Discord.Net/src/Discord.Net.WebSocket/Entities/Messages/SocketUserMessage.cs

using Discord.API.Rest;
using Discord.Rest;
using System;
using System.Collections.Generic;
using System.Collections.Immutable;
using System.Diagnostics;
using System.Threading.Tasks;
using Model = Discord.API.Message;

namespace Discord.WebSocket
{
    [DebuggerDisplay(@"{DebuggerDisplay,nq}")]
    public class SocketUserMessage : SocketMessage, IUserMessage
    {
        private bool _isMentioningEveryone, _isTTS, _isPinned;
        private long? _editedTimestampTicks;
        private ulong? _webhookId;
        private ImmutableArray<Attachment> _attachments;
        private ImmutableArray<Embed> _embeds;
        private ImmutableArray<ITag> _tags;
        
        public override bool IsTTS => _isTTS;
        public override bool IsPinned => _isPinned;
        public override ulong? WebhookId => _webhookId;
        public override DateTimeOffset? EditedTimestamp => DateTimeUtils.FromTicks(_editedTimestampTicks);
        public override IReadOnlyCollection<Attachment> Attachments => _attachments;
        public override IReadOnlyCollection<Embed> Embeds => _embeds;
        public override IReadOnlyCollection<ITag> Tags => _tags;
        public override IReadOnlyCollection<SocketGuildChannel> MentionedChannels => MessageHelper.FilterTagsByValue<SocketGuildChannel>(TagType.ChannelMention, _tags);
        public override IReadOnlyCollection<SocketRole> MentionedRoles => MessageHelper.FilterTagsByValue<SocketRole>(TagType.RoleMention, _tags);
        public override IReadOnlyCollection<SocketUser> MentionedUsers => MessageHelper.FilterTagsByValue<SocketUser>(TagType.UserMention, _tags);

        internal SocketUserMessage(DiscordSocketClient discord, ulong id, ISocketMessageChannel channel, SocketUser author)
            : base(discord, id, channel, author)
        {
        }
        internal new static SocketUserMessage Create(DiscordSocketClient discord, ClientState state, SocketUser author, ISocketMessageChannel channel, Model model)
        {
            var entity = new SocketUserMessage(discord, model.Id, channel, author);
            entity.Update(state, model);
            return entity;
        }

        internal override void Update(ClientState state, Model model)
        {
            base.Update(state, model);

            if (model.IsTextToSpeech.IsSpecified)
                _isTTS = model.IsTextToSpeech.Value;
            if (model.Pinned.IsSpecified)
                _isPinned = model.Pinned.Value;
            if (model.EditedTimestamp.IsSpecified)
                _editedTimestampTicks = model.EditedTimestamp.Value?.UtcTicks;
            if (model.MentionEveryone.IsSpecified)
                _isMentioningEveryone = model.MentionEveryone.Value;
            if (model.WebhookId.IsSpecified)
                _webhookId = model.WebhookId.Value;

            if (model.Attachments.IsSpecified)
            {
                var value = model.Attachments.Value;
                if (value.Length > 0)
                {
                    var attachments = ImmutableArray.CreateBuilder<Attachment>(value.Length);
                    for (int i = 0; i < value.Length; i++)
                        attachments.Add(Attachment.Create(value[i]));
                    _attachments = attachments.ToImmutable();
                }
                else
                    _attachments = ImmutableArray.Create<Attachment>();
            }

            if (model.Embeds.IsSpecified)
            {
                var value = model.Embeds.Value;
                if (value.Length > 0)
                {
                    var embeds = ImmutableArray.CreateBuilder<Embed>(value.Length);
                    for (int i = 0; i < value.Length; i++)
                        embeds.Add(Embed.Create(value[i]));
                    _embeds = embeds.ToImmutable();
                }
                else
                    _embeds = ImmutableArray.Create<Embed>();
            }

            ImmutableArray<IUser> mentions = ImmutableArray.Create<IUser>();
            if (model.UserMentions.IsSpecified)
            {
                var value = model.UserMentions.Value;
                if (value.Length > 0)
                {
                    var newMentions = ImmutableArray.CreateBuilder<IUser>(value.Length);
                    for (int i = 0; i < value.Length; i++)
                    {
                        var val = value[i];
                        if (val.Object != null)
                            newMentions.Add(SocketSimpleUser.Create(Discord, Discord.State, val.Object));
                    }
                    mentions = newMentions.ToImmutable();
                }
            }

            if (model.Content.IsSpecified)
            {
                var text = model.Content.Value;
                var guild = (Channel as SocketGuildChannel)?.Guild;
                _tags = MessageHelper.ParseTags(text, Channel, guild, mentions);
                model.Content = text;
            }
        }

        public Task ModifyAsync(Action<ModifyMessageParams> func, RequestOptions options = null)
            => MessageHelper.ModifyAsync(this, Discord, func, options);

        public Task AddReactionAsync(Emoji emoji, RequestOptions options)
            => MessageHelper.AddReactionAsync(this, emoji, Discord, options);
        public Task AddReactionAsync(string emoji, RequestOptions options)
            => MessageHelper.AddReactionAsync(this, emoji, Discord, options);

        public Task RemoveReactionAsync(Emoji emoji, IUser user, RequestOptions options)
            => MessageHelper.RemoveReactionAsync(this, user, emoji, Discord, options);
        public Task RemoveReactionAsync(string emoji, IUser user, RequestOptions options)
            => MessageHelper.RemoveReactionAsync(this, user, emoji, Discord, options);
        
        public Task<IReadOnlyCollection<IUser>> GetReactionUsersAsync(string emoji, Action<GetReactionUsersParams> func, RequestOptions options)
            => MessageHelper.GetReactionUsersAsync(this, emoji, func, Discord, options);

        public Task PinAsync(RequestOptions options = null)
            => MessageHelper.PinAsync(this, Discord, options);
        public Task UnpinAsync(RequestOptions options = null)
            => MessageHelper.UnpinAsync(this, Discord, options);

        public string Resolve(TagHandling userHandling = TagHandling.Name, TagHandling channelHandling = TagHandling.Name,
            TagHandling roleHandling = TagHandling.Name, TagHandling everyoneHandling = TagHandling.Ignore, TagHandling emojiHandling = TagHandling.Name)
            => MentionUtils.Resolve(this, userHandling, channelHandling, roleHandling, everyoneHandling, emojiHandling);

        private string DebuggerDisplay => $"{Author}: {Content} ({Id}{(Attachments.Count > 0 ? $", {Attachments.Count} Attachments" : "")})";
        internal new SocketUserMessage Clone() => MemberwiseClone() as SocketUserMessage;
    }
}