using HospitalDatabaseImplement.Models;
using System.Xml.Linq;

namespace HospitalDatabaseImplement
{
    public class LoaderFromXML
    {       
        private static readonly string PatientFileName = "XMLData\\Patient.xml";
        private static readonly string TreatmentFileName = "XMLData\\Treatment.xml";
        private static readonly string ProcedureFileName = "XMLData\\Procedure.xml";

        private static List<T>? LoadData<T>(string filename, string xmlNodeName, Func<XElement, T> selectFunction)
        {           
            if (File.Exists(filename))
            {
                return XDocument.Load(filename)?.Root?.Elements(xmlNodeName)?.Select(selectFunction)?.ToList();
            }
            return new List<T>();
        }
        /// <summary>
        /// Чтение пациентов из XML-файла 
        /// </summary>
        /// <returns></returns>
        public static void LoadPatients()
        {           
            using var context = new HospitalDatabase();
            if (context.Patients.ToList().Count > 0)
                return;
            var list = LoadData(PatientFileName, "Patient", x => Patient.Create(x)!)!;
            list.ForEach(x =>
            {
                context.Patients.Add(x);                             
            });
            context.SaveChanges(); 
            
        }
        /// <summary>
        /// Чтение лечений из XML-файла
        /// </summary>
        /// <returns></returns>
        public static void LoadTreatments()
        {
            using var context = new HospitalDatabase();
            if (context.Treatments.ToList().Count > 0) 
                return;
            var list = LoadData(TreatmentFileName, "Treatment", x => Treatment.Create(context, x)!)!;
            list.ForEach(x =>
            {
                context.Treatments.Add(x);
            });
            context.SaveChanges();
        }
        /// <summary>
        /// Чтение поцедур из XML-файла
        /// </summary>
        /// <returns></returns>
        public static void LoadProcedures()
        {
            using var context = new HospitalDatabase();
            if (context.Procedures.ToList().Count > 0)
                return;           
            var list = LoadData(ProcedureFileName, "Procedure", x => Procedure.Create(x)!)!;
            list.ForEach(x =>
            {
                context.Procedures.Add(x);
                context.SaveChanges();
            });
            
        }
    }
}