Umbraco-CMS/src/Umbraco.Cms.Api.Management/Controllers/Language/UpdateLanguageController.cs

using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;
using Umbraco.Cms.Core.Mapping;
using Umbraco.Cms.Core.Models;
using Umbraco.Cms.Core.Services;
using Umbraco.Cms.Api.Management.ViewModels.Language;
using Umbraco.New.Cms.Core.Services.Installer;

namespace Umbraco.Cms.Api.Management.Controllers.Language;

public class UpdateLanguageController : LanguageControllerBase
{
    private readonly ILanguageService _languageService;
    private readonly IUmbracoMapper _umbracoMapper;
    private readonly ILocalizationService _localizationService;

    public UpdateLanguageController(ILanguageService languageService, IUmbracoMapper umbracoMapper, ILocalizationService localizationService)
    {
        _languageService = languageService;
        _umbracoMapper = umbracoMapper;
        _localizationService = localizationService;
    }

    /// <summary>
    ///     Updates a language
    /// </summary>
    [HttpPut("update")]
    [MapToApiVersion("1.0")]
    [ProducesResponseType(typeof(NotFoundResult), StatusCodes.Status404NotFound)]
    [ProducesResponseType(typeof(ProblemDetails), StatusCodes.Status400BadRequest)]
    [ProducesResponseType(StatusCodes.Status200OK)]
    // TODO: This needs to be an authorized endpoint.
    public async Task<ActionResult> Update(LanguageViewModel language)
    {
        ILanguage? existingById = language.Id != default ? _localizationService.GetLanguageById(language.Id) : null;
        if (existingById is null)
        {
            return await Task.FromResult(NotFound());
        }

        // note that the service will prevent the default language from being "un-defaulted"
        // but does not hurt to test here - though the UI should prevent it too
        if (existingById.IsDefault && !language.IsDefault)
        {
            ModelState.AddModelError("IsDefault", "Cannot un-default the default language.");
            return await Task.FromResult(ValidationProblem(ModelState));
        }

        existingById = _umbracoMapper.Map(language, existingById);

        if (!_languageService.CanUseLanguagesFallbackLanguage(existingById))
        {
            ModelState.AddModelError("FallbackLanguage", "The selected fall back language does not exist.");
            return await Task.FromResult(ValidationProblem(ModelState));
        }

        if (!_languageService.CanGetProperFallbackLanguage(existingById))
        {
            ModelState.AddModelError("FallbackLanguage", $"The selected fall back language {_localizationService.GetLanguageById(existingById.FallbackLanguageId!.Value)} would create a circular path.");
            return await Task.FromResult(ValidationProblem(ModelState));
        }

        _localizationService.Save(existingById);
        return await Task.FromResult(Ok());
    }
}