#include <ruby.h>
#include <string.h>
#include <math.h>
#include <ctype.h>
#include <time.h>
#include <my_global.h>
#include <mysql.h>
#include <errmsg.h>
#include <mysqld_error.h>

#define RUBY_CLASS(name) rb_const_get(rb_cObject, rb_intern(name))
#define RUBY_STRING(char_ptr) rb_str_new2(char_ptr)
#define TAINTED_STRING(name, length) rb_tainted_str_new(name, length)
#define DRIVER_CLASS(klass, parent) (rb_define_class_under(mDOMysql, klass, parent))
#define CONST_GET(scope, constant) (rb_funcall(scope, ID_CONST_GET, 1, rb_str_new2(constant)))
#define CHECK_AND_RAISE(mysql_result_value, str) if (0 != mysql_result_value) { raise_mysql_error(connection, db, mysql_result_value, str); }
#define PUTS(string) rb_funcall(rb_mKernel, rb_intern("puts"), 1, RUBY_STRING(string))

#ifndef RSTRING_PTR
#define RSTRING_PTR(s) (RSTRING(s)->ptr)
#endif

#ifndef RSTRING_LEN
#define RSTRING_LEN(s) (RSTRING(s)->len)
#endif

#ifndef RARRAY_LEN
#define RARRAY_LEN(a) RARRAY(a)->len
#endif

#ifdef _WIN32
#define do_int64 signed __int64
#else
#define do_int64 signed long long int
#endif

// To store rb_intern values
static ID ID_TO_I;
static ID ID_TO_F;
static ID ID_TO_S;
static ID ID_TO_TIME;
static ID ID_NEW;
static ID ID_NEW_RATIONAL;
static ID ID_NEW_DATE;
static ID ID_CONST_GET;
static ID ID_UTC;
static ID ID_ESCAPE_SQL;
static ID ID_STRFTIME;
static ID ID_LOGGER;
static ID ID_DEBUG;
static ID ID_LEVEL;

// References to DataObjects base classes
static VALUE mDO;
static VALUE cDO_Quoting;
static VALUE cDO_Connection;
static VALUE cDO_Command;
static VALUE cDO_Result;
static VALUE cDO_Reader;

// References to Ruby classes that we'll need
static VALUE rb_cDate;
static VALUE rb_cDateTime;
#ifndef RUBY_19_COMPATIBILITY
static VALUE rb_cRational;
#endif
static VALUE rb_cBigDecimal;

// Classes that we'll build in Init
static VALUE mDOMysql;
static VALUE cConnection;
static VALUE cCommand;
static VALUE cResult;
static VALUE cReader;
static VALUE eMysqlError;

// Figures out what we should cast a given mysql field type to
static VALUE infer_ruby_type(MYSQL_FIELD *field) {

  char* ruby_type;

  switch(field->type) {
    case MYSQL_TYPE_NULL: {
      ruby_type = NULL;
      break;
    }
    case MYSQL_TYPE_TINY: {
      ruby_type = "TrueClass";
      break;
    }
    case MYSQL_TYPE_BIT:
    case MYSQL_TYPE_SHORT:
    case MYSQL_TYPE_LONG:
    case MYSQL_TYPE_INT24:
    case MYSQL_TYPE_LONGLONG:
    case MYSQL_TYPE_YEAR: {
      ruby_type = "Fixnum";
      break;
    }
    case MYSQL_TYPE_DECIMAL:
    case MYSQL_TYPE_NEWDECIMAL: {
      ruby_type = "BigDecimal";
      break;
    }
    case MYSQL_TYPE_FLOAT:
    case MYSQL_TYPE_DOUBLE: {
      ruby_type = "Float";
      break;
    }
    case MYSQL_TYPE_TIMESTAMP:
    case MYSQL_TYPE_DATETIME: {
      ruby_type = "DateTime";
      break;
    }
    case MYSQL_TYPE_TIME: {
      ruby_type = "DateTime";
      break;
    }
    case MYSQL_TYPE_DATE:
    case MYSQL_TYPE_NEWDATE: {
      ruby_type = "Date";
      break;
    }
    default: {
      ruby_type = "String";
      break;
    }
  }

  return rb_str_new2(ruby_type);
}

// Find the greatest common denominator and reduce the provided numerator and denominator.
// This replaces calles to Rational.reduce! which does the same thing, but really slowly.
static void reduce( do_int64 *numerator, do_int64 *denominator ) {
  do_int64 a, b, c;
  a = *numerator;
  b = *denominator;
  while ( a != 0 ) {
  c = a; a = b % a; b = c;
  }
  *numerator = *numerator / b;
  *denominator = *denominator / b;
}

// Generate the date integer which Date.civil_to_jd returns
static int jd_from_date(int year, int month, int day) {
  int a, b;
  if ( month <= 2 ) {
  year -= 1;
  month += 12;
  }
  a = year / 100;
  b = 2 - a + (a / 4);
  return floor(365.25 * (year + 4716)) + floor(30.6001 * (month + 1)) + day + b - 1524;
}

static VALUE seconds_to_offset(long seconds_offset) {
  do_int64 num = seconds_offset, den = 86400;
  reduce(&num, &den);
  return rb_funcall(rb_cRational, rb_intern("new!"), 2, rb_ll2inum(num), rb_ll2inum(den));
}

static VALUE timezone_to_offset(int hour_offset, int minute_offset) {
  do_int64 seconds = 0;

  seconds += hour_offset * 3600;
  seconds += minute_offset * 60;

  return seconds_to_offset(seconds);
}

static VALUE parse_date(const char *date) {
  int year, month, day;
  int jd, ajd;
  VALUE rational;

  sscanf(date, "%4d-%2d-%2d", &year, &month, &day);

  jd = jd_from_date(year, month, day);

  // Math from Date.jd_to_ajd
  ajd = jd * 2 - 1;
  rational = rb_funcall(rb_cRational, ID_NEW_RATIONAL, 2, INT2NUM(ajd), INT2NUM(2));
  return rb_funcall(rb_cDate, ID_NEW_DATE, 3, rational, INT2NUM(0), INT2NUM(2299161));
}

static VALUE parse_time(const char *date) {

  int year, month, day, hour, min, sec, usec;
  char subsec[7];

  if (0 != strchr(date, '.')) {
    // right padding usec with 0. e.g. '012' will become 12000 microsecond, since Time#local use microsecond
    sscanf(date, "%4d-%2d-%2d %2d:%2d:%2d.%s", &year, &month, &day, &hour, &min, &sec, subsec);
    sscanf(subsec, "%d", &usec);
  } else {
    sscanf(date, "%4d-%2d-%2d %2d:%2d:%2d", &year, &month, &day, &hour, &min, &sec);
    usec = 0;
  }

  if ( year + month + day + hour + min + sec + usec == 0 ) { // Mysql TIMESTAMPS can default to 0
    return Qnil;
  }

  return rb_funcall(rb_cTime, rb_intern("local"), 7, INT2NUM(year), INT2NUM(month), INT2NUM(day), INT2NUM(hour), INT2NUM(min), INT2NUM(sec), INT2NUM(usec));
}

static VALUE parse_date_time(const char *date) {
  VALUE ajd, offset;

  int year, month, day, hour, min, sec, usec, hour_offset, minute_offset;
  int jd;
  do_int64 num, den;


  long int gmt_offset;
  int is_dst;

  time_t rawtime;
  struct tm * timeinfo;

  int tokens_read, max_tokens;

  if ( strcmp(date, "") == 0 ) {
    return Qnil;
  }

  if (0 != strchr(date, '.')) {
    // This is a datetime with sub-second precision
    tokens_read = sscanf(date, "%4d-%2d-%2d%*c%2d:%2d:%2d.%d%3d:%2d", &year, &month, &day, &hour, &min, &sec, &usec, &hour_offset, &minute_offset);
    max_tokens = 9;
  } else {
    // This is a datetime second precision
    tokens_read = sscanf(date, "%4d-%2d-%2d%*c%2d:%2d:%2d%3d:%2d", &year, &month, &day, &hour, &min, &sec, &hour_offset, &minute_offset);
    max_tokens = 8;
  }

  if (max_tokens == tokens_read) {
    // We read the Date, Time, and Timezone info
    minute_offset *= hour_offset < 0 ? -1 : 1;
  } else if ((max_tokens - 1) == tokens_read) {
    // We read the Date and Time, but no Minute Offset
    minute_offset = 0;
  } else if (tokens_read == 3) {
    return parse_date(date);
  } else if (tokens_read >= (max_tokens - 3)) {
    // We read the Date and Time, default to the current locale's offset

    // Get localtime
    time(&rawtime);
    timeinfo = localtime(&rawtime);

    is_dst = timeinfo->tm_isdst * 3600;

    // Reset to GM Time
    timeinfo = gmtime(&rawtime);

    gmt_offset = mktime(timeinfo) - rawtime;

    if ( is_dst > 0 )
      gmt_offset -= is_dst;

    hour_offset = -(gmt_offset / 3600);
    minute_offset = -(gmt_offset % 3600 / 60);

  } else {
    // Something went terribly wrong
    rb_raise(eMysqlError, "Couldn't parse date: %s", date);
  }

  jd = jd_from_date(year, month, day);

  // Generate ajd with fractional days for the time
  // Extracted from Date#jd_to_ajd, Date#day_fraction_to_time, and Rational#+ and #-
  num = (hour * 1440) + (min * 24);

  // Modify the numerator so when we apply the timezone everything works out
  num -= (hour_offset * 1440) + (minute_offset * 24);

  den = (24 * 1440);
  reduce(&num, &den);

  num = (num * 86400) + (sec * den);
  den = den * 86400;
  reduce(&num, &den);

  num = (jd * den) + num;

  num = num * 2;
  num = num - den;
  den = den * 2;

  reduce(&num, &den);

  ajd = rb_funcall(rb_cRational, rb_intern("new!"), 2, rb_ull2inum(num), rb_ull2inum(den));
  offset = timezone_to_offset(hour_offset, minute_offset);

  return rb_funcall(rb_cDateTime, ID_NEW_DATE, 3, ajd, offset, INT2NUM(2299161));
}

// Convert C-string to a Ruby instance of Ruby type "type"
static VALUE typecast(const char* value, unsigned long length, char* type) {
  if (NULL == value)
    return Qnil;

  if ( strcmp(type, "Class") == 0) {
    return rb_funcall(mDO, rb_intern("find_const"), 1, TAINTED_STRING(value, length));
  } else if ( strcmp(type, "Integer") == 0 || strcmp(type, "Fixnum") == 0 || strcmp(type, "Bignum") == 0 ) {
    return rb_cstr2inum(value, 10);
  } else if (0 == strcmp("String", type)) {
    return TAINTED_STRING(value, length);
  } else if (0 == strcmp("Float", type) ) {
    return rb_float_new(rb_cstr_to_dbl(value, Qfalse));
  } else if (0 == strcmp("BigDecimal", type) ) {
    return rb_funcall(rb_cBigDecimal, ID_NEW, 1, TAINTED_STRING(value, length));
  } else if (0 == strcmp("TrueClass", type) || 0 == strcmp("FalseClass", type)) {
    return (0 == value || 0 == strcmp("0", value)) ? Qfalse : Qtrue;
  } else if (0 == strcmp("Date", type)) {
    return parse_date(value);
  } else if (0 == strcmp("DateTime", type)) {
    return parse_date_time(value);
  } else if (0 == strcmp("Time", type)) {
    return parse_time(value);
  } else {
    return TAINTED_STRING(value, length);
  }
}

static void data_objects_debug(VALUE string, struct timeval* start) {
  struct timeval stop;
  char *message;

  char *query = RSTRING_PTR(string);
  int length  = RSTRING_LEN(string);
  char total_time[32];
  do_int64 duration = 0;

  VALUE logger = rb_funcall(mDOMysql, ID_LOGGER, 0);
  int log_level = NUM2INT(rb_funcall(logger, ID_LEVEL, 0));

  if (0 == log_level) {
    gettimeofday(&stop, NULL);

    duration = (stop.tv_sec - start->tv_sec) * 1000000 + stop.tv_usec - start->tv_usec;
    if(stop.tv_usec < start->tv_usec) {
      duration += 1000000;
    }

    snprintf(total_time, 32, "%.6f", duration / 1000000.0);
    message = (char *)calloc(length + strlen(total_time) + 4, sizeof(char));
    snprintf(message, length + strlen(total_time) + 4, "(%s) %s", total_time, query);
    rb_funcall(logger, ID_DEBUG, 1, rb_str_new(message, length + strlen(total_time) + 3));
  }
}
static void raise_mysql_error(VALUE connection, MYSQL *db, int mysql_error_code, char* str) {
  char *mysql_error_message = (char *)mysql_error(db);

  if(mysql_error_code == 1) {
    mysql_error_code = mysql_errno(db);
  }
  if(str) {
    rb_raise(eMysqlError, "(mysql_errno=%04d, sql_state=%s) %s\nQuery: %s", mysql_error_code, mysql_sqlstate(db), mysql_error_message, str);
  } else {
    rb_raise(eMysqlError, "(mysql_errno=%04d, sql_state=%s) %s", mysql_error_code, mysql_sqlstate(db), mysql_error_message);
  }
}

static char * get_uri_option(VALUE query_hash, char * key) {
  VALUE query_value;
  char * value = NULL;

  if(!rb_obj_is_kind_of(query_hash, rb_cHash)) { return NULL; }

  query_value = rb_hash_aref(query_hash, RUBY_STRING(key));

  if (Qnil != query_value) {
    value = StringValuePtr(query_value);
  }

  return value;
}

static MYSQL_RES* cCommand_execute_async(VALUE self, MYSQL* db, VALUE query) {
  int socket_fd;
  int retval;
  fd_set rset;
  struct timeval start;
  char* str = RSTRING_PTR(query);
  int len   = RSTRING_LEN(query);

  VALUE connection = rb_iv_get(self, "@connection");

  retval = mysql_ping(db);
  if(retval == CR_SERVER_GONE_ERROR) {
    CHECK_AND_RAISE(retval, "Mysql server has gone away. \
                             Please report this issue to the Datamapper project. \
                             Specify your at least your MySQL version when filing a ticket");
  }
  retval = mysql_send_query(db, str, len);

  CHECK_AND_RAISE(retval, str);
  gettimeofday(&start, NULL);

  socket_fd = db->net.fd;

  for(;;) {
    FD_ZERO(&rset);
    FD_SET(socket_fd, &rset);

    retval = rb_thread_select(socket_fd + 1, &rset, NULL, NULL, NULL);

    if (retval < 0) {
        rb_sys_fail(0);
    }

    if (retval == 0) {
        continue;
    }

    if (db->status == MYSQL_STATUS_READY) {
      break;
    }
  }

  retval = mysql_read_query_result(db);
  CHECK_AND_RAISE(retval, str);

  data_objects_debug(query, &start);

  return mysql_store_result(db);
}

static VALUE cConnection_initialize(VALUE self, VALUE uri) {
  VALUE r_host, r_user, r_password, r_path, r_query, r_port;

  char *host = "localhost", *user = "root", *password = NULL, *path;
  char *database = "", *socket = NULL;
  char *encoding = NULL;

  int port = 3306;
  unsigned long client_flags = 0;
  int encoding_error;

  MYSQL *db = 0, *result;
  db = (MYSQL *)mysql_init(NULL);

  rb_iv_set(self, "@using_socket", Qfalse);

  r_host = rb_funcall(uri, rb_intern("host"), 0);
  if (Qnil != r_host) {
    host = StringValuePtr(r_host);
  }

  r_user = rb_funcall(uri, rb_intern("user"), 0);
  if (Qnil != r_user) {
    user = StringValuePtr(r_user);
  }

  r_password = rb_funcall(uri, rb_intern("password"), 0);
  if (Qnil != r_password) {
    password = StringValuePtr(r_password);
  }

  r_path = rb_funcall(uri, rb_intern("path"), 0);
  path = StringValuePtr(r_path);
  if (Qnil != r_path) {
    database = strtok(path, "/");
  }

  if (NULL == database || 0 == strlen(database)) {
    rb_raise(eMysqlError, "Database must be specified");
  }

  // Pull the querystring off the URI
  r_query = rb_funcall(uri, rb_intern("query"), 0);

  // Check to see if we're on the db machine.  If so, try to use the socket
  if (0 == strcasecmp(host, "localhost")) {
    socket = get_uri_option(r_query, "socket");
    if (NULL != socket) {
      rb_iv_set(self, "@using_socket", Qtrue);
    }
  }

  r_port = rb_funcall(uri, rb_intern("port"), 0);
  if (Qnil != r_port) {
    port = NUM2INT(r_port);
  }

  encoding = get_uri_option(r_query, "encoding");
  if (!encoding) { encoding = get_uri_option(r_query, "charset"); }
  if (!encoding) { encoding = "utf8"; }

  // If ssl? {
  //   mysql_ssl_set(db, key, cert, ca, capath, cipher)
  // }

  my_bool reconnect = 1;
  mysql_options(db, MYSQL_OPT_RECONNECT, &reconnect);

  result = (MYSQL *)mysql_real_connect(
    db,
    host,
    user,
    password,
    database,
    port,
    socket,
    client_flags
  );

  if (NULL == result) {
    raise_mysql_error(Qnil, db, -1, NULL);
  }

  // Set the connections character set
  encoding_error = mysql_set_character_set(db, encoding);
  if (0 != encoding_error) {
    raise_mysql_error(Qnil, db, encoding_error, NULL);
  }

  // Disable sql_auto_is_null
  cCommand_execute_async(self, db, rb_str_new2("SET sql_auto_is_null = 0"));
  cCommand_execute_async(self, db, rb_str_new2("SET SESSION sql_mode = 'ANSI,NO_AUTO_VALUE_ON_ZERO,NO_DIR_IN_CREATE,NO_ENGINE_SUBSTITUTION,NO_UNSIGNED_SUBTRACTION,TRADITIONAL'"));

  rb_iv_set(self, "@uri", uri);
  rb_iv_set(self, "@connection", Data_Wrap_Struct(rb_cObject, 0, 0, db));

  return Qtrue;
}

static VALUE cConnection_character_set(VALUE self) {
  VALUE connection_container = rb_iv_get(self, "@connection");
  MYSQL *db;

  const char *encoding;

  if (Qnil == connection_container)
    return Qfalse;

  db = DATA_PTR(connection_container);

  encoding = mysql_character_set_name(db);

  return RUBY_STRING(encoding);
}

static VALUE cConnection_is_using_socket(VALUE self) {
  return rb_iv_get(self, "@using_socket");
}

static VALUE cConnection_dispose(VALUE self) {
  VALUE connection_container = rb_iv_get(self, "@connection");

  MYSQL *db;

  if (Qnil == connection_container)
    return Qfalse;

  db = DATA_PTR(connection_container);

  if (NULL == db)
    return Qfalse;

  mysql_close(db);
  rb_iv_set(self, "@connection", Qnil);

  return Qtrue;
}

/*
Accepts an array of Ruby types (Fixnum, Float, String, etc...) and turns them
into Ruby-strings so we can easily typecast later
*/
static VALUE cCommand_set_types(VALUE self, VALUE array) {
  VALUE type_strings = rb_ary_new();
  int i;

  for (i = 0; i < RARRAY_LEN(array); i++) {
    rb_ary_push(type_strings, RUBY_STRING(rb_class2name(rb_ary_entry(array, i))));
  }

  rb_iv_set(self, "@field_types", type_strings);

  return array;
}

VALUE cCommand_quote_time(VALUE self, VALUE value) {
  return rb_funcall(value, ID_STRFTIME, 1, RUBY_STRING("'%Y-%m-%d %H:%M:%S'"));
}


VALUE cCommand_quote_date_time(VALUE self, VALUE value) {
  // TODO: Support non-local dates. we need to call #new_offset on the date to be
  // quoted and pass in the current locale's date offset (self.new_offset((hours * 3600).to_r / 86400)
  return rb_funcall(value, ID_STRFTIME, 1, RUBY_STRING("'%Y-%m-%d %H:%M:%S'"));
}

VALUE cCommand_quote_date(VALUE self, VALUE value) {
  return rb_funcall(value, ID_STRFTIME, 1, RUBY_STRING("'%Y-%m-%d'"));
}

static VALUE cCommand_quote_string(VALUE self, VALUE string) {
  MYSQL *db = DATA_PTR(rb_iv_get(rb_iv_get(self, "@connection"), "@connection"));
  const char *source = RSTRING_PTR(string);
  int source_len     = RSTRING_LEN(string);
  char *escaped;
  VALUE result;

  int quoted_length = 0;

  // Allocate space for the escaped version of 'string'.  Use + 3 allocate space for null term.
  // and the leading and trailing single-quotes.
  // Thanks to http://www.browardphp.com/mysql_manual_en/manual_MySQL_APIs.html#mysql_real_escape_string
  escaped = (char *)calloc(source_len * 2 + 3, sizeof(char));

  // Escape 'source' using the current encoding in use on the conection 'db'
  quoted_length = mysql_real_escape_string(db, escaped + 1, source, source_len);

  // Wrap the escaped string in single-quotes, this is DO's convention
  escaped[0] = escaped[quoted_length + 1] = '\'';
  result = rb_str_new(escaped, quoted_length + 2);
  free(escaped);
  return result;
}

static VALUE build_query_from_args(VALUE klass, int count, VALUE *args) {
  VALUE query = rb_iv_get(klass, "@text");
  if ( count > 0 ) {
    int i;
    VALUE array = rb_ary_new();
    for ( i = 0; i < count; i++) {
      rb_ary_push(array, (VALUE)args[i]);
    }
    query = rb_funcall(klass, ID_ESCAPE_SQL, 1, array);
  }
  return query;
}

static VALUE cCommand_execute_non_query(int argc, VALUE *argv, VALUE self) {
  VALUE query;

  MYSQL_RES *response = 0;

  my_ulonglong affected_rows;
  VALUE connection = rb_iv_get(self, "@connection");
  VALUE mysql_connection = rb_iv_get(connection, "@connection");
  if (Qnil == mysql_connection)
    rb_raise(eMysqlError, "This connection has already been closed.");

  MYSQL *db = DATA_PTR(mysql_connection);
  query = build_query_from_args(self, argc, argv);

  response = cCommand_execute_async(self, db, query);

  affected_rows = mysql_affected_rows(db);
  mysql_free_result(response);

  if (-1 == affected_rows)
    return Qnil;

  return rb_funcall(cResult, ID_NEW, 3, self, INT2NUM(affected_rows), INT2NUM(mysql_insert_id(db)));
}

static VALUE cCommand_execute_reader(int argc, VALUE *argv, VALUE self) {
  VALUE query, reader;
  VALUE field_names, field_types;

  unsigned int field_count;
  int i;

  char guess_default_field_types = 0;
  VALUE connection = rb_iv_get(self, "@connection");
  VALUE mysql_connection = rb_iv_get(connection, "@connection");
  if (Qnil == mysql_connection) {
    rb_raise(eMysqlError, "This connection has already been closed.");
  }

  MYSQL *db = DATA_PTR(mysql_connection);

  MYSQL_RES *response = 0;
  MYSQL_FIELD *field;

  query = build_query_from_args(self, argc, argv);

  response = cCommand_execute_async(self, db, query);

  if (!response) {
    return Qnil;
  }

  field_count = mysql_field_count(db);

  reader = rb_funcall(cReader, ID_NEW, 0);
  rb_iv_set(reader, "@reader", Data_Wrap_Struct(rb_cObject, 0, 0, response));
  rb_iv_set(reader, "@opened", Qtrue);
  rb_iv_set(reader, "@field_count", INT2NUM(field_count));

  field_names = rb_ary_new();
  field_types = rb_iv_get(self, "@field_types");

  if ( field_types == Qnil || 0 == RARRAY_LEN(field_types) ) {
    field_types = rb_ary_new();
    guess_default_field_types = 1;
  } else if (RARRAY_LEN(field_types) != field_count) {
    // Whoops...  wrong number of types passed to set_types.  Close the reader and raise
    // and error
    rb_funcall(reader, rb_intern("close"), 0);
    rb_raise(eMysqlError, "Field-count mismatch. Expected %ld fields, but the query yielded %d", RARRAY_LEN(field_types), field_count);
  }

  for(i = 0; i < field_count; i++) {
    field = mysql_fetch_field_direct(response, i);
    rb_ary_push(field_names, RUBY_STRING(field->name));

    if (1 == guess_default_field_types) {
      rb_ary_push(field_types, infer_ruby_type(field));
    }
  }

  rb_iv_set(reader, "@fields", field_names);
  rb_iv_set(reader, "@field_types", field_types);

  if (rb_block_given_p()) {
    rb_yield(reader);
    rb_funcall(reader, rb_intern("close"), 0);
  }

  return reader;
}

// This should be called to ensure that the internal result reader is freed
static VALUE cReader_close(VALUE self) {
  // Get the reader from the instance variable, maybe refactor this?
  VALUE reader_container = rb_iv_get(self, "@reader");

  MYSQL_RES *reader;

  if (Qnil == reader_container)
    return Qfalse;

  reader = DATA_PTR(reader_container);

  // The Meat
  if (NULL == reader)
    return Qfalse;

  mysql_free_result(reader);
  rb_iv_set(self, "@reader", Qnil);

  return Qtrue;
}

// Retrieve a single row
static VALUE cReader_next(VALUE self) {
  // Get the reader from the instance variable, maybe refactor this?
  VALUE reader_container = rb_iv_get(self, "@reader");
  VALUE ruby_field_type_strings, row;

  MYSQL_RES *reader;
  MYSQL_ROW result;
  unsigned long *lengths;

  int i;
  char *field_type;

  if (Qnil == reader_container)
    return Qfalse;

  reader = DATA_PTR(reader_container);

  // The Meat
  ruby_field_type_strings = rb_iv_get(self, "@field_types");
  row = rb_ary_new();
  result = (MYSQL_ROW)mysql_fetch_row(reader);
  lengths = mysql_fetch_lengths(reader);

  rb_iv_set(self, "@state", result ? Qtrue : Qfalse);

  if (!result)
    return Qnil;

  for (i = 0; i < reader->field_count; i++) {
    // The field_type data could be cached in a c-array
    field_type = RSTRING_PTR(rb_ary_entry(ruby_field_type_strings, i));
    rb_ary_push(row, typecast(result[i], lengths[i], field_type));
  }

  rb_iv_set(self, "@values", row);

  return Qtrue;
}

static VALUE cReader_values(VALUE self) {
  VALUE state = rb_iv_get(self, "@state");
  if ( state == Qnil || state == Qfalse ) {
    rb_raise(eMysqlError, "Reader is not initialized");
  }
  else {
    return rb_iv_get(self, "@values");
  }
}

static VALUE cReader_fields(VALUE self) {
  return rb_iv_get(self, "@fields");
}

void Init_do_mysql_ext() {
  rb_require("bigdecimal");
  rb_require("date");

  rb_funcall(rb_mKernel, rb_intern("require"), 1, RUBY_STRING("data_objects"));

  ID_TO_I = rb_intern("to_i");
  ID_TO_F = rb_intern("to_f");
  ID_TO_S = rb_intern("to_s");
  ID_TO_TIME = rb_intern("to_time");
  ID_NEW = rb_intern("new");
  ID_NEW_RATIONAL = rb_intern("new!");
#ifdef RUBY_LESS_THAN_186
  ID_NEW_DATE = rb_intern("new0");
#else
  ID_NEW_DATE = rb_intern("new!");
#endif
  ID_CONST_GET = rb_intern("const_get");
  ID_UTC = rb_intern("utc");
  ID_ESCAPE_SQL = rb_intern("escape_sql");
  ID_STRFTIME = rb_intern("strftime");
  ID_LOGGER = rb_intern("logger");
  ID_DEBUG = rb_intern("debug");
  ID_LEVEL = rb_intern("level");

  // Store references to a few helpful clases that aren't in Ruby Core
  rb_cDate = RUBY_CLASS("Date");
  rb_cDateTime = RUBY_CLASS("DateTime");
  rb_cRational = RUBY_CLASS("Rational");
  rb_cBigDecimal = RUBY_CLASS("BigDecimal");

  // Get references to the DataObjects module and its classes
  mDO = CONST_GET(rb_mKernel, "DataObjects");
  cDO_Quoting = CONST_GET(mDO, "Quoting");
  cDO_Connection = CONST_GET(mDO, "Connection");
  cDO_Command = CONST_GET(mDO, "Command");
  cDO_Result = CONST_GET(mDO, "Result");
  cDO_Reader = CONST_GET(mDO, "Reader");

  // Top Level Module that all the classes live under
  mDOMysql = rb_define_module_under(mDO, "Mysql");

  eMysqlError = rb_define_class("MysqlError", rb_eStandardError);

  cConnection = DRIVER_CLASS("Connection", cDO_Connection);
  rb_define_method(cConnection, "initialize", cConnection_initialize, 1);
  rb_define_method(cConnection, "using_socket?", cConnection_is_using_socket, 0);
  rb_define_method(cConnection, "character_set", cConnection_character_set , 0);
  rb_define_method(cConnection, "dispose", cConnection_dispose, 0);

  cCommand = DRIVER_CLASS("Command", cDO_Command);
  rb_include_module(cCommand, cDO_Quoting);
  rb_define_method(cCommand, "set_types", cCommand_set_types, 1);
  rb_define_method(cCommand, "execute_non_query", cCommand_execute_non_query, -1);
  rb_define_method(cCommand, "execute_reader", cCommand_execute_reader, -1);
  rb_define_method(cCommand, "quote_string", cCommand_quote_string, 1);
  rb_define_method(cCommand, "quote_date", cCommand_quote_date, 1);
  rb_define_method(cCommand, "quote_time", cCommand_quote_time, 1);
  rb_define_method(cCommand, "quote_datetime", cCommand_quote_date_time, 1);

  // Non-Query result
  cResult = DRIVER_CLASS("Result", cDO_Result);

  // Query result
  cReader = DRIVER_CLASS("Reader", cDO_Reader);
  rb_define_method(cReader, "close", cReader_close, 0);
  rb_define_method(cReader, "next!", cReader_next, 0);
  rb_define_method(cReader, "values", cReader_values, 0);
  rb_define_method(cReader, "fields", cReader_fields, 0);
}