#include "ruby.h"
#include "ruby/encoding.h"
#include <stdio.h>
#include <stdbool.h>

#ifndef bool
  #define bool int
  #define false ((bool)0)
  #define true  ((bool)1)
#endif

/*
   max_size: pass nil if no limit is specified
 */
static VALUE rb_parse_csv_line(VALUE self, VALUE line, VALUE col_sep, VALUE quote_char, VALUE max_size) {
  if (RB_TYPE_P(line, T_NIL) == 1) {
    return rb_ary_new();

  } else if (RB_TYPE_P(line, T_STRING) == 1) {
    rb_encoding *encoding = rb_enc_get(line); /* get the encoding from the input line */
    char *startP = RSTRING_PTR(line); /* may not be null terminated */
    long line_len = RSTRING_LEN(line);
    char *endP = startP + line_len ; /* points behind the string */
    char *p = startP;

    char *col_sepP = RSTRING_PTR(col_sep);
    long col_sep_len = RSTRING_LEN(col_sep);

    char *quoteP = RSTRING_PTR(quote_char);
    long quote_len = RSTRING_LEN(quote_char);
    long quote_count = 0;

    bool col_sep_found = true;

    VALUE elements = rb_ary_new();
    VALUE field;
    long i;

    while (p < endP) {
      /* does the remaining string start with col_sep ? */
      col_sep_found = true;
      for(i=0; (i < col_sep_len) && (p+i < endP) ; i++) {
        col_sep_found = col_sep_found && (*(p+i) == *(col_sepP+i));
      }
      /* if col_sep was found and we have even quotes */
      if (col_sep_found && (quote_count % 2 == 0)) {
        /* if max_size != nil && lements.size >= header_size */
        if ((max_size != Qnil) && RARRAY_LEN(elements) >= NUM2INT(max_size)) {
          break;
        } else {
          /* push that field with original encoding onto the results */
          field = rb_enc_str_new(startP, p - startP, encoding);
          rb_ary_push(elements, field);

          p += col_sep_len;
          startP = p;
        }
      } else {
        if (*p == *quoteP) {
          quote_count += 1;
        }
        p++;
      }
    } /* while */

    /* check if the last part of the line needs to be processed */
    if ((max_size == Qnil) || RARRAY_LEN(elements) < NUM2INT(max_size)) {
      /* copy the remaining line as a field with original encoding onto the results */
      field = rb_enc_str_new(startP, endP - startP, encoding);
      rb_ary_push(elements, field);
    }

    return elements;
  }

  rb_raise(rb_eTypeError, "ERROR in SmarterCSV.parse_line: line has to be a string or nil");
}


VALUE SmarterCSV = Qnil;

void Init_smarter_csv(void) {
  VALUE SmarterCSV = rb_define_module("SmarterCSV");

  rb_define_module_function(SmarterCSV, "parse_csv_line_c", rb_parse_csv_line, 4);
}