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#include "hama/Pipes.hh"
#include "hama/TemplateFactory.hh"
#include "hadoop/StringUtils.hh"

#include <time.h>
#include <math.h>
#include <string>
#include <iostream>
#include <cstdlib>

using std::string;
using std::cout;

using HamaPipes::BSP;
using HamaPipes::BSPContext;
using namespace HadoopUtils;

class PiCalculationBSP: public BSP {
private:
    string masterTask;
    int iterations;
public:
  PiCalculationBSP(BSPContext& context) {
      iterations = 10000;
  }
    
  inline double closed_interval_rand(double x0, double x1) {
    return x0 + (x1 - x0) * rand() / ((double) RAND_MAX);
  }

  void bsp(BSPContext& context) {
      
    // initialize random seed
    srand(time(NULL));
    
    int in = 0;
    for (int i = 0; i < iterations; i++) {
      //rand() -> greater than or equal to 0.0 and less than 1.0. 
      double x = 2.0 * closed_interval_rand(0, 1) - 1.0;
      double y = 2.0 * closed_interval_rand(0, 1) - 1.0;    
      if (sqrt(x * x + y * y) < 1.0) {
        in++;
      }
    }      
      
    double data = 4.0 * in / iterations;
      
    context.sendMessage(masterTask, toString(data));
    context.sync();
  }
    
  void setup(BSPContext& context) {
    // Choose one as a master
    masterTask = context.getPeerName(context.getNumPeers() / 2);
  }
    
  void cleanup(BSPContext& context) {
    if (context.getPeerName().compare(masterTask)==0) {
      double pi = 0.0;
      int msgCount = context.getNumCurrentMessages();
      string received;
      for (int i=0; i<msgCount; i++) {
        string received = context.getCurrentMessage();
        pi += toDouble(received);
      }

      pi = pi / msgCount; //msgCount = numPeers
      context.write("Estimated value of PI is", toString(pi));
    }
  }
};

int main(int argc, char *argv[]) {
  return HamaPipes::runTask(HamaPipes::TemplateFactory<PiCalculationBSP>());
}