package com.company;

import com.google.gson.*;

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.Statement;

public class Main {

    public static void main(String[] args) {
        int pageNum = 0;
        String query = "https://api.hh.ru/vacancies?area=4&specialization=1&page=";

        HttpURLConnection connection = null;
        String url = "jdbc:mysql://localhost:3306/qwe?verifyServerCertificate=false&useSSL=false&characterEncoding=utf8";
        String user = "root";
        String passwd = "kargat";

        try {
            connection = (HttpURLConnection) new URL(query + Integer.toString(pageNum)).openConnection();
            connection.setRequestMethod("GET");
            connection.setUseCaches(false);
            connection.setConnectTimeout(250);
            connection.setReadTimeout(250);
            connection.connect();

            StringBuilder sb = new StringBuilder();
            int pages = 80;
            int found = 1500;
            int displayPerPage = 20;
            if (HttpURLConnection.HTTP_OK == connection.getResponseCode()) {
                BufferedReader in = new BufferedReader(
                        new InputStreamReader(connection.getInputStream(), "utf8"));
                sb.append(in.readLine());

                JsonParser parser = new JsonParser();
                JsonElement jsonElement = parser.parse(sb.toString());
                JsonObject vacancies = jsonElement.getAsJsonObject();
                pages = vacancies.get("pages").getAsInt();
                found = vacancies.get("found").getAsInt();
                connection.disconnect();
            }

            System.out.print("Connecting to database.........");
            Connection dataBaseConnect = DriverManager.getConnection(url, user, passwd);
            Statement statement = dataBaseConnect.createStatement();
            System.out.println("Connected!");

            Gson gson = new GsonBuilder().setPrettyPrinting().disableHtmlEscaping().create();
            for (int i = 0, id = 0; i < pages; i++, id += 20) {
                System.out.print("Reading page #" + Integer.toString(i) + ".........");
                connection = (HttpURLConnection) new URL(query + Integer.toString(i)).openConnection();
                connection.setRequestMethod("GET");
                connection.setUseCaches(false);
                connection.setConnectTimeout(500);
                connection.setReadTimeout(500);
                connection.connect();

                sb.setLength(0);
                if (HttpURLConnection.HTTP_OK == connection.getResponseCode()) {
                    BufferedReader in = new BufferedReader(
                            new InputStreamReader(connection.getInputStream(),"utf8"));
                    sb.append(in.readLine());

                    JsonParser parser = new JsonParser();
                    JsonElement jsonElement = gson.toJsonTree(parser.parse(sb.toString()));
                    JsonObject vacancies = jsonElement.getAsJsonObject();
                    JsonArray vacanciesArray = vacancies.getAsJsonArray("items");

                    if (i == (pages - 1)) {
                        displayPerPage = found - (pages - 1) * displayPerPage;
                    }
                    for (int j = 0; j < displayPerPage; j++) {
                        id += j;
                        JsonElement vacancy = vacanciesArray.get(j);

                        JsonObject vacancyObject = vacancy.getAsJsonObject();
                        JsonObject employerObject = vacancyObject.getAsJsonObject("employer");

                        String vacancyName =  vacancyObject.get("name").getAsString();
                        String employer = employerObject.get("name").getAsString();
                        String date = vacancyObject.get("published_at").getAsString().substring(0, 10);
                        try {
                            JsonObject salary = vacancyObject.getAsJsonObject("salary");
                            int money = salary.get("from").getAsInt();
                            String sql = String.format("INSERT INTO vacancies (name, employer_name, date, salary)" +
                                            " VALUES (\"%s\", \"%s\", \"%s\", %d)",
                                    vacancyName.replace("\"", "'"),
                                    employer.replace("\"", "'"), date, money);
                            statement.executeUpdate(sql);
                        } catch (Throwable cause) {
                            String sql = String.format("INSERT INTO vacancies (name, employer_name, date, salary)" +
                                            " VALUES (\"%s\", \"%s\", \"%s\", NULL)",
                                    vacancyName.replace("\"", "'"),
                                    employer.replace("\"", "'"), date);
                            statement.executeUpdate(sql);
                        }
                    }
                } else {
                    System.out.println("fail " + connection.getResponseCode() + ", " + connection.getResponseMessage());
                }
                connection.disconnect();
                System.out.println("Readed!");
            }
            dataBaseConnect.close();
        } catch (Throwable cause) {
            cause.printStackTrace();
        } finally {
            if (connection != null) {
                connection.disconnect();
            }
        }
    }
}