nadekobot/src/NadekoBot/Modules/Utility/UnitConversionCommands.cs

using NadekoBot.Modules.Utility.Services;

namespace NadekoBot.Modules.Utility;

public partial class Utility
{
    [Group]
    public class UnitConverterCommands : NadekoSubmodule<ConverterService>
    {
        [NadekoCommand, Aliases]
        public async Task ConvertList()
        {
            var units = _service.Units;

            var embed = _eb.Create()
                .WithTitle(GetText(strs.convertlist))
                .WithOkColor();


            foreach (var g in units.GroupBy(x => x.UnitType))
            {
                embed.AddField(g.Key.ToTitleCase(),
                    String.Join(", ", g.Select(x => x.Triggers.FirstOrDefault()).OrderBy(x => x)));
            }
                
            await ctx.Channel.EmbedAsync(embed).ConfigureAwait(false);
        }

        [NadekoCommand, Aliases]
        [Priority(0)]
        public async Task Convert(string origin, string target, decimal value)
        {
            var originUnit = _service.Units.FirstOrDefault(x => x.Triggers.Select(y => y.ToUpperInvariant()).Contains(origin.ToUpperInvariant()));
            var targetUnit = _service.Units.FirstOrDefault(x => x.Triggers.Select(y => y.ToUpperInvariant()).Contains(target.ToUpperInvariant()));
            if (originUnit is null || targetUnit is null)
            {
                await ReplyErrorLocalizedAsync(strs.convert_not_found(Format.Bold(origin), Format.Bold(target))).ConfigureAwait(false);
                return;
            }
            if (originUnit.UnitType != targetUnit.UnitType)
            {
                await ReplyErrorLocalizedAsync(strs.convert_type_error(Format.Bold(originUnit.Triggers.First()), Format.Bold(targetUnit.Triggers.First()))).ConfigureAwait(false);
                return;
            }
            decimal res;
            if (originUnit.Triggers == targetUnit.Triggers) res = value;
            else if (originUnit.UnitType == "temperature")
            {
                //don't really care too much about efficiency, so just convert to Kelvin, then to target
                switch (originUnit.Triggers.First().ToUpperInvariant())
                {
                    case "C":
                        res = value + 273.15m; //celcius!
                        break;
                    case "F":
                        res = (value + 459.67m) * (5m / 9m);
                        break;
                    default:
                        res = value;
                        break;
                }
                //from Kelvin to target
                switch (targetUnit.Triggers.First().ToUpperInvariant())
                {
                    case "C":
                        res = res - 273.15m; //celcius!
                        break;
                    case "F":
                        res = res * (9m / 5m) - 459.67m;
                        break;
                }
            }
            else
            {
                if (originUnit.UnitType == "currency")
                {
                    res = value * targetUnit.Modifier / originUnit.Modifier;
                }
                else
                    res = value * originUnit.Modifier / targetUnit.Modifier;
            }
            res = Math.Round(res, 4);

            await SendConfirmAsync(GetText(strs.convert(value, originUnit.Triggers.Last(), res, targetUnit.Triggers.Last())));
        }
    }
}