using Microsoft.Extensions.Logging;
using SQLVision.Core.Models;
using System.Data;
using System.Text.Json;

namespace SQLVision.Services.Exporters;

public class JsonExporter : IExportHandler
{
    private readonly ILogger<JsonExporter> _logger;
    private readonly JsonSerializerOptions _jsonOptions;

    public string FormatName => "JSON";

    public JsonExporter(ILogger<JsonExporter> logger)
    {
        _logger = logger;
        _jsonOptions = new JsonSerializerOptions
        {
            WriteIndented = true,
            PropertyNamingPolicy = JsonNamingPolicy.CamelCase
        };
    }

    public async Task ExportAsync(DataTable data, string filePath, ExportOptions options)
    {
        var records = ConvertDataTableToList(data);
        var json = JsonSerializer.Serialize(records, _jsonOptions);
        await File.WriteAllTextAsync(filePath, json);

        _logger.LogInformation("Exported {Rows} rows to JSON: {FilePath}", data.Rows.Count, filePath);
    }

    public async Task<byte[]> ExportToMemoryAsync(DataTable data, ExportOptions options)
    {
        var records = ConvertDataTableToList(data);
        var json = JsonSerializer.Serialize(records, _jsonOptions);
        return System.Text.Encoding.UTF8.GetBytes(json);
    }

    private List<Dictionary<string, object>> ConvertDataTableToList(DataTable data)
    {
        var list = new List<Dictionary<string, object>>();

        foreach (DataRow row in data.Rows)
        {
            var dict = new Dictionary<string, object>();

            foreach (DataColumn column in data.Columns)
            {
                dict[column.ColumnName] = row[column] ?? DBNull.Value;
            }

            list.Add(dict);
        }

        return list;
    }
}