//******************************************************************************************************
//  ActiveMeasurementsTableLookup.cs - Gbtc
//
//  Copyright © 2016, Grid Protection Alliance.  All Rights Reserved.
//
//  Licensed to the Grid Protection Alliance (GPA) under one or more contributor license agreements. See
//  the NOTICE file distributed with this work for additional information regarding copyright ownership.
//  The GPA licenses this file to you under the MIT License (MIT), the "License"; you may not use this
//  file except in compliance with the License. You may obtain a copy of the License at:
//
//      http://opensource.org/licenses/MIT
//
//  Unless agreed to in writing, the subject software distributed under the License is distributed on an
//  "AS-IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. Refer to the
//  License for the specific language governing permissions and limitations.
//
//  Code Modification History:
//  ----------------------------------------------------------------------------------------------------
//  10/31/2016 - Steven E. Chisholm
//       Generated original version of source code.
//
//******************************************************************************************************

using System;
using System.Collections.Generic;
using System.Data;
using GSF.Data;

namespace GSF.TimeSeries.Data
{
    /// <summary>
    /// Represents a table lookup for active measurements.
    /// </summary>
    public class ActiveMeasurementsTableLookup
    {
        private readonly Dictionary<uint, List<DataRow>> m_lookupByDeviceID;
        private readonly Dictionary<string, List<DataRow>> m_lookupByDeviceNameNoStats;
        private readonly List<DataRow> m_emptySet;

        internal ActiveMeasurementsTableLookup(DataSet dataSet)
        {
            m_emptySet = new List<DataRow>();
            m_lookupByDeviceID = new Dictionary<uint, List<DataRow>>();
            m_lookupByDeviceNameNoStats = new Dictionary<string, List<DataRow>>(StringComparer.CurrentCultureIgnoreCase);

            if (!dataSet.Tables.Contains("ActiveMeasurements"))
                return;

            DataTable table = dataSet.Tables["ActiveMeasurements"];
            List<DataRow> rowList;

            foreach (DataRow row in table.Rows)
            {
                uint? id = row.AsUInt32("DeviceID");

                if (id.HasValue)
                {
                    if (!m_lookupByDeviceID.TryGetValue(id.Value, out rowList))
                    {
                        rowList = new List<DataRow>();
                        m_lookupByDeviceID[id.Value] = rowList;
                    }

                    rowList.Add(row);
                }

                if (row.AsString("SignalType", string.Empty).Equals("STAT", StringComparison.CurrentCultureIgnoreCase))
                    continue;

                string device = row.AsString("Device");

                if (device == null)
                    continue;

                if (!m_lookupByDeviceNameNoStats.TryGetValue(device, out rowList))
                {
                    rowList = new List<DataRow>();
                    m_lookupByDeviceNameNoStats[device] = rowList;
                }

                rowList.Add(row);
            }
        }

        /// <summary>
        /// Gets all of the rows with the provided deviceID. 
        /// Returns an empty set if the deviceID could not be found.
        /// </summary>
        /// <param name="deviceId">the deviceID to lookup.</param>
        /// <returns>
        /// Returns an empty set if the deviceID could not be found.
        /// </returns>
        public IEnumerable<DataRow> LookupByDeviceID(uint deviceId) => m_lookupByDeviceID.TryGetValue(deviceId, out List<DataRow> rows) ? rows : m_emptySet;

        /// <summary>
        /// Gets all of the rows with the provided device name. This will exclude
        /// all ActiveMeasurements that are classified as SignalType='STAT'. This is because 
        /// 'STAT's are not associated with a device in the database.
        /// Returns an empty set if the deviceID could not be found.
        /// </summary>
        /// <param name="deviceName">the device to lookup.</param>
        /// <returns>
        /// Returns an empty set if the device could not be found.
        /// </returns>
        public IEnumerable<DataRow> LookupByDeviceNameNoStat(string deviceName) => m_lookupByDeviceNameNoStats.TryGetValue(deviceName, out List<DataRow> rows) ? rows : m_emptySet;
    }
}