARN("Couldn't open '%s' - %m", path);
    return LE_IO_ERROR;
  }
  int numScanned = scanCallback(f, value);
  if (numScanned != 1)
    return LE_FORMAT_ERROR;
  fclose(f);
  return LE_OK;
}

int scanIntCallback(FILE* f, void* value) {
  int* val = value;
  return fscanf(f, "%d", val);
}

int scanDoubleCallback(FILE* f, void* value) {
  double* val = value;
  return fscanf(f, "%lf", val);
}

le_result_t ioutil_readIntFromFile(const char* path, int* value) {
  return readFromFile(path, value, scanIntCallback);
}

le_result_t ioutil_readDoubleFromFile(const char* path, double* value) {
  return readFromFile(path, value, scanDoubleCallback);
}

le_result_t writeToFile(const char* path,
                        void* value,
                        size_t size,
                        size_t count,
                        const char* openMode) {
  FILE* f = fopen(path, openMode);
  if (f == NULL) {
    LE_WARN("Failed to open %s for writing", path);
    return LE_IO_ERROR;
  }
  fwrite(value, size, count, f);
  fflush(f);
  fclose(f);
  return LE_OK;
}

le_result_t ioutil_writeToFile(const char* path,
                               void* value,
                               size_t size,
                               size_t count) {
  return writeToFile(path, value, size, count, "w");
}

le_result_t ioutil_appendToFile(const char* path,
                                void* value,
                                size_t size,
                                size_t count) {
  return writeToFile(path, value, size, count, "a");
}

le_result_t util_flattenRes(le_result_t* res, int nRes) {
  for (int i = 0; i < nRes; i++) {
    if (res[i] != LE_OK)
      return res[i];
  }
  return LE_OK;
}

int util_getUnixDatetime() {
  struct timeval tv;
  gettimeofday(&tv, NULL);
  return tv.tv_sec;
}

/**
 * Get the last modified datetime
 * of the file at path
 */
time_t util_getMTime(char* path) {
  struct stat st;
  if (stat(path, &st) != 0)
    return -1;
  else
    return st.st_mtime;
}

bool util_fileExists(const char* path) {
  struct stat st;
  return stat(path, &st) == 0;
}

bool util_alreadyMounted(const char* devPath) {
  char content[2048];
  FILE* f = fopen("/proc/mounts", "r");
  if (f == NULL) {
    return false;
  }
  fread(content, sizeof(char), sizeof(content), f);
  // if this ref is non-null, we found a match
  return strstr(content, devPath) != NULL;
}

uint64_t GetCurrentTimestamp(void) {
  struct timeval tv;
  gettimeofday(&tv, NULL);
  uint64_t utcMilliSec =
      (uint64_t)(tv.tv_sec) * 1000 + (uint64_t)(tv.tv_usec) / 1000;
  return utcMilliSec;
}

// TODO verify this is working
le_result_t gpio_exportPin(char* pin) {
  int len = strlen(pin);
  return ioutil_writeToFile("/sys/class/gpio/export", &pin, sizeof(char), len);
}

le_result_t gpio_unexportPin(char* pin) {
  int len = strlen(pin);
  return ioutil_writeToFile("/sys/class/gpio/unexport", &pin, sizeof(char),
                            len);
}

void getGpioPath(char* outputStr, char* pin, char* subDir) {
  sprintf(outputStr, "/sys/class/gpio/gpio%s/%s", pin, subDir);
}

le_result_t gpio_setDirection(char* pin, char* direction) {
  char path[100];
  getGpioPath(path, pin, "direction");
  return ioutil_writeToFile(path, direction, sizeof(char), strlen(direction));
}

le_result_t gpio_setPull(char* pin, char* pull) {
  char path[100];
  getGpioPath(path, pin, "pull");
  return ioutil_writeToFile(path, pull, sizeof(char), strlen(pull));
}

le_result_t gpio_pullDown(char* pin) {
  return gpio_setPull(pin, "down");
}

le_result_t gpio_pullUp(char* pin) {
  return gpio_setPull(pin, "up");
}

le_result_t gpio_setInput(char* pin) {
  return gpio_setDirection(pin, "in");
}

le_result_t gpio_setOutput(char* pin) {
  return gpio_setDirection(pin, "out");
}

le_result_t gpio_setActiveState(char* pin, bool isActiveLow) {
  // Any non zero value toggles the existing value
  // so we must read the existing value first
  char path[100];
  int isActiveLowSet;
  getGpioPath(path, pin, "active_low");
  le_result_t readRes = ioutil_readIntFromFile(path, &isActiveLowSet);
  le_result_t writeRes = LE_OK;
  if (isActiveLow != isActiveLowSet) {
    writeRes = ioutil_writeToFile(path, "1", sizeof(char), 1);
  }
  return readRes == LE_OK && writeRes == LE_OK ? LE_OK : LE_FAULT;
}

le_result_t gpio_isActive(char* pin, bool* isActive) {
  char path[50];
  getGpioPath(path, pin, "value");
  int val;
  le_result_t readRes = ioutil_readIntFromFile(path, &val);
  *isActive = val;
  return readRes;
}

le_result_t gpio_setValue(char* pin, bool state) {
  char path[50];
  getGpioPath(path, pin, "value");
  char* strState = state ? "1" : "0";
  return ioutil_writeToFile(path, &strState, sizeof(char), strlen(strState));
}

le_result_t gpio_setLow(char* pin) {
  return gpio_setValue(pin, LOW);
}

le_result_t gpio_setHigh(char* pin) {
  return gpio_setValue(pin, HIGH);
}

void* util_find(Functional* f) {
  f->args.i = 0;
  while (f->args.i < f->n) {
    if (f->callback(&f->args)) {
      return f->derefCallback(f->args.i, f->args.arr);
    }
    f->args.i++;
  }
  return NULL;
}

void util_listDir(const char* dir, char* dest, size_t size) {
  struct dirent* de;
  char toConcat[1024];
  DIR* dr = opendir(dir);
  if (dr == NULL)
    return;
  while ((de = readdir(dr)) != NULL) {
    if (de->d_name[0] != '.') {
      snprintf(toConcat, size, "%s,", de->d_name);
      strncat(dest, toConcat, size);
    }
  }
  closedir(dr);
}

/**
 * Convert an integer baud rate to a speed_t
 */
speed_t fd_convertBaud(int baud) {
  speed_t b;
  switch (baud) {
    case 50:
      b = B50;
      break;
    case 75:
      b = B75;
      break;
    case 110:
      b = B110;
      break;
    case 134:
      b = B134;
      break;
    case 150:
      b = B150;
      break;
    case 200:
      b = B200;
      break;
    case 300:
      b = B300;
      break;
    case 600:
      b = B600;
      break;
    case 1200:
      b = B1200;
      break;
    case 1800:
      b = B1800;
      break;
    case 2400:
      b = B2400;
      break;
    case 9600:
      b = B9600;
      break;
    case 19200:
      b = B19200;
      break;
    case 38400:
      b = B38400;
      break;
    case 57600:
      b = B57600;
      break;
    case 115200:
      b = B115200;
      break;
    case 230400:
      b = B230400;
      break;
    case 921600:
      b = B921600;
      break;
    default:
      b = -2;
  }
  return b;
}

/**
 * Open a serial connection on device
 *
 * Lifted from here
 * https://github.com/WiringPi/WiringPi/blob/master/wiringPi/wiringSerial.c
 */
int fd_openSerial(const char* device, int baud) {
  struct termios options;
  speed_t binaryBaud = fd_convertBaud(baud);
  int status, fd;
  if ((fd = open(device, O_RDWR | O_NOCTTY | O_NDELAY | O_NONBLOCK)) == -1)
    return -1;
  fcntl(fd, F_SETFL, O_RDWR);
  tcgetattr(fd, &options);
  cfmakeraw(&options);
  cfsetispeed(&options, binaryBaud);
  cfsetospeed(&options, binaryBaud);

  options.c_cflag |= (CLOCAL | CREAD);
  options.c_cflag &= ~PARENB;
  options.c_cflag &= ~CSTOPB;
  options.c_cflag &= ~CSIZE;
  options.c_cflag |= CS8;
  options.c_lflag &= ~(ICANON | ECHO | ECHOE | ISIG);
  options.c_oflag &= ~OPOST;

  options.c_cc[VMIN] = 0;
  options.c_cc[VTIME] = 10;  // Ten seconds (100 deciseconds)

  tcsetattr(fd, TCSANOW | TCSAFLUSH, &options);

  ioctl(fd, TIOCMGET, &status);

  status |= TIOCM_DTR;
  status |= TIOCM_RTS;

  ioctl(fd, TIOCMSET, &status);
  usleep(10000);  // 10mS
  return fd;
}

int fd_puts(const int fd, const char* s) {
  return write(fd, s, strlen(s));
}

int fd_getChar(const int fd) {
  uint8_t x;

  if (read(fd, &x, 1) != 1)
    return -1;

  return ((int)x) & 0xFF;
}

void fd_flush(const int fd) {
  // tcflush(fd, TCIOFLUSH);
  tcdrain(fd);
}

void fd_flushInput(const int fd) {
  tcflush(fd, TCIFLUSH);
}

int fd_dataAvail(int fd, int* data) {
  return ioctl(fd, FIONREAD, data);
}

double util_avgDouble(double* readings, int nReadings) {
  double sum = 0;
  for (int i = 0; i < nReadings; i++) {
    sum += readings[i];
  }

  return sum / nReadings;
}