using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace crusherScanner
{
    // TODO: Caution memory leak be here. Consider flushing buffer SIDs after a period of time.
    internal class LimsAccess
    {
        /// <summary>
        /// Buffer of sample ID's from LIMS or sample list file.
        /// </summary>
        private static HashSet<string> SIDs = new();

        /// <summary>
        ///  Check if barcode is found in LIMS samples.
        /// </summary>
        /// <param name="barcode">Barcode as string to check LIMS for.</param>
        public static Scan IsInLims(Scan barcode)
        {

            // Is sample ID in buffer
            if(CheckBuffer(barcode))
            {
                barcode.isInLims = true;
                return barcode;
            }

            // LIMS connection enabled, ask LIMS for sample ID.
            if (Properties.Settings.Default.LimsConnection)
            {

                //TODO: Actully check LIMS for sample ID. And fill buffer.
                barcode.isInLims = true;
                return barcode;
                //https://www.guru99.com/c-sharp-access-database.html#:~:text=Code%20Explanation%3A-%201%20The%20first%20step%20is%20to,connection%20to%20the%20database.%20...%20More%20items...%20
                //string connetionString;
                //SqlConnection cnn;
                //connetionString = @"Data Source=WIN-50GP30FGO75;Initial Catalog=Demodb;User ID=sa;Password=demol23";
                //cnn = new SqlConnection(connetionString);
                //cnn.Open();
                //MessageBox.Show("Connection Open  !");
                //cnn.Close();
                //or
                //https://dax.tips/2020/08/24/using-visual-studio-code-to-query-power-bi/
            }
            else // LIMS connection disabled. Check for a fall back file or return true.
            {
                if (CheckFileStore("sampleList.csv") && CheckFileStore(Properties.Settings.Default.OreDefWorkFile + "\\sampleList.csv") && CheckBuffer(barcode))
                {
                    barcode.isInLims = true;
                    return barcode;
                }
                else 
                {
                    barcode.isInLims = false;
                    return barcode;
                }
            }
        }

        /// <summary>
        /// Check if the sample list file is available and load into the buffer.
        /// </summary>
        /// <returns></returns>
        private static bool CheckFileStore(string LimsList)
        {
            // No file list found, assume no checking and return true.
            if(!File.Exists(LimsList))
            {
                return true;
            }

            // File list found, load into buffer and check if barcode exists.
            using FileStream sampleList = new(LimsList, FileMode.Open, System.IO.FileAccess.Read, FileShare.None);
            {
                using StreamReader Reader = new(sampleList);
                {
                    while (true)
                    {
                        var line = Reader.ReadLine();
                        if (line != null && line != "")
                        {
                            SIDs.Add(line.Trim());
                        }
                        else
                        {
                            break;
                        }
                    }
                }
            }
            return false;
        }

        /// <summary>
        /// Check to see if the sample ID is in the buffer.
        /// </summary>
        /// <param name="barcode">barcode (sample ID)</param>
        /// <returns></returns>
        private static bool CheckBuffer(Scan barcode)
        {

            if(SIDs.Contains(barcode.barcode))
            {
                return true;
            }

            return false;

        }

    }
}