Add command line interface and change solution structure (#26)

DiscordChatExporter.Core/Services/DataService.cs

@@ -0,0 +1,321 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Net.Http;
+using System.Text.RegularExpressions;
+using System.Threading.Tasks;
+using DiscordChatExporter.Core.Exceptions;
+using DiscordChatExporter.Core.Models;
+using Newtonsoft.Json.Linq;
+using Tyrrrz.Extensions;
+
+namespace DiscordChatExporter.Core.Services
+{
+    public partial class DataService : IDataService, IDisposable
+    {
+        private const string ApiRoot = "https://discordapp.com/api/v6";
+
+        private readonly HttpClient _httpClient = new HttpClient();
+        private readonly Dictionary<string, Role> _roleCache = new Dictionary<string, Role>();
+        private readonly Dictionary<string, Channel> _channelCache = new Dictionary<string, Channel>();
+
+        private User ParseUser(JToken token)
+        {
+            var id = token["id"].Value<string>();
+            var discriminator = token["discriminator"].Value<int>();
+            var name = token["username"].Value<string>();
+            var avatarHash = token["avatar"].Value<string>();
+
+            return new User(id, discriminator, name, avatarHash);
+        }
+
+        private Role ParseRole(JToken token)
+        {
+            var id = token["id"].Value<string>();
+            var name = token["name"].Value<string>();
+
+            return new Role(id, name);
+        }
+
+        private Guild ParseGuild(JToken token)
+        {
+            var id = token["id"].Value<string>();
+            var name = token["name"].Value<string>();
+            var iconHash = token["icon"].Value<string>();
+            var roles = token["roles"].Select(ParseRole).ToArray();
+
+            return new Guild(id, name, iconHash, roles);
+        }
+
+        private Channel ParseChannel(JToken token)
+        {
+            // Get basic data
+            var id = token["id"].Value<string>();
+            var guildId = token["guild_id"]?.Value<string>();
+            var type = (ChannelType) token["type"].Value<int>();
+            var topic = token["topic"]?.Value<string>();
+
+            // Extract name based on type
+            string name;
+            if (type.IsEither(ChannelType.DirectTextChat, ChannelType.DirectGroupTextChat))
+            {
+                guildId = Guild.DirectMessages.Id;
+                var recipients = token["recipients"].Select(ParseUser);
+                name = recipients.Select(r => r.Name).JoinToString(", ");
+            }
+            else
+            {
+                name = token["name"].Value<string>();
+            }
+
+            return new Channel(id, guildId, name, topic, type);
+        }
+
+        private Message ParseMessage(JToken token)
+        {
+            // Get basic data
+            var id = token["id"].Value<string>();
+            var channelId = token["channel_id"].Value<string>();
+            var timeStamp = token["timestamp"].Value<DateTime>();
+            var editedTimeStamp = token["edited_timestamp"]?.Value<DateTime?>();
+            var content = token["content"].Value<string>();
+            var type = (MessageType) token["type"].Value<int>();
+
+            // Workarounds for non-default types
+            if (type == MessageType.RecipientAdd)
+                content = "Added a recipient.";
+            else if (type == MessageType.RecipientRemove)
+                content = "Removed a recipient.";
+            else if (type == MessageType.Call)
+                content = "Started a call.";
+            else if (type == MessageType.ChannelNameChange)
+                content = "Changed the channel name.";
+            else if (type == MessageType.ChannelIconChange)
+                content = "Changed the channel icon.";
+            else if (type == MessageType.ChannelPinnedMessage)
+                content = "Pinned a message.";
+            else if (type == MessageType.GuildMemberJoin)
+                content = "Joined the server.";
+
+            // Get author
+            var author = ParseUser(token["author"]);
+
+            // Get attachment
+            var attachments = new List<Attachment>();
+            foreach (var attachmentJson in token["attachments"].EmptyIfNull())
+            {
+                var attachmentId = attachmentJson["id"].Value<string>();
+                var attachmentUrl = attachmentJson["url"].Value<string>();
+                var attachmentType = attachmentJson["width"] != null
+                    ? AttachmentType.Image
+                    : AttachmentType.Other;
+                var attachmentFileName = attachmentJson["filename"].Value<string>();
+                var attachmentFileSize = attachmentJson["size"].Value<long>();
+
+                var attachment = new Attachment(
+                    attachmentId, attachmentType, attachmentUrl,
+                    attachmentFileName, attachmentFileSize);
+                attachments.Add(attachment);
+            }
+
+            // Get user mentions
+            var mentionedUsers = token["mentions"].Select(ParseUser).ToArray();
+
+            // Get role mentions
+            var mentionedRoles = token["mention_roles"]
+                .Values<string>()
+                .Select(i => _roleCache.GetOrDefault(i) ?? Role.CreateDeletedRole(id))
+                .ToArray();
+
+            // Get channel mentions
+            var mentionedChannels = Regex.Matches(content, "<#(\\d+)>")
+                .Cast<Match>()
+                .Select(m => m.Groups[1].Value)
+                .ExceptBlank()
+                .Select(i => _channelCache.GetOrDefault(i) ?? Channel.CreateDeletedChannel(id))
+                .ToArray();
+
+            return new Message(id, channelId, type, author, timeStamp, editedTimeStamp, content, attachments,
+                mentionedUsers, mentionedRoles, mentionedChannels);
+        }
+
+        private async Task<string> GetStringAsync(string url)
+        {
+            using (var response = await _httpClient.GetAsync(url))
+            {
+                // Check status code
+                // We throw our own exception here because default one doesn't have status code
+                if (!response.IsSuccessStatusCode)
+                    throw new HttpErrorStatusCodeException(response.StatusCode);
+
+                // Get content
+                return await response.Content.ReadAsStringAsync();
+            }
+        }
+
+        public async Task<Guild> GetGuildAsync(string token, string guildId)
+        {
+            // Form request url
+            var url = $"{ApiRoot}/guilds/{guildId}?token={token}";
+
+            // Get response
+            var content = await GetStringAsync(url);
+
+            // Parse
+            var guild = ParseGuild(JToken.Parse(content));
+
+            // Add roles to cache
+            foreach (var role in guild.Roles)
+                _roleCache[role.Id] = role;
+
+            return guild;
+        }
+
+        public async Task<Channel> GetChannelAsync(string token, string channelId)
+        {
+            // Form request url
+            var url = $"{ApiRoot}/channels/{channelId}?token={token}";
+
+            // Get response
+            var content = await GetStringAsync(url);
+
+            // Parse
+            var channel = ParseChannel(JToken.Parse(content));
+
+            // Add channel to cache
+            _channelCache[channel.Id] = channel;
+
+            return channel;
+        }
+
+        public async Task<IReadOnlyList<Channel>> GetGuildChannelsAsync(string token, string guildId)
+        {
+            // Form request url
+            var url = $"{ApiRoot}/guilds/{guildId}/channels?token={token}";
+
+            // Get response
+            var content = await GetStringAsync(url);
+
+            // Parse
+            var channels = JArray.Parse(content).Select(ParseChannel).ToArray();
+
+            // Add channels to cache
+            foreach (var channel in channels)
+                _channelCache[channel.Id] = channel;
+
+            return channels;
+        }
+
+        public async Task<IReadOnlyList<Guild>> GetUserGuildsAsync(string token)
+        {
+            // Form request url
+            var url = $"{ApiRoot}/users/@me/guilds?token={token}&limit=100";
+
+            // Get response
+            var content = await GetStringAsync(url);
+
+            // Parse IDs
+            var guildIds = JArray.Parse(content).Select(t => t["id"].Value<string>());
+
+            // Get full guild infos
+            var guilds = new List<Guild>();
+            foreach (var guildId in guildIds)
+            {
+                var guild = await GetGuildAsync(token, guildId);
+                guilds.Add(guild);
+            }
+
+            return guilds;
+        }
+
+        public async Task<IReadOnlyList<Channel>> GetDirectMessageChannelsAsync(string token)
+        {
+            // Form request url
+            var url = $"{ApiRoot}/users/@me/channels?token={token}";
+
+            // Get response
+            var content = await GetStringAsync(url);
+
+            // Parse
+            var channels = JArray.Parse(content).Select(ParseChannel).ToArray();
+
+            return channels;
+        }
+
+        public async Task<IReadOnlyList<Message>> GetChannelMessagesAsync(string token, string channelId,
+            DateTime? from, DateTime? to)
+        {
+            var result = new List<Message>();
+
+            // We are going backwards from last message to first
+            // collecting everything between them in batches
+            var beforeId = to != null ? DateTimeToSnowflake(to.Value) : null;
+            while (true)
+            {
+                // Form request url
+                var url = $"{ApiRoot}/channels/{channelId}/messages?token={token}&limit=100";
+                if (beforeId.IsNotBlank())
+                    url += $"&before={beforeId}";
+
+                // Get response
+                var content = await GetStringAsync(url);
+
+                // Parse
+                var messages = JArray.Parse(content).Select(ParseMessage);
+
+                // Add messages to list
+                string currentMessageId = null;
+                foreach (var message in messages)
+                {
+                    // Break when the message is older than from date
+                    if (from != null && message.TimeStamp < from)
+                    {
+                        currentMessageId = null;
+                        break;
+                    }
+
+                    // Add message
+                    result.Add(message);
+                    currentMessageId = message.Id;
+                }
+
+                // If no messages - break
+                if (currentMessageId == null)
+                    break;
+
+                // Otherwise offset the next request
+                beforeId = currentMessageId;
+            }
+
+            // Messages appear newest first, we need to reverse
+            result.Reverse();
+
+            return result;
+        }
+
+        protected virtual void Dispose(bool disposing)
+        {
+            if (disposing)
+            {
+                _httpClient.Dispose();
+            }
+        }
+
+        public void Dispose()
+        {
+            Dispose(true);
+            GC.SuppressFinalize(this);
+        }
+    }
+
+    public partial class DataService
+    {
+        private static string DateTimeToSnowflake(DateTime dateTime)
+        {
+            const long epoch = 62135596800000;
+            var unixTime = dateTime.ToUniversalTime().Ticks / TimeSpan.TicksPerMillisecond - epoch;
+            var value = ((ulong) unixTime - 1420070400000UL) << 22;
+            return value.ToString();
+        }
+    }
+}

DiscordChatExporter.Core/Services/ExportService.cs

@@ -0,0 +1,322 @@
+using System;
+using System.IO;
+using System.Net;
+using System.Text;
+using System.Text.RegularExpressions;
+using System.Threading.Tasks;
+using DiscordChatExporter.Core.Internal;
+using DiscordChatExporter.Core.Models;
+using Tyrrrz.Extensions;
+
+namespace DiscordChatExporter.Core.Services
+{
+    public partial class ExportService : IExportService
+    {
+        private readonly ISettingsService _settingsService;
+
+        public ExportService(ISettingsService settingsService)
+        {
+            _settingsService = settingsService;
+        }
+
+        private async Task ExportAsTextAsync(string filePath, ChannelChatLog log)
+        {
+            using (var writer = new StreamWriter(filePath, false, Encoding.UTF8, 128 * 1024))
+            {
+                // Generation info
+                await writer.WriteLineAsync("https://github.com/Tyrrrz/DiscordChatExporter");
+                await writer.WriteLineAsync();
+
+                // Guild and channel info
+                await writer.WriteLineAsync('='.Repeat(48));
+                await writer.WriteLineAsync($"Guild: {log.Guild.Name}");
+                await writer.WriteLineAsync($"Channel: {log.Channel.Name}");
+                await writer.WriteLineAsync($"Topic: {log.Channel.Topic}");
+                await writer.WriteLineAsync($"Messages: {log.TotalMessageCount:N0}");
+                await writer.WriteLineAsync('='.Repeat(48));
+                await writer.WriteLineAsync();
+
+                // Chat log
+                foreach (var group in log.MessageGroups)
+                {
+                    var timeStampFormatted = group.TimeStamp.ToString(_settingsService.DateFormat);
+                    await writer.WriteLineAsync($"{group.Author.FullyQualifiedName}  [{timeStampFormatted}]");
+
+                    // Messages
+                    foreach (var message in group.Messages)
+                    {
+                        // Content
+                        if (message.Content.IsNotBlank())
+                        {
+                            var contentFormatted = FormatMessageContentText(message);
+                            await writer.WriteLineAsync(contentFormatted);
+                        }
+
+                        // Attachments
+                        foreach (var attachment in message.Attachments)
+                        {
+                            await writer.WriteLineAsync(attachment.Url);
+                        }
+                    }
+
+                    await writer.WriteLineAsync();
+                }
+            }
+        }
+
+        private async Task ExportAsHtmlAsync(string filePath, ChannelChatLog log, string css)
+        {
+            using (var writer = new StreamWriter(filePath, false, Encoding.UTF8, 128 * 1024))
+            {
+                // Generation info
+                await writer.WriteLineAsync("<!-- https://github.com/Tyrrrz/DiscordChatExporter -->");
+
+                // Html start
+                await writer.WriteLineAsync("<!DOCTYPE html>");
+                await writer.WriteLineAsync("<html lang=\"en\">");
+
+                // HEAD
+                await writer.WriteLineAsync("<head>");
+                await writer.WriteLineAsync($"<title>{log.Guild.Name} - {log.Channel.Name}</title>");
+                await writer.WriteLineAsync("<meta charset=\"utf-8\" />");
+                await writer.WriteLineAsync("<meta name=\"viewport\" content=\"width=device-width\" />");
+                await writer.WriteLineAsync($"<style>{css}</style>");
+                await writer.WriteLineAsync("</head>");
+
+                // Body start
+                await writer.WriteLineAsync("<body>");
+
+                // Guild and channel info
+                await writer.WriteLineAsync("<div id=\"info\">");
+                await writer.WriteLineAsync("<div class=\"info-left\">");
+                await writer.WriteLineAsync($"<img class=\"guild-icon\" src=\"{log.Guild.IconUrl}\" />");
+                await writer.WriteLineAsync("</div>"); // info-left
+                await writer.WriteLineAsync("<div class=\"info-right\">");
+                await writer.WriteLineAsync($"<div class=\"guild-name\">{log.Guild.Name}</div>");
+                await writer.WriteLineAsync($"<div class=\"channel-name\">{log.Channel.Name}</div>");
+                await writer.WriteLineAsync($"<div class=\"channel-topic\">{log.Channel.Topic}</div>");
+                await writer.WriteLineAsync(
+                    $"<div class=\"channel-messagecount\">{log.TotalMessageCount:N0} messages</div>");
+                await writer.WriteLineAsync("</div>"); // info-right
+                await writer.WriteLineAsync("</div>"); // info
+
+                // Chat log
+                await writer.WriteLineAsync("<div id=\"log\">");
+                foreach (var group in log.MessageGroups)
+                {
+                    await writer.WriteLineAsync("<div class=\"msg\">");
+                    await writer.WriteLineAsync("<div class=\"msg-left\">");
+                    await writer.WriteLineAsync($"<img class=\"msg-avatar\" src=\"{group.Author.AvatarUrl}\" />");
+                    await writer.WriteLineAsync("</div>");
+
+                    await writer.WriteLineAsync("<div class=\"msg-right\">");
+                    await writer.WriteAsync(
+                        $"<span class=\"msg-user\" title=\"{HtmlEncode(group.Author.FullyQualifiedName)}\">");
+                    await writer.WriteAsync(HtmlEncode(group.Author.Name));
+                    await writer.WriteLineAsync("</span>");
+                    var timeStampFormatted = HtmlEncode(group.TimeStamp.ToString(_settingsService.DateFormat));
+                    await writer.WriteLineAsync($"<span class=\"msg-date\">{timeStampFormatted}</span>");
+
+                    // Messages
+                    foreach (var message in group.Messages)
+                    {
+                        // Content
+                        if (message.Content.IsNotBlank())
+                        {
+                            await writer.WriteLineAsync("<div class=\"msg-content\">");
+                            var contentFormatted = FormatMessageContentHtml(message);
+                            await writer.WriteAsync(contentFormatted);
+
+                            // Edited timestamp
+                            if (message.EditedTimeStamp != null)
+                            {
+                                var editedTimeStampFormatted =
+                                    HtmlEncode(message.EditedTimeStamp.Value.ToString(_settingsService.DateFormat));
+                                await writer.WriteAsync(
+                                    $"<span class=\"msg-edited\" title=\"{editedTimeStampFormatted}\">(edited)</span>");
+                            }
+
+                            await writer.WriteLineAsync("</div>"); // msg-content
+                        }
+
+                        // Attachments
+                        foreach (var attachment in message.Attachments)
+                        {
+                            if (attachment.Type == AttachmentType.Image)
+                            {
+                                await writer.WriteLineAsync("<div class=\"msg-attachment\">");
+                                await writer.WriteLineAsync($"<a href=\"{attachment.Url}\">");
+                                await writer.WriteLineAsync(
+                                    $"<img class=\"msg-attachment\" src=\"{attachment.Url}\" />");
+                                await writer.WriteLineAsync("</a>");
+                                await writer.WriteLineAsync("</div>");
+                            }
+                            else
+                            {
+                                await writer.WriteLineAsync("<div class=\"msg-attachment\">");
+                                await writer.WriteLineAsync($"<a href=\"{attachment.Url}\">");
+                                var fileSizeFormatted = FormatFileSize(attachment.FileSize);
+                                await writer.WriteLineAsync($"Attachment: {attachment.FileName} ({fileSizeFormatted})");
+                                await writer.WriteLineAsync("</a>");
+                                await writer.WriteLineAsync("</div>");
+                            }
+                        }
+                    }
+                    await writer.WriteLineAsync("</div>"); // msg-right
+                    await writer.WriteLineAsync("</div>"); // msg
+                }
+                await writer.WriteLineAsync("</div>"); // log
+
+                await writer.WriteLineAsync("</body>");
+                await writer.WriteLineAsync("</html>");
+            }
+        }
+
+        public Task ExportAsync(ExportFormat format, string filePath, ChannelChatLog log)
+        {
+            if (format == ExportFormat.PlainText)
+            {
+                return ExportAsTextAsync(filePath, log);
+            }
+            if (format == ExportFormat.HtmlDark)
+            {
+                var css = AssemblyHelper.GetResourceString("DiscordChatExporter.Core.Resources.ExportService.DarkTheme.css");
+                return ExportAsHtmlAsync(filePath, log, css);
+            }
+            if (format == ExportFormat.HtmlLight)
+            {
+                var css = AssemblyHelper.GetResourceString("DiscordChatExporter.Core.Resources.ExportService.LightTheme.css");
+                return ExportAsHtmlAsync(filePath, log, css);
+            }
+
+            throw new ArgumentOutOfRangeException(nameof(format));
+        }
+    }
+
+    public partial class ExportService
+    {
+        private static string HtmlEncode(string str)
+        {
+            return WebUtility.HtmlEncode(str);
+        }
+
+        private static string HtmlEncode(object obj)
+        {
+            return WebUtility.HtmlEncode(obj.ToString());
+        }
+
+        private static string FormatFileSize(long fileSize)
+        {
+            string[] units = {"B", "KB", "MB", "GB", "TB", "PB", "EB", "ZB", "YB"};
+            double size = fileSize;
+            var unit = 0;
+
+            while (size >= 1024)
+            {
+                size /= 1024;
+                ++unit;
+            }
+
+            return $"{size:0.#} {units[unit]}";
+        }
+
+        public static string FormatMessageContentText(Message message)
+        {
+            var content = message.Content;
+
+            // New lines
+            content = content.Replace("\n", Environment.NewLine);
+
+            // User mentions (<@id> and <@!id>)
+            foreach (var mentionedUser in message.MentionedUsers)
+                content = Regex.Replace(content, $"<@!?{mentionedUser.Id}>", $"@{mentionedUser}");
+
+            // Role mentions (<@&id>)
+            foreach (var mentionedRole in message.MentionedRoles)
+                content = content.Replace($"<@&{mentionedRole.Id}>", $"@{mentionedRole.Name}");
+
+            // Channel mentions (<#id>)
+            foreach (var mentionedChannel in message.MentionedChannels)
+                content = content.Replace($"<#{mentionedChannel.Id}>", $"#{mentionedChannel.Name}");
+
+            // Custom emojis (<:name:id>)
+            content = Regex.Replace(content, "<(:.*?:)\\d*>", "$1");
+
+            return content;
+        }
+
+        private static string FormatMessageContentHtml(Message message)
+        {
+            var content = message.Content;
+
+            // Encode HTML
+            content = HtmlEncode(content);
+
+            // Pre multiline (```text```)
+            content = Regex.Replace(content, "```+(?:[^`]*?\\n)?([^`]+)\\n?```+", "<div class=\"pre\">$1</div>");
+
+            // Pre inline (`text`)
+            content = Regex.Replace(content, "`([^`]+)`", "<span class=\"pre\">$1</span>");
+
+            // Bold (**text**)
+            content = Regex.Replace(content, "\\*\\*([^\\*]*?)\\*\\*", "<b>$1</b>");
+
+            // Italic (*text*)
+            content = Regex.Replace(content, "\\*([^\\*]*?)\\*", "<i>$1</i>");
+
+            // Underline (__text__)
+            content = Regex.Replace(content, "__([^_]*?)__", "<u>$1</u>");
+
+            // Italic (_text_)
+            content = Regex.Replace(content, "_([^_]*?)_", "<i>$1</i>");
+
+            // Strike through (~~text~~)
+            content = Regex.Replace(content, "~~([^~]*?)~~", "<s>$1</s>");
+
+            // New lines
+            content = content.Replace("\n", "<br />");
+
+            // URL links
+            content = Regex.Replace(content, "((https?|ftp)://[^\\s/$.?#].[^\\s<>]*)", "<a href=\"$1\">$1</a>");
+
+            // Meta mentions (@everyone)
+            content = content.Replace("@everyone", "<span class=\"mention\">@everyone</span>");
+
+            // Meta mentions (@here)
+            content = content.Replace("@here", "<span class=\"mention\">@here</span>");
+
+            // User mentions (<@id> and <@!id>)
+            foreach (var mentionedUser in message.MentionedUsers)
+            {
+                content = Regex.Replace(content, $"&lt;@!?{mentionedUser.Id}&gt;",
+                    $"<span class=\"mention\" title=\"{HtmlEncode(mentionedUser)}\">" +
+                    $"@{HtmlEncode(mentionedUser.Name)}" +
+                    "</span>");
+            }
+
+            // Role mentions (<@&id>)
+            foreach (var mentionedRole in message.MentionedRoles)
+            {
+                content = content.Replace($"&lt;@&amp;{mentionedRole.Id}&gt;",
+                    "<span class=\"mention\">" +
+                    $"@{HtmlEncode(mentionedRole.Name)}" +
+                    "</span>");
+            }
+
+            // Channel mentions (<#id>)
+            foreach (var mentionedChannel in message.MentionedChannels)
+            {
+                content = content.Replace($"&lt;#{mentionedChannel.Id}&gt;",
+                    "<span class=\"mention\">" +
+                    $"#{HtmlEncode(mentionedChannel.Name)}" +
+                    "</span>");
+            }
+
+            // Custom emojis (<:name:id>)
+            content = Regex.Replace(content, "&lt;(:.*?:)(\\d*)&gt;",
+                "<img class=\"emoji\" title=\"$1\" src=\"https://cdn.discordapp.com/emojis/$2.png\" />");
+
+            return content;
+        }
+    }
+}

DiscordChatExporter.Core/Services/IDataService.cs

@@ -0,0 +1,23 @@
+using System;
+using System.Collections.Generic;
+using System.Threading.Tasks;
+using DiscordChatExporter.Core.Models;
+
+namespace DiscordChatExporter.Core.Services
+{
+    public interface IDataService
+    {
+        Task<Guild> GetGuildAsync(string token, string guildId);
+
+        Task<Channel> GetChannelAsync(string token, string channelId);
+
+        Task<IReadOnlyList<Channel>> GetGuildChannelsAsync(string token, string guildId);
+
+        Task<IReadOnlyList<Guild>> GetUserGuildsAsync(string token);
+
+        Task<IReadOnlyList<Channel>> GetDirectMessageChannelsAsync(string token);
+
+        Task<IReadOnlyList<Message>> GetChannelMessagesAsync(string token, string channelId,
+            DateTime? from, DateTime? to);
+    }
+}

DiscordChatExporter.Core/Services/IExportService.cs

@@ -0,0 +1,10 @@
+using System.Threading.Tasks;
+using DiscordChatExporter.Core.Models;
+
+namespace DiscordChatExporter.Core.Services
+{
+    public interface IExportService
+    {
+        Task ExportAsync(ExportFormat format, string filePath, ChannelChatLog log);
+    }
+}

DiscordChatExporter.Core/Services/IMessageGroupService.cs

@@ -0,0 +1,10 @@
+using System.Collections.Generic;
+using DiscordChatExporter.Core.Models;
+
+namespace DiscordChatExporter.Core.Services
+{
+    public interface IMessageGroupService
+    {
+        IReadOnlyList<MessageGroup> GroupMessages(IReadOnlyList<Message> messages);
+    }
+}

DiscordChatExporter.Core/Services/ISettingsService.cs

@@ -0,0 +1,16 @@
+using DiscordChatExporter.Core.Models;
+
+namespace DiscordChatExporter.Core.Services
+{
+    public interface ISettingsService
+    {
+        string DateFormat { get; set; }
+        int MessageGroupLimit { get; set; }
+
+        string LastToken { get; set; }
+        ExportFormat LastExportFormat { get; set; }
+
+        void Load();
+        void Save();
+    }
+}

DiscordChatExporter.Core/Services/MessageGroupService.cs

@@ -0,0 +1,59 @@
+using System.Collections.Generic;
+using System.Linq;
+using DiscordChatExporter.Core.Models;
+
+namespace DiscordChatExporter.Core.Services
+{
+    public class MessageGroupService : IMessageGroupService
+    {
+        private readonly ISettingsService _settingsService;
+
+        public MessageGroupService(ISettingsService settingsService)
+        {
+            _settingsService = settingsService;
+        }
+
+        public IReadOnlyList<MessageGroup> GroupMessages(IReadOnlyList<Message> messages)
+        {
+            var result = new List<MessageGroup>();
+
+            // Group adjacent messages by timestamp and author
+            var groupBuffer = new List<Message>();
+            foreach (var message in messages)
+            {
+                var groupFirst = groupBuffer.FirstOrDefault();
+
+                // Group break condition
+                var breakCondition =
+                    groupFirst != null &&
+                    (
+                        message.Author.Id != groupFirst.Author.Id ||
+                        (message.TimeStamp - groupFirst.TimeStamp).TotalHours > 1 ||
+                        message.TimeStamp.Hour != groupFirst.TimeStamp.Hour ||
+                        groupBuffer.Count >= _settingsService.MessageGroupLimit
+                    );
+
+                // If condition is true - flush buffer
+                if (breakCondition)
+                {
+                    var group = new MessageGroup(groupFirst.Author, groupFirst.TimeStamp, groupBuffer.ToArray());
+                    result.Add(group);
+                    groupBuffer.Clear();
+                }
+
+                // Add message to buffer
+                groupBuffer.Add(message);
+            }
+
+            // Add what's remaining in buffer
+            if (groupBuffer.Any())
+            {
+                var groupFirst = groupBuffer.First();
+                var group = new MessageGroup(groupFirst.Author, groupFirst.TimeStamp, groupBuffer.ToArray());
+                result.Add(group);
+            }
+
+            return result;
+        }
+    }
+}

DiscordChatExporter.Core/Services/SettingsService.cs

@@ -0,0 +1,21 @@
+using DiscordChatExporter.Core.Models;
+using Tyrrrz.Settings;
+
+namespace DiscordChatExporter.Core.Services
+{
+    public class SettingsService : SettingsManager, ISettingsService
+    {
+        public string DateFormat { get; set; } = "dd-MMM-yy hh:mm tt";
+        public int MessageGroupLimit { get; set; } = 20;
+
+        public string LastToken { get; set; }
+        public ExportFormat LastExportFormat { get; set; } = ExportFormat.HtmlDark;
+
+        public SettingsService()
+        {
+            Configuration.StorageSpace = StorageSpace.Instance;
+            Configuration.SubDirectoryPath = "";
+            Configuration.FileName = "Settings.dat";
+        }
+    }
+}