package parseInteresting.complete;

import com.opencsv.bean.CsvToBean;
import com.opencsv.bean.CsvToBeanBuilder;

import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.util.*;

/**
 * This class is part of a demo to demonstrate how csv data can be parsed using Java
 * This class uses the CSVReader to read a CSV file and read the file line by line
 * This part of the demo will use UfoSightingModel.java and will create an object for each line
 * The created objects will then be used to look at aggregate data trends and information
 */
public class UfoDataParser {

    /**
     * The path of the csv from the root
     */
    private static final String CSV_FILENAME = "ufo-data.csv";

    /**
     * Reads the csv file and analyzes the aggregate data
     *
     * @param args
     */
    public static void main(String[] args) {
        InputStream stream = UfoDataParser.class.getResourceAsStream("/data/" + CSV_FILENAME);
        if(stream == null) {
            System.err.println("File not found: " + CSV_FILENAME);
            System.exit(1);
        }
        Reader reader = new BufferedReader(new InputStreamReader(stream));
        //
        CsvToBean<UfoSightingModel> csvToBean = new CsvToBeanBuilder<UfoSightingModel>(reader)
                .withType(UfoSightingModel.class)
                .withIgnoreLeadingWhiteSpace(true)
                .build();

        Iterator<UfoSightingModel> csvUserIterator = csvToBean.iterator();

        Map<String, Integer> stateUfoObservations = new HashMap<>();

        while(csvUserIterator.hasNext()) {
            UfoSightingModel ufoSightingRecord = csvUserIterator.next();
            String country = ufoSightingRecord.getCountry();
            if(!country.equals("us")) {
                continue;
            }

            String state = ufoSightingRecord.getState();
            if(!stateUfoObservations.containsKey(state)) {
                stateUfoObservations.put(state, 0);
            }
            stateUfoObservations.put(state, stateUfoObservations.get(state) + 1);
        }


        Map<Integer, Set<String>> observationsToStateReverseOrdered = new TreeMap<>(Collections.reverseOrder());

        for(String state : stateUfoObservations.keySet()) {
            int observations = stateUfoObservations.get(state);
            if(!observationsToStateReverseOrdered.containsKey(observations)) {
                observationsToStateReverseOrdered.put(observations, new HashSet<>());
            }
            observationsToStateReverseOrdered.get(observations).add(state);
        }

        System.out.println(observationsToStateReverseOrdered);
    }
}