EventsBaseCommand.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Text.RegularExpressions;
using System.Threading.Tasks;
using CompatApiClient.Utils;
using CompatBot.Commands.Attributes;
using CompatBot.Database;
using CompatBot.Database.Providers;
using CompatBot.Utils;
using CompatBot.Utils.Extensions;
using DSharpPlus;
using DSharpPlus.CommandsNext;
using DSharpPlus.Entities;
using DSharpPlus.EventArgs;
using DSharpPlus.Interactivity.Extensions;
using Microsoft.EntityFrameworkCore;

namespace CompatBot.Commands;

internal partial class EventsBaseCommand: BaseCommandModuleCustom
{
    private static readonly TimeSpan InteractTimeout = TimeSpan.FromMinutes(5);

    [GeneratedRegex(@"((?<days>\d+)(\.|d\s*))?((?<hours>\d+)(\:|h\s*))?((?<mins>\d+)m?)?", RegexOptions.IgnoreCase | RegexOptions.Singleline | RegexOptions.ExplicitCapture)]
    private static partial Regex Duration();

    protected static async Task NearestEvent(CommandContext ctx, string? eventName = null)
    {
        var originalEventName = eventName = eventName?.Trim(40);
        var current = DateTime.UtcNow;
        var currentTicks = current.Ticks;
        await using var db = new BotDb();
        var currentEvents = await db.EventSchedule.OrderBy(e => e.End).Where(e => e.Start <= currentTicks && e.End >= currentTicks).ToListAsync().ConfigureAwait(false);
        var nextEvent = await db.EventSchedule.OrderBy(e => e.Start).FirstOrDefaultAsync(e => e.Start > currentTicks).ConfigureAwait(false);
        if (string.IsNullOrEmpty(eventName))
        {
            var nearestEventMsg = "";
            if (currentEvents.Count > 0)
            {
                if (currentEvents.Count == 1)
                    nearestEventMsg = $"Current event: {currentEvents[0].Name} (going for {FormatCountdown(current - currentEvents[0].Start.AsUtc())})\n";
                else
                {
                    nearestEventMsg = "Current events:\n";
                    foreach (var e in currentEvents)
                        nearestEventMsg += $"{e.Name} (going for {FormatCountdown(current - e.Start.AsUtc())})\n";
                }
            }
            if (nextEvent != null)
                nearestEventMsg += $"Next event: {nextEvent.Name} (starts in {FormatCountdown(nextEvent.Start.AsUtc() - current)})";
            await ctx.Channel.SendMessageAsync(nearestEventMsg.TrimEnd()).ConfigureAwait(false);
            return;
        }

        eventName = await FuzzyMatchEventName(db, eventName).ConfigureAwait(false);
        var promo = "";
        if (currentEvents.Count > 0)
            promo = $"\nMeanwhile check out this {(string.IsNullOrEmpty(currentEvents[0].EventName) ? "" : currentEvents[0].EventName + " " + currentEvents[0].Year + " ")}event in progress: {currentEvents[0].Name} (going for {FormatCountdown(current - currentEvents[0].Start.AsUtc())})";
        else if (nextEvent != null)
            promo = $"\nMeanwhile check out this upcoming {(string.IsNullOrEmpty(nextEvent.EventName) ? "" : nextEvent.EventName + " " + nextEvent.Year + " ")}event: {nextEvent.Name} (starts in {FormatCountdown(nextEvent.Start.AsUtc() - current)})";
        var firstNamedEvent = await db.EventSchedule.OrderBy(e => e.Start).FirstOrDefaultAsync(e => e.Year >= current.Year && e.EventName == eventName).ConfigureAwait(false);
        if (firstNamedEvent == null)
        {
            var scheduleEntry = await FuzzyMatchEntryName(db, originalEventName).ConfigureAwait(false);
            var events = await db.EventSchedule.OrderBy(e => e.Start).Where(e => e.End > current.Ticks && e.Name == scheduleEntry).ToListAsync().ConfigureAwait(false);
            if (events.Any())
            {
                var eventListMsg = new StringBuilder();
                foreach (var eventEntry in events)
                {
                    if (eventEntry.Start < current.Ticks)
                        eventListMsg.AppendLine($"{eventEntry.Name} ends in {FormatCountdown(eventEntry.End.AsUtc() - current)}");
                    else
                        eventListMsg.AppendLine($"{eventEntry.Name} starts in {FormatCountdown(eventEntry.Start.AsUtc() - current)}");
                }
                await ctx.SendAutosplitMessageAsync(eventListMsg.ToString(), blockStart: "", blockEnd: "").ConfigureAwait(false);
                return;
            }

            var noEventMsg = $"No information about the upcoming {eventName?.Sanitize(replaceBackTicks: true)} at the moment";
            if (eventName?.Length > 10)
                noEventMsg = "No information about such event at the moment";
            else if (ctx.User.Id is 259997001880436737ul or 377190919327318018ul)
            {
                noEventMsg = $"Haha, very funny, {ctx.User.Mention}. So original. Never saw this joke before.";
                promo = null;
            }
            if (!string.IsNullOrEmpty(promo))
                noEventMsg += promo;
            await ctx.Channel.SendMessageAsync(noEventMsg).ConfigureAwait(false);
            return;
        }

        if (firstNamedEvent.Start >= currentTicks)
        {
            var upcomingNamedEventMsg = $"__{FormatCountdown(firstNamedEvent.Start.AsUtc() - current)} until {eventName} {firstNamedEvent.Year}!__";
            if (string.IsNullOrEmpty(promo) || nextEvent?.Id == firstNamedEvent.Id)
                upcomingNamedEventMsg += $"\nFirst event: {firstNamedEvent.Name}";
            else
                upcomingNamedEventMsg += promo;
            await ctx.Channel.SendMessageAsync(upcomingNamedEventMsg).ConfigureAwait(false);
            return;
        }

        var lastNamedEvent = await db.EventSchedule.OrderByDescending(e => e.End).FirstOrDefaultAsync(e => e.Year == current.Year && e.EventName == eventName).ConfigureAwait(false);
        if (lastNamedEvent is not null && lastNamedEvent.End <= currentTicks)
        {
            if (lastNamedEvent.End < current.AddMonths(-1).Ticks)
            {
                firstNamedEvent = await db.EventSchedule.OrderBy(e => e.Start).FirstOrDefaultAsync(e => e.Year >= current.Year + 1 && e.EventName == eventName).ConfigureAwait(false);
                if (firstNamedEvent == null)
                {
                    var noEventMsg = $"No information about the upcoming {eventName?.Sanitize(replaceBackTicks: true)} at the moment";
                    if (eventName?.Length > 10)
                        noEventMsg = "No information about such event at the moment";
                    else if (ctx.User.Id is 259997001880436737ul or 377190919327318018ul)
                    {
                        noEventMsg = $"Haha, very funny, {ctx.User.Mention}. So original. Never saw this joke before.";
                        promo = null;
                    }
                    if (!string.IsNullOrEmpty(promo))
                        noEventMsg += promo;
                    await ctx.Channel.SendMessageAsync(noEventMsg).ConfigureAwait(false);
                    return;
                }
                        
                var upcomingNamedEventMsg = $"__{FormatCountdown(firstNamedEvent.Start.AsUtc() - current)} until {eventName} {firstNamedEvent.Year}!__";
                if (string.IsNullOrEmpty(promo) || nextEvent?.Id == firstNamedEvent.Id)
                    upcomingNamedEventMsg += $"\nFirst event: {firstNamedEvent.Name}";
                else
                    upcomingNamedEventMsg += promo;
                await ctx.Channel.SendMessageAsync(upcomingNamedEventMsg).ConfigureAwait(false);
                return;
            }

            var e3EndedMsg = $"__{eventName} {current.Year} has concluded. See you next year! (maybe)__";
            if (!string.IsNullOrEmpty(promo))
                e3EndedMsg += promo;
            await ctx.Channel.SendMessageAsync(e3EndedMsg).ConfigureAwait(false);
            return;
        }

        var currentNamedEvent = await db.EventSchedule.OrderBy(e => e.End).FirstOrDefaultAsync(e => e.Start <= currentTicks && e.End >= currentTicks && e.EventName == eventName).ConfigureAwait(false);
        var nextNamedEvent = await db.EventSchedule.OrderBy(e => e.Start).FirstOrDefaultAsync(e => e.Start > currentTicks && e.EventName == eventName).ConfigureAwait(false);
        var msg = $"__{eventName} {current.Year} is already in progress!__\n";
        if (currentNamedEvent != null)
            msg += $"Current event: {currentNamedEvent.Name} (going for {FormatCountdown(current - currentNamedEvent.Start.AsUtc())})\n";
        if (nextNamedEvent != null)
            msg += $"Next event: {nextNamedEvent.Name} (starts in {FormatCountdown(nextNamedEvent.Start.AsUtc() - current)})";
        await ctx.SendAutosplitMessageAsync(msg.TrimEnd(), blockStart: "", blockEnd: "").ConfigureAwait(false);
    }

    protected static async Task Add(CommandContext ctx, string? eventName = null)
    {
        var evt = new EventSchedule();
        var (success, msg) = await EditEventPropertiesAsync(ctx, evt, eventName).ConfigureAwait(false);
        if (success)
        {
            await using var db = new BotDb();
            await db.EventSchedule.AddAsync(evt).ConfigureAwait(false);
            await db.SaveChangesAsync().ConfigureAwait(false);
            await ctx.ReactWithAsync(Config.Reactions.Success).ConfigureAwait(false);
            if (LimitedToSpamChannel.IsSpamChannel(ctx.Channel))
                await msg.UpdateOrCreateMessageAsync(ctx.Channel, embed: FormatEvent(evt).WithTitle("Created new event schedule entry #" + evt.Id)).ConfigureAwait(false);
            else
                await msg.UpdateOrCreateMessageAsync(ctx.Channel, "Added a new schedule entry").ConfigureAwait(false);
        }
        else
            await msg.UpdateOrCreateMessageAsync(ctx.Channel, "Event creation aborted").ConfigureAwait(false);
    }

    protected static async Task Remove(CommandContext ctx, params int[] ids)
    {
        await using var db = new BotDb();
        var eventsToRemove = await db.EventSchedule.Where(e3e => ids.Contains(e3e.Id)).ToListAsync().ConfigureAwait(false);
        db.EventSchedule.RemoveRange(eventsToRemove);
        var removedCount = await db.SaveChangesAsync().ConfigureAwait(false);
        if (removedCount == ids.Length)
            await ctx.Channel.SendMessageAsync($"Event{StringUtils.GetSuffix(ids.Length)} successfully removed!").ConfigureAwait(false);
        else
            await ctx.Channel.SendMessageAsync($"Removed {removedCount} event{StringUtils.GetSuffix(removedCount)}, but was asked to remove {ids.Length}").ConfigureAwait(false);
    }

    protected static async Task Clear(CommandContext ctx, int? year = null)
    {
        var currentYear = DateTime.UtcNow.Year;
        await using var db = new BotDb();
        var itemsToRemove = await db.EventSchedule.Where(e =>
            year.HasValue
                ? e.Year == year
                : e.Year < currentYear
        ).ToListAsync().ConfigureAwait(false);
        db.EventSchedule.RemoveRange(itemsToRemove);
        var removedCount = await db.SaveChangesAsync().ConfigureAwait(false);
        await ctx.Channel.SendMessageAsync($"Removed {removedCount} event{(removedCount == 1 ? "" : "s")}").ConfigureAwait(false);
    }

    protected static async Task Update(CommandContext ctx, int id, string? eventName = null)
    {
        await using var db = new BotDb();
        var evt = eventName == null
            ? db.EventSchedule.FirstOrDefault(e => e.Id == id)
            : db.EventSchedule.FirstOrDefault(e => e.Id == id && e.EventName == eventName);
        if (evt == null)
        {
            await ctx.ReactWithAsync(Config.Reactions.Failure, $"No event with id {id}").ConfigureAwait(false);
            return;
        }

        var (success, msg) = await EditEventPropertiesAsync(ctx, evt, eventName).ConfigureAwait(false);
        if (success)
        {
            await db.SaveChangesAsync().ConfigureAwait(false);
            if (LimitedToSpamChannel.IsSpamChannel(ctx.Channel))
                await msg.UpdateOrCreateMessageAsync(ctx.Channel, embed: FormatEvent(evt).WithTitle("Updated event schedule entry #" + evt.Id)).ConfigureAwait(false);
            else
                await msg.UpdateOrCreateMessageAsync(ctx.Channel, "Updated the schedule entry").ConfigureAwait(false);
        }
        else
            await msg.UpdateOrCreateMessageAsync(ctx.Channel, "Event update aborted, changes weren't saved").ConfigureAwait(false);
    }

    protected static async Task List(CommandContext ctx, string? eventName = null, int? year = null)
    {
        var showAll = "all".Equals(eventName, StringComparison.InvariantCultureIgnoreCase);
        var currentTicks = DateTime.UtcNow.Ticks;
        await using var db = new BotDb();
        IQueryable<EventSchedule> query = db.EventSchedule;
        if (year.HasValue)
            query = query.Where(e => e.Year == year);
        else if (!showAll)
            query = query.Where(e => e.End > currentTicks);
        if (!string.IsNullOrEmpty(eventName) && !showAll)
        {
            eventName = await FuzzyMatchEventName(db, eventName).ConfigureAwait(false);
            query = query.Where(e => e.EventName == eventName);
        }
        List<EventSchedule> events = await query
            .OrderBy(e => e.Start)
            .ToListAsync()
            .ConfigureAwait(false);
        if (events.Count == 0)
        {
            await ctx.Channel.SendMessageAsync("There are no events to show").ConfigureAwait(false);
            return;
        }

        var msg = new StringBuilder();
        var currentYear = -1;
        var currentEvent = Guid.NewGuid().ToString();
        foreach (var evt in events)
        {
            if (evt.Year != currentYear)
            {
                if (currentYear > 0)
                    msg.AppendLine().AppendLine($"__Year {evt.Year}__");
                currentEvent = Guid.NewGuid().ToString();
                currentYear = evt.Year;
            }

            var evtName = evt.EventName ?? "";
            if (currentEvent != evtName)
            {
                currentEvent = evtName;
                var printName = string.IsNullOrEmpty(currentEvent) ? "Various independent events" : $"**{currentEvent} {currentYear} schedule**";
                msg.AppendLine($"{printName} (UTC):");
            }
            msg.Append(StringUtils.InvisibleSpacer).Append('`');
            if (ModProvider.IsMod(ctx.Message.Author.Id))
                msg.Append($"[{evt.Id:0000}] ");
            msg.Append($"{evt.Start.AsUtc():u}");
            if (ctx.Channel.IsPrivate)
                msg.Append($@" - {evt.End.AsUtc():u}");
            msg.AppendLine($@" ({evt.End.AsUtc() - evt.Start.AsUtc():h\:mm})`: {evt.Name}");
        }
        var ch = await ctx.GetChannelForSpamAsync().ConfigureAwait(false);
        await ch.SendAutosplitMessageAsync(msg, blockStart: "", blockEnd: "").ConfigureAwait(false);
    }

    private static async Task<(bool success, DiscordMessage? message)> EditEventPropertiesAsync(CommandContext ctx, EventSchedule evt, string? eventName = null)
    {
        var interact = ctx.Client.GetInteractivity();
        var abort = new DiscordButtonComponent(ButtonStyle.Danger, "event:edit:abort", "Cancel", emoji: new(DiscordEmoji.FromUnicode("✖")));
        var lastPage = new DiscordButtonComponent(ButtonStyle.Secondary, "event:edit:last", "To Last Field", emoji: new(DiscordEmoji.FromUnicode("⏭")));
        var firstPage = new DiscordButtonComponent(ButtonStyle.Secondary, "event:edit:first", "To First Field", emoji: new(DiscordEmoji.FromUnicode("⏮")));
        var previousPage = new DiscordButtonComponent(ButtonStyle.Secondary, "event:edit:previous", "Previous", emoji: new(DiscordEmoji.FromUnicode("◀")));
        var nextPage = new DiscordButtonComponent(ButtonStyle.Primary, "event:edit:next", "Next", emoji: new(DiscordEmoji.FromUnicode("▶")));
        var trash = new DiscordButtonComponent(ButtonStyle.Secondary, "event:edit:trash", "Clear", emoji: new(DiscordEmoji.FromUnicode("🗑")));
        var saveEdit = new DiscordButtonComponent(ButtonStyle.Success, "event:edit:save", "Save", emoji: new(DiscordEmoji.FromUnicode("💾")));

        var skipEventNameStep = !string.IsNullOrEmpty(eventName);
        DiscordMessage? msg = null;
        string? errorMsg = null;
        DiscordMessage? txt;
        ComponentInteractionCreateEventArgs? btn;
        DiscordMessageBuilder messageBuilder;

        step1:
        // step 1: get the new start date
        saveEdit.SetEnabled(evt.IsComplete());
        messageBuilder = new DiscordMessageBuilder()
            .WithContent("Please specify a new **start date and time**")
            .WithEmbed(FormatEvent(evt, errorMsg, 1).WithDescription($"""
                Example: `{DateTime.UtcNow:yyyy-MM-dd HH:mm}`
                By default all times use UTC, only limited number of time zones supported
                """))
            .AddComponents(lastPage, nextPage)
            .AddComponents(saveEdit, abort);
        errorMsg = null;
        msg = await msg.UpdateOrCreateMessageAsync(ctx.Channel, messageBuilder).ConfigureAwait(false);
        (txt, btn) = await interact.WaitForMessageOrButtonAsync(msg, ctx.User, InteractTimeout).ConfigureAwait(false);
        if (btn != null)
        {
            if (btn.Id == abort.CustomId)
                return (false, msg);

            if (btn.Id == saveEdit.CustomId)
                return (true, msg);

            if (btn.Id == lastPage.CustomId)
                goto step4;
        }
        else if (txt != null)
        {
            if (!TimeParser.TryParse(txt.Content, out var newTime))
            {
                errorMsg = $"Couldn't parse `{txt.Content}` as a start date and time";
                goto step1;
            }
            if (newTime < DateTime.UtcNow && evt.End == default)
                errorMsg = "Specified time is in the past, are you sure it is correct?";

            var duration = evt.End - evt.Start;
            evt.Start = newTime.Ticks;
            evt.End = evt.Start + duration;
            evt.Year = newTime.Year;
        }
        else
            return (false, msg);

        step2:
        // step 2: get the new duration
        saveEdit.SetEnabled(evt.IsComplete());
        messageBuilder = new DiscordMessageBuilder()
            .WithContent("Please specify a new **event duration**")
            .WithEmbed(FormatEvent(evt, errorMsg, 2).WithDescription("Example: `2d 1h 15m`, or `2.1:00`"))
            .AddComponents(previousPage, nextPage)
            .AddComponents(saveEdit, abort);
        errorMsg = null;
        msg = await msg.UpdateOrCreateMessageAsync(ctx.Channel, messageBuilder).ConfigureAwait(false);
        (txt, btn) = await interact.WaitForMessageOrButtonAsync(msg, ctx.User, InteractTimeout).ConfigureAwait(false);
        if (btn != null)
        {
            if (btn.Id == abort.CustomId)
                return (false, msg);

            if (btn.Id == saveEdit.CustomId)
                return (true, msg);

            if (btn.Id == previousPage.CustomId)
                goto step1;

            if (skipEventNameStep)
                goto step4;
        }
        else if (txt != null)
        {
            var newLength = await TryParseTimeSpanAsync(ctx, txt.Content, false).ConfigureAwait(false);
            if (!newLength.HasValue)
            {
                errorMsg = $"Couldn't parse `{txt.Content}` as a duration";
                goto step2;
            }

            evt.End = (evt.Start.AsUtc() + newLength.Value).Ticks;
        }
        else
            return (false, msg);

        step3:
        // step 3: get the new event name
        saveEdit.SetEnabled(evt.IsComplete());
        trash.SetDisabled(string.IsNullOrEmpty(evt.EventName));
        messageBuilder = new DiscordMessageBuilder()
            .WithContent("Please specify a new **event name**")
            .WithEmbed(FormatEvent(evt, errorMsg, 3))
            .AddComponents(previousPage, nextPage, trash)
            .AddComponents(saveEdit, abort);
        errorMsg = null;
        msg = await msg.UpdateOrCreateMessageAsync(ctx.Channel, messageBuilder).ConfigureAwait(false);
        (txt, btn) = await interact.WaitForMessageOrButtonAsync(msg, ctx.User, InteractTimeout).ConfigureAwait(false);
        if (btn != null)
        {
            if (btn.Id == abort.CustomId)
                return (false, msg);

            if (btn.Id == saveEdit.CustomId)
                return (true, msg);

            if (btn.Id == previousPage.CustomId)
                goto step2;

            if (btn.Id == trash.CustomId)
                evt.EventName = null;
        }
        else if (txt != null)
            evt.EventName = string.IsNullOrWhiteSpace(txt.Content) || txt.Content == "-" ? null : txt.Content;
        else
            return (false, msg);

        step4:
        // step 4: get the new schedule entry name
        saveEdit.SetEnabled(evt.IsComplete());
        messageBuilder = new DiscordMessageBuilder()
            .WithContent("Please specify a new **schedule entry title**")
            .WithEmbed(FormatEvent(evt, errorMsg, 4))
            .AddComponents(previousPage, firstPage)
            .AddComponents(saveEdit, abort);
        errorMsg = null;
        msg = await msg.UpdateOrCreateMessageAsync(ctx.Channel, messageBuilder).ConfigureAwait(false);
        (txt, btn) = await interact.WaitForMessageOrButtonAsync(msg, ctx.User, InteractTimeout).ConfigureAwait(false);
        if (btn != null)
        {
            if (btn.Id == abort.CustomId)
                return (false, msg);

            if (btn.Id == saveEdit.CustomId)
                return (true, msg);

            if (btn.Id == firstPage.CustomId)
                goto step1;

            if (btn.Id == previousPage.CustomId)
            {
                if (skipEventNameStep)
                    goto step2;
                goto step3;
            }
        }
        else if (txt != null)
        {
            if (string.IsNullOrEmpty(txt.Content))
            {
                errorMsg = "Entry title cannot be empty";
                goto step4;
            }

            evt.Name = txt.Content;
        }
        else
            return (false, msg);

        step5:
        // step 5: confirm
        if (errorMsg == null && !evt.IsComplete())
            errorMsg = "Some required properties are not defined";
        saveEdit.SetEnabled(evt.IsComplete());
        messageBuilder = new DiscordMessageBuilder()
            .WithContent("Does this look good? (y/n)")
            .WithEmbed(FormatEvent(evt, errorMsg))
            .AddComponents(previousPage, firstPage)
            .AddComponents(saveEdit, abort);
        errorMsg = null;
        msg = await msg.UpdateOrCreateMessageAsync(ctx.Channel, messageBuilder).ConfigureAwait(false);
        (txt, btn) = await interact.WaitForMessageOrButtonAsync(msg, ctx.User, InteractTimeout).ConfigureAwait(false);
        if (btn != null)
        {
            if (btn.Id == abort.CustomId)
                return (false, msg);

            if (btn.Id == saveEdit.CustomId)
                return (true, msg);

            if (btn.Id == previousPage.CustomId)
                goto step4;

            if (btn.Id == firstPage.CustomId)
                goto step1;
        }
        else if (!string.IsNullOrEmpty(txt?.Content))
        {
            if (!evt.IsComplete())
                goto step5;

            switch (txt.Content.ToLowerInvariant())
            {
                case "yes":
                case "y":
                case "✅":
                case "☑":
                case "✔":
                case "👌":
                case "👍":
                    return (true, msg);
                case "no":
                case "n":
                case "❎":
                case "❌":
                case "👎":
                    return (false, msg);
                default:
                    errorMsg = "I don't know what you mean, so I'll just abort";
                    goto step5;
            }
        }
        else
        {
            return (false, msg);
        }

        return (false, msg);
    }

    private static string? NameWithoutLink(string? name)
    {
        if (string.IsNullOrEmpty(name))
            return name;

        var lastPartIdx = name.LastIndexOf(' ');
        if (lastPartIdx < 0)
            return name;

        if (name.Length - lastPartIdx > 5
            && name.Substring(lastPartIdx + 1, 5).ToLowerInvariant() is string lnk
            && (lnk.StartsWith("<http") || lnk.StartsWith("http")))
            return name[..lastPartIdx];

        return name;
    }

    private static async Task<string?> FuzzyMatchEventName(BotDb db, string? eventName)
    {
        var knownEventNames = await db.EventSchedule.Select(e => e.EventName).Distinct().ToListAsync().ConfigureAwait(false);
        var (score, name) = knownEventNames.Select(n => (score: eventName.GetFuzzyCoefficientCached(n), name: n)).OrderByDescending(t => t.score).FirstOrDefault();
        return score > 0.8 ? name : eventName;
    }

    private static async Task<string?> FuzzyMatchEntryName(BotDb db, string? eventName)
    {
        var now = DateTime.UtcNow.Ticks;
        var knownNames = await db.EventSchedule.Where(e => e.End > now).Select(e => e.Name).ToListAsync().ConfigureAwait(false);
        var (score, name) = knownNames.Select(n => (score: eventName.GetFuzzyCoefficientCached(NameWithoutLink(n)), name: n)).OrderByDescending(t => t.score).FirstOrDefault();
        return score > 0.5 ? name : eventName;
    }

    private static async Task<TimeSpan?> TryParseTimeSpanAsync(CommandContext ctx, string duration, bool react = true)
    {
        var d = Duration().Match(duration);
        if (!d.Success)
        {
            if (react)
                await ctx.ReactWithAsync(Config.Reactions.Failure, $"Failed to parse `{duration}` as a time", true).ConfigureAwait(false);
            return null;
        }

        _ = int.TryParse(d.Groups["days"].Value, out var days);
        _ = int.TryParse(d.Groups["hours"].Value, out var hours);
        _ = int.TryParse(d.Groups["mins"].Value, out var mins);
        if (days == 0 && hours == 0 && mins == 0)
        {
            if (react)
                await ctx.ReactWithAsync(Config.Reactions.Failure, $"Failed to parse `{duration}` as a time", true).ConfigureAwait(false);
            return null;
        }

        return new TimeSpan(days, hours, mins, 0);
    }

    private static string FormatCountdown(TimeSpan timeSpan)
    {
        var result = "";
        var days = (int)timeSpan.TotalDays;
        if (days > 0)
            timeSpan -= TimeSpan.FromDays(days);
        var hours = (int)timeSpan.TotalHours;
        if (hours > 0)
            timeSpan -= TimeSpan.FromHours(hours);
        var mins = (int)timeSpan.TotalMinutes;
        if (mins > 0)
            timeSpan -= TimeSpan.FromMinutes(mins);
        var secs = (int)timeSpan.TotalSeconds;
        if (days > 0)
            result += $"{days} day{(days == 1 ? "" : "s")} ";
        if (hours > 0 || days > 0)
            result += $"{hours} hour{(hours == 1 ? "" : "s")} ";
        if (mins > 0 || hours > 0 || days > 0)
            result += $"{mins} minute{(mins == 1 ? "" : "s")} ";
        result += $"{secs} second{(secs == 1 ? "" : "s")}";
        return result;
    }

    private static DiscordEmbedBuilder FormatEvent(EventSchedule evt, string? error = null, int highlight = -1)
    {
        var start = evt.Start.AsUtc();
        var field = 1;
        var result = new DiscordEmbedBuilder
        {
            Title = "Schedule entry preview",
            Color = string.IsNullOrEmpty(error) ? Config.Colors.Help : Config.Colors.Maintenance,
        };
        if (!string.IsNullOrEmpty(error))
            result.AddField("Entry error", error);
        var currentTime = DateTime.UtcNow;
        if (evt.Start > currentTime.Ticks)
            result.WithFooter($"Starts in {FormatCountdown(evt.Start.AsUtc() - currentTime)}");
        else if (evt.End > currentTime.Ticks)
            result.WithFooter($"Ends in {FormatCountdown(evt.End.AsUtc() - currentTime)}");
        var eventDuration = evt.End.AsUtc() - start;
        var durationFormat = eventDuration.TotalDays > 0 ? @"d\d\ h\h\ m\m" : @"h\h\ m\m";
        var startWarn = start < DateTime.UtcNow ? "⚠️ " : "";
        result
            .AddFieldEx(startWarn + "Start time", evt.Start == 0 ? "-" : start.ToString("u"), highlight == field++, true)
            .AddFieldEx("Duration", evt.Start == evt.End ? "-" : eventDuration.ToString(durationFormat), highlight == field++, true)
            .AddFieldEx("Event name", string.IsNullOrEmpty(evt.EventName) ? "-" : evt.EventName, highlight == field++, true)
            .AddFieldEx("Schedule entry title", string.IsNullOrEmpty(evt.Name) ? "-" : evt.Name, highlight == field++, true);
#if DEBUG
        result.WithFooter("Test bot instance");
#endif
        return result;
    }
}