using Npgsql;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using PhilExampleCrawler.DataBase.Models;
using System.Data;

namespace PhilExampleCrawler.DataBase
{
    public class CrawlSessionAccess
    {
        private readonly string _dbconn;

        public CrawlSessionAccess(DBSettings dbSettings)
        {
            _dbconn = dbSettings.ToString();
        }

        public async Task<DB_CrawlSession?> AddCrawlSessionAsync(DB_CrawlSession newCS)
        {
            DB_CrawlSession? cs = null;
            try
            {
                using var conn = new NpgsqlConnection(_dbconn);
                conn.Open();

                var cmd = conn.CreateCommand();
                cmd.CommandText = SQL_InsertCrawlSession(newCS);
                if (await cmd.ExecuteScalarAsync() is int csID)
                    cs = new DB_CrawlSession(id: csID,
                                             user_id: newCS.UserID,
                                             keywords: newCS.Keywords,
                                             location_text: newCS.LocationText,
                                             category_id: newCS.CategoryID,
                                             radius_km: newCS.RadiusKM,
                                             minPrice: newCS.MinPrice,
                                             maxPrice: newCS.MaxPrice,
                                             isPrivate: newCS.IsPrivate,
                                             isCommerial: newCS.IsCommercial);

                conn.Close();
            }
            catch (Exception ex)
            {
                Console.WriteLine(ex);
                //TODO: log
            }
            return cs;
        }


        public async Task<bool> UpdateCrawlSessionAsync(DB_CrawlSession cs)
        {
            try
            {
                using var conn = new NpgsqlConnection(_dbconn);
                conn.Open();

                var cmd = conn.CreateCommand();
                cmd.CommandText = SQL_UpdateCrawlSession(cs);
                if (await cmd.ExecuteNonQueryAsync() > 0)
                    return true;

                conn.Close();
            }
            catch (Exception ex)
            {
                Console.WriteLine(ex);
                //TODO: log
            }
            return false;
        }

        public async Task<List<DB_CrawlSession>> GetCrawlSessionsAsync(int userID)
        {
            List<DB_CrawlSession> l = new();
            try
            {
                using var conn = new NpgsqlConnection(_dbconn);
                conn.Open();

                var cmd = conn.CreateCommand();
                cmd.CommandText = SQL_SeletCrawlSession(userID);
                using (var dr = await cmd.ExecuteReaderAsync())
                    while (await dr.ReadAsync())
                        l.Add(new DB_CrawlSession(id: dr.GetInt32("id"),
                                                  user_id: userID,
                                                  keywords: dr.GetString("keywords"),
                                                  location_text: dr.GetString("location_text"),
                                                  category_id: dr.GetInt32("category_id"),
                                                  radius_km: dr.GetInt32("radius_km"),
                                                  minPrice: dr.GetInt32("min_price"),
                                                  maxPrice: dr.GetInt32("max_price"),
                                                  isPrivate: dr.GetBoolean("is_private"),
                                                  isCommerial: dr.GetBoolean("is_commercial")));

                conn.Close();
            }
            catch (Exception ex)
            {
                Console.WriteLine(ex);
                //TODO: log
            }
            return l;
        }

        public async Task<List<DB_CrawlSession>> GetAllCrawlSessionsAsync()
        {
            List<DB_CrawlSession> l = new();
            try
            {
                using var conn = new NpgsqlConnection(_dbconn);
                conn.Open();

                var cmd = conn.CreateCommand();
                cmd.CommandText = SQL_SeletAllCrawlSessions();
                using (var dr = await cmd.ExecuteReaderAsync())
                    while (await dr.ReadAsync())
                        l.Add(new DB_CrawlSession(id: dr.GetInt32("id"),
                                                  user_id: dr.GetInt32("user_id"),
                                                  keywords: dr.GetString("keywords"),
                                                  location_text: dr.GetString("location_text"),
                                                  category_id: dr.GetInt32("category_id"),
                                                  radius_km: dr.GetInt32("radius_km"),
                                                  minPrice: dr.GetInt32("min_price"),
                                                  maxPrice: dr.GetInt32("max_price"),
                                                  isPrivate: dr.GetBoolean("is_private"),
                                                  isCommerial: dr.GetBoolean("is_commercial")));

                conn.Close();
            }
            catch (Exception ex)
            {
                Console.WriteLine(ex);
                //TODO: log
            }
            return l;
        }

        public async Task<bool> RemoveCrawlSessionAsync(int crawlSessionID)
        {
            bool deleted = false;
            try
            {
                using var conn = new NpgsqlConnection(_dbconn);
                conn.Open();

                var cmd = conn.CreateCommand();
                cmd.CommandText = SQL_DeleteCrawlSession(crawlSessionID);
                await cmd.ExecuteNonQueryAsync();
                deleted = true;

                conn.Close();
            }
            catch (Exception ex)
            {
                Console.WriteLine(ex);
                //TODO: log
            }
            return deleted;
        }


        public async Task<List<DB_Insertion>> AddInsertionsAsync(IEnumerable<DB_Insertion> insertions)
        {
            List<DB_Insertion> l = new();

            if (!insertions.Any())
                return l;

            try
            {
                using var conn = new NpgsqlConnection(_dbconn);
                conn.Open();

                var cmd = conn.CreateCommand();
                foreach(var i in insertions)
                {
                    cmd.CommandText = SQL_InsertInsertion(i.Href, i.CrawlSessionID, i.Name, i.PostCode, i.LocationStr, i.Price, i.Is_VB,
                                                          i.Date, i.IsTopAd, i.IsHighlight, i.IsRequest);
                    if (await cmd.ExecuteNonQueryAsync() > 0)
                        l.Add(new DB_Insertion(i));
                }
                conn.Close();
            }
            catch (Exception ex)
            {
                Console.WriteLine(ex);
                //TODO: log
            }
            return l;
        }

        public async Task<List<DB_Insertion>> GetInsertions(int userID, int? limitPerCrawlSession = 5)
        {
            List<DB_Insertion> ins = new();
            try
            {
                using var conn = new NpgsqlConnection(_dbconn);
                conn.Open();

                var cmd = conn.CreateCommand();
                cmd.CommandText = SQL_SeletAllCrawlSessionIDs(userID);

                //crawl session ids
                List<int> csIDs = new();
                using (var dr = await cmd.ExecuteReaderAsync())
                    while (await dr.ReadAsync())
                        csIDs.Add(dr.GetInt32("id"));

                //insertions
                foreach (int csID in csIDs)
                {
                    cmd.CommandText = SQL_SelectInsertions(csID, limitPerCrawlSession);
                    using var dr = await cmd.ExecuteReaderAsync();
                    while (await dr.ReadAsync())
                        ins.Add(new DB_Insertion(href: dr.GetString("href"),
                                                 crawlSessionID: csID,
                                                 name: dr.GetString("name"),
                                                 postCode: dr.ReadNullableInt("post_code"),
                                                 locationStr: dr.ReadNullableString("location_text"),
                                                 price: dr.GetDecimal("price"),
                                                 is_vb: dr.GetBoolean("is_vb"),
                                                 date: dr.ReadNullableDateTime("date"),
                                                 isTopAd: dr.GetBoolean("is_topad"),
                                                 isHighlight: dr.GetBoolean("is_highlight"),
                                                 isRequest: dr.GetBoolean("is_request")));
                }

                conn.Close();
            }
            catch (Exception ex)
            {
                Console.WriteLine(ex);
                //TODO: log
            }
            return ins;
        }




        #region SQLQueries
        private static string SQL_InsertCrawlSession (DB_CrawlSession cs) 
            => $"INSERT INTO " +
                    "crawl_session" +
                    "(user_id, keywords, location_text, category_id, radius_km, min_price, max_price, is_private, is_commercial)" +
               " VALUES " +
                        "(" +
                    $"{cs.UserID}," +
                    $"'{cs.Keywords}'," +
                    $"'{cs.LocationText}'," +
                    $"{cs.CategoryID}," +
                    $"{cs.RadiusKM}," +
                    $"{cs.MinPrice}," +
                    $"{cs.MaxPrice}," +
                    $"{cs.IsPrivate}," +
                    $"{cs.IsCommercial}" +
                        ")" +
               " RETURNING id;";
        private static string SQL_UpdateCrawlSession(DB_CrawlSession cs)
            => "UPDATE " +
                    "crawl_session" +
              " SET " +
                   $"keywords = '{cs.Keywords}'," +
                   $"location_text = '{cs.LocationText}'," +
                   $"category_id = {cs.CategoryID}," +
                   $"radius_km = {cs.RadiusKM}," +
                   $"min_price = {cs.MinPrice}," +
                   $"max_price = {cs.MaxPrice}," +
                   $"is_private = {cs.IsPrivate}," +
                   $"is_commercial = {cs.IsCommercial}" +
            " WHERE " +
                    $"id = {cs.ID}" +
               $" and user_id = {cs.UserID};";
        private static string SQL_SeletCrawlSession(int userID) => $"SELECT " +
                                                                        "id," +
                                                                        "keywords," +
                                                                        "location_text," +
                                                                        "category_id," +
                                                                        "radius_km," +
                                                                        "min_price," +
                                                                        "max_price," +
                                                                        "is_private," +
                                                                        "is_commercial" +
                                                                   " FROM " +
                                                                        "crawl_session" +
                                                                   " WHERE " +
                                                                        $"user_id = {userID};";
        private static string SQL_SeletAllCrawlSessions() => $"SELECT " +
                                                                "id," +
                                                                "user_id," +
                                                                "keywords," +
                                                                "location_text," +
                                                                "category_id," +
                                                                "radius_km," +
                                                                "min_price," +
                                                                "max_price," +
                                                                "is_private," +
                                                                "is_commercial" +
                                                            " FROM " +
                                                                "crawl_session;";
        private static string SQL_SeletAllCrawlSessionIDs(int userID) 
            => $"SELECT " +
                    "id" +
               " FROM " +
                    "crawl_session" +
               " WHERE " +
                    $"user_id = {userID};";
        private static string SQL_DeleteCrawlSession(int crawlSessionID) 
            => $"DELETE FROM " +
                    "crawl_session" +
               " WHERE " +
                   $"id = {crawlSessionID}";
        private static string SQL_InsertInsertion(string href, int crawlSessionID, string name, int? postCode, string? locStr, decimal price, bool is_vb, 
                                                  DateTime? date, bool isTopAd, bool isHighlight, bool isRequest)
             => $"INSERT INTO " +
                     "insertion" +
                     "(href, crawl_session_id, name, post_code, location_text, price, is_vb, date, " +
                      "is_topad, is_highlight, is_request)" +
                " VALUES " +
                         "(" +
                     $"'{href}'," +
                     $"{crawlSessionID}," +
                     $"'{name}'," +
                     $"{Extensions.WriteNullableInt(postCode)}," +
                     $"{Extensions.WriteNullableString(locStr)}," +
                     $"{price}," +
                     $"{is_vb}," +
                     $"{Extensions.WriteNullableDateTime(date)}," +
                     $"{isTopAd}," +
                     $"{isHighlight}," +
                     $"{isRequest}" +
                         ");";
        private static string SQL_SelectInsertions(int crawlSessionID, int? limit)
            => $"SELECT " +
                    "href," +
                    "name," +
                    "post_code," +
                    "location_text," +
                    "price," +
                    "is_vb," +
                    "date," +
                    "is_topad," +
                    "is_highlight," +
                    "is_request" +
               " FROM " +
                    "insertion" +
               " WHERE " +
                    $"crawl_session_id = {crawlSessionID}" +
                " and is_topad = false" +
                " and is_highlight = false" +       //TODO: these 3 booleans are untested
                " and is_request = false" +
               " ORDER BY id desc " +
              $" LIMIT {limit?.ToString() ?? "null"}";
        #endregion
    }
}