ophelias-oasis/OpheliasOasis/Managers/DatabaseManager.cs

using System.Data.SQLite;
using Ophelias.Models;

namespace Ophelias.Managers
{
    internal class DatabaseManager : IDisposable
    {
        internal SQLiteConnection con = new SQLiteConnection("OpheliasOasis.sqlite");
        internal SQLiteCommand? cur;

        internal DatabaseManager()
        {
            cur = new SQLiteCommand(con);
        }
        internal void Connect()
        {
            con.Open();
        }
        internal void Close()
        {
            con.Close();
            con.Dispose();
        }
        internal void InitializeTables()
        {
            if (cur == null)
                return;

            string tableCommands =
                @"CREATE TABLE IF NOT EXISTS [transactions] (
                  [ID] INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT,
                  [Rate] INTEGER NOT NULL,
                  [Owed] INTEGER NOT NULL,
                  [Penalty] INTEGER NULL,
                  [Multiplier] INTEGER NOT NULL,
                  [RefundAmount] INTEGER NOT NULL,
                  [IsLate] BOOLEAN NOT NULL CHECK ([IsLate] IN (0,1)),
                  [PaidOff] BOOLEAN NOT NULL CHECK ([PaidOff] IN (0,1)),
                  [PayBy] TEXT NOT NULL,
                  [PaidOn] TEXT NULL);

                CREATE TABLE IF NOT EXISTS [reservations] (
                  [ID] INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT,
                  [RoomID] INTEGER NOT NULL,
                  [GuestID] INTEGER NOT NULL,
                  [TransactionID] INTEGER NOT NULL,
                  [IsNoShow] BOOLEAN NOT NULL CHECK ([IsNoShow] IN (0,1)),
                  [Type] INTEGER NOT NULL CHECK ([Type] IN (0,1,2,3)),
                  [Status] INTEGER NOT NULL CHECK ([Status] IN (0,1,2,3)),
                  [CreationDate] TEXT NOT NULL,
                  [StartDate] TEXT NOT NULL,
                  [EndDate] TEXT NOT NULL,
                  [CheckIn] TEXT NOT NULL,
                  [CheckOut] TEXT NOT NULL,
                  [DateChanged] TEXT NOT NULL,
                  FOREIGN KEY ([RoomID]) REFERENCES ROOMS(ID),
                  FOREIGN KEY ([GuestID]) REFERENCES GUESTS(ID),
                  FOREIGN KEY ([TransactionID]) REFERENCES TRANSACTIONS(ID));

                CREATE TABLE IF NOT EXISTS [guests] (
                  [ID] INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT,
                  [Fname] TEXT NOT NULL,
                  [Lname] TEXT NOT NULL,
                  [Email] TEXT NULL,
                  [Phone] TEXT NULL,
                  [CreditCard] TEXT NULL,
                  [CCV] TEXT NULL,
                  [CCExpiration] TEXT NULL);
  
                CREATE TABLE IF NOT EXISTS [rooms] (
                  [ID] INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT);

                CREATE TABLE IF NOT EXISTS [rates] (
                  [ID] INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT,
                  [Rate] INTEGER NOT NULL,
                  [DateSet] TEXT NOT NULL);";

            cur.CommandText = tableCommands;
            cur.ExecuteNonQuery();
        }

        internal void InitializeRoomsTable()
        {
            if (cur == null)
                return;

            // Initialize Rooms
            for (int i = 1; i < 46; i++)
            {
                cur.CommandText = $"INSERT INTO ROOMS (ID) VALUES ({i});";
                cur.ExecuteNonQuery();
            }
        }
        public void Dispose()
        {
            Close();
        }
    }

    internal static class DatabaseFunctions
    {
        internal static int GetLastId(SQLiteCommand cmd, string tableName)
        {
            if (cmd == null)
                throw new NotImplementedException();

            cmd.CommandText = $"SELECT SEQ FROM sqlite_sequence WHERE name=\"{tableName}\";";
            cmd.ExecuteNonQuery();
            using (SQLiteDataReader reader = cmd.ExecuteReader())
            {
                reader.Read();
                return reader.GetInt32(0);
            }
        }
        internal static int GetThirtyDayOccupancy(SQLiteCommand cmd, DateTime start)
        {
            if (cmd == null)
                throw new NotImplementedException();

            cmd.CommandText = $@"SELECT COUNT(*) 
                                 FROM reservations 
                                 WHERE StartDate => date({start.ToString("yyyy-MM-dd")}) AND EndDate <= date({start.AddDays(30).ToString("yyyy-MM-dd")});";
            cmd.ExecuteNonQuery();
            int thirtyDayOcc;
            using (SQLiteDataReader reader = cmd.ExecuteReader())
            {
                reader.Read();
                thirtyDayOcc = reader.GetInt32(0);
            }
            return thirtyDayOcc;
        }
    }
    internal static class QueryBuilder
    {

        internal static string? UpdateTransaction(int id,
            double? rate = null, double? owed = null, double? penalty = null,
            double? multiplier = null, double? refund = null, bool? isLate = null,
            bool? paidOff = null, DateTime? paidBy = null, DateTime? paidOn = null)
        {
            List<string> queryComponents = new List<string>();
            string query = "UPDATE transactions SET";

            if (rate.HasValue)
                queryComponents.Add($"Rate = {rate}");
            if (owed.HasValue)
                queryComponents.Add($"Owed = {owed}");
            if (penalty.HasValue)
                queryComponents.Add($"Penalty = {penalty}");
            if (multiplier.HasValue)
                queryComponents.Add($"Multiplier = {multiplier}");
            if (refund.HasValue)
                queryComponents.Add($"Refund = {refund}");
            if (isLate.HasValue)
                queryComponents.Add($"IsLate = {Convert.ToInt32(isLate)}");
            if (paidOff.HasValue)
                queryComponents.Add($"PaidOff = {Convert.ToInt32(paidOff)}");
            if (paidBy.HasValue)
                queryComponents.Add($"PaidBy = {paidBy.Value.ToString("yyyy-MM-dd")}");
            if (paidOn.HasValue)
                queryComponents.Add($"PaidOn = {paidOn.Value.ToString("yyyy-MM-dd")}");

            if (queryComponents.Count == 0)
                query += " " + string.Join(", ", queryComponents) + " " + $"WHERE ID = {id};";
            else
                return null;

            return query;
        }

        internal static string? UpdateReservation(int id,
            int? roomid = null, int? guestid = null, int? transactionid = null, bool? isnoshow = null, ReservationType? type = null,
            ReservationStatus? status = null, DateTime? creationdate = null, DateTime? startdate = null, DateTime? enddate = null,
            DateTime? checkin = null, DateTime? checkout = null, DateTime? datechanged = null)
        {
            List<string> queryComponents = new List<string>();
            string query = "UPDATE reservations SET";

            if (roomid.HasValue)
                queryComponents.Add($"RoomID = {roomid}");
            if (guestid.HasValue)
                queryComponents.Add($"GuestID = {guestid}");
            if (transactionid.HasValue)
                queryComponents.Add($"TransactionID = {transactionid}");
            if (isnoshow.HasValue)
                queryComponents.Add($"IsNoShow = {Convert.ToInt32(isnoshow)}");
            if (type.HasValue)
                queryComponents.Add($"Type = {(int)type}");
            if (status.HasValue)
                queryComponents.Add($"Type = {(int)status}");
            if (creationdate.HasValue)
                queryComponents.Add($"CreationDate = {creationdate.Value.ToString("yyyy-MM-dd")}");
            if (startdate.HasValue)
                queryComponents.Add($"StartDate = {startdate.Value.ToString("yyyy-MM-dd")}");
            if (enddate.HasValue)
                queryComponents.Add($"EndDate = {enddate.Value.ToString("yyyy-MM-dd")}");
            if (checkin.HasValue)
                queryComponents.Add($"CheckIn = {checkin.Value.ToString("yyyy-MM-dd")}");
            if (checkout.HasValue)
                queryComponents.Add($"CheckOut = {checkout.Value.ToString("yyyy-MM-dd")}");
            if (datechanged.HasValue)
                queryComponents.Add($"CheckOut = {datechanged.Value.ToString("yyyy-MM-dd")}");

            if (queryComponents.Count == 0)
                query += " " + string.Join(", ", queryComponents) + " " + $"WHERE ID = {id};";
            else
                return null;

            return query;
        }
    }
}