FictionArchive/FictionArchive.Service.TranslationService/Services/TranslationEngines/DeepLTranslate/DeepLTranslationEngine.cs

using DeepL;
using DeepL.Model;
using FictionArchive.Service.TranslationService.Models;
using Language = FictionArchive.Common.Enums.Language;

namespace FictionArchive.Service.TranslationService.Services.TranslationEngines.DeepLTranslate;

public class DeepLTranslationEngine : ITranslationEngine
{
    private readonly DeepLClient _deepLClient;
    private readonly ILogger<DeepLTranslationEngine> _logger;

    private const string DisplayName = "DeepL";
    private const string Key = "deepl";

    public DeepLTranslationEngine(DeepLClient deepLClient, ILogger<DeepLTranslationEngine> logger)
    {
        _deepLClient = deepLClient;
        _logger = logger;
    }

    public TranslationEngineDescriptor Descriptor
    {
        get
        {
            return new TranslationEngineDescriptor()
            {
                DisplayName = DisplayName,
                Key = Key,
            };
        }
    }

    public async Task<string?> GetTranslation(string body, Language from, Language to)
    {
        TextResult translationResult = await _deepLClient.TranslateTextAsync(body, GetLanguageCode(from), GetLanguageCode(to));
        _logger.LogInformation("Translated text. Usage statistics: CHARACTERS BILLED {TranslationResultBilledCharacters}", translationResult.BilledCharacters);
        return translationResult.Text;
    }

    private string GetLanguageCode(Language language)
    {
        return language switch
        {
            Language.En => LanguageCode.EnglishAmerican,
            Language.Kr => LanguageCode.Korean,
            Language.Ch => LanguageCode.Chinese,
            Language.Ja => LanguageCode.Japanese,
            _ => throw new ArgumentOutOfRangeException(nameof(language), language, null)
        };
    }
}