feat(markdown): mask spoilers (#820)

internal/config/config.go

@@ -65,8 +65,9 @@ type (
 	}
 
 	MarkdownConfig struct {
-		Enabled bool   `toml:"enabled"`
-		Theme   string `toml:"theme"`
+		Enabled      bool   `toml:"enabled"`
+		MaskSpoilers bool   `toml:"mask_spoilers"`
+		Theme        string `toml:"theme"`
 	}
 
 	HelpConfig struct {

internal/config/config.toml

@@ -28,6 +28,8 @@ max_height = 10
 [markdown]
 # Whether to parse and render markdown in messages or not.
 enabled = true
+# Replace spoiler contents with a placeholder.
+mask_spoilers = false
 # Theme for fenced code blocks. Available themes: https://xyproto.github.io/splash/docs
 theme = "monokai"
 

internal/markdown/renderer.go

@@ -118,6 +118,12 @@ func (r *Renderer) RenderLines(source []byte, node ast.Node, base tcell.Style) [
 				builder.NewLine()
 			}
 		case *discordmd.Inline:
+			if r.cfg.Markdown.MaskSpoilers && node.Attr&discordmd.AttrSpoiler != 0 {
+				if entering {
+					builder.Write("[spoiler]", currentStyle())
+				}
+				return ast.WalkSkipChildren, nil
+			}
 			if entering {
 				pushStyle(applyInlineAttr(currentStyle(), node.Attr, linkDepth > 0))
 			} else {

internal/markdown/renderer_test.go

@@ -0,0 +1,39 @@
+package markdown
+
+import (
+	"strings"
+	"testing"
+
+	"github.com/ayn2op/discordo/internal/config"
+	"github.com/ayn2op/ningen/v3/discordmd"
+	"github.com/gdamore/tcell/v3"
+	"github.com/yuin/goldmark/parser"
+	"github.com/yuin/goldmark/text"
+)
+
+func TestRendererMasksSpoilers(t *testing.T) {
+	source := []byte("before ||secret|| after")
+	node := parser.NewParser(
+		parser.WithBlockParsers(discordmd.BlockParsers()...),
+		parser.WithInlineParsers(discordmd.InlineParserWithLink()...),
+	).Parse(text.NewReader(source))
+
+	for _, test := range []struct {
+		mask bool
+		want string
+	}{
+		{true, "before [spoiler] after"},
+		{false, "before secret after"},
+	} {
+		lines := NewRenderer(&config.Config{Markdown: config.MarkdownConfig{MaskSpoilers: test.mask}}).RenderLines(source, node, tcell.StyleDefault)
+		var got strings.Builder
+		for _, line := range lines {
+			for _, segment := range line {
+				got.WriteString(segment.Text)
+			}
+		}
+		if got.String() != test.want {
+			t.Fatalf("mask=%t: got %q, want %q", test.mask, got.String(), test.want)
+		}
+	}
+}