Add custom emojis

Closes #6

Pachyderm/Model/Emoji.swift

@@ -9,17 +9,16 @@
 import Foundation
 
 public class Emoji: Decodable {
-    let shortcode: String
-    let url: URL
-    let staticURL: URL
-    // TODO: missing in pleroma
-//    let visibleInPicker: Bool
+    public let shortcode: String
+    public let url: URL
+    public let staticURL: URL
+    public let visibleInPicker: Bool
     
     private enum CodingKeys: String, CodingKey {
         case shortcode
         case url
         case staticURL = "static_url"
-//        case visibleInPicker = "visible_in_picker"
+        case visibleInPicker = "visible_in_picker"
     }
 }
 

Tusker/Caching/ImageCache.swift

@@ -14,6 +14,7 @@ class ImageCache {
     static let avatars = ImageCache(name: "Avatars", memoryExpiry: .seconds(60 * 60), diskExpiry: .seconds(60 * 60 * 24))
     static let headers = ImageCache(name: "Headers", memoryExpiry: .seconds(60 * 60), diskExpiry: .seconds(60 * 60 * 24))
     static let attachments = ImageCache(name: "Attachments", memoryExpiry: .seconds(60 * 2))
+    static let emojis = ImageCache(name: "Emojis", memoryExpiry: .seconds(60 * 5), diskExpiry: .seconds(60 * 60))
 
     let cache: Cache<Data>
     

Tusker/Views/ContentLabel.swift

@@ -8,14 +8,74 @@
 
 import UIKit
 import SafariServices
-import TTTAttributedLabel
 import Pachyderm
 import SwiftSoup
 
 class ContentLabel: LinkLabel {
     
+    private static let emojiRegex = try! NSRegularExpression(pattern: ":(\\w+):", options: [])
+    
     var navigationDelegate: TuskerNavigationDelegate?
     
+    // MARK: - Emojis
+    func setEmojis(_ emojis: [Emoji]) {
+        guard !emojis.isEmpty else { return }
+        
+        let group = DispatchGroup()
+
+        let mutAttrString = NSMutableAttributedString(attributedString: self.attributedText!)
+        let string = mutAttrString.string
+        let matches = ContentLabel.emojiRegex.matches(in: string, options: [], range: NSRange(location: 0, length: mutAttrString.length))
+        for match in matches.reversed() {
+            let shortcode = (string as NSString).substring(with: match.range(at: 1))
+            guard let emoji = emojis.first(where: { $0.shortcode == shortcode }) else {
+                continue
+            }
+
+            group.enter()
+            ImageCache.emojis.get(emoji.url) { (data) in
+                guard let data = data, let image = UIImage(data: data) else {
+                    group.leave()
+                    return
+                }
+                DispatchQueue.main.async {
+                    let attachment = self.createEmojiTextAttachment(image: image, index: match.range.location)
+                    mutAttrString.replaceCharacters(in: match.range, with: NSAttributedString(attachment: attachment))
+                    
+                    group.leave()
+                }
+            }
+        }
+
+        group.notify(queue: .main) {
+            self.attributedText = mutAttrString
+            self.setNeedsLayout()
+            self.setNeedsDisplay()
+        }
+    }
+    
+    // Based on https://github.com/ReticentJohn/Amaroq/blob/7c5b7088eb9fd1611dcb0f47d43bf8df093e142c/DireFloof/InlineImageHelpers.m
+    func createEmojiTextAttachment(image: UIImage, index: Int) -> NSTextAttachment {
+        let font = self.font!
+        
+        let adjustedCapHeight = font.capHeight - 1
+        var imageSizeMatchingFontSize = CGSize(width: image.size.width * (adjustedCapHeight / image.size.height), height: adjustedCapHeight)
+        
+        let defaultScale: CGFloat = 1.4
+        imageSizeMatchingFontSize = CGSize(width: imageSizeMatchingFontSize.width * defaultScale, height: imageSizeMatchingFontSize.height * defaultScale)
+        let textColor = self.textColor!
+        
+        UIGraphicsBeginImageContextWithOptions(imageSizeMatchingFontSize, false, 0.0)
+        textColor.set()
+        image.draw(in: CGRect(origin: .zero, size: imageSizeMatchingFontSize))
+        let attachmentImage = UIGraphicsGetImageFromCurrentImageContext()
+        UIGraphicsEndImageContext()
+        
+        let attachment = NSTextAttachment()
+        attachment.image = attachmentImage
+        return attachment
+    }
+    
     // MARK: - HTML Parsing
     func setTextFromHtml(_ html: String) {
         let doc = try! SwiftSoup.parse(html)

Tusker/Views/StatusContentLabel.swift

@@ -16,6 +16,7 @@ class StatusContentLabel: ContentLabel {
             guard let statusID = statusID else { return }
             guard let status = MastodonCache.status(for: statusID) else { fatalError("Can't set StatusContentLabel text without cached status \(statusID)") }
             setTextFromHtml(status.content)
+            setEmojis(status.emojis)
         }
     }