Feature: emoji editor (#2411)

* Custom emoji editor: implement backend

This reuses the logo upload code

* Implement emoji edit admin interface

Again reuse base64 logic from the logo upload

* Allow toggling between uploaded and default emojis

* Add route that always serves uploaded emojis

This is needed for the admin emoji interface,
as otherwise the emojis will 404 if custom emojis are disabled

* Fix linter warnings

* Remove custom/uploaded emoji logic

* Reset timer after emoji deletion

* Setup: copy built-in emojis to emoji directory

core/data/emoji.go

@@ -0,0 +1,84 @@
+package data
+
+import (
+	"fmt"
+	"io"
+	"io/fs"
+	"os"
+	"path/filepath"
+
+	"github.com/owncast/owncast/config"
+	"github.com/owncast/owncast/models"
+	"github.com/owncast/owncast/static"
+	"github.com/owncast/owncast/utils"
+	log "github.com/sirupsen/logrus"
+)
+
+// GetEmojiList returns a list of custom emoji from the emoji directory.
+func GetEmojiList() []models.CustomEmoji {
+	var emojiFS = os.DirFS(config.CustomEmojiPath)
+
+	emojiResponse := make([]models.CustomEmoji, 0)
+
+	files, err := fs.Glob(emojiFS, "*")
+	if err != nil {
+		log.Errorln(err)
+		return emojiResponse
+	}
+
+	for _, name := range files {
+		emojiPath := filepath.Join(config.EmojiDir, name)
+		singleEmoji := models.CustomEmoji{Name: name, URL: emojiPath}
+		emojiResponse = append(emojiResponse, singleEmoji)
+	}
+
+	return emojiResponse
+}
+
+// SetupEmojiDirectory sets up the custom emoji directory by copying all built-in
+// emojis if the directory does not yet exist.
+func SetupEmojiDirectory() (err error) {
+	if utils.DoesFileExists(config.CustomEmojiPath) {
+		return nil
+	}
+
+	if err = os.MkdirAll(config.CustomEmojiPath, 0o750); err != nil {
+		return fmt.Errorf("unable to create custom emoji directory: %w", err)
+	}
+
+	staticFS := static.GetEmoji()
+	files, err := fs.Glob(staticFS, "*")
+	if err != nil {
+		return fmt.Errorf("unable to read built-in emoji files: %w", err)
+	}
+
+	// Now copy all built-in emojis to the custom emoji directory
+	for _, name := range files {
+		emojiPath := filepath.Join(config.CustomEmojiPath, filepath.Base(name))
+
+		// nolint:gosec
+		diskFile, err := os.Create(emojiPath)
+		if err != nil {
+			return fmt.Errorf("unable to create custom emoji file on disk: %w", err)
+		}
+
+		memFile, err := staticFS.Open(name)
+		if err != nil {
+			_ = diskFile.Close()
+			return fmt.Errorf("unable to open built-in emoji file: %w", err)
+		}
+
+		if _, err = io.Copy(diskFile, memFile); err != nil {
+			_ = diskFile.Close()
+			_ = os.Remove(emojiPath)
+			return fmt.Errorf("unable to copy built-in emoji file to disk: %w", err)
+		}
+
+		if err = diskFile.Close(); err != nil {
+			_ = os.Remove(emojiPath)
+			return fmt.Errorf("unable to close custom emoji file on disk: %w", err)
+		}
+	}
+
+	return nil
+}