using System;
using System.Data;
using Ease.Core.Utility;
using System.Collections.Generic;

namespace Ease.Core.DataAccess
{
    #region Conntection context

    /// <summary>
    /// Summary description for ConnectionContext.
    /// Pass key of database connection according to config file 
    /// </summary>	
    public sealed class ConnectionContext
    {
        private readonly string _ctxKey = string.Empty;

        public ConnectionContext()
        {
            _ctxKey = "default";
        }

        public ConnectionContext(string ctxKey)
        {
            _ctxKey = ctxKey;
        }

        public string ContextKey
        {
            get { return _ctxKey; }
        }
    }

    #endregion

    /// <summary>
    /// This class is used to help to fill dataset.
    /// </summary>
    internal class DataAccessHelper
    {
        #region Fill Data set

        /// <summary>
        /// Fills a typed DataSet using the DataReader's current result. This method 
        /// allows paginated access to the database.
        /// </summary>
        /// <param name="dataReader">The DataReader used to fetch the values.</param>
        /// <param name="dataSet">The DataSet used to store the values.</param>
        /// <param name="tableName">The name of the DataSet table used to add the 
        /// DataReader records.</param>
        /// <param name="from">The quantity of records skipped before placing
        /// values on the DataReader on the DataSet.</param>
        /// <param name="count">The maximum quantity of records alloed to fill on the
        /// DataSet.</param>
        public static void Fill(IDataReader dataReader, DataSet dataSet, string tableName, int from, int count)
        {
            string fieldName;
            DataTable fillTable;
            DataRow fillRow;
            int recNumber = 0;
            int totalRecords = from + count;

            //If table name is null then set the string 
            if (tableName == null)
            {
                tableName = "unknownTable";
            }

            //If table does not exist in data set then add table
            if (dataSet.Tables[tableName] == null)
            {
                dataSet.Tables.Add(tableName);
            }

            // Get the DataTable reference
            if (tableName == null)
            {
                fillTable = dataSet.Tables[0];
            }
            else
            {
                fillTable = dataSet.Tables[tableName];
            }

            while (dataReader.Read())
            {
                if (recNumber++ >= from)
                {
                    fillRow = fillTable.NewRow();
                    for (int fieldIdx = 0; fieldIdx < dataReader.FieldCount; fieldIdx++)
                    {
                        fieldName = dataReader.GetName(fieldIdx);
                        Type fieldType = dataReader.GetValue(fieldIdx).GetType();
                        if (fillTable.Columns.IndexOf(fieldName) == -1)
                        {
                            fillTable.Columns.Add(fieldName, fieldType);
                        }

                        fillRow[fieldName] = GetValue(dataReader.GetValue(fieldIdx), fieldType);
                    }

                    fillTable.Rows.Add(fillRow);
                }

                if (count != 0 && totalRecords <= recNumber)
                {
                    break;
                }
            }

            dataSet.AcceptChanges();
        }

        /// <summary>
        /// Fills a typed DataSet using the DataReader's current result. This method 
        /// allows paginated access to the database.
        /// </summary>
        /// <param name="dataReader">The DataReader used to fetch the values.</param>
        /// <param name="dataSet">The DataSet used to store the values.</param>
        /// <param name="tableName">The name of the DataSet table used to add the DataReader records.</param>
        public static void Fill(IDataReader dataReader, DataSet dataSet, string tableName)
        {
            Fill(dataReader, dataSet, tableName, 0, 0);
        }

        #endregion

        #region private function

        private static object GetValue(object fieldValue, Type fieldType)
        {
            switch (fieldType.Name)
            {
                case "Int16":
                case "Int32":
                case "Int64":
                case "UInt16":
                case "UInt32":
                case "UInt64":
                    return fieldValue == DBNull.Value ? 0 : fieldValue;
            }

            return fieldValue;
        }

        #endregion
    }
}