EbayListingTool/EbayListingTool/Services/BulkImportService.cs

using System.Globalization;
using ClosedXML.Excel;
using CsvHelper;
using CsvHelper.Configuration;
using EbayListingTool.Models;

namespace EbayListingTool.Services;

public class BulkImportService
{
    public List<BulkImportRow> ImportFile(string filePath)
    {
        var ext = Path.GetExtension(filePath).ToLower();
        return ext switch
        {
            ".csv" => ImportCsv(filePath),
            ".xlsx" or ".xls" => ImportExcel(filePath),
            _ => throw new NotSupportedException($"File type '{ext}' is not supported. Use .csv or .xlsx")
        };
    }

    private List<BulkImportRow> ImportCsv(string filePath)
    {
        var config = new CsvConfiguration(CultureInfo.InvariantCulture)
        {
            HasHeaderRecord = true,
            MissingFieldFound = null,
            HeaderValidated = null
        };

        using var reader = new StreamReader(filePath);
        using var csv = new CsvReader(reader, config);

        var rows = new List<BulkImportRow>();
        csv.Read();
        csv.ReadHeader();

        while (csv.Read())
        {
            rows.Add(new BulkImportRow
            {
                Title = csv.TryGetField("Title", out string? t) ? t ?? "" : "",
                Description = csv.TryGetField("Description", out string? d) ? d ?? "" : "",
                Price = csv.TryGetField("Price", out string? p) ? p ?? "" : "",
                Condition = csv.TryGetField("Condition", out string? c) ? c ?? "Used" : "Used",
                CategoryKeyword = csv.TryGetField("CategoryKeyword", out string? k) ? k ?? "" : "",
                Quantity = csv.TryGetField("Quantity", out string? q) ? q ?? "1" : "1",
                PhotoPaths = csv.TryGetField("PhotoPaths", out string? ph) ? ph ?? "" : ""
            });
        }

        return rows;
    }

    private List<BulkImportRow> ImportExcel(string filePath)
    {
        var rows = new List<BulkImportRow>();

        using var workbook = new XLWorkbook(filePath);
        var ws = workbook.Worksheets.First();

        // Find header row (row 1)
        var headers = new Dictionary<string, int>(StringComparer.OrdinalIgnoreCase);
        var headerRow = ws.Row(1);
        foreach (var cell in headerRow.CellsUsed())
            headers[cell.GetString()] = cell.Address.ColumnNumber;

        string GetValue(IXLRow row, string colName)
        {
            if (!headers.TryGetValue(colName, out var col)) return "";
            return row.Cell(col).GetString().Trim();
        }

        int lastRow = ws.LastRowUsed()?.RowNumber() ?? 1;
        for (int i = 2; i <= lastRow; i++)
        {
            var row = ws.Row(i);
            if (row.IsEmpty()) continue;

            rows.Add(new BulkImportRow
            {
                Title = GetValue(row, "Title"),
                Description = GetValue(row, "Description"),
                Price = GetValue(row, "Price"),
                Condition = GetValue(row, "Condition").OrDefault("Used"),
                CategoryKeyword = GetValue(row, "CategoryKeyword"),
                Quantity = GetValue(row, "Quantity").OrDefault("1"),
                PhotoPaths = GetValue(row, "PhotoPaths")
            });
        }

        return rows;
    }
}

internal static class StringExtensions
{
    public static string OrDefault(this string value, string defaultValue)
        => string.IsNullOrWhiteSpace(value) ? defaultValue : value;
}