#include <iostream>
#include <vector>
#include <fstream>
#include <map>

typedef struct CrimeReportRow {
  std::string address;
  std::string district;
  std::string crime;
} CrimeReportRow;

class CrimeReport {
  private:
    std::vector<CrimeReportRow*> rows;

    std::vector<std::string> split(const std::string& line, const std::string delimiter = ",") {
      std::vector<std::string> columns;
      std::string column;
      int last = 0;
      int next = 0;

      while ((next = line.find(delimiter, last)) != std::string::npos) {
        columns.push_back(line.substr(last, next - last));
        last = next + 1;
      }

      columns.push_back(line.substr(last));
      return columns;
    }

    void read_rows(std::string filename) {
      std::ifstream file(filename);
      std::string line;
      int rownumber = 0;

      if (file.is_open()) {
        while (std::getline(file, line)) {
          rownumber++;

          // skip the first line of the file because it is the heading.
          if (rownumber == 1) {
            continue;
          }

          std::vector<std::string> columns = split(line);

          // skip rows with an unexpected amount of columns.
          if (columns.size() != 9) {
            std::cout << "Line " << rownumber << " is not valid!" << std::endl;
          }

          CrimeReportRow* row = new CrimeReportRow;
          row->district = columns[2];
          row->address = columns[1];
          row->crime = columns[5];
          rows.push_back(row);
        }

        file.close();
      }
    }

  public:
    CrimeReport(std::string filename) {
      read_rows(filename);
    }

    ~CrimeReport() {
      for (CrimeReportRow* row : rows) {
        delete row;
      }
      
      rows.clear();
      rows.shrink_to_fit();
    }

    int get_number_of_crimes() {
      return rows.size();
    }

    std::string get_most_frequent_crime() {
      std::map<std::string, int> crimes;

      for (CrimeReportRow* row : rows) {
        crimes[row->crime] += 1;
      }

      std::pair<std::string, int> crime;

      for (std::map<std::string, int>::iterator it = crimes.begin(); it != crimes.end(); it++) {
        if (it->second > crime.second) {
          crime = std::make_pair(it->first, it->second);
        }
      }

      return crime.first;
    }

    std::string get_most_dangerous_district() {
      std::map<std::string, int> districts;

      for (CrimeReportRow* row : rows) {
        districts[row->district] += 1;
      }

      std::pair<std::string, int> district;

      for (std::map<std::string, int>::iterator it = districts.begin(); it != districts.end(); it++) {
        if (it->second > district.second) {
          district = std::make_pair(it->first, it->second);
        }
      }

      return district.first;
    }

    std::vector<std::string> get_list_of_address_with_multiple_crimes() {
      std::map<std::string, int> addresses;

      for (CrimeReportRow* row : rows) {
        addresses[row->address] += 1;
      }

      std::vector<std::string> addresses_crimes;

      for (std::map<std::string, int>::iterator it = addresses.begin(); it != addresses.end(); it++) {
        if (it->second > 1) {
          addresses_crimes.push_back(it->first);
        }
      }

      return addresses_crimes;
    }
};

int main() {
  CrimeReport* report = new CrimeReport("input.csv");
  std::cout << "Anzahl der Verbrechen: " << report->get_number_of_crimes() << std::endl;
  std::cout << "Häufigstes Verbrechen: " << report->get_most_frequent_crime() << std::endl;
  std::cout << "Gefährlichster District: " << report->get_most_dangerous_district() << std::endl;
  
  std::cout << "Adresse mit mehr als einem Verbrechen: " << std::endl;

  for (std::string address : report->get_list_of_address_with_multiple_crimes()) {
    std::cout << "\t" << address << std::endl;
  }

  return 0;
}