<?php

  // add XOR.  No symbolic form in C++ or sql.  Be sure to add spaces on both
  // sides in the code that is generated.

  // add alerts in { }, and mark the formula as not available on the top
  // list.

  // Add a limit on the size of the output.


$parser_test_cases = 
    array("1+2--3", "null", "  null ", "if(1>3,1,3)", 
	  "if(1>3,1)",
	  "if([Price]<10,[RSI15]*5,[RV]+min([BS],5))",
	  "if([Price]<10,[RSI15]*5,[RV]+max([BS],5))",
	  "if([Price]<10,[RSI15]*5,[RV]+min(6,5))",
	  "if([Price]<10,[RSI15]*5,[RV]+min(6,quality))",
	  "if([Price]<10,[RV]*5,[BAR]+min(6,quality))+abs(1)+ceil(1)+floor(1)+exp(1)+ln(1)+log(2,1024)+pow(2,3)+sqrt(4)",
);

function pretty_print_source($source)
{
  global $static_base;
  $match = "/\\[([A-Za-z0-9_]*)\\]/";
  $replace = 
    // Add help.
    '<IMG SRC="' . $static_base . 'Filters/Min$1.gif" ALT="$0">';
  return preg_replace($match, $replace, htmlspecialchars($source));
}

class Parser
{
  public static function make_tokens($input)
  {
    $output = array();
    $position = 0;
    while ($input != "")
      {
	if (preg_match('/^([\s]+)(.*)$/', $input, $pieces))
	  {
	    $position += strlen($pieces[1]);
	    $input = $pieces[2];
	    continue;
	  }
	$token = substr($input, 0, 2);
	//echo "<P>possible token ", htmlspecialchars($token), "</P>";
	switch ($token)
	  {
	  case '!=':
	  case '<=':
	  case '>=':
	  case '==':
	  case '||':
	  case '&&':
	  case '??':
	    //echo "<p>HERE</p>";
	    $output[] = 
	      array("position" => $position,
		    "original" => $token,
		    "type" => "punctuation",
		    "punctuation" => $token);		  
	    $position += 2;
	    $input = substr($input, 2);
	    continue 2;
	  }
	//echo "<P>and gone</P>";
	$token = $input[0];
	//echo "<P>possible token ", htmlspecialchars($token), "</P>";
	switch ($token)
	  {
	  case '!':
	  case '<':
	  case '>':
	  case '+':
	  case '-':
	  case '*':
	  case '/':
	  case '(':
	  case ')':
	  case '{':
	  case '}':
	  case ',':
	    $output[] = 
	      array("position" => $position,
		    "original" => $token,
		    "type" => "punctuation",
		    "punctuation" => $token);		  
	    $position += 1;
	    $input = substr($input, 1);
	    continue 2;
	  }
	if (preg_match('/^(\\[([0-9a-zA-Z_]+)\\])(.*)$/', $input, $pieces))
	  {
	    $output[] = 
	      array("position" => $position,
		    "original" => $pieces[1],
		    "type" => 'filter',
		    "filter" => $pieces[2]);
	    $position += strlen($pieces[1]);
	    $input = $pieces[3];
	    continue;
	  }
	if (preg_match('/^([a-zA-Z_][0-9a-zA-Z_]*)(.*)$/', $input, $pieces))
	  {
	    $output[] =
	      array("position" => $position,
		    "original" => $pieces[1],
		    "type" => 'symbol',
		    "symbol" => $pieces[1]);
	    $position += strlen($pieces[1]);
	    $input = $pieces[2];
	    continue;
	  }
	if (preg_match('/^([0-9]+(\\.[0-9]+)?)(.*)$/', $input, $pieces))
	  {
	    $output[] =
	      array("position" => $position,
		    "original" => $pieces[1],
		    "type" => 'number',
		    "number" => $pieces[1]+0);
	    $position += strlen($pieces[1]);
	    $input = $pieces[3];
	    continue;
	  }
	throw new Exception("Unexpected character", $position);
      }
    return $output;
  }

  private $tokens;
  private function peek_token($skip=0)
  {
    if ($skip >= count($this->tokens))
      return array("type" => "end", "position" => -1);
    return $this->tokens[$skip];
  }
  private function pop_token()
  {
    $result = $this->peek_token();
    array_shift($this->tokens);
    return $result;
  }

  private function report_parse_error($token, $msg = "parse error")
  {
    throw new Exception($msg, $token['position']);
  }

  private $success;
  private $allow_top_list;
  private $result;
  private $error_message;
  private $error_location;
  private $source;
  public function parse($input)
  {
    $this->source = $input;
    $this->success = false;
    $this->allow_top_list = true;
    $this->result = "NULL";
    $this->error_message = "Unknown error";
    $this->error_location = 0;
    try
      {
	$this->tokens = self::make_tokens($input);
	$this->result = $this->parse_binary_ops();
	$next = $this->peek_token();
	if ($next['type'] != "end")
	  $this->report_parse_error($next);
	$this->success = true;
	return true;
      }
    catch (Exception $ex)
      {
	$this->success = false;
	$this->result = "NULL";
	$this->error_message = $ex->getMessage();
	$this->error_location = $ex->getCode();
	return false;
      }
  }

  public function getSuccess()
  {
    return $this->success;
  }
  public function getAllowTopList()
  {
    return $this->allow_top_list;
  }
  public function getResult()
  {
    return $this->result;
  }
  public function getErrorMessage()
  {
    return $this->error_message;
  }
  public function getErrorLocation()
  {
    return $this->error_location;
  }

  public function getTestQueries()
  {
    $result = array();
    $expr = strtr($this->result, array("$$$" => "price"));
    $result[] = "SELECT " . $expr
      . " FROM alerts LEFT JOIN alerts_daily "
      . "ON symbol=d_symbol AND date=date(timestamp) LIMIT 1";
    if ($this->allow_top_list)
      $result[] = "SELECT " . $expr
	. " FROM top_list LEFT JOIN alerts_daily "
	. "ON symbol=d_symbol AND date=date(timestamp) LIMIT 1";
    return $result;
  }

  private function parse_binary_ops()
  {
    $result = $this->parse_binary_ops1();
    $next = $this->peek_token();
    if ($next['punctuation'] != "??")
      return $result;
    array_shift($this->tokens);
    return "IFNULL(" . $result . "," . $this->parse_binary_ops() . ")";
  }

  private function parse_binary_ops1()
  {
    $result = $this->parse_unary_ops();
    while (true)
      {
	$next = $this->peek_token();
	$p = $next['punctuation'];
	switch ($p)
	  {
	  case '!':
	  case '<':
	  case '>':
	  case '+':
	  case '-':
	  case '*':
	  case '/':
	  case '!=':
	  case '<=':
	  case '>=':
	  case '||':
	  case '&&':
	    $result .= $p;
	    break;
	  case '==':
	    $result .= "=";
	    break;
	  default:
	    break 2;
	  }
	array_shift($this->tokens);
	$result .= $this->parse_unary_ops();
      }
    return $result;
  }

  private function parse_unary_ops()
  {
    $next = $this->peek_token();
    $p = $next['punctuation'];
    if ($p == "-")
      {
	array_shift($this->tokens);
	return "-" . $this->parse_unary_ops();
      }
    else
      return $this->parse_base();
  }

  private function parse_base()
  {
    $next = $this->pop_token();
    if ($next['punctuation'] == "(")
      {
	$result = "(" . $this->parse_binary_ops() . ")";
	$next = $this->pop_token();
	if ($next['punctuation'] != ")")
	  $this->report_parse_error($next, "Expecting )");
	return $result;
      }
  else if ($next['type'] == "number")
    {
      return $next['number'];
    }
  else if ($next['type'] == "symbol")
    {
      switch ($next['symbol'])
	{
	case 'null':
	  return 'NULL';
	case 'min':
	  return $this->parse_min_max_f("LEAST");
	case 'max':
	  return $this->parse_min_max_f("GREATEST");
	case 'if':
	  return $this->parse_if_f();
	case 'abs':
	  return $this->parse_function("ABS", 1);
	case 'ceil':
	  return $this->parse_function("CEIL", 1);
	case 'floor':
	  return $this->parse_function("FLOOR", 1);
	case 'exp':
	  return $this->parse_function("EXP", 1);
	case 'ln':
	  return $this->parse_function("LN", 1);
	case 'log':
	  // The first argument is the base.  The first argument is optional
	  // in mysql, but I didn't see the value in that.
	  return $this->parse_function("LOG", 2);
	case 'pow':
	  // This is strange.  pow(-2,0.5) returns nan, not null.
	  // if(pow(-2,0.5), "true","false") returns true, not false.
	  // I haven't see anything else like this.
	  // I'm not sure what happens to TI Pro, etc, if nan is returned.
	  return $this->parse_function("POW", 2);
	case 'sqrt':
	  return $this->parse_function("SQRT", 1);
	case 'quality':
	  $this->allow_top_list = false;
	  // fall through!
	case 'price':
	case 'last':
	case 'most_recent_close':
	case 'expected_open':
	case 't_high':
	case 't_low':
	case 'v_up_1':
	case 'v_up_5':
	case 'v_up_10':
	case 'v_up_15':
	case 'v_up_30':
	case 'sma_2_8':
	case 'sma_2_20':
	case 'sma_2_200':
	case 'sma_5_8':
	case 'sma_5_20':
	case 'sma_5_200':
	case 'sma_15_8':
	case 'sma_15_20':
	case 'sma_15_200':
	case 'sma_60_8':
	case 'sma_60_20':
	case 'sma_60_200':
	case 'std_5_20':
	case 'std_15_20':
	case 'std_60_20':
	case 'vwap':
	case 'p_up_1':
	case 'v_up_1':
	  // alerts_daily
	case 'sma_200':
	case 'sma_50':
	case 'sma_20':
	case 'sma_8':
	case 'high_p':
	case 'low_p':
	case 'close_p':
	case 'open_p':
	case 'volume_p':
	case 'high_52w':
	case 'low_52w':
	case 'std_20':
	case 'consolidation_high':
	case 'consolidation_low':
	case 'last_price':
	case 'high_life':
	case 'low_life':
	case 'prev_put_volume':
	case 'prev_call_volume':
	case 'avg_put_call_volume':
	case 'high_5d':
	case 'low_5d':
	case 'close_5d':
	case 'high_10d':
	case 'low_10d':
	case 'close_10d':
	case 'high_20d':
	case 'low_20d':
	case 'close_20d':
	case 'adx_14d':
	case 'pdi_14d':
	case 'mdi_14d':
	case 'shares_per_print':
	case 'short_interest':
	case 'vf_buy':
	case 'vf_sell':
	case 'vf_expect':
	  return $next['symbol'];
	case 'seconds_after_open' :
	  return '(TIMESTAMPDIFF(SECOND, date, timestamp)-23400)';
	}
      $this->report_parse_error($next, "Unknown symbol");
    }
  else if ($next['type'] == "filter")
    {
      global $window_filters;
      $info = $window_filters[$next['filter']];
      if (!$info)
	$this->report_parse_error($next, "Unknown filter");
      if ($info['alerts_only'])
        $this->allow_top_list = false;
      // This might include $$$
      return "(" . $info['sql'] . ")";
    }
  $this->report_parse_error($next);
}

  private function parse_min_max_f($f_name)
  {
    $result = $f_name . "(";
    $next = $this->pop_token();
    if ($next['punctuation'] != "(")
      $this->report_parse_error($next, "Expecting (");
    $result .= $this->parse_binary_ops();
    $next = $this->pop_token();
    if ($next['punctuation'] != ",")
      $this->report_parse_error($next, "Expecting ,");
    $result .= ",";
    $result .= $this->parse_binary_ops();
    while (true)
      {
	$next = $this->pop_token();
	if ($next['punctuation'] == ")")
	  {
	    return $result . ")";
	  }
	else if ($next['punctuation'] != ",")
	  {
	    $this->report_parse_error($next, "Expecting , or )");
	  }
	$result .= ",";
	$result .= $this->parse_binary_ops();
      }
  }

  private function parse_if_f()
  {
    $result = "if(";
    $next = $this->pop_token($tokens);
    if ($next['punctuation'] != "(")
      $this->report_parse_error($next, "Expecting (");
    $result .= $this->parse_binary_ops();
    $next = $this->pop_token();
    if ($next['punctuation'] != ",")
      $this->report_parse_error($next, "Expecting ,");
    $result .= ",";
    $result .= $this->parse_binary_ops();
    $next = $this->pop_token();
    if ($next['punctuation'] == ")")
      {
	return $result . ",NULL)";
      }
    else if ($next['punctuation'] != ",")
      {
	$this->report_parse_error($next, "Expecting , or )");
      }
    $result .= ",";
    $result .= $this->parse_binary_ops();
    $next = $this->pop_token($tokens);
    if ($next['punctuation'] != ")")
      {
      $this->report_parse_error($next, "Expecting )");
      }
    return $result . ")";
  }

  private function parse_function($f_name, $arg_count)
  {
    $result = $f_name . "(";
    $next = $this->pop_token();
    if ($next['punctuation'] != "(")
      $this->report_parse_error($next, "Expecting (");
    while (true)
      {
	$result .= $this->parse_binary_ops();
	$next = $this->pop_token();
	$p = $next['punctuation'];
	$arg_count--;
	if (!$arg_count)
	  break;
	if ($p != ',')
	  $this->report_parse_error($next, "Expecting ,");
	$result .= ",";
      }
    if ($p != ')')
      $this->report_parse_error($next, "Expecting )");
    return $result . ")";
  }

  // Make these memeber variables rather than function parameters so you
  // can reference them by name.
  public $user_id;
  public $internal_code;
  public $description;
  public $units;
  public $format;
  public $graphics;

  public function getInsertQuery()
  {
    return "REPLACE INTO user_filters(user_id, internal_code, source, sql_code, description, units, top_list, format, graphics) values ("
      . ($this->user_id + 0)
      . ", '" . mysql_escape_string($this->internal_code) 
      . "', '" . mysql_escape_string($this->source)
      . "', '" . mysql_escape_string($this->result)
      . "', '" . mysql_escape_string($this->description)
      . "', '" . mysql_escape_string($this->units)
      . "', '" . ($this->allow_top_list?"Y":"N")
      . "', '" . mysql_escape_string($this->format)
      . "', '" . mysql_escape_string($this->graphics)
      . "')";
  }

  public function safeSave()
  {
    $list = $this->getTestQueries();
    $list[] = $this->getInsertQuery();
    foreach ($list as $sql)
      {
	$result = mysql_query($sql);
	if (!$result)
	  {
	    error_log('safeSave(' . $source . ') => ' . $sql . ' => ' . mysql_error());
	    return false;
	  }
      }
    return true;
  }

}

?>