first commit

pigo/internal/cli/ui/markdown.go

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+// This file renders assistant replies as Markdown for interactive terminals.
+// The line-oriented REPL streams model text token-by-token, but Markdown can
+// only be laid out once the whole block is known (a table or fenced code span
+// needs its full extent). So rendering is a turn-end concern: the caller buffers
+// the streamed text and calls RenderMarkdown once the assistant turn closes.
+//
+// Rendering is gated exactly like color (Enabled): only an interactive,
+// NO_COLOR-unset stdout gets styled output. Pipes, files, CI, and tests receive
+// the raw Markdown source unchanged, so machine consumers and golden tests are
+// unaffected. Any renderer failure also falls back to the raw source — pretty
+// output is never allowed to lose content.
+package ui
+
+import (
+	"strings"
+	"sync"
+
+	"github.com/charmbracelet/glamour"
+)
+
+// mdRenderer is the lazily-built glamour renderer. Building it parses a style
+// and compiles a chroma lexer set, so it is created once and reused across
+// turns. A build failure leaves it nil, degrading to raw output.
+var (
+	mdOnce     sync.Once
+	mdRenderer *glamour.TermRenderer
+)
+
+// initMarkdown builds the shared renderer on first use. It uses glamour's
+// auto style, which follows the terminal's dark/light background.
+//
+// WithWordWrap(0) disables glamour's hard word-wrap. That matters: with a fixed
+// wrap width glamour pads every line with trailing-space background cells out to
+// the full column count, so a three-line reply balloons into kilobytes of ANSI
+// noise (measured: ~8KB for a short block at width 100 vs. ~0.5KB unwrapped).
+// Disabling the wrap lets the terminal soft-wrap long lines itself and keeps the
+// rendered output tight — the REPL doesn't track terminal size anyway.
+func initMarkdown() {
+	mdOnce.Do(func() {
+		r, err := glamour.NewTermRenderer(
+			glamour.WithAutoStyle(),
+			glamour.WithWordWrap(0),
+		)
+		if err != nil {
+			return
+		}
+		mdRenderer = r
+	})
+}
+
+// RenderMarkdown returns src rendered as styled terminal Markdown when output
+// is an interactive terminal, and src unchanged otherwise. A nil/broken
+// renderer or a render error also returns src, so content is never dropped in
+// favor of styling. The returned string carries its own trailing newline from
+// glamour; callers should not add another.
+func RenderMarkdown(src string) string {
+	if !Enabled() {
+		return src
+	}
+	if strings.TrimSpace(src) == "" {
+		return src
+	}
+	initMarkdown()
+	if mdRenderer == nil {
+		return src
+	}
+	out, err := mdRenderer.Render(src)
+	if err != nil {
+		return src
+	}
+	return out
+}