//
// Hash code tests and analytics.
//

// g++ -std=c++20 -o hashing hashing.cpp

#include <iostream>     // cout, endl
using std::cout;
using std::endl;

#include <fstream>      // ifstream
using std::ifstream;

#include <string>       // string, getline
using std::string;
using std::getline;

#include <vector>       // vector
using std::vector;


//
// Global structures, constants, and variables
//

const string FILE_NAME    = "magicitems.txt";
const int LINES_IN_FILE   = 666;
const int HASH_TABLE_SIZE = 250;

void readFileIntoVector(vector<string>& victor)
{
   string line = "";
   ifstream fileStream(FILE_NAME); // Implicitly opens the file too. It's a C++ thing, I guess.
   while( getline(fileStream, line) ) {
      victor.push_back(line);
   }
   fileStream.close();
}

int makeHashCode(string item)
{
   // Transform item to UPPER CASE.
   transform(item.begin(), item.end(), item.begin(),::toupper);

   // Iterate over all letters in the item string, totalling their ASCII values.
   int letterTotal = 0;
   for (int i = 0; i < item.length(); i++) {
      letterTotal = letterTotal + (int)item[i];
   }

   // Scale letterTotal to fit in HASH_TABLE_SIZE.
   int hashCode = letterTotal % HASH_TABLE_SIZE;  // % is the "mod" operator
   // TODO: Experiment with letterTotal * 2, 3, 5, 50, etc.

   return hashCode;
}

//
// Main entry point for this program.
//
int main(int argc, char* argv[])
{
   int retCode = 0;

   cout << "----------------------------" << endl;
   cout << "Hash code tests and analysis" << endl;
   cout << "----------------------------" << endl;
   cout << "Hash table size = " << HASH_TABLE_SIZE << endl;
   cout << "Reading " << LINES_IN_FILE << " lines from file [" << FILE_NAME << "] . . ." << endl;

   vector<string> magicItems;
   readFileIntoVector(magicItems);

   // Print the items in the vector and each of their hash code values.
   for (int i = 0; i < magicItems.size(); i++) {
      cout << "Item " << i << ": " << magicItems[i] << " = " << makeHashCode(magicItems[i]) << endl;
   }

   return retCode;
}