FACULTATE-DELIVERY_PLANNER/Server Delivery Planner/src/main/java/com/andreicerbu/Algorithm.java

package com.andreicerbu;

import com.andreicerbu.exceptions.*;
import com.andreicerbu.items.database.TableDeposit;
import com.andreicerbu.json.JsonFields;
import org.json.JSONArray;
import org.json.JSONObject;

import java.sql.*;
import java.util.*;

import static com.andreicerbu.json.JsonFields.listOfDeposits;

public class Algorithm {
    JSONObject order = null;
    Integer id_user = null;
    String name = null;
    Float lat_coord = null;
    Float long_coord = null;

    JSONObject routeJson = null;
    JSONObject destination = null;
    JSONArray deposits = null;

    List<TableDeposit> listOfDeposits = new ArrayList<>();
    Map<Integer, String> mapProductIdToName = new HashMap<>();

    public Algorithm(JSONObject order) throws SQLException, ProductUnavailableAnymoreException {
        this.order = new JSONObject(order.toString());
        this.id_user = this.order.getInt(JsonFields.id_user);
        this.order.remove(JsonFields.id_user);

        run();
    }

    private void getUserInformation(Connection conn) throws SQLException{
        PreparedStatement pstmt = conn.prepareStatement("SELECT * FROM users WHERE id = ?");
        pstmt.setInt(1, id_user);

        ResultSet resultSet = pstmt.executeQuery();
        resultSet.next();

        name = resultSet.getString("username");
        lat_coord = resultSet.getFloat(JsonFields.lat_coord);
        long_coord = resultSet.getFloat(JsonFields.long_coord);

        destination = new JSONObject();
        destination.put(JsonFields.id_user, id_user);
        destination.put(JsonFields.name, name);
        destination.put(JsonFields.lat_coord, lat_coord);
        destination.put(JsonFields.long_coord, long_coord);
    }

    private void getDeposits(Connection conn) throws SQLException{
        PreparedStatement pstmt = conn.prepareStatement("SELECT * FROM deposits");
        ResultSet resultSet = pstmt.executeQuery();

        while(resultSet.next()){
            listOfDeposits.add(new TableDeposit(
                    resultSet.getInt("id"), resultSet.getString("name"),
                    resultSet.getFloat("lat_coord"), resultSet.getFloat("long_coord")
            ));
        }

        listOfDeposits.sort(new Comparator<TableDeposit>() {
            @Override
            public int compare(TableDeposit d1, TableDeposit d2) {
                return (int) (findDistanceBetweenCoord(d2.getLat_coord(), d2.getLong_coord(), lat_coord, long_coord) -
                        findDistanceBetweenCoord(d1.getLat_coord(), d1.getLong_coord(), lat_coord, long_coord));
            }
        });
    }

    private float findDistanceBetweenCoord(Float x1, Float y1, Float x2, Float y2){
        return (float) Math.sqrt(
                Math.pow((x2 - x1), 2) + Math.pow((y2 - y1), 2)
        );
    }

    private void getProductNames(Connection conn) throws SQLException {
        JSONArray products = new JSONArray(order.get(JsonFields.listOfProducts).toString());
        Statement stmt = conn.createStatement();
        ResultSet resultSet = stmt.executeQuery("SELECT id, name FROM products");

        while (resultSet.next()) {
            int id_product = resultSet.getInt("id");
            String name = resultSet.getString("name");

            for (int index = 0; index < products.length(); index++) {
                JSONObject item = products.getJSONObject(index);

                if(id_product == item.getInt(JsonFields.id_product)){
                    mapProductIdToName.put(id_product, name);
                    break;
                }
            }
        }
    }

    private void createRoute(Connection conn) throws SQLException, ProductUnavailableAnymoreException {
        deposits = new JSONArray();
        JSONArray products = new JSONArray(order.get(JsonFields.listOfProducts).toString());

        PreparedStatement pstmt;
        for(TableDeposit deposit : listOfDeposits){//we take each deposit
            JSONObject depositJSON = new JSONObject(createDepositJSONForRoute(deposit).toString());
            JSONArray listOfProductsJSON = depositJSON.getJSONArray(JsonFields.listOfProducts);

            pstmt = conn.prepareStatement("SELECT * FROM prod_in_depo WHERE id_deposit = ?");
            pstmt.setInt(1, deposit.getId_deposit());
            ResultSet resultSet = pstmt.executeQuery();//we take all the products that exists in a deposit

            while(resultSet.next()){
                int id_product = resultSet.getInt("id_product");
                int quantity = resultSet.getInt("quantity");
                String name = mapProductIdToName.get(id_product);

                for(int index = 0; index < products.length(); index++){//iterate through our order
                    JSONObject item = products.getJSONObject(index);
                    JSONObject itemForList = new JSONObject();

                    if(item.getInt(JsonFields.id_product) == id_product){
                        itemForList.put(JsonFields.id_product, id_product);
                        itemForList.put(JsonFields.name, name);
                        int newQuantity = item.getInt(JsonFields.quantity) - quantity;

                        if(newQuantity > 0){
                            item.put(JsonFields.quantity, newQuantity);
                            itemForList.put(JsonFields.quantity, quantity);
                        }else{
                            itemForList.put(JsonFields.quantity, item.getInt(JsonFields.quantity));
                            products.remove(index);
                        }

                        listOfProductsJSON.put(itemForList);
                    }
                }
            }

            if(!depositJSON.getJSONArray(JsonFields.listOfProducts).isEmpty()) {
                deposits.put(depositJSON);
            }

            if(products.isEmpty()){
                return;
            }
        }

        if(!products.isEmpty()){
            throw new ProductUnavailableAnymoreException("One of the chosen products is not available anymore");
        }
    }

    private JSONObject createDepositJSONForRoute(TableDeposit deposit){
        JSONObject depositJSON = new JSONObject();

        depositJSON.put(JsonFields.id_deposit, deposit.getId_deposit());
        depositJSON.put(JsonFields.name, deposit.getName());
        depositJSON.put(JsonFields.lat_coord, deposit.getLat_coord());
        depositJSON.put(JsonFields.long_coord, deposit.getLong_coord());
        depositJSON.put(JsonFields.listOfProducts, new JSONArray());
        depositJSON.put(JsonFields.distance, findDistanceBetweenCoord(lat_coord, long_coord, deposit.getLat_coord(), deposit.getLong_coord()));

        return depositJSON;
    }


    private void createJsonRoute(){
        routeJson = new JSONObject();

        routeJson.put(JsonFields.destination, destination);
        routeJson.put(JsonFields.listOfDeposits, deposits);
        routeJson.put(JsonFields.listOfProducts, order.getJSONArray(JsonFields.listOfProducts));
    }

    private synchronized void run() throws SQLException, ProductUnavailableAnymoreException{
        Connection conn = Database.getConnection();

        getUserInformation(conn);
        getDeposits(conn);
        getProductNames(conn);

        createRoute(conn);
        createJsonRoute();
    }

    public JSONObject getRouteJson() {
        return routeJson;
    }
}