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

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

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

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

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

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

    public async Task<TranslationResult> GetTranslation(string body, Language from, Language to)
    {
        TextResult translationResult = await _pipeline.ExecuteAsync(
            async _ => await _deepLClient.TranslateTextAsync(body, GetLanguageCode(from), GetLanguageCode(to)));

        _logger.LogInformation(
            "Translated text. Usage statistics: CHARACTERS BILLED {TranslationResultBilledCharacters}",
            translationResult.BilledCharacters);

        return new TranslationResult
        {
            OriginalText = body,
            From = from,
            To = to,
            TranslationEngineKey = Key,
            BilledCharacterCount = (uint)translationResult.BilledCharacters,
            Status = TranslationRequestStatus.Success,
            TranslatedText = 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)
        };
    }
}