FileParser.cs

// Copyright © 2016-2025 ASM-SW
//asm-sw@outlook.com  https://github.com/asm-sw
using Microsoft.VisualBasic.FileIO;
using System;
using System.Collections.Generic;
using System.Data;
using System.Linq;

namespace DonorStatement
{
    public partial class FileParser : IDisposable
    {
        readonly LogMessageDelegate m_logger;
        DataTable m_dataTable = new();
        public bool FileHasBeenRead { get; set; }
        bool m_disposed = false;

        public FileParser(LogMessageDelegate logger)
        {
            m_logger = logger;
            FileHasBeenRead = false;
        }

        public bool ParseInputFile()
        {
            if (string.IsNullOrWhiteSpace(FormMain.Config.InputFileName))
            {
                m_logger("Input file name has not been set");
                FormMain.MessageBox("Input file name has not been set");
                return false;
            }

            m_logger("Parsing input file: " + FormMain.Config.InputFileName);
            if (FileHasBeenRead)
                m_dataTable = new DataTable();

            try
            {
                using TextFieldParser csvReader = new(FormMain.Config.InputFileName);
                csvReader.SetDelimiters([","]);
                csvReader.HasFieldsEnclosedInQuotes = true;

                // get column headers
                while (!csvReader.EndOfData)
                {
                    string[] colFields = csvReader.ReadFields();
                    if ((colFields.Length < 1) || !colFields.Contains(ColumnMap.Lookup("Customer")))
                    {
                        m_logger("Skipping header line: starting with: " + colFields[0]);
                        continue;
                    }
                    foreach (string item in colFields)
                    {
                        DataColumn column = new(item);
                        m_dataTable.Columns.Add(column);
                    }
                    break;
                }
                // read data
                while (!csvReader.EndOfData)
                {
                    string[] fieldData = csvReader.ReadFields();
                    if (fieldData.Length < 2 || string.IsNullOrEmpty(fieldData[1]))
                    {
                        // the footer has data in only the first field.
                        m_logger("skipping line with not enough columns: " + fieldData[0]);
                        continue;
                    }
                    m_dataTable.Rows.Add(fieldData);
                }
            }
            catch (Exception ex)
            {
                m_logger(ex.ToString());
                m_logger("Error reading input file: " + FormMain.Config.InputFileName);
                return false;
            }

            FileHasBeenRead = true;
            return true;
        } //end ParseInputFile

        public void GetColumnNames(out List<string> columnNames)
        {
            columnNames = [];
            foreach (DataColumn col in m_dataTable.Columns)
                columnNames.Add(col.ColumnName);
        }

        private void GetColumnContentsUnique(string columnName, out List<string> items)
        {
            items = [];
            DataView view = new(m_dataTable)
            {
                Sort = columnName
            };

            DataTable distinctValues = view.ToTable(true, columnName);

            foreach (DataRow row in distinctValues.Rows)
            {
                string value = row[columnName].ToString();
                if (!string.IsNullOrWhiteSpace(value))
                    items.Add(value);
            }
        }

        public void GetItemList(out List<string> items)
        {
            GetColumnContentsUnique(ColumnMap.Lookup("Product/Service"), out items);  // was Item
        }

        public void GetNameList(out List<string> names)
        {
            GetColumnContentsUnique(ColumnMap.Lookup("Customer"), out names);  // was Name
        }

        public void GetDataForName(string name, out DataTable table)
        {
            // need to duplicate the single quote in a name  "O'Donald" -> "O''Donald"
            string filter = string.Format("[Customer] = '{0}'", name.Replace("'", "''"));
            string date = ColumnMap.Lookup("Date") + " ASC";
            DataRow[] rows = m_dataTable.Select(filter, date);

            table = m_dataTable.Clone();
            foreach (DataRow row in rows)
            {
                table.Rows.Add(row.ItemArray);
            }
        }

        public void Dispose()
        {
            Dispose(true);
            GC.SuppressFinalize(this);
        }

        protected virtual void Dispose(bool disposing)
        {
            if (m_disposed)
                return;

            if (disposing)
            {
                m_dataTable.Dispose();
            }

            m_disposed = true;
        }
    } // end class FileParser
}