Improve performance (#162)

DiscordChatExporter.Core.Rendering/HtmlChatLogRenderer.cs

@@ -0,0 +1,197 @@
+using System;
+using System.Collections.Generic;
+using System.Globalization;
+using System.IO;
+using System.Linq;
+using System.Net;
+using System.Threading.Tasks;
+using DiscordChatExporter.Core.Markdown;
+using DiscordChatExporter.Core.Markdown.Nodes;
+using DiscordChatExporter.Core.Models;
+using Scriban;
+using Scriban.Runtime;
+using Tyrrrz.Extensions;
+
+namespace DiscordChatExporter.Core.Rendering
+{
+    public partial class HtmlChatLogRenderer : IChatLogRenderer
+    {
+        private readonly ChatLog _chatLog;
+        private readonly string _themeName;
+        private readonly string _dateFormat;
+
+        public HtmlChatLogRenderer(ChatLog chatLog, string themeName, string dateFormat)
+        {
+            _chatLog = chatLog;
+            _themeName = themeName;
+            _dateFormat = dateFormat;
+        }
+
+        private string HtmlEncode(string s) => WebUtility.HtmlEncode(s);
+
+        private string FormatDate(DateTime date) => date.ToString(_dateFormat, CultureInfo.InvariantCulture);
+
+        private IEnumerable<MessageGroup> GroupMessages(IEnumerable<Message> messages) =>
+            messages.GroupContiguous((buffer, message) =>
+            {
+                // Break group if the author changed
+                if (buffer.Last().Author.Id != message.Author.Id)
+                    return false;
+
+                // Break group if last message was more than 7 minutes ago
+                if ((message.Timestamp - buffer.Last().Timestamp).TotalMinutes > 7)
+                    return false;
+
+                return true;
+            }).Select(g => new MessageGroup(g.First().Author, g.First().Timestamp, g));
+
+        private string FormatMarkdown(Node node, bool isTopLevel, bool isSingle)
+        {
+            // Text node
+            if (node is TextNode textNode)
+            {
+                // Return HTML-encoded text
+                return HtmlEncode(textNode.Text);
+            }
+
+            // Formatted node
+            if (node is FormattedNode formattedNode)
+            {
+                // Recursively get inner html
+                var innerHtml = FormatMarkdown(formattedNode.Children, false);
+
+                // Bold
+                if (formattedNode.Formatting == TextFormatting.Bold)
+                    return $"<strong>{innerHtml}</strong>";
+
+                // Italic
+                if (formattedNode.Formatting == TextFormatting.Italic)
+                    return $"<em>{innerHtml}</em>";
+
+                // Underline
+                if (formattedNode.Formatting == TextFormatting.Underline)
+                    return $"<u>{innerHtml}</u>";
+
+                // Strikethrough
+                if (formattedNode.Formatting == TextFormatting.Strikethrough)
+                    return $"<s>{innerHtml}</s>";
+
+                // Spoiler
+                if (formattedNode.Formatting == TextFormatting.Spoiler)
+                    return $"<span class=\"spoiler\">{innerHtml}</span>";
+            }
+
+            // Inline code block node
+            if (node is InlineCodeBlockNode inlineCodeBlockNode)
+            {
+                return $"<span class=\"pre pre--inline\">{HtmlEncode(inlineCodeBlockNode.Code)}</span>";
+            }
+
+            // Multi-line code block node
+            if (node is MultilineCodeBlockNode multilineCodeBlockNode)
+            {
+                // Set language class for syntax highlighting
+                var languageCssClass = multilineCodeBlockNode.Language != null
+                    ? "language-" + multilineCodeBlockNode.Language
+                    : null;
+
+                return $"<div class=\"pre pre--multiline {languageCssClass}\">{HtmlEncode(multilineCodeBlockNode.Code)}</div>";
+            }
+
+            // Mention node
+            if (node is MentionNode mentionNode)
+            {
+                // Meta mention node
+                if (mentionNode.Type == MentionType.Meta)
+                {
+                    return $"<span class=\"mention\">@{HtmlEncode(mentionNode.Id)}</span>";
+                }
+
+                // User mention node
+                if (mentionNode.Type == MentionType.User)
+                {
+                    var user = _chatLog.Mentionables.GetUser(mentionNode.Id);
+                    return $"<span class=\"mention\" title=\"{HtmlEncode(user.FullName)}\">@{HtmlEncode(user.Name)}</span>";
+                }
+
+                // Channel mention node
+                if (mentionNode.Type == MentionType.Channel)
+                {
+                    var channel = _chatLog.Mentionables.GetChannel(mentionNode.Id);
+                    return $"<span class=\"mention\">#{HtmlEncode(channel.Name)}</span>";
+                }
+
+                // Role mention node
+                if (mentionNode.Type == MentionType.Role)
+                {
+                    var role = _chatLog.Mentionables.GetRole(mentionNode.Id);
+                    return $"<span class=\"mention\">@{HtmlEncode(role.Name)}</span>";
+                }
+            }
+
+            // Emoji node
+            if (node is EmojiNode emojiNode)
+            {
+                // Get emoji image URL
+                var emojiImageUrl = Emoji.GetImageUrl(emojiNode.Id, emojiNode.Name, emojiNode.IsAnimated);
+
+                // Emoji can be jumboable if it's the only top-level node
+                var jumboableCssClass = isTopLevel && isSingle ? "emoji--large" : null;
+
+                return $"<img class=\"emoji {jumboableCssClass}\" alt=\"{emojiNode.Name}\" title=\"{emojiNode.Name}\" src=\"{emojiImageUrl}\" />";
+            }
+
+            // Link node
+            if (node is LinkNode linkNode)
+            {
+                return $"<a href=\"{Uri.EscapeUriString(linkNode.Url)}\">{HtmlEncode(linkNode.Title)}</a>";
+            }
+
+            // All other nodes - simply return source
+            return node.Source;
+        }
+
+        private string FormatMarkdown(IReadOnlyList<Node> nodes, bool isTopLevel)
+        {
+            var isSingle = nodes.Count == 1;
+            return nodes.Select(n => FormatMarkdown(n, isTopLevel, isSingle)).JoinToString("");
+        }
+
+        private string FormatMarkdown(string markdown) => FormatMarkdown(MarkdownParser.Parse(markdown), true);
+
+        public async Task RenderAsync(TextWriter writer)
+        {
+            // Create template loader
+            var loader = new TemplateLoader();
+
+            // Get template
+            var templateCode = loader.Load($"Html{_themeName}.html");
+            var template = Template.Parse(templateCode);
+
+            // Create template context
+            var context = new TemplateContext
+            {
+                TemplateLoader = loader,
+                MemberRenamer = m => m.Name,
+                MemberFilter = m => true,
+                LoopLimit = int.MaxValue,
+                StrictVariables = true
+            };
+
+            // Create template model
+            var model = new ScriptObject();
+            model.SetValue("Model", _chatLog, true);
+            model.Import(nameof(GroupMessages), new Func<IEnumerable<Message>, IEnumerable<MessageGroup>>(GroupMessages));
+            model.Import(nameof(FormatDate), new Func<DateTime, string>(FormatDate));
+            model.Import(nameof(FormatMarkdown), new Func<string, string>(FormatMarkdown));
+            context.PushGlobal(model);
+
+            // Configure output
+            context.PushOutput(new TextWriterOutput(writer));
+
+            // HACK: Render output in a separate thread
+            // (even though Scriban has async API, it still makes a lot of blocking CPU-bound calls)
+            await Task.Run(async () => await context.EvaluateAsync(template.Page));
+        }
+    }
+}