#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "Debug.h"

int debugLevel = 0;

FILE* debugFile = 0;

static const char* prefix = "-debug";

/** This routine will initialize the variables from the arguments
 *  passed to <tt>main()</tt>. If the <b>first</b> argument is, or starts with
 *  <tt>-debug</tt> the class is initialized and the first parameter is
 *  removed from the <tt>args</tt>. The first parameter may have one of
 *  three forms:
 *  <ol>
 *  <li><tt>-debug</tt> - turn on debugging at level 1</li>
 *  <li><tt>-debugValue</tt> - set debugging level to <tt>Value</tt>
 *  (e.g. <tt>-debug5</tt>)</li>
 *  <li><tt>-debugValue@fileName</tt> set debugging level to <tt>Value</tt>
 *  and send debugging output to the file <tt>fileName</tt>. If you use
 *  this option, the file must b closed using <tt>debugClose()</tt>.</li>
 *  </ol>
 *  On return, <tt>argc</tt> and <tt>argv[]</tt> may be modified.
 *  @param  argc - the number of parameters passed to <tt>main</tt>
 *  @param  args the array of arguments passed to <tt>main</tt>
 */

void debugInit (int* argc, const char* argv[]) {
  debugFile = stderr;

  if (*argc > 1) {
    const char* arg1 = argv[1];
    size_t len = strlen(prefix);

    if (strncmp(arg1, prefix, len) == 0) {
      debugLevel = 1;

      char* ats = strchr(arg1, '@');

      if (ats) {
        *ats = '\0'; 
	debugToFile(ats+1);
      }

      if (strlen(arg1) > len)
        debugLevel = atoi(arg1 + len);

      (*argc)--; // decrement number of arguments

      for (int i = 1; i < *argc; i++) // remove first argument
        argv[i] = argv[i+1];
    }
  }
}

/** Send debugging output to a file.
 *  @param fileName name of file to send output to
 */

void debugToFile (const char* fileName) {
  debugClose();

  FILE* f = fopen(fileName, "w"); // "w+" ?

  if (f)
    debugFile = f;
}

/** Close the output file if it was set in <tt>toFile()</tt> */

void debugClose(void) {
  if (debugFile && (debugFile != stderr)) {
    fclose(debugFile);
    debugFile = stderr;
  }
}