BirthdayCheckerService.cs

using DSharpPlus;
using DSharpPlus.Entities;

namespace BirthdayBot
{
    public class BirthdayCheckerService
    {
        private readonly DiscordClient _client;
        private readonly CancellationTokenSource _cts;
        
        public BirthdayCheckerService(DiscordClient client)
        {
            _client = client;
            _cts = new CancellationTokenSource();
        }

        public void Start()
        {
            Task.Run(async () =>
            {
                while (!_cts.IsCancellationRequested)
                {
                    DateTime now = DateTime.UtcNow;
                    DateTime nextCheck = now.Date.AddDays(1);

                    await Task.Delay(nextCheck - now, _cts.Token);

                    await CheckBirthdaysAsync();

                }
            });
        }

        public void Stop()
        {
            _cts.Cancel();
        }

        public async Task CheckBirthdaysAsync()
        {
            List<(ulong guildId, ulong userId, DateTime birthday)> birthdays = await Database.GetBirthdays(0);
            DateTime today = DateTime.UtcNow.Date;

            foreach (var (guildId, userId, birthday) in birthdays)
            {
                DiscordGuild guild = await _client.GetGuildAsync(guildId);
                DiscordMember member = await guild.GetMemberAsync(userId);

                ulong? roleId = await Database.GetRoleId(guildId);

                if (birthday.Month == today.Month && birthday.Day == today.Day)
                {
                    int? age = null;

                    if (birthday.Year != 0001)
                    {
                        DateTime nextBirthday = new(today.Year, birthday.Month, birthday.Day);
                        age = today.Year - birthday.Year;
                        if (today < nextBirthday)
                            age--;
                    }

                    await HBDBuilder(guildId, member, age);

                    if (roleId.HasValue)
                    {
                        ulong rId = roleId.Value;
                        DiscordRole bdayRole = guild.GetRole(rId);
                        await member.GrantRoleAsync(bdayRole, "It's their birthday today!");
                    }

                    await Functions.UpdateListEmbeds(guild, _client);

                }
                else{

                    if (roleId.HasValue)
                    {
                        IEnumerable<DiscordRole> roles = member.Roles;
                        ulong rId = roleId.Value;
                        DiscordRole bdayRole = guild.GetRole(rId);

                        if (roles.Contains(bdayRole))
                        {
                            await member.RevokeRoleAsync(bdayRole, "It is no longer their birthday.");
                        }
                    }

                }
            }

        }

        public async Task HBDBuilder(ulong guildId, DiscordMember member, int? age)
        {
            ulong? channelId = await Database.GetChannelId(guildId);
            //For testing purposes only:
            //ulong? channelId = await Database.GetChannelId(702106468849156127); 
            if (!channelId.HasValue)
                return;

            DiscordChannel channel = await _client.GetChannelAsync(channelId.Value);
            if (channel == null)
                return;

            string ageExtra = age.HasValue && age.Value > 1 ? $"*They are {age.Value} years old today!*\r\n" : "\r\n";

            List<string> videos = new()
            {
                "https://cdn.discordapp.com/attachments/1106239191559454893/1106239377547473057/Today_is_Birthday_in_VRChat.mp4",
                "https://cdn.discordapp.com/attachments/1106239191559454893/1106239378046591068/Today_is_my_birthday.mp4"
            };
            Random random = new();
            int randomVid = random.Next(videos.Count);
            string attachmentUrl = videos[randomVid];

            string contentMsg = $"# Birthday Announcement!\r\n" +
                                $"**Please wish {member.Mention} a happy birthday! 🎂**\r\n" +
                                $"{ageExtra}" +
                                $"\r\n|| @everyone ||";

            DiscordMessageBuilder messageBuilder = new DiscordMessageBuilder()
                                    .WithContent(contentMsg)
                                    .AddFile("video.mp4", await Functions.DownloadFile(attachmentUrl))
                                    .WithAllowedMentions(new IMention[] { new UserMention(member), new EveryoneMention() });
            
            await channel.SendMessageAsync(messageBuilder);

        }
    }
}