using CsvHelper;
using CsvHelper.Configuration;
using Microsoft.Extensions.Logging;
using SQLVision.Core.Models;
using System.Data;

namespace SQLVision.Services.Exporters;

public class CsvExporter : IExportHandler
{
    private readonly ILogger<CsvExporter> _logger;

    public string FormatName => "CSV";

    public CsvExporter(ILogger<CsvExporter> logger)
    {
        _logger = logger;
    }

    public async Task ExportAsync(DataTable data, string filePath, ExportOptions options)
    {
        var config = new CsvConfiguration(System.Globalization.CultureInfo.CurrentCulture)
        {
            Delimiter = options.CustomOptions.TryGetValue("Delimiter", out var delimiter)
                ? delimiter.ToString() ?? ","
                : ","
        };

        using var writer = new StreamWriter(filePath);
        using var csv = new CsvWriter(writer, config);

        // Запись заголовков
        if (options.IncludeHeaders)
        {
            foreach (DataColumn column in data.Columns)
            {
                csv.WriteField(column.ColumnName);
            }
            csv.NextRecord();
        }

        // Запись данных
        foreach (DataRow row in data.Rows)
        {
            for (int i = 0; i < data.Columns.Count; i++)
            {
                csv.WriteField(row[i]);
            }
            csv.NextRecord();
        }

        await csv.FlushAsync();
        _logger.LogInformation("Exported {Rows} rows to CSV: {FilePath}", data.Rows.Count, filePath);
    }

    public async Task<byte[]> ExportToMemoryAsync(DataTable data, ExportOptions options)
    {
        using var stream = new MemoryStream();
        using var writer = new StreamWriter(stream);
        using var csv = new CsvWriter(writer, System.Globalization.CultureInfo.CurrentCulture);

        // Запись заголовков
        if (options.IncludeHeaders)
        {
            foreach (DataColumn column in data.Columns)
            {
                csv.WriteField(column.ColumnName);
            }
            csv.NextRecord();
        }

        // Запись данных
        foreach (DataRow row in data.Rows)
        {
            for (int i = 0; i < data.Columns.Count; i++)
            {
                csv.WriteField(row[i]);
            }
            csv.NextRecord();
        }

        await csv.FlushAsync();
        await writer.FlushAsync();
        return stream.ToArray();
    }
}