// Dr. Berna Massingill
// 2000 Jan 29
// CS1321

// CS1321 Sample Document Generator

// Documented by Jeffrey D. Oldham, 2000 Jan 30.  I.e., he is
// responsible for misleading you with the following comments. :)

// This program generates random documents to test the web search
// engine.
//
// To use the program, type
//	generate wordsfile file-prefix number-of-files min-words max-words
// This will create "number-of-files" files called "file-prefix00",
// "file-prefix-01," ... "file-prefix<number-of-files-1>".  Each file
// contains between "min-words" and
// "max-words" randomly chosen from the file "wordsfile".

// wordsfile = file containing a universe of words from which to draw
// file-prefix = filename prefix for all generated files
// number-of-files = number of generated files to produce
// min-words = minimum number of words to place in each generated file
// max-words = maxnimum number of words to place in each generated file


#include <iostream.h>
#include <stdlib.h>
#include <fstream.h>
#include <vector>
#include <string>
#include <utility>		// has pair
#include <assert.h>

typedef pair<string,int> StringIntPair;

// ----------------------------------------

// Print error message and exit.
void errorExit(const string & msg)
{
  cerr << msg << endl;
  exit(EXIT_FAILURE);
}

// ----------------------------------------

// Read words from filename into wordData.
// Exits program if unable to open filename.
void getWords(const char filename[], vector<StringIntPair> & wordData)
{
  ifstream inStr;
  string temp;

  inStr.open(filename);
  if (inStr.fail())
    errorExit("Unable to open input file");
  while (inStr >> temp)
    wordData.push_back(make_pair(temp, static_cast<int>(0)));
  inStr.close();
  if (wordData.size() == 0)
    errorExit("No words in input file");
  return;
}

// Generates 2-character string version of "num", which is assumed
// to be between 0 and 99 inclusive.
string num2str(const int num)
{
  assert(num >= 0 && num < 100);
  string temp;
  temp += (static_cast<char> (num/10 + static_cast<int> ('0')));
  temp += (static_cast<char> (num%10 + static_cast<int> ('0')));
  return temp;
}

// Returns a random integer in the range [min, max].
int randInRange(const int min, const int max)
{
  return min + 
    static_cast<int>(static_cast<double>(max-min+1) *
		     rand() / (RAND_MAX + 1.0));
}

// Generates one output file.
// outFileName is filename, outFileWords is number of words total,
//   wordsPerLine is words per line, wordData is vector of words and
//   frequencies.
void generateOutFile(const char outFileName[], const int outFileWords, 
		     const int wordsPerLine, vector<StringIntPair> & wordData)
{
  ofstream outStr;
  outStr.open(outFileName);
  if (outStr.fail())
    errorExit("Unable to open output file");
  cout << "Generating output file " << outFileName << ", size = " <<
    outFileWords << endl;
  for (int i = 0; i < outFileWords; ++i)
    {
      int wordNum = randInRange(0, wordData.size() - 1);
      outStr << wordData[wordNum].first;
      ++wordData[wordNum].second;
      if (((i % wordsPerLine) == 0) && i > 0)
	outStr << endl;
      else
	outStr << " ";
    }
  outStr << endl;
  outStr.close();
  return;
}

// ----------------------------------------

int main(int argc, char *argv[])
{
  vector< pair<string,int> > wordData;
  string outFileName;
  const int wordsPerLine = 4;

  if (argc < 6)
    errorExit("Arguments:  wordsfile outprefix numfiles minwords maxwords");

  getWords(argv[1], wordData);
  string outPrefix = string(argv[2]);
  int numfiles = strtol(argv[3], static_cast<char **>(0), 10);
  if (numfiles > 100)
    errorExit("Maximum of 100 input files");
  int minwords = strtol(argv[4], static_cast<char **>(0), 10);
  int maxwords = strtol(argv[5], static_cast<char **>(0), 10);

  for (int i = 0; i < numfiles; ++i)
    {
      outFileName = outPrefix + "." + num2str(i);
      generateOutFile(outFileName.c_str(), 
		      randInRange(minwords,maxwords), wordsPerLine,
		      wordData);
    }

  cout << "\nWord frequencies:\n";
  for (unsigned int i = wordData.size(); i > 0; --i)
      cout << wordData[i-1].first << " used " << wordData[i-1].second << 
	" times\n";

  return EXIT_SUCCESS;
}