#include "_easycsv.h"

/* (Constructor) Initialise _easycsv */
_easycsv*
_easycsv_priv_init(const char *fp,
		   const EASYCSV_MODE mode,
		   const EASYCSV_ERRORMSG error)
{
  _easycsv *_priv = malloc(sizeof(_easycsv));

  _priv->file = NULL;
  _priv->temp = NULL;
  _priv->fp = NULL;
  _priv->tmpfp = NULL;
  _priv->rows = 0;
  _priv->cols = 0;
#ifdef EASYCSV_DEBUG
  _priv->start = 0;
#endif

  _priv->error = error;
  
  /* Open file according to mode */
  switch (mode) {
  case EASYCSV_R: {
    _priv->file = fopen(fp, "r");
    break;
  }
  case EASYCSV_W: {
    _priv->file = fopen(fp, "w");
    break;
  }
  default: {
    _easycsv_printerror(_priv, EASYCSV_UNKNOWNIOMODE);
    _easycsv_priv_free(_priv);
    return NULL;
  }
  }
  
  if (_priv->file == NULL)
  {
    _easycsv_printerror(_priv, EASYCSV_OPENFAIL);
    _easycsv_priv_free(_priv);
    return NULL;
  }

  size_t stfp = strlen(fp);
  
  /* Allocate memory for char* */
  _priv->fp = malloc(stfp + 1); // + 1 for null
  
  strcpy(_priv->fp, fp);

  /* Calculate rows and cols if file exists */
  if (access(_priv->fp, F_OK) == 0) {
    _priv->rows = _easycsv_rows(_priv, mode);
    _priv->cols = _easycsv_columns(_priv, mode);
  }

  if (mode == EASYCSV_W) {
   
   /* csv->tmpfp = malloc(16 + stfp + 1); */
   /* strncpy(csv->tmpfp, prefix, 16); */

    /* strncat(csv->tmpfp, fp, stfp); */
   
    do {
      /* Write to temporary file */
      unsigned int i = 1;
      char buffer[21] = "/tmp/easycsv-"; // 13 char,  3 for digits, 4 for .csv, 1 for NULL
    
      if (i < 100)
	strncat(buffer, "0", 1);
	
      if (i < 10)
	strncat(buffer, "0", 1);
	
      sprintf(buffer + strlen(buffer), "%i", i);
      strcat(buffer, ".csv");

      if (access(buffer, F_OK) < 0) {
	i++;
      }
      else {
	_priv->tmpfp = malloc(21);
	strncpy(_priv->tmpfp, buffer, 21);
	break;
      }
      
    } while (1);

    _priv->temp = fopen(_priv->tmpfp, "w");
    if (_priv->temp == NULL) {
      _easycsv_printerror(_priv, EASYCSV_OPENFAIL);
      _easycsv_priv_free(_priv);
      return NULL;
    }
    /*
#ifdef EASYCSV_DEBUG
    printf("[%i] easycsv_debug: temp file %s opened\n", clock() - csv->start, csv->tmpfp);
    #endif*/
    /*
   
    if (freopen(csv->fp, csv->mode, csv->file) == NULL) {
      fprintf(stderr, "easycsv: failed to set temporary file %s to %s mode\n", csv->tmpfp, csv->mode);
      return NULL;
    }

    if (freopen(csv->tmpfp, csv->mode, csv->temp) == NULL) {
      fprintf(stderr, "easycsv: failed to set temporary file %s to %s mode\n", csv->tmpfp, csv->mode);
      return NULL;
    }
    */
    
  }
   
  return _priv;
}

/* (Destructor) Free _easycsv memory */
void
_easycsv_priv_free(_easycsv *_priv)
{
  /* ARGS CHECK */
  if (_priv == NULL)
    return;
  /* ARGS CHECK */
  if (_priv->file != NULL)
    fclose(_priv->file);
  if (_priv->temp != NULL)
    fclose(_priv->temp);
  if (_priv->fp != NULL)
    free(_priv->fp);
  if (_priv->tmpfp != NULL)
    free(_priv->tmpfp);
  free(_priv);
}

int
_easycsv_update(_easycsv *csv)
{
  /* ARGS CHECK */
  if (csv == NULL) {
    _easycsv_printerror(csv, EASYCSV_NULLCSV);
    return -1;
  }
  /* ARGS CHECK */
  
  /* Set temp file to read binary */
  if (freopen(csv->tmpfp, "rb", csv->temp) == NULL) {
    _easycsv_printerror(csv, EASYCSV_REOPENFAIL);
    easycsv_free(csv);
    return -1;
  }

  /* Set file to write binary */
  if (freopen(csv->fp, "wb", csv->file) == NULL) {
    _easycsv_printerror(csv, EASYCSV_REOPENFAIL);
    easycsv_free(csv);
    return -1;
  }

  /* Copy entire file */
  char buf[BUFSIZ];
  size_t size;    
  while (size = fread(buf, 1, BUFSIZ, csv->temp)) {
    fwrite(buf, 1, size, csv->file);
  }

  /* Set temp file back to write */
  if (freopen(csv->tmpfp, "w", csv->temp) == NULL) {
    _easycsv_printerror(csv, EASYCSV_REOPENFAIL);
    easycsv_free(csv);
    return -1;
  }

  /* Set file back to read */
  if (freopen(csv->fp, "r", csv->file) == NULL) {
    _easycsv_printerror(csv, EASYCSV_REOPENFAIL);
    easycsv_free(csv);
    return -1;
  }

  return 0;
}

int
_easycsv_rows(_easycsv *_priv,
	      const EASYCSV_MODE mode)
{
  // no need to check _priv for NULL

  if (_easycsv_rewind(_priv, mode) < 0)
    return -1;

  int rows = 1;
  char c;

  /* Go through each character in the file and count the number of \n
     in it */
  while ((c = fgetc(_priv->file)) != EOF) {
    if (c == '\n') rows++;
  }

  return rows;
}

int
_easycsv_columns(_easycsv *_priv,
		 const EASYCSV_MODE mode)
{
  // no need to check _priv for NULL
  
  /* Prepare it for reading */
  if (_easycsv_rewind(_priv, mode) < 0) return -1;
  
  /*
  1. check if empty file
  2. check if only one column -> 0 commas
  3. if >1 column, n commas = n+1 columns
  */

  int col = 1;
  char c;

  while ((c = fgetc(_priv->file)) != '\n') {
    if (c == ',') col++;
  }

  return col;
}

char*
_easycsv_getrow(const _easycsv *csv,
		const unsigned int row)
{
  /* ARGS CHECK */
  if (csv == NULL) {
    _easycsv_printerror(csv, EASYCSV_NULLCSV);
    return NULL;
  }
  
  if (row > csv->rows) {
    _easycsv_printerror(csv, EASYCSV_OVERMAXROW);
    return NULL;
  }

  if (row == 0) {
    _easycsv_printerror(csv, EASYCSV_ZEROROW);
    return NULL;
  }
  /* END ARGS CHECK */

  /* Allocate memory */
  char *str = malloc(BUFSIZ);

  /* Set file pointer to start */
  rewind(csv->file);
  
  for (int i = 1; i < row; i++)
  {
    /* skip until row is reached */
    fscanf(csv->file, "%*[^\n]\n", NULL);
  }

  /* Grab the row and store it in str */
  fscanf(csv->file, "%s\n", str);

  // printf("row: %s\n", str);
  
  return str;
}

int
_easycsv_rewind(_easycsv *_priv,
		const EASYCSV_MODE mode)
{  
  /* Check if empty file */
  if (fscanf(_priv->file, "\n") == EOF) {
    _easycsv_printerror(_priv, EASYCSV_EMPTYCSV);
    return -1;
  }
  
  /* Check if file is readable */
  if (mode != EASYCSV_R) {
    _easycsv_printerror(_priv, EASYCSV_UNREADABLE);
    return -1;
  }

  /* Set file pointer to the start */
  rewind(_priv->file);

  return 0;
}

int
_easycsv_getcolumn(const _easycsv *csv,
		   const char *col)
{
  /* ARGS CHECK */
  if (_easycsv_checkcsvandstring_one(csv, col) < 0)
    return -1;
  /* ARGS CHECK */

  /* Grab str of row 1 */
  char *firstrow = _easycsv_getrow(csv, 1);  
  
  if (firstrow == NULL) {
    _easycsv_printerror(csv, EASYCSV_ROWNOTEXIST);
    return -1;
  }
  
  unsigned int commas = 0;

  // printf("FIRST COLUMN: %s\n", firstrow);

  /* Find first occurance of col in firstrow */
  char *str = strstr(firstrow, col);

  if (str == NULL) {
    _easycsv_printerror(csv, EASYCSV_COLNOTEXIST);
    return -1;
  }

  /* Count numbers of commas following str */
  char *c = strpbrk(str, ",");
  while (c != NULL) {
    commas++;
    c = strpbrk(c + 1, ",");
  }

  /* no need to free c as it is already NULL at this point */
  // free((char*) str); apparently invalid pointer
  
  // printf("ROW: %i\nCOL: %i\n", row, csv->cols - commas);
  /*
#ifdef EASYCSV_DEBUG
  printf("[%i] rcv_commas: %i\n", clock() - csv->start, commas);
#endif
  */
  free(firstrow);

  return csv->cols - commas;
}

/*
int _easycsv_checkifvalue(struct easycsv *csv, const int col, const int row)
{
  const char *rowstr = _easycsv_getrow(csv, row);
  
  return 0;
}
*/

char*
_easycsv_getvalueinrow(const _easycsv *_priv,
		       const char *row,
		       const unsigned int col)
{
  size_t st;
  char *pch = NULL;
  
  /* If not first column */
  if (col != 1) {
    
    /* Get first occurance of comma in str,
       the first value is ommited but not the comma */
    char *pch = strpbrk(row, ",");

    /* Repeat until desired col is found */
    for (int i = 2; i < col; i++) { 
      pch = strpbrk(pch + 1, ",");
    }
  }

  /* Get span from start of string to first occurence 
     of comma */
  st = strcspn(pch + 1, ",");

  /* If 0, no string exists! */
  if (st == 0) {
    _easycsv_printerror(_priv, EASYCSV_EMPTYVALUE);
    return NULL;
  }
  
  char *val = malloc(st + 1);
  strncpy(val, pch + 1, st);
  strncat(val, "\0", 1);
  
  return val;
}

char*
_easycsv_setcharptovalue(const _easycsv *_priv,
			 const char *rowstr,
			 const unsigned int col)
{
  char *pch = rowstr;

  for (unsigned int i = 1; i < col; i++) {
    pch = strchr(rowstr, ',');
    if (pch == NULL) {
      _easycsv_printerror(_priv, EASYCSV_NULLPTR);
      return NULL;
    }
    pch++;
  }

  return pch;
}

void
_easycsv_printerror(const _easycsv *_priv,
		    const EASYCSV_ERROR error)
{ 
  switch (_priv->error) {
  case EASYCSV_ERROROFF: return;
  case EASYCSV_ERRORSTDOUT: _easycsv_geterror(_priv, error, stdout); break;
  case EASYCSV_ERRORSTDERR: 
  default: _easycsv_geterror(_priv, error, stderr); return;
  }
}

void
_easycsv_geterror(const _easycsv *_priv,
		  const EASYCSV_ERROR error,
		  FILE *fs)
{
#ifdef EASYCSV_DEBUG
  fprintf(stderr, "[%i] ", clock() - _priv->start);
#endif
  
  fputs("easycsv: ", fs);
  
  switch (error) {

  /* Generic errors */
  case EASYCSV_NOERROR: fputs("no error", fs); break;
  case EASYCSV_NULLCSV: fputs("easycsv pointer is NULL", fs); break;
  case EASYCSV_NULLPTR: fputs("pointer is NULL", fs); break;
  case EASYCSV_EMPTYSTRING: fputs("string is empty", fs); break;
  case EASYCSV_EMPTYVALUE: fputs("value in CSV file is empty", fs); break;
  case EASYCSV_OVERMAXROW: fprintf(fs, "int exceeds row limit %i", _priv->rows); break;
  case EASYCSV_OVERMAXCOL: fprintf(fs, "int exceeds column limit %i", _priv->cols); break;
  case EASYCSV_ZEROROW: fputs("parameterised row number is zero", fs); break;
  case EASYCSV_ZEROCOL: fputs("parameterised column number is zero", fs); break;
  
  /* File input/output errors */
  case EASYCSV_UNKNOWNIOMODE: fputs("unknown file IO mode", fs); break;
  case EASYCSV_OPENFAIL: fputs("failed to open file", fs); break;
  case EASYCSV_REOPENFAIL: fputs("failed to reopen file", fs); break;
  case EASYCSV_EMPTYCSV: fputs("CSV file is empty", fs); break;
  case EASYCSV_UNWRITABLE: fputs("CSV file is not in a writable mode", fs); break;
  case EASYCSV_UNREADABLE: fputs("CSV file is not in a readable mode", fs); break;
  case EASYCSV_UPDATEFAIL: fputs("CSV file has failed to update", fs); break;
  case EASYCSV_UPDATETEMPFAIL: fputs("failed to update temp CSV file", fs); break;
  case EASYCSV_FILEPTRFAIL: fputs("failed to move FILE pointer", fs); break;

  /* Non-existant elements */
  case EASYCSV_ROWNOTEXIST: fputs("given row does not exist", fs); break;
  case EASYCSV_COLNOTEXIST: fputs("given column does not exist", fs); break;

  /* User-facing failure */
  case EASYCSV_PUSHCOLFAIL: fputs("failed to push value under column", fs); break;
  case EASYCSV_COLNUMFAIL: fputs("failed to determine the column number of a value in the first row", fs); break;
  default: fputs("unknown error, easycsv* is possibly NULL", fs); break;
  }

  if (_priv->fp != NULL)
    fprintf(fs, " in %s", _priv->fp);

  fputc('\n', fs);
}

int
_easycsv_checkcsvandstring_one(const _easycsv *csv,
			       const char *one)
{
  if (csv == NULL) {
    _easycsv_printerror(csv, EASYCSV_NULLCSV);
    return -1;
  }

  if (one == NULL) {
    _easycsv_printerror(csv, EASYCSV_EMPTYSTRING);
    return -1;
  }

  return 0;
}

int
_easycsv_checkcsvandstring_two(const _easycsv *csv,
			      const char *one,
			      const char *two)
{
  if (_easycsv_checkcsvandstring_one(csv, one) < 0)
    return -1;

  if (two == NULL) {
    _easycsv_printerror(csv, EASYCSV_EMPTYSTRING);
    return -1;
  }

  return 0;
}