using System;
using System.Collections.Generic;
using System.Linq;
using Kreta.Framework.Collections.Generic;

namespace Kreta.Framework.Entities.Generic
{
    public abstract class EntityDBHelper<EntityType> : IEntityDBHelper<EntityType> //, IEntityDBHelper
        where EntityType : Kreta.Framework.Entities.Entity
    {
        protected abstract EntityType CreateEntityInstance();

        #region IEntityDBHelper<EntityType> Members

        public abstract string EmptyQueryCommandText
        {
            get;
        }

        public abstract string DynamicQueryCommandText
        {
            get;
        }

        public abstract IDictionary<string, string> DynamicColumns
        {
            get;
        }

        public SDA.DataProvider.SDACommand CreateEmptyQueryCommand()
        {
            return DAUtil.CreateCommand(EmptyQueryCommandText);
        }

        public SDA.DataProvider.SDACommand CreateDynamicQueryCommand(ColumnFilterMode columnFilterMode, IEnumerable<string> columns)
        {
            if (columns == null)
            {
                columns = new List<string>();
            }

            var columnText = "";
            foreach (var column in DynamicColumns.Where(dc => (columnFilterMode == ColumnFilterMode.DEFAULT_ALLOWED) ^ (columns.Contains(dc.Key))))
            {
                columnText += column.Value + ",";
            }

            var queryCommandText = DynamicQueryCommandText.Replace("{COLUMNS}", columnText);
            return DAUtil.CreateCommand(queryCommandText);
        }

        public abstract void LoadEntityFields(EntityType entity, SDA.DataProvider.SDADataReader reader, ColumnFilterMode columnFilterMode, IEnumerable<string> columns);
        public abstract void LoadEntityFields(EntityType entity, SDA.DataProvider.SDADataReader reader);

        public void LoadFromReader(EntityType entity, SDA.DataProvider.SDADataReader reader)
        {
            entity.ID = ((int)reader.GetDecimal(0));

            LoadEntityFields(entity, reader);

            int index = reader.FieldCount - 6;
            entity.Torolt = reader[index] != DBNull.Value && reader.GetBoolean(index);
            index++;
            entity.Serial = ((int)reader.GetDecimal(index++));
            entity.EntityCreated = DAUtil.ReadDateTime(reader, index++);
            entity.EntityCreator = reader[index] != DBNull.Value ? reader.GetInt32(index) : 0;
            index++;
            entity.EntityLastChanged = DAUtil.ReadDateTime(reader, index++);
            entity.EntityModifier = reader[index] != DBNull.Value ? reader.GetInt32(index) : new int?();

            entity.SetLoaded();
        }

        public void LoadFromReader(EntityType entity, SDA.DataProvider.SDADataReader reader, ColumnFilterMode columnFilterMode, IEnumerable<string> columns)
        {
            entity.ID = ((int)reader.GetDecimal(0));

            LoadEntityFields(entity, reader, columnFilterMode, columns);

            int index = reader.FieldCount - 6;
            entity.Torolt = reader[index] != DBNull.Value && reader.GetBoolean(index);
            index++;
            entity.Serial = ((int)reader.GetDecimal(index++));
            entity.EntityCreated = DAUtil.ReadDateTime(reader, index++);
            entity.EntityCreator = reader[index] != DBNull.Value ? reader.GetInt32(index) : 0;
            index++;
            entity.EntityLastChanged = DAUtil.ReadDateTime(reader, index++);
            entity.EntityModifier = reader[index] != DBNull.Value ? reader.GetInt32(index++) : new int?();
            entity.SetLoaded();
        }

        public bool LoadEntityCollection(IEntityCollection<EntityType> collection, SDA.DataProvider.SDACommand command)
        {
            using (SDA.DataProvider.SDADataReader reader = command.ExecuteReader())
            {
                while (reader.Read())
                {
                    EntityType entity = CreateEntityInstance();
                    LoadFromReader(entity, reader);
                    ((EntityCollection<EntityType>)collection).InternalAdd(entity);
                }
                return true;
            }
        }

        public bool LoadEntityCollection(IEntityCollection<EntityType> collection, SDA.DataProvider.SDACommand command, ColumnFilterMode columnFilterMode, IEnumerable<string> columns)
        {
            using (SDA.DataProvider.SDADataReader reader = command.ExecuteReader())
            {
                while (reader.Read())
                {
                    EntityType entity = CreateEntityInstance();
                    LoadFromReader(entity, reader, columnFilterMode, columns);
                    ((EntityCollection<EntityType>)collection).InternalAdd(entity);
                }
                return true;
            }
        }

        public bool LoadSingleEntity(EntityType entity, SDA.DataProvider.SDACommand command)
        {
            using (SDA.DataProvider.SDADataReader reader = command.ExecuteReader())
            {
                if (reader.Read())
                {
                    LoadFromReader(entity, reader);

                    if (reader.Read())
                    {
                        throw new Kreta.Framework.DataIntegrityException("Egyediség megsértése: " + entity.GetEntityName());
                    }
                    return true;
                }

                return false;
            }
        }

        public bool LoadSingleEntity(EntityType entity, SDA.DataProvider.SDACommand command, ColumnFilterMode columnFilterMode, IEnumerable<string> columns)
        {
            using (SDA.DataProvider.SDADataReader reader = command.ExecuteReader())
            {
                if (reader.Read())
                {
                    LoadFromReader(entity, reader, columnFilterMode, columns);

                    if (reader.Read())
                    {
                        throw new Kreta.Framework.DataIntegrityException("Egyediség megsértése: " + entity.GetEntityName());
                    }
                    return true;
                }

                return false;
            }
        }

        public bool LoadByPartnerId(EntityType entity, string filterText, int partnerId)
        {
            using (SDA.DataProvider.SDACommand command = CreateEmptyQueryCommand())
            {
                command.CommandText += filterText;
                command.Parameters.Add("pID", SDA.DataProvider.SDADBType.Int).Value = partnerId;
                return LoadSingleEntity(entity, command, ColumnFilterMode.DEFAULT_ALLOWED, null);
            }
        }

        public bool LoadByPartnerId(IEntityCollection<EntityType> collection, string filterText, int partnerId)
        {
            using (SDA.DataProvider.SDACommand command = CreateEmptyQueryCommand())
            {
                command.CommandText += filterText;
                command.Parameters.Add("pID", SDA.DataProvider.SDADBType.Int).Value = partnerId;
                return LoadEntityCollection(collection, command, ColumnFilterMode.DEFAULT_ALLOWED, null);
            }
        }

        public abstract void BindAttributes(EntityType entity, SDA.DataProvider.SDACommand command);

        public abstract void BindAssociations(EntityType entity, SDA.DataProvider.SDACommand command);

        public abstract void DynamicBindAttributes(EntityType entity, SDA.DataProvider.SDACommand command);

        public void CreateParameterBinding(SDA.DataProvider.SDACommand command, Dictionary<string, object> commandParameters)
        {
            if (commandParameters != null)
            {
                foreach (KeyValuePair<string, object> kvp in commandParameters)
                {
                    // mssql nem szereti parameter nevben a ":"-ot
                    string pName = kvp.Key;
                    if (pName.StartsWith(":"))
                    {
                        pName = pName.TrimStart(new char[] { ':' });
                    }

                    if (kvp.Value.GetType() == typeof(int))
                    {
                        command.Parameters.Add(pName, SDA.DataProvider.SDADBType.Int).Value = Convert.ToInt32(kvp.Value);
                    }
                    if (kvp.Value.GetType() == typeof(string))
                    {
                        command.Parameters.Add(pName, SDA.DataProvider.SDADBType.String).Value = Convert.ToString(kvp.Value);
                    }
                    if (kvp.Value.GetType() == typeof(DateTime))
                    {
                        command.Parameters.Add(pName, SDA.DataProvider.SDADBType.DateTime).Value = Convert.ToDateTime(kvp.Value, LanguageContext.Current.RegionSettings);
                    }
                }
            }
        }

        #endregion
    }
}