using System;
using System.Data;
using System.Data.Common;
using System.Data.OleDb;

namespace BLToolkit.Data.DataProvider
{
    /// <summary>
    /// Implements access to the Data Provider for OLE DB.
    /// </summary>
    /// <remarks>
    /// See the <see cref="DbManager.AddDataProvider(DataProviderBase)"/> method to find an example.
    /// </remarks>
    /// <seealso cref="DbManager.AddDataProvider(DataProviderBase)">AddDataManager Method</seealso>
    public class OleDbDataProvider : DataProviderBase
    {
        /// <summary>
        /// Creates the database connection object.
        /// </summary>
        /// <remarks>
        /// See the <see cref="DbManager.AddDataProvider(DataProviderBase)"/> method to find an example.
        /// </remarks>
        /// <seealso cref="DbManager.AddDataProvider(DataProviderBase)">AddDataManager Method</seealso>
        /// <returns>The database connection object.</returns>
        public override IDbConnection CreateConnectionObject()
        {
            return new OleDbConnection();
        }

        /// <summary>
        /// Creates the data adapter object.
        /// </summary>
        /// <remarks>
        /// See the <see cref="DbManager.AddDataProvider(DataProviderBase)"/> method to find an example.
        /// </remarks>
        /// <seealso cref="DbManager.AddDataProvider(DataProviderBase)">AddDataManager Method</seealso>
        /// <returns>A data adapter object.</returns>
        public override DbDataAdapter CreateDataAdapterObject()
        {
            return new OleDbDataAdapter();
        }

        /// <summary>
        /// Populates the specified <see cref="IDbCommand"/> object's Parameters collection with 
        /// parameter information for the stored procedure specified in the <see cref="IDbCommand"/>.
        /// </summary>
        /// <remarks>
        /// See the <see cref="DbManager.AddDataProvider(DataProviderBase)"/> method to find an example.
        /// </remarks>
        /// <seealso cref="DbManager.AddDataProvider(DataProviderBase)">AddDataManager Method</seealso>
        /// <param name="command">The <see cref="IDbCommand"/> referencing the stored procedure for which 
        /// the parameter information is to be derived. The derived parameters will be 
        /// populated into the Parameters of this command.</param>
        public override bool DeriveParameters(IDbCommand command)
        {
            OleDbCommandBuilder.DeriveParameters((OleDbCommand)command);
            return true;
        }

        public override object Convert(object value, ConvertType convertType)
        {
            switch (convertType)
            {
                case ConvertType.NameToQueryParameter:
                case ConvertType.NameToCommandParameter:
                case ConvertType.NameToSprocParameter:
                    return "@" + value;

                case ConvertType.NameToQueryField:
                case ConvertType.NameToQueryFieldAlias:
                case ConvertType.NameToQueryTableAlias:
                    {
                        string name = value.ToString();

                        if (name.Length > 0 && name[0] == '[')
                            return value;
                    }

                    return "[" + value + "]";

                case ConvertType.NameToDatabase:
                case ConvertType.NameToOwner:
                case ConvertType.NameToQueryTable:
                    {
                        string name = value.ToString();

                        if (name.Length > 0 && name[0] == '[')
                            return value;

                        if (name.IndexOf('.') > 0)
                            value = string.Join("].[", name.Split('.'));
                    }

                    return "[" + value + "]";

                case ConvertType.SprocParameterToName:
                    if (value != null)
                    {
                        string str = value.ToString();
                        return str.Length > 0 && str[0] == '@'? str.Substring(1): str;
                    }

                    break;

                case ConvertType.ExceptionToErrorNumber:
                    if (value is OleDbException)
                    {
                        OleDbException ex = (OleDbException)value;
                        if (ex.Errors.Count > 0)
                            return ex.Errors[0].NativeError;
                    }

                    break;
            }

            return value;
        }

        /// <summary>
        /// Returns connection type.
        /// </summary>
        /// <remarks>
        /// See the <see cref="DbManager.AddDataProvider(DataProviderBase)"/> method to find an example.
        /// </remarks>
        /// <seealso cref="DbManager.AddDataProvider(DataProviderBase)">AddDataManager Method</seealso>
        /// <value>An instance of the <see cref="Type"/> class.</value>
        public override Type ConnectionType
        {
            get { return typeof(OleDbConnection); }
        }

        public const string NameString = DataProvider.ProviderName.OleDb;

        /// <summary>
        /// Returns the data provider name.
        /// </summary>
        /// <remarks>
        /// See the <see cref="DbManager.AddDataProvider(DataProviderBase)"/> method to find an example.
        /// </remarks>
        /// <seealso cref="DbManager.AddDataProvider(DataProviderBase)">AddDataProvider Method</seealso>
        /// <value>Data provider name.</value>
        public override string Name
        {
            get { return NameString; }
        }
    }
}