using System;
using System.Collections.Generic;
using System.Globalization;
using System.Linq;
using System.Security.Cryptography.X509Certificates;
using Interfaces;
using SQLite.Net;
using SQLite.Net.Platform.Win32;

namespace SQLiteRepository
{
    public class SQLiteRepository : IRepository
    {
        private readonly SQLiteConnection _connection;
        private readonly ILogger _logger;
        private string _path = "flexitimedb.db";

        public SQLiteRepository(ILogger logger)
        {
            if (logger == null) throw new ArgumentNullException(nameof(logger));
            _logger = logger;

            _connection = new SQLiteConnection(new SQLitePlatformWin32(), _path);

            _connection.CreateTable<CardUniqueId>();
            _connection.CreateTable<UserIdentity>();
            _connection.CreateTable<TimeLogDb>();
            _logger.Trace("Initialised SQLite Repository");
        }

        public UserList GetUsers(int pageNumber = -1, int pageSize = -1)
        {
            var ret = new UserList();
            List<UserIdentity> users;
            int userCount;
            if (pageNumber == -1 && pageSize == -1)
            {
                users = _connection.Query<UserIdentity>(SQLiteProcedures.GET_ALL_USERS);
                userCount = users.Count;
            }
            else
            {
                users = _connection.Query<UserIdentity>(SQLiteProcedures.GET_ALL_USERS_PAGINATE,
                    pageSize, (pageNumber - 1) * pageSize);
                userCount = _connection.ExecuteScalar<int>(SQLiteProcedures.GET_TOTAL_USER_COUNT);
            }

            if (!users.Any())
            {
                if (pageNumber == -1 && pageSize == -1)
                {
                    ret.PageNumber = 1;
                    ret.PageSize = 20;
                }
                else
                {
                    ret.PageNumber = pageNumber;
                    ret.PageSize = pageSize;
                }
                return ret;
            }

            foreach (var user in users)
            {
                var userObj = ChangeToUserObject(user);
                var cards = _connection.Query<CardUniqueId>(
                    SQLiteProcedures.GET_CARDS_BY_USER_ID,
                    user.Id);

                foreach (var card in cards)
                {
                    userObj.AssociatedIdentifiers.Add(new Identifier()
                    {
                        UniqueId = card.CardUId,
                        IsAssociatedToUser = true,
                        Id = card.Id
                    });
                }
                ret.Users.Add(userObj);
            }
            if (pageNumber == -1 && pageSize == -1)
            {
                ret.PageSize = 1; //TODO: switch to ret.UserCount
                ret.PageNumber = 1;
            }
            else
            {
                ret.PageSize = pageSize;
                ret.PageNumber = pageNumber;
            }
            ret.TotalUserCount = userCount;
            return ret;
        }

        public UserList Search(string searchParam)
        {
            _logger.Trace("Searching SQLite database for the term: {0}", searchParam);
            var ret = new UserList();
            searchParam = string.Format("%{0}%", searchParam);
            var users = _connection.Query<UserIdentity>(
                SQLiteProcedures.SEARCH_USER_LIST,
                searchParam, searchParam);

            _logger.Trace("Got {0} results for term: {1}", users.Count, searchParam);
            if (!users.Any())
            {
                ret.PageNumber = 1;
                ret.PageSize = 20;
                return ret;
            }

            foreach (var user in users)
            {
                var userObj = ChangeToUserObject(user);
                var cards = _connection.Query<CardUniqueId>(
                    SQLiteProcedures.GET_CARDS_BY_USER_ID,
                    user.Id);

                foreach (var card in cards)
                {
                    userObj.AssociatedIdentifiers.Add(new Identifier()
                    {
                        UniqueId = card.CardUId,
                        IsAssociatedToUser = true,
                        Id = card.Id
                    });
                }
                ret.Users.Add(userObj);
            }
            //TODO: figure out paging here. - should there be any?
            ret.PageSize = 20;
            ret.PageNumber = 1;

            return ret;
        }

        public User GetUser(int id)
        {
            var ret = new User();

            try
            {
                var users = _connection.Query<UserIdentity>(
                        SQLiteProcedures.GET_USER_BY_ID,
                        id);

                if (!users.Any()) return ret;

                var user = users.First();
                ret = ChangeToUserObject(user);
                var cards = _connection.Query<CardUniqueId>(
                    SQLiteProcedures.GET_CARDS_BY_USER_ID,
                    user.Id);

                foreach (var card in cards)
                {
                    ret.AssociatedIdentifiers.Add(new Identifier { UniqueId = card.CardUId, IsAssociatedToUser = true, Id = card.Id });
                }
            }
            catch (Exception ex)
            {
                _logger.Error(ex, "Error in GetUser with Id: {0}", id);
                ret.UserId = id;
                ret.FirstName = ret.LastName = string.Empty;
                ret.HoursPerWeek = -1.0f;
                ret.IsContractor = false;
                ret.AssociatedIdentifiers.Clear();
            }

            return ret;
        }
        //TODO: refac this as it duplicates a lot of code.
        public TimeLogList GetTimeLogs(int userId)
        {
            return GetTimeLogs(userId, DateTime.UtcNow);
        }

        public TimeLogList GetTimeLogs(int userId, DateTime selectedDate)
        {
            var ret = new TimeLogList { SelectedDate = selectedDate.Date };
            var calendarWeek = GetIso8601CalendarWeek(selectedDate);
            ret.CalendarWeek = calendarWeek;

            try
            {
                ret.TimeLogs = GetTimeLogList(userId, calendarWeek, selectedDate.Year);
            }
            catch (Exception ex)
            {
                _logger.Error(ex, "Error in GetTimeLogs with Id: {0} and selected date: {1}, Exception: {2}", userId, selectedDate, ex);
            }

            try
            {
                ret.HoursPerWeekMinutes = GetUserContractedHours(userId) * 60.0f;
            }
            catch (Exception ex)
            {
                _logger.Error(ex, "Error in GetUserContracterHours with Id: {0} and selected date: {1}, Exception: {2}", userId, selectedDate, ex);
            }

            return ret;
        }

        private float GetUserContractedHours(int userId)
        {
            var hoursQuery = _connection.Query<UserIdentity>(SQLiteProcedures.GET_USER_CONTRACTED_HOURS, userId);
            if (hoursQuery.Any())
            {
                return hoursQuery.First().HoursPerWeek;
            }
            return -1.0f;
        }

        public IdentifierList GetUnassignedIdentifierList()
        {
            var ret = new IdentifierList();
            var cardQuery = _connection.Query<CardUniqueId>(
                SQLiteProcedures.GET_UNASSIGNED_CARD_LIST,
                Constants.UNASSIGNED_CARD_USER_ID);

            foreach (var card in cardQuery)
            {
                ret.data.Add(new Identifier
                {
                    Id = card.Id,
                    IsAssociatedToUser = card.UserId_FK != Constants.UNASSIGNED_CARD_USER_ID,
                    UniqueId = card.CardUId
                });
            }
            return ret;
        }

        //TODO: Check time logs table on update to ensure associated cards/unique identifiers are removed/added as appropriate.
        public OperationResponse UpdateUser(User user, out int userIdResult)
        {
            //if(user.UserId <=0) return OperationResponse.FAILED;

            var ret = OperationResponse.NONE;
            var cardIds = new List<int>();

            //Get a list of current associated identifiers, convert into a list of Identifier Objects..
            var currentCards =
                _connection.Query<CardUniqueId>(SQLiteProcedures.GET_CARDS_BY_USER_ID, user.UserId)
                    .Select(x => new Identifier { Id = x.Id, IsAssociatedToUser = true, UniqueId = x.CardUId });
            var cardsToRemove = currentCards.Except(user.AssociatedIdentifiers).Select(x => x.Id).ToList();

            #region GetUnique Identifiers
            foreach (var card in user.AssociatedIdentifiers)
            {
                var existingCard = _connection.Query<CardUniqueId>(
                    SQLiteProcedures.GET_CARDS_BY_UNIQUE_ID, card.UniqueId);

                if (!existingCard.Any())
                {
                    var cardInsert = new CardUniqueId { CardUId = card.UniqueId, UserId_FK = -1 };
                    _connection.Insert(cardInsert);
                    cardIds.Add(cardInsert.Id);
                    if (ret < OperationResponse.CREATED)
                        ret = OperationResponse.CREATED;    //only change it if my status supercedes.
                }
                else
                {
                    cardIds.Add(existingCard.First().Id);
                    if (ret < OperationResponse.UPDATED)
                        ret = OperationResponse.UPDATED;
                }
            }
            #endregion

            #region Update/Create User
            int userId;

            if (user.UserId != -1)
            {
                //edit..
                _connection.Query<UserIdentity>(
                    "update UserIdentity set FirstName=?, LastName=?, HoursPerWeek=?,IsContractor=? where Id=?",
                    user.FirstName,
                    user.LastName,
                    user.HoursPerWeek,
                    user.IsContractor,
                    user.UserId
                );
                userId = user.UserId;
            }
            else
            {
                var userInsert = new UserIdentity
                {
                    FirstName = user.FirstName,
                    LastName = user.LastName,
                    HoursPerWeek = user.HoursPerWeek,
                    IsContractor = user.IsContractor
                };
                _connection.Insert(userInsert);
                userId = userInsert.Id;
                if (ret < OperationResponse.CREATED)
                    ret = OperationResponse.CREATED;
            }
            #endregion

            #region Update Card/Unique Id entries.
            foreach (var cardId in cardIds)
            {
                _connection.Query<CardUniqueId>(
                    SQLiteProcedures.UPDATE_CARD_USER_ID,
                    userId, cardId);
            }
            foreach (var card in cardsToRemove)
            {
                _connection.Query<CardUniqueId>(
                    SQLiteProcedures.UPDATE_CARD_USER_ID,
                    -1, card);
            }
            #endregion

            userIdResult = userId;
            return ret;
        }

        public OperationResponse LogEventTime(Identifier identifier, out int logId)
        {
            var cardIdQuery = _connection.Query<CardUniqueId>(
                   SQLiteProcedures.GET_CARDS_BY_UNIQUE_ID,
                   identifier.UniqueId);

            #region Get/Insert the PK Id Identifier to associate the time log to.
            var ident = new CardUniqueId();
            if (!cardIdQuery.Any())
            {
                //new card, create it!
                ident.UserId_FK = -1;
                ident.CardUId = identifier.UniqueId;
                _connection.Insert(ident);
            }
            else
            {
                //TODO: log when more than one comes back. should NEVER happen but....
                ident = cardIdQuery.First();
            }
            #endregion

            // Get The User Direction (are they going in or out)?
            var logDirection = GetLogDirection(ident.UserId_FK);

            #region Get the current time (for swiping). and calendar week/year to help recall the data.
            var logTime = DateTime.UtcNow;
            var calendarWeek = GetIso8601CalendarWeek(logTime);
            var year = logTime.Year;
            #endregion

            //TODO: Handle When the identifier is assigned to a user (identifier has -1)
            //when identifier not assigned to user, just store it anyway and carry on, can update later.

            var timeLog = new TimeLogDb
            {
                SwipeEventDateTime = DateTime.UtcNow,
                UserId_FK = ident.UserId_FK,
                IdentifierId = ident.Id,
                Direction = logDirection,
                Year = year,
                CalendarWeek = calendarWeek
            };

            _connection.Insert(timeLog);
            logId = timeLog.Id;

            return OperationResponse.SUCCESS;
        }

        private List<DailyLogs> GetTimeLogList(int userId, int calendarWeek, int year)
        {
            var timeLogList = _connection.Query<TimeLogDb>(
                SQLiteProcedures.GET_TIMELOGS,
                userId, calendarWeek, year);

            var timeLogs = timeLogList.Select(x => new TimeLog
            {
                Id = x.Id,
                CalendarWeek = x.CalendarWeek,
                Direction = (LogDirection)x.Direction,
                IdentifierId = x.IdentifierId,
                EventTime = x.SwipeEventDateTime,
                UserId = x.UserId_FK,
                Year = x.Year
            }).ToList();

            var dict = new Dictionary<DayOfWeek, DailyLogs>();
            var logList = new List<DailyLogs>();

            //make sure each day of the week is accounted for in the dictionary.
            foreach (DayOfWeek day in Enum.GetValues(typeof(DayOfWeek)))
            {
                dict.Add(day, new DailyLogs());
            }

            //add the logs to the respective day of the week.
            foreach (var log in timeLogs)
            {
                dict[log.EventTime.DayOfWeek].Logs.Add(log);
            }
            var logGroups = timeLogs.GroupBy(x => x.EventTime.DayOfWeek);
            foreach (var group in logGroups)
            {
                var groupLogs = group.ToList();
                var dailyLog = new DailyLogs
                {
                    Logs = groupLogs,
                    Day = group.Key,
                    DayOfWeek = group.Key.ToString()
                };
                dailyLog.DailyTotal = CalculateDailyTotal(dailyLog);
                logList.Add(dailyLog);
            }
            foreach (DayOfWeek day in Enum.GetValues(typeof(DayOfWeek)))
            {
                if (logList.Any(x => x.Day == day)) continue;
                var dailyLog = new DailyLogs {Day = day, DayOfWeek = day.ToString()};
                logList.Add(dailyLog);
            }

            foreach (var dailyCollection in dict)
            {
                dailyCollection.Value.DailyTotal = CalculateDailyTotal(dailyCollection.Value);
            }

            return logList.OrderBy(x => ((int) x.Day + 6)%7).ToList();
        }

        private double CalculateDailyTotal(DailyLogs dailyLogs)
        {
            var totalInTime = TimeSpan.FromSeconds(0);
            var logs = dailyLogs.Logs.OrderBy(x => x.Id).ToArray();
            var totalCalcMax = IsOdd(logs.Length) ? logs.Length - 1 : logs.Length;
            for (int i = 0; i < totalCalcMax; i += 2)
            {
                totalInTime += (logs[i + 1].EventTime - logs[i].EventTime);
            }
            return Math.Round(totalInTime.TotalMinutes, 2);
        }

        /// <summary>
        /// determines if the number is an odd or even value
        /// </summary>
        /// <param name="value">number to determine is odd or even</param>
        /// <returns>true - number is odd</returns>
        private bool IsOdd(int value)
        {
            return value % 2 != 0;
        }

        /// <summary>
        /// Get the new direction for the user based on previous entry logs in the system.
        /// </summary>
        /// <remarks>
        /// If the user has not logged in today, the direction will be In.
        /// If the user has logged in already today, the direction will be the opposite of the last
        /// recorded log direction. ("out" if "in", "in" if "out")
        /// </remarks>
        /// <param name="userId">Id of the user to get the log direction of.</param>
        /// <returns><see cref="LogDirectionDb"/> indicating what direction the new log is.</returns>
        private LogDirectionDb GetLogDirection(int userId)
        {
            var logDirection = LogDirectionDb.UNKNOWN;
            if (userId != -1)
            {
                var lastEntry = _connection.Query<TimeLogDb>(
                    SQLiteProcedures.GET_LAST_TIMELOG_DIRECTION,
                    userId);
                if (lastEntry.Any())
                {
                    var lastLog = lastEntry.First();
                    // See if the datetime retrieved is yesterday. If yesterday, logDirection = true (in)
                    if (IsLogDateTimeYesterdayOrOlder(lastLog.SwipeEventDateTime.DateTime))
                    {
                        logDirection = LogDirectionDb.IN;
                    }
                    else
                    {
                        // we have a time log from today already, so just do the opposite of what we last did!
                        if (lastLog.Direction == LogDirectionDb.IN)
                            logDirection = LogDirectionDb.OUT;
                        else if (lastLog.Direction == LogDirectionDb.OUT)
                            logDirection = LogDirectionDb.IN;
                    }
                }
                else
                {
                    //assume its the first then!
                    logDirection = LogDirectionDb.IN;
                }
            }
            return logDirection;
        }

        /// <summary>
        /// Get the calendar week of the year according to the ISO8601 standard (starts monday).
        /// </summary>
        /// <param name="date">the date to get the calendar week of.</param>
        /// <returns>the calendar week of the year in integer form (1-52)</returns>
        private int GetIso8601CalendarWeek(DateTime date)
        {
            var day = CultureInfo.InvariantCulture.Calendar.GetDayOfWeek(date);
            if (day >= DayOfWeek.Monday && day <= DayOfWeek.Wednesday)
            {
                date = date.AddDays(3);
            }
            return CultureInfo.InvariantCulture.Calendar.GetWeekOfYear(date, CalendarWeekRule.FirstFourDayWeek,
                DayOfWeek.Monday);
        }

        /// <summary>
        /// Check whether the specified DateTime is from yesterday or older.
        /// </summary>
        /// <param name="dt">the DateTime object to check is yesterday or older</param>
        /// <returns>true - is yesterday or older.</returns>
        private bool IsLogDateTimeYesterdayOrOlder(DateTime dt)
        {
            return dt.Date.CompareTo(DateTime.Today.Date) < 0;
        }

        private User ChangeToUserObject(UserIdentity user)
        {
            return new User
            {
                UserId = user.Id,
                FirstName = user.FirstName,
                LastName = user.LastName,
                HoursPerWeek = user.HoursPerWeek,
                IsContractor = user.IsContractor
            };
        }
    }
}