<?php
// calculator.php - RJM Programming - April, 2018
// Calculator via middleman Tcl

if (isset($_GET['read']) && isset($_GET['via'])) {
  echo "<html><head><title>Calculator via TCL - RJM Programming - April, 2018</title></head><body style='background-color:yellow;'><p align='center'>";
  echo file_get_contents(dirname(__FILE__) . "/calculator.txt") . " = " . urldecode($_GET['read']);
  echo "</p><br><br><h1 align='center'>Calculator via TCL</h1><br><br><div  align='center'><form align='center' method='GET' action='./calculator.php'>First Number: <input type='text' name='firstnum' value='1.0'></input>
  
  
  <select name=oper>
<option value='+'>+</option>                                                                                      
<option value='-'>-</option> 
<option value='*'>*</option>                                                                                      
<option value='/'>/</option>                                                                               
<option value='**'>**</option> 
<option value='%'>%</option> 
<option value='~'>~</option> 
<option value='!'>!</option> 
<option value='<<'><<</option> 
<option value='>>'>>></option> 
<option value='&'>&</option>                                                                                      
<option value='^'>^</option>                                                                                      
<option value='||'>||</option>                                                                                      
<option value='&&'>&&</option>   
<option value='<'><</option> 
<option value='>'>></option>    
<option value='<='><=</option>   
<option value='>='>>=</option></select><input type='text' name='secnum' value='1.0'> :Second Number</input><input type='submit' name='submit' value='Calculate' id='submit'></input></form></div></body></html>";
} else if (isset($_GET['firstnum']) && isset($_GET['oper']) && isset($_GET['secnum'])) {
  file_put_contents(dirname(__FILE__) . "/calculator.txt", urldecode($_GET['firstnum']) . "\n" .  str_replace(" ","",str_replace("  ","+",(" " . urldecode($_GET['oper']) . " "))) . "\n" .  urldecode($_GET['secnum']));
  exec("tclsh " . dirname(__FILE__) . "/calculator.tcl < " . dirname(__FILE__) . "/calculator.txt | tail -1 > " . dirname(__FILE__) . "/calculator.out");
  header("Location: ./calculator.php?read=" . urlencode(file_get_contents(dirname(__FILE__) . "/calculator.out")) . "&via=" . urlencode(file_get_contents(dirname(__FILE__) . "/calculator.txt")));
  exit;
} else {
  echo "<html><head><title>Calculator via TCL - RJM Programming - October, 2014</title></head><body style='background-color:yellow;'><p align='center'>";
  echo "</p><br><br><h1 align='center'>Calculator via TCL</h1><br><br><div  align='center'><form align='center' method='GET' action='./calculator.php'>First Number: <input type='text' name='firstnum' value='1.0'></input>
  
  
  <select name=oper>
<option value='+'>+</option>                                                                                      
<option value='-'>-</option> 
<option value='*'>*</option>                                                                                      
<option value='/'>/</option>                                                                               
<option value='**'>**</option> 
<option value='%'>%</option> 
<option value='~'>~</option> 
<option value='!'>!</option> 
<option value='<<'><<</option> 
<option value='>>'>>></option> 
<option value='&'>&</option>                                                                                      
<option value='^'>^</option>                                                                                      
<option value='||'>||</option>                                                                                      
<option value='&&'>&&</option>   
<option value='<'><</option> 
<option value='>'>></option>    
<option value='<='><=</option>   
<option value='>='>>=</option></select><input type='text' name='secnum' value='1.0'></input> :Second Number<input type='submit' name='submit' value='Calculate' id='submit'></input></form></div></body></html>";
}
?>