Improve performance (#162)

DiscordChatExporter.Core.Rendering/CsvChatLogRenderer.cs

@@ -0,0 +1,112 @@
+using System;
+using System.Collections.Generic;
+using System.Globalization;
+using System.IO;
+using System.Linq;
+using System.Threading.Tasks;
+using DiscordChatExporter.Core.Markdown;
+using DiscordChatExporter.Core.Markdown.Nodes;
+using DiscordChatExporter.Core.Models;
+using Tyrrrz.Extensions;
+
+namespace DiscordChatExporter.Core.Rendering
+{
+    public class CsvChatLogRenderer : IChatLogRenderer
+    {
+        private readonly ChatLog _chatLog;
+        private readonly string _dateFormat;
+
+        public CsvChatLogRenderer(ChatLog chatLog, string dateFormat)
+        {
+            _chatLog = chatLog;
+            _dateFormat = dateFormat;
+        }
+
+        private string FormatDate(DateTime date) => date.ToString(_dateFormat, CultureInfo.InvariantCulture);
+
+        private string FormatMarkdown(Node node)
+        {
+            // Formatted node
+            if (node is FormattedNode formattedNode)
+            {
+                // Recursively get inner text
+                var innerText = FormatMarkdown(formattedNode.Children);
+
+                return $"{formattedNode.Token}{innerText}{formattedNode.Token}";
+            }
+
+            // Non-meta mention node
+            if (node is MentionNode mentionNode && mentionNode.Type != MentionType.Meta)
+            {
+                // User mention node
+                if (mentionNode.Type == MentionType.User)
+                {
+                    var user = _chatLog.Mentionables.GetUser(mentionNode.Id);
+                    return $"@{user.Name}";
+                }
+
+                // Channel mention node
+                if (mentionNode.Type == MentionType.Channel)
+                {
+                    var channel = _chatLog.Mentionables.GetChannel(mentionNode.Id);
+                    return $"#{channel.Name}";
+                }
+
+                // Role mention node
+                if (mentionNode.Type == MentionType.Role)
+                {
+                    var role = _chatLog.Mentionables.GetRole(mentionNode.Id);
+                    return $"@{role.Name}";
+                }
+            }
+
+            // Custom emoji node
+            if (node is EmojiNode emojiNode && emojiNode.IsCustomEmoji)
+            {
+                return $":{emojiNode.Name}:";
+            }
+
+            // All other nodes - simply return source
+            return node.Source;
+        }
+
+        private string FormatMarkdown(IEnumerable<Node> nodes) => nodes.Select(FormatMarkdown).JoinToString("");
+
+        private string FormatMarkdown(string markdown) => FormatMarkdown(MarkdownParser.Parse(markdown));
+
+        private async Task RenderFieldAsync(TextWriter writer, string value)
+        {
+            var encodedValue = value.Replace("\"", "\"\"");
+            await writer.WriteAsync($"\"{encodedValue}\";");
+        }
+
+        private async Task RenderMessageAsync(TextWriter writer, Message message)
+        {
+            // Author
+            await RenderFieldAsync(writer, message.Author.FullName);
+
+            // Timestamp
+            await RenderFieldAsync(writer, FormatDate(message.Timestamp));
+
+            // Content
+            await RenderFieldAsync(writer, FormatMarkdown(message.Content));
+
+            // Attachments
+            var formattedAttachments = message.Attachments.Select(a => a.Url).JoinToString(",");
+            await RenderFieldAsync(writer, formattedAttachments);
+
+            // Line break
+            await writer.WriteLineAsync();
+        }
+
+        public async Task RenderAsync(TextWriter writer)
+        {
+            // Headers
+            await writer.WriteLineAsync("Author;Date;Content;Attachments;");
+
+            // Log
+            foreach (var message in _chatLog.Messages)
+                await RenderMessageAsync(writer, message);
+        }
+    }
+}