telegram-bot/Core/Service/EntityFormatter.cs

#nullable enable

using System.Collections.Generic;
using System.Linq;
using Telegram.Bot.Types;
using Telegram.Bot.Types.Enums;

namespace Kruzya.TelegramBot.Core.Service;

internal class EntityFormatter
{
    private static readonly Dictionary<MessageEntityType, string> HtmlMap = new()
    {
        { MessageEntityType.Bold, "<b>{0}</b>" },
        { MessageEntityType.Code, "<code>{0}</code>" },
        { MessageEntityType.Italic, "<i>{0}</i>" },
        { MessageEntityType.TextMention, "<a href=\"tg://user?id={1}\">{0}</a>" },
        { MessageEntityType.Pre, "<pre>{0}</pre>" },
        { MessageEntityType.Underline, "<u>{0}</u>" }
    };

    private static readonly Dictionary<MessageEntityType, string> MarkdownMap = new()
    {
        { MessageEntityType.Bold, "*{0}*" },
        { MessageEntityType.Code, "```{0}```" },
        { MessageEntityType.Italic, "_{0}_" },
        { MessageEntityType.TextMention, "[{0}](tg://user?id={1})" },
        { MessageEntityType.Pre, "```{0}```" },
        { MessageEntityType.Underline, "__{0}__" }
    };

    public string? FormatMessage(Message msg)
    {
        var text = msg.Text;
        var entities = msg.Entities;

        if (entities == null || text == null) return text;

        foreach (var entity in entities.Reverse())
        {
            var entityText = text.Substring(entity.Offset, entity.Length);
            text = text
                .Remove(entity.Offset, entity.Length);
        }

        return text;
    }
}