cmpt213-a3/src/cmpt213/assignment3/packagedeliveries/control/PackageDeliveriesTracker.java

package cmpt213.assignment3.packagedeliveries.control;

import cmpt213.assignment3.packagedeliveries.gson.extras.RuntimeTypeAdapterFactory;
import cmpt213.assignment3.packagedeliveries.model.BookPackage;
import cmpt213.assignment3.packagedeliveries.model.ElectronicPackage;
import cmpt213.assignment3.packagedeliveries.model.PackageInfo;
import cmpt213.assignment3.packagedeliveries.model.PerishablePackage;
import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import com.google.gson.TypeAdapter;
import com.google.gson.reflect.TypeToken;
import com.google.gson.stream.JsonReader;
import com.google.gson.stream.JsonWriter;
import java.io.*;
import java.lang.reflect.Type;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.time.LocalDateTime;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Scanner;

/**
 * It's a class that contains a main method that creates a TextMenu object, loads a list of packages
 * from a file, and then loops through a menu of options until the user chooses to quit
 */
public class PackageDeliveriesTracker {
    private static final String fileName = "list.json";
    private static final RuntimeTypeAdapterFactory<PackageInfo> r = RuntimeTypeAdapterFactory.of(PackageInfo.class, "type")
            .registerSubtype(BookPackage.class, "book")
            .registerSubtype(PerishablePackage.class, "perishable")
            .registerSubtype(ElectronicPackage.class, "electronic");
    private static final Gson gson = new GsonBuilder().registerTypeAdapter(LocalDateTime.class,
            new TypeAdapter<LocalDateTime>() {
                @Override
                public void write(JsonWriter jsonWriter,
                                  LocalDateTime localDateTime) throws IOException {
                    jsonWriter.value(localDateTime.toString());
                }

                @Override
                public LocalDateTime read(JsonReader jsonReader) throws IOException {
                    return LocalDateTime.parse(jsonReader.nextString());
                }
            }).registerTypeAdapterFactory(r).create();
    private static ArrayList<PackageInfo> packageList = new ArrayList<>();

    private static PackageDeliveriesTracker instance;

    public static PackageDeliveriesTracker getInstance(){
    if (instance == null){
        instance=new PackageDeliveriesTracker();
    }
    return instance;
    }

    /**
     * It saves the packageList to a file.
     */
    public void save() {
        try {
            Writer w = new FileWriter(fileName);
            gson.toJson(packageList, w);
            w.flush();
            w.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    /**
     * It reads the json file, converts it to a list of PackageInfo objects, and then sets the type of
     * each object to the appropriate type
     */
    public void load() {
        File file = new File(fileName);
        try {
            String json = Files.readString(Paths.get(fileName));
            Type lType = new TypeToken<ArrayList<PackageInfo>>() {
            }.getType();
            packageList = gson.fromJson(json, lType);
            for (PackageInfo p : packageList) {
                if (p instanceof BookPackage) {
                    p.setType("book");
                } else if (p instanceof PerishablePackage) {
                    p.setType("perishable");
                } else if (p instanceof ElectronicPackage) {
                    p.setType("electronic");
                }
            }
            System.out.println("packages loaded");
        } catch (FileNotFoundException e) {
            System.out.println("no packages to load");
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }

    public String getAllPackages(){
        StringBuilder b= new StringBuilder();
        if (packageList.size() == 0) {
            return("No packages to show");
        } else {
            Collections.sort(packageList);
            for (int i = 0; i < packageList.size(); i++) {
                String bString=("Package #" + (i + 1)) + "\n" + packageList.get(i) + "\n";
                b.append(bString);
            }
        }
return b.toString();
    }
}