btcpayserver/BTCPayServer/TagHelpers/TranslateTagHelper.cs

using System.Globalization;
using System.Runtime.CompilerServices;
using System.Threading.Tasks;
using AngleSharp.Html;
using BTCPayServer.Abstractions.Services;
using Microsoft.AspNetCore.Html;
using Microsoft.AspNetCore.Mvc.Localization;
using Microsoft.AspNetCore.Mvc.TagHelpers;
using Microsoft.AspNetCore.Razor.TagHelpers;
using Microsoft.Extensions.Localization;
using Microsoft.Extensions.Logging;

namespace BTCPayServer.TagHelpers
{
    [HtmlTargetElement(Attributes = "text-translate")]
    [HtmlTargetElement(Attributes = "html-translate")]
    [HtmlTargetElement("input", Attributes = "[type=submit]")]
    [HtmlTargetElement(Attributes = "[id=page-primary]")]
    public class TranslateTagHelper : TagHelper
    {
        private readonly IStringLocalizer<TranslateTagHelper> _localizer;
        private readonly Safe _safe;

        public bool TextTranslate { get; set; }
        public bool HtmlTranslate { get; set; }
        public string Value { get; set; }


        public TranslateTagHelper(
            IStringLocalizer<TranslateTagHelper> localizer,
            Safe safe)
        {
            _localizer = localizer;
            _safe = safe;
        }


        public override int Order
        {
            get
            {
                // Run this TagHelper before others
                return -10;
            }
        }

        public override async Task ProcessAsync(TagHelperContext context, TagHelperOutput output)
        {
            if (Value != null)
            {
                output.CopyHtmlAttribute("value", context);
            }
            if (context.TagName == "input")
            {
                var newContent = _localizer[Value];
                output.Attributes.SetAttribute("value", newContent.Value);
            }
            else
            {
                var originalContent = output.Content.IsModified
                    ? output.Content.GetContent()
                    : (await output.GetChildContentAsync()).GetContent();
                var newContent = _localizer[originalContent.Trim()];
                if (HtmlTranslate)
                    output.Content.SetHtmlContent(_safe.Raw(newContent.Value));
                else
                    output.Content.SetContent(newContent);
            }
        }
    }
}