feat: render Markdown in rich parameter descriptions (#6098)

coderd/parameter/plaintext.go

@@ -0,0 +1,97 @@
+package parameter
+
+import (
+	"strings"
+
+	"github.com/charmbracelet/glamour"
+	"github.com/charmbracelet/glamour/ansi"
+	"golang.org/x/xerrors"
+)
+
+var plaintextStyle = ansi.StyleConfig{
+	Document: ansi.StyleBlock{
+		StylePrimitive: ansi.StylePrimitive{},
+	},
+	BlockQuote: ansi.StyleBlock{
+		StylePrimitive: ansi.StylePrimitive{},
+	},
+	Paragraph: ansi.StyleBlock{
+		StylePrimitive: ansi.StylePrimitive{},
+	},
+	List: ansi.StyleList{
+		StyleBlock: ansi.StyleBlock{
+			StylePrimitive: ansi.StylePrimitive{},
+		},
+		LevelIndent: 4,
+	},
+	Heading: ansi.StyleBlock{
+		StylePrimitive: ansi.StylePrimitive{},
+	},
+	H1: ansi.StyleBlock{
+		StylePrimitive: ansi.StylePrimitive{},
+	},
+	H2: ansi.StyleBlock{
+		StylePrimitive: ansi.StylePrimitive{},
+	},
+	H3: ansi.StyleBlock{
+		StylePrimitive: ansi.StylePrimitive{},
+	},
+	H4: ansi.StyleBlock{
+		StylePrimitive: ansi.StylePrimitive{},
+	},
+	H5: ansi.StyleBlock{
+		StylePrimitive: ansi.StylePrimitive{},
+	},
+	H6: ansi.StyleBlock{
+		StylePrimitive: ansi.StylePrimitive{},
+	},
+	Strikethrough:  ansi.StylePrimitive{},
+	Emph:           ansi.StylePrimitive{},
+	Strong:         ansi.StylePrimitive{},
+	HorizontalRule: ansi.StylePrimitive{},
+	Item:           ansi.StylePrimitive{},
+	Enumeration: ansi.StylePrimitive{
+		BlockPrefix: ". ",
+	}, Task: ansi.StyleTask{},
+	Link: ansi.StylePrimitive{
+		Format: "({{.text}})",
+	},
+	LinkText: ansi.StylePrimitive{
+		Format: "{{.text}}",
+	},
+	ImageText: ansi.StylePrimitive{
+		Format: "{{.text}}",
+	},
+	Image: ansi.StylePrimitive{
+		Format: "({{.text}})",
+	},
+	Code: ansi.StyleBlock{
+		StylePrimitive: ansi.StylePrimitive{},
+	},
+	CodeBlock: ansi.StyleCodeBlock{
+		StyleBlock: ansi.StyleBlock{},
+	},
+	Table:                 ansi.StyleTable{},
+	DefinitionDescription: ansi.StylePrimitive{},
+}
+
+// Plaintext function converts the description with optional Markdown tags
+// to the plaintext form.
+func Plaintext(markdown string) (string, error) {
+	renderer, err := glamour.NewTermRenderer(
+		glamour.WithStandardStyle("ascii"),
+		glamour.WithWordWrap(0), // don't need to add spaces in the end of line
+		glamour.WithStyles(plaintextStyle),
+	)
+	if err != nil {
+		return "", xerrors.Errorf("can't initialize the Markdown renderer: %w", err)
+	}
+
+	output, err := renderer.Render(markdown)
+	if err != nil {
+		return "", xerrors.Errorf("can't render description to plaintext: %w", err)
+	}
+	defer renderer.Close()
+
+	return strings.TrimSpace(output), nil
+}