// Copyright (C) Stichting Deltares 2016. All rights reserved.
//
// This file is part of Ringtoets.
//
// Ringtoets is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
// 
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
//
// All names, logos, and references to "Deltares" are registered trademarks of
// Stichting Deltares and remain full property of Stichting Deltares at all times.
// All rights reserved.

using System;
using System.Data;
using System.Data.SQLite;

using Core.Common.IO.Exceptions;
using Core.Common.IO.Readers;
using Core.Common.Utils.Builders;

using Ringtoets.Piping.IO.Builders;
using Ringtoets.Piping.IO.Exceptions;
using Ringtoets.Piping.IO.Properties;
using Ringtoets.Piping.Primitives;

using UtilsResources = Core.Common.Utils.Properties.Resources;

namespace Ringtoets.Piping.IO.SoilProfile
{
    /// <summary>
    /// This class reads a SqLite database file and constructs <see cref="PipingSoilProfile"/> instances from this database.
    /// </summary>
    public class PipingSoilProfileReader : SqLiteDatabaseReaderBase, IRowBasedDatabaseReader
    {
        private const string pipingMechanismName = "Piping";
        private const string mechanismParameterName = "mechanism";

        private SQLiteDataReader dataReader;

        /// <summary>
        /// Creates a new instance of <see cref="PipingSoilProfileReader"/> which will use the <paramref name="databaseFilePath"/>
        /// as its source. The reader will not point to any record at the start. Use <see cref="MoveNext"/> to start reading
        /// profiles.
        /// </summary>
        /// <param name="databaseFilePath">The path of the database file to open.</param>
        /// <exception cref="Core.Common.IO.Exceptions.CriticalFileReadException">Thrown when:
        /// <list type="bullet">
        /// <item>The <paramref name="databaseFilePath"/> contains invalid characters.</item>
        /// <item>No file could be found at <paramref name="databaseFilePath"/>.</item>
        /// <item>Preparing the queries to read from the database failed.</item>
        /// </list>
        /// </exception>
        public PipingSoilProfileReader(string databaseFilePath) : base(databaseFilePath)
        {
            VerifyVersion(databaseFilePath);
            InitializeReader();
        }

        /// <summary>
        /// Gets the total number of profiles that can be read from the database.
        /// </summary>
        public int Count { get; private set; }

        /// <summary>
        /// Gets a value indicating whether or not more soil profiles can be read using 
        /// the <see cref="PipingSoilProfileReader"/>.
        /// </summary>
        public bool HasNext { get; private set; }

        /// <summary>
        /// Reads the information for the next profile from the database and creates a 
        /// <see cref="PipingSoilProfile"/> instance of the information.
        /// </summary>
        /// <returns>The next <see cref="PipingSoilProfile"/> from the database, or <c>null</c> if no more profiles can be read.</returns>
        /// <exception cref="PipingSoilProfileReadException">Thrown when reading the profile in the database contained a non-parsable geometry.</exception>
        /// <exception cref="CriticalFileReadException">Thrown when the database returned incorrect values for required properties.</exception>
        public PipingSoilProfile ReadProfile()
        {
            if (!HasNext)
            {
                return null;
            }

            try
            {
                return ReadPipingSoilProfile();
            }
            catch (InvalidCastException e)
            {
                var message = new FileReaderErrorMessageBuilder(Path).Build(Resources.PipingSoilProfileReader_Critical_Unexpected_value_on_column);
                throw new CriticalFileReadException(message, e);
            }
        }

        public override void Dispose()
        {
            if (dataReader != null)
            {
                dataReader.Dispose();
            }
            base.Dispose();
        }

        /// <summary>
        /// Moves the reader to the next record in the database.
        /// </summary>
        public void MoveNext()
        {
            HasNext = MoveNext(dataReader);
        }

        /// <summary>
        /// Reads the value in the column with name <paramref name="columnName"/> from the 
        /// current row that's being pointed at.
        /// </summary>
        /// <typeparam name="T">The type of object to read.</typeparam>
        /// <param name="columnName">The name of the column to read from.</param>
        /// <returns>The value in the column, or <c>null</c> if the value was <see cref="DBNull.Value"/>.</returns>
        /// <exception cref="InvalidCastException">Thrown when the value in the column could not be casted to type <typeparamref name="T"/>.</exception>
        public T ReadOrDefault<T>(string columnName)
        {
            var valueObject = dataReader[columnName];
            if (valueObject.Equals(DBNull.Value))
            {
                return default(T);
            }
            return (T)valueObject;
        }

        /// <summary>
        /// Reads a value at column <paramref name="columnName"/> from the database.
        /// </summary>
        /// <typeparam name="T">The expected type of value in the column with name <paramref name="columnName"/>.</typeparam>
        /// <param name="columnName">The name of the column to read from.</param>
        /// <returns>The read value from the column with name <paramref name="columnName"/>.</returns>
        /// <exception cref="InvalidCastException">Thrown when the value in the column was not of type <typeparamref name="T"/>.</exception>
        public T Read<T>(string columnName)
        {
            return (T)dataReader[columnName];
        }

        private void VerifyVersion(string databaseFilePath)
        {
            using (var versionReader = new SoilDatabaseVersionReader(databaseFilePath))
            {
                try
                {
                    versionReader.VerifyVersion();
                }
                catch (CriticalFileReadException)
                {
                    CloseConnection();
                    throw;
                }
            }
        }

        /// <summary>
        /// Reads a <see cref="PipingSoilProfile"/> from the database.
        /// </summary>
        /// <returns>A new <see cref="PipingSoilProfile"/>.</returns>
        /// <exception cref="PipingSoilProfileReadException">Thrown when a recoverable error occurred while reading from the database.</exception>
        /// <exception cref="InvalidCastException">Thrown when recovering from the <see cref="PipingSoilProfileReadException"/> failed.</exception>
        private PipingSoilProfile ReadPipingSoilProfile()
        {
            try
            {
                var dimensionValue = Read<long>(SoilProfileDatabaseColumns.Dimension);
                return dimensionValue == 1 ? SoilProfile1DReader.ReadFrom(this) : SoilProfile2DReader.ReadFrom(this);
            }
            catch (PipingSoilProfileReadException e)
            {
                MoveToNextProfile(e.ProfileName);
                throw;
            }
        }

        /// <summary>
        /// Steps through the result rows until a row is read which' profile name differs from <paramref name="profileName"/>.
        /// </summary>
        /// <param name="profileName">The name of the profile to skip.</param>
        private void MoveToNextProfile(string profileName)
        {
            while (HasNext && Read<string>(SoilProfileDatabaseColumns.ProfileName).Equals(profileName))
            {
                MoveNext();
            }
        }

        /// <summary>
        /// Prepares a new data reader with queries for obtaining the profiles and updates the reader
        /// so that it points to the first row of the result set.
        /// </summary>
        /// <exception cref="PipingSoilProfileReadException">Thrown when the amount of profiles in database could not be read.</exception>
        /// <exception cref="CriticalFileReadException">A query could not be executed on the database schema.</exception>
        private void InitializeReader()
        {
            try
            {
                PrepareReader();
                GetCount();
            }
            catch (SQLiteException e)
            {
                Dispose();
                var message = new FileReaderErrorMessageBuilder(Path).Build(Resources.Error_SoilProfile_read_from_database);
                throw new CriticalFileReadException(message, e);
            }
            MoveNext();
        }

        /// <summary>
        /// Prepares the two queries required for obtaining all the SoilProfile1D and SoilProfile2D with an x defined
        /// to take an intersection from. Since two separate queries are used, the <see cref="dataReader"/> will
        /// have two result sets which the <see cref="MoveNext()"/> method takes into account.
        /// </summary>
        /// <exception cref="SQLiteException">A query could not be executed on the database schema.</exception>
        private void PrepareReader()
        {
            string countQuery = SoilDatabaseQueryBuilder.GetPipingSoilProfileCountQuery();

            string subQueryGetNumberOfLayerProfile1D =
                string.Format("SELECT SP1D_ID, COUNT(*) as {0} " +
                              "FROM SoilLayer1D " +
                              "GROUP BY SP1D_ID",
                              SoilProfileDatabaseColumns.LayerCount);
            string subQueryGetNumberOfLayerProfile2D =
                string.Format("SELECT SP2D_ID, COUNT(*) as {0} " +
                              "FROM SoilLayer2D " +
                              "GROUP BY SP2D_ID",
                              SoilProfileDatabaseColumns.LayerCount);
            string subQueryGetMaterialPropertiesOfLayer =
                String.Format(
                    "SELECT " +
                    "mat.MA_ID, " +
                    "mat.MA_Name as {4}, " +
                    "MAX(case when pn.PN_NAME = '{0}' then pv.PV_Value end) {0}, " +
                    "MAX(case when pn.PN_NAME = '{1}' then pv.PV_Value end) {1}, " +
                    "MAX(case when pn.PN_NAME = '{2}' then pv.PV_Value end) {2}, " +
                    "MAX(case when pn.PN_NAME = '{3}' then pv.PV_Value end) {3} " +
                    "FROM ParameterNames as pn " +
                    "JOIN ParameterValues as pv USING(PN_ID) " +
                    "JOIN Materials as mat USING(MA_ID) " +
                    "GROUP BY mat.MA_ID",
                    SoilProfileDatabaseColumns.AbovePhreaticLevel,
                    SoilProfileDatabaseColumns.BelowPhreaticLevel,
                    SoilProfileDatabaseColumns.DryUnitWeight,
                    SoilProfileDatabaseColumns.Color,
                    SoilProfileDatabaseColumns.MaterialName);
            string subQueryGetLayerPropertiesOfLayer1D =
                String.Format(
                    "SELECT " +
                    "SL1D_ID, " +
                    "MAX(case when pn.PN_NAME = '{0}' then pv.PV_Value end) {0} " +
                    "FROM ParameterNames as pn " +
                    "JOIN LayerParameterValues as pv USING(PN_ID) " +
                    "GROUP BY pv.SL1D_ID",
                    SoilProfileDatabaseColumns.IsAquifer);
            string subQueryGetLayerPropertiesOfLayer2D =
                String.Format(
                    "SELECT " +
                    "SL2D_ID, " +
                    "MAX(case when pn.PN_NAME = '{0}' then pv.PV_Value end) {0} " +
                    "FROM ParameterNames as pn " +
                    "JOIN LayerParameterValues as pv USING(PN_ID) " +
                    "GROUP BY pv.SL2D_ID",
                    SoilProfileDatabaseColumns.IsAquifer);

            var query1D = string.Format(
                "SELECT " +
                "1 AS {0}, " +
                "sp1d.SP1D_Name AS {1}, " +
                "layerCount.{2}, " +
                "sp1d.BottomLevel AS {3}, " +
                "sl1d.TopLevel AS {4}, " +
                "{5}, " + 
                "{6}, " +
                "{7}, " +
                "{8}, " +
                "{9}, " +
                "{10}, " +
                "sp1d.SP1D_ID AS {11} " +
                "FROM Mechanism AS m " +
                "JOIN Segment AS segment USING(ME_ID) " +
                "JOIN StochasticSoilProfile ssp USING(SSM_ID) " +
                "JOIN SoilProfile1D sp1d USING (SP1D_ID) " +
                "JOIN (" +
                subQueryGetNumberOfLayerProfile1D +
                ") layerCount USING (SP1D_ID) " +
                "JOIN SoilLayer1D sl1d USING (SP1D_ID) " +
                "LEFT JOIN (" +
                subQueryGetMaterialPropertiesOfLayer +
                ") materialProperties USING(MA_ID) " +
                "LEFT JOIN (" +
                subQueryGetLayerPropertiesOfLayer1D +
                ") layerProperties USING(SL1D_ID) " +
                "WHERE m.{12} = @{12};",
                SoilProfileDatabaseColumns.Dimension,
                SoilProfileDatabaseColumns.ProfileName,
                SoilProfileDatabaseColumns.LayerCount,
                SoilProfileDatabaseColumns.Bottom,
                SoilProfileDatabaseColumns.Top,
                SoilProfileDatabaseColumns.MaterialName,
                SoilProfileDatabaseColumns.AbovePhreaticLevel,
                SoilProfileDatabaseColumns.BelowPhreaticLevel,
                SoilProfileDatabaseColumns.DryUnitWeight,
                SoilProfileDatabaseColumns.IsAquifer,
                SoilProfileDatabaseColumns.Color,
                SoilProfileDatabaseColumns.SoilProfileId,
                MechanismDatabaseColumns.MechanismName);

            var query2D = string.Format(
                "Select " +
                "2 as {0}, " +
                "sp2d.SP2D_Name as {1}, " +
                "layerCount.{2}, " +
                "sl2d.GeometrySurface as {3}, " +
                "mpl.X as {4}, " +
                "{5}, " +
                "{6}, " +
                "{7}, " +
                "{8}, " +
                "{9}, " +
                "{10}, " +
                "sp2d.SP2D_ID as {11} " +
                "FROM Mechanism AS m " +
                "JOIN Segment AS segment USING(ME_ID) " +
                "JOIN StochasticSoilProfile ssp USING(SSM_ID) " +
                "JOIN SoilProfile2D sp2d USING (SP2D_ID) " +
                "JOIN (" +
                subQueryGetNumberOfLayerProfile2D +
                ") layerCount USING (SP2D_ID) " +
                "JOIN SoilLayer2D sl2d USING (SP2D_ID) " +
                "JOIN MechanismPointLocation mpl USING(ME_ID, SP2D_ID) " +
                "LEFT JOIN (" +
                subQueryGetMaterialPropertiesOfLayer +
                ") materialProperties USING(MA_ID) " +
                "LEFT JOIN (" +
                subQueryGetLayerPropertiesOfLayer2D +
                ") layerProperties USING(SL2D_ID) " +
                "WHERE m.{12} = @{12};",
                SoilProfileDatabaseColumns.Dimension,
                SoilProfileDatabaseColumns.ProfileName,
                SoilProfileDatabaseColumns.LayerCount,
                SoilProfileDatabaseColumns.LayerGeometry,
                SoilProfileDatabaseColumns.IntersectionX,
                SoilProfileDatabaseColumns.MaterialName,
                SoilProfileDatabaseColumns.AbovePhreaticLevel,
                SoilProfileDatabaseColumns.BelowPhreaticLevel,
                SoilProfileDatabaseColumns.DryUnitWeight,
                SoilProfileDatabaseColumns.IsAquifer,
                SoilProfileDatabaseColumns.Color,
                SoilProfileDatabaseColumns.SoilProfileId,
                MechanismDatabaseColumns.MechanismName);

            dataReader = CreateDataReader(countQuery + query2D + query1D, new SQLiteParameter
            {
                DbType = DbType.String,
                Value = pipingMechanismName,
                ParameterName = mechanismParameterName
            }, new SQLiteParameter
            {
                DbType = DbType.String,
                ParameterName = String.Format("@{0}", MechanismDatabaseColumns.MechanismName),
                Value = pipingMechanismName
            });
        }

        private void GetCount()
        {
            dataReader.Read();
            Count = (int)Read<long>(SoilProfileDatabaseColumns.ProfileCount);
            dataReader.NextResult();
        }
    }
}