using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using ConstructionCompanyPsqlImplement.Models;
using ConstructionCompanyContracts.BindingModels;
using Microsoft.EntityFrameworkCore;
using Npgsql;
using ConstructionCompanyDataModels.Enums;

namespace ConstructionCompanyPsqlImplement
{
    public class ConstructionCompanyDatabase
    {
        static string connectionString = "Server=172.20.10.10;Port=5432;Database=ConstructionCompanyForwardEngineerd;User Id=postgres;Password=postgres;";

        private static ConstructionCompanyDatabase? _instance;
        private List<Material> _materials = new List<Material>();
        private List<Employee> _employees = new List<Employee>();
        private List<Position> _positions = new List<Position>();
        private List<Order> _orders = new List<Order>();
        private List<EmployeeOrder> _employeeOrders = new List<EmployeeOrder>();
        private List<MaterialOrder> _materialOrders = new List<MaterialOrder>();
        public List<Material> Materials 
        {
            get
            {
                refreshDb();
                return _materials;
            }
        }
        public List<Employee> Employees
        {
            get
            {
                refreshDb();
                return _employees;
            }
        }
        public List<Position> Positions
        {
            get
            {
                refreshDb();
                return _positions;
            }
        }
        public List<Order> Orders
        {
            get
            {
                refreshDb();
                return _orders;
            }
        }

        public List<EmployeeOrder> EmployeeOrders
        {
            get
            {
                refreshDb();
                return _employeeOrders;
            }
        }

        public List<MaterialOrder> MaterialOrders
        {
            get
            {
                refreshDb();
                return _materialOrders;
            }
        }

        public static ConstructionCompanyDatabase GetInstance()
        {
            if (_instance == null)
            {
                _instance = new ConstructionCompanyDatabase();
            }
            return _instance;
        }

        public void ExecuteSql(string commandString)
        {
            using var connection = new NpgsqlConnection(connectionString);
            connection.Open();
            using var command = connection.CreateCommand();
            command.CommandText = commandString;
            command.ExecuteNonQuery();
            refreshDb();
            connection.Close();
        }

        private void refreshDb()
        {
            _materials.Clear();
            _positions.Clear();
            _employees.Clear();
            _orders.Clear();
            _employeeOrders.Clear();
            _materialOrders.Clear();
            using var connection = new NpgsqlConnection(connectionString);
            connection.Open();

            using var commandMaterials = connection.CreateCommand();
            commandMaterials.CommandText = "SELECT * FROM material;";
            using var readerMaterials =  commandMaterials.ExecuteReader();
            while (readerMaterials.Read())
            {
                int id = readerMaterials.GetInt32(0);
                string name = readerMaterials.GetString(1);
                int quantity = readerMaterials.GetInt32(2);
                Material? mat = Material.Create(new MaterialBindingModel { Id = id, MaterialName = name, Quantity = quantity });
                if (mat != null) _materials.Add(mat);
            }
            readerMaterials.Close();

            using var commandPositions = connection.CreateCommand();
            commandPositions.CommandText = "SELECT * FROM position;";
            using var readerPositions = commandPositions.ExecuteReader();
            while (readerPositions.Read())
            {
                int id = readerPositions.GetInt32(0);
                string name = readerPositions.GetString(1);
                double salary = readerPositions.GetDouble(2);
                Position? position = Position.Create(new PositionBindingModel { Id = id, PositionName = name, Salary = salary });
                if (position != null) _positions.Add(position);
            }
            readerPositions.Close();

            using var commandEmployees = connection.CreateCommand();
            commandEmployees.CommandText = "SELECT * FROM employee;";
            using var readerEmployees = commandEmployees.ExecuteReader();
            while (readerEmployees.Read())
            {
                int id = readerEmployees.GetInt32(0);
                string name = readerEmployees.GetString(1);
                int positionId = readerEmployees.GetInt32(2);
                Employee? employee = Employee.Create(new EmployeeBindingModel { Id = id, EmployeeName = name, PositionID = positionId }, _positions);
                if (employee != null) _employees.Add(employee);
            }
            readerEmployees.Close();

            using var commandOrders = connection.CreateCommand();
            commandOrders.CommandText = "SELECT * FROM \"order\";";
            using var readerOrders = commandOrders.ExecuteReader();
            while (readerOrders.Read())
            {
                int id = readerOrders.GetInt32(0);
                string description = readerOrders.GetString(1);
                string adress = readerOrders.GetString(2);
                double price = readerOrders.GetDouble(3);
                string statusString = readerOrders.GetString(4);
                OrderStatus status;
                switch (statusString)
                {
                    case "Принят":
                        status = OrderStatus.Принят;
                        break;
                    case "Выполняется":
                        status = OrderStatus.Выполняется;
                        break;
                    case "Завершён":
                        status = OrderStatus.Завершён;
                        break;
                    default:
                        status = OrderStatus.Неизвестен;
                        break;
                }
                string customerNumber = readerOrders.GetString(5);
                DateTime dateBegin = readerOrders.GetDateTime(6);
                Order? order;
                if (status == OrderStatus.Завершён)
                {
                    DateTime? dateEnd = readerOrders.GetDateTime(7);
                    order = Order.Create(new OrderBindingModel { Id = id, Description = description, Adress = adress, Price = price, Status = status, CustomerNumber = customerNumber, DateBegin = dateBegin, DateEnd = dateEnd });
                }
                else
                {
                    order = Order.Create(new OrderBindingModel { Id = id, Description = description, Adress = adress, Price = price, Status = status, CustomerNumber = customerNumber, DateBegin = dateBegin});
                }
                if (order != null) _orders.Add(order);
            }
            readerOrders.Close();

            using var commandEmployeeOrders = connection.CreateCommand();
            commandEmployeeOrders.CommandText = "SELECT * FROM employee_order;";
            using var readerEmployeeOrders = commandEmployeeOrders.ExecuteReader();
            while (readerEmployeeOrders.Read())
            {
                int employeeId = readerEmployeeOrders.GetInt32(0);
                int orderId = readerEmployeeOrders.GetInt32(1);
                EmployeeOrder? employeeOrder = EmployeeOrder.Create(new EmployeeOrderBindingModel { EmployeeId = employeeId, OrderId = orderId}, _employees, _orders);
                if (employeeOrder != null) _employeeOrders.Add(employeeOrder);
            }
            readerEmployeeOrders.Close();

            using var commandMaterialOrders = connection.CreateCommand();
            commandMaterialOrders.CommandText = "SELECT * FROM material_order;";
            using var readerMaterialOrders = commandMaterialOrders.ExecuteReader();
            while (readerMaterialOrders.Read())
            {
                int materialId = readerMaterialOrders.GetInt32(0);
                int orderId = readerMaterialOrders.GetInt32(1);
                int quantity = readerMaterialOrders.GetInt32(2);
                MaterialOrder? materialOrder = MaterialOrder.Create(new MaterialOrderBindingModel { MaterialId = materialId, OrderId = orderId, Quantity = quantity}, _materials, _orders);
                if (materialOrder != null) _materialOrders.Add(materialOrder);
            }
            readerMaterialOrders.Close();

            connection.Close();
        }
    }
}