using System;
using System.Linq;
using System.Net;
using HtmlAgilityPack;
using MySql.Data.MySqlClient;

namespace Grabber
{
    class Parser
    {
        string _website;
        int _tempID = 1;
        int _dateID = 1;
        int _counter = 0;
        int _day = 0;
        int _nodeCounter = 0;
        string _error = null;
        WebClient _wclient = new WebClient();
        HtmlDocument _doc = new HtmlDocument();

        public Parser(string town)
        {
            try //исключаем некорректный ввод или отсутствие связи
            {
                _website = _wclient.DownloadString($"https://yandex.ru/pogoda/{town}");
                _error = null;
                _doc.LoadHtml(_website);
                SelectData();
            }
            catch
            {
                _error = "error";
                SelectData();
            }
        }

        private void SelectData()
        {
            if (_error == "error") //проверка наличия ошибки ввода или отсутствия связи
            {
                SetData("UPDATE weather SET town='error' WHERE id=2");
            }
            else
            {
                string[] div = { "//div [@class='temp fact__temp']",
                "//div [@class='temp forecast-briefly__temp forecast-briefly__temp_day']",
                "//div [@class='temp forecast-briefly__temp forecast-briefly__temp_night']"}; //создаем массив с html узлами
                foreach (string str in div)
                {
                    foreach (string query in GetWeather(str))
                    {
                        SetData(query); // записываем значения температуры в БД
                        SetData(GetDate()); // записываем значения температуры в БД
                    }
                    _day = 0;
                    _counter++;
                }
            }
        }

        private void SetData (string query)
        {
            string connmysql = "server=localhost;user=root;database=grabber;password=root;";
            MySqlConnection conn = new MySqlConnection(connmysql);
            conn.Open();
            MySqlCommand command = new MySqlCommand(query, conn);
            command.ExecuteNonQuery();
            conn.Close();
        }

        private string[] GetWeather(string div)
        {
            HtmlNodeCollection nodes = _doc.DocumentNode.SelectNodes(div); // ищем узлы html
            _nodeCounter = nodes.Count();
            string[] temperatureArray = new string[_nodeCounter];
            int i = 0;
            foreach (HtmlNode node in nodes)
            {
                var temperatureNode = node.SelectSingleNode("span [@class='temp__value']").InnerText;
                string query = $"UPDATE weather SET temp = '{temperatureNode}' WHERE id ={Convert.ToString(_tempID)}";
                temperatureArray[i] = query;
                i++;
                _tempID++;
            }
            return temperatureArray;
        }

        private string GetDate()
        {
            DateTime date = DateTime.Today.AddDays(_day);
            string query = $"UPDATE weather SET descriptor = '{date.ToString("d")}' WHERE id={_dateID}";
            _dateID++;
            _day++;
            return query;
        }

        public static string GetTown ()
        {
            string connmysql = "server=localhost;user=root;database=grabber;password=root;";
            MySqlConnection conn = new MySqlConnection(connmysql);
            conn.Open();
            string query = "SELECT town FROM weather WHERE id=1";
            MySqlCommand comm = new MySqlCommand(query, conn);
            string town = comm.ExecuteScalar().ToString();
            comm.ExecuteNonQuery();
            conn.Close();
            return town;
        }
    }
}