cli · samcoe · Sep 28, 2020 · Sep 23, 2020 · Sep 24, 2020 · Sep 25, 2020
@@ -18,6 +18,7 @@ require (
 	github.com/mattn/go-runewidth v0.0.9
 	github.com/mgutz/ansi v0.0.0-20200706080929-d51e80ef957d
 	github.com/mitchellh/go-homedir v1.1.0
+	github.com/muesli/termenv v0.7.2
 	github.com/rivo/uniseg v0.1.0
 	github.com/shurcooL/githubv4 v0.0.0-20200802174311-f27d2ca7f6d5
 	github.com/shurcooL/graphql v0.0.0-20181231061246-d48a9a75455f

@@ -132,6 +132,8 @@ github.com/muesli/reflow v0.1.0 h1:oQdpLfO56lr5pgLvqD0TcjW85rDjSYSBVdiG1Ch1ddM=
 github.com/muesli/reflow v0.1.0/go.mod h1:I9bWAt7QTg/que/qmUCJBGlj7wEq8OAFBjPNjc6xK4I=
 github.com/muesli/termenv v0.6.0 h1:zxvzTBmo4ZcxhNGGWeMz+Tttm51eF5bmPjfy4MCRYlk=
 github.com/muesli/termenv v0.6.0/go.mod h1:SohX91w6swWA4AYU+QmPx+aSgXhWO0juiyID9UZmbpA=
+github.com/muesli/termenv v0.7.2 h1:r1raklL3uKE7rOvWgSenmEm2px+dnc33OTisZ8YR1fw=
+github.com/muesli/termenv v0.7.2/go.mod h1:ct2L5N2lmix82RaY3bMWwVu/jUFc9Ule0KGDCiKYPh8=
 github.com/mwitkow/go-conntrack v0.0.0-20161129095857-cc309e4a2223/go.mod h1:qRWi+5nqEBWmkhHvq77mSJWrCKwh8bxhgT7d/eI7P4U=
 github.com/oklog/ulid v1.3.1/go.mod h1:CirwcVhetQ6Lv90oh/F+FBtV6XMibvdAFo93nm5qn4U=
 github.com/olekukonko/tablewriter v0.0.4 h1:vHD/YYe1Wolo78koG299f7V/VAS08c6IpCLn+Ejf/w8=

@@ -10,6 +10,7 @@ import (
 	"github.com/cli/cli/pkg/cmd/gist/shared"
 	"github.com/cli/cli/pkg/cmdutil"
 	"github.com/cli/cli/pkg/iostreams"
+	"github.com/cli/cli/pkg/markdown"
 	"github.com/cli/cli/utils"
 	"github.com/spf13/cobra"
 )
@@ -115,7 +116,8 @@ func viewRun(opts *ViewOptions) error {
 		}
 		content := gistFile.Content
 		if strings.Contains(gistFile.Type, "markdown") && !opts.Raw {
-			rendered, err := utils.RenderMarkdown(gistFile.Content)
+			style := markdown.GetStyle(opts.IO.DetectTerminalTheme())
+			rendered, err := markdown.Render(gistFile.Content, style)
 			if err == nil {
 				content = rendered
 			}

@@ -16,6 +16,7 @@ import (
 	prShared "github.com/cli/cli/pkg/cmd/pr/shared"
 	"github.com/cli/cli/pkg/cmdutil"
 	"github.com/cli/cli/pkg/iostreams"
+	"github.com/cli/cli/pkg/markdown"
 	"github.com/cli/cli/utils"
 	"github.com/spf13/cobra"
 )
@@ -89,14 +90,16 @@ func viewRun(opts *ViewOptions) error {
 		return utils.OpenInBrowser(openURL)
 	}
 
+	opts.IO.DetectTerminalTheme()
+
 	err = opts.IO.StartPager()
 	if err != nil {
 		return err
 	}
 	defer opts.IO.StopPager()
 
 	if opts.IO.IsStdoutTTY() {
-		return printHumanIssuePreview(opts.IO.Out, issue)
+		return printHumanIssuePreview(opts.IO, issue)
 	}
 	return printRawIssuePreview(opts.IO.Out, issue)
 }
@@ -122,7 +125,8 @@ func printRawIssuePreview(out io.Writer, issue *api.Issue) error {
 	return nil
 }
 
-func printHumanIssuePreview(out io.Writer, issue *api.Issue) error {
+func printHumanIssuePreview(io *iostreams.IOStreams, issue *api.Issue) error {
+	out := io.Out
 	now := time.Now()
 	ago := now.Sub(issue.CreatedAt)
 
@@ -158,7 +162,8 @@ func printHumanIssuePreview(out io.Writer, issue *api.Issue) error {
 	// Body
 	if issue.Body != "" {
 		fmt.Fprintln(out)
-		md, err := utils.RenderMarkdown(issue.Body)
+		style := markdown.GetStyle(io.TerminalTheme())
+		md, err := markdown.Render(issue.Body, style)
 		if err != nil {
 			return err
 		}

@@ -14,6 +14,7 @@ import (
 	"github.com/cli/cli/pkg/cmd/pr/shared"
 	"github.com/cli/cli/pkg/cmdutil"
 	"github.com/cli/cli/pkg/iostreams"
+	"github.com/cli/cli/pkg/markdown"
 	"github.com/cli/cli/pkg/prompt"
 	"github.com/cli/cli/pkg/surveyext"
 	"github.com/cli/cli/utils"
@@ -252,7 +253,8 @@ func reviewSurvey(io *iostreams.IOStreams, editorCommand string) (*api.PullReque
 	}
 
 	if len(bodyAnswers.Body) > 0 {
-		renderedBody, err := utils.RenderMarkdown(bodyAnswers.Body)
+		style := markdown.GetStyle(io.DetectTerminalTheme())
+		renderedBody, err := markdown.Render(bodyAnswers.Body, style)
 		if err != nil {
 			return nil, err
 		}

@@ -16,6 +16,7 @@ import (
 	"github.com/cli/cli/pkg/cmd/pr/shared"
 	"github.com/cli/cli/pkg/cmdutil"
 	"github.com/cli/cli/pkg/iostreams"
+	"github.com/cli/cli/pkg/markdown"
 	"github.com/cli/cli/utils"
 	"github.com/spf13/cobra"
 )
@@ -99,14 +100,16 @@ func viewRun(opts *ViewOptions) error {
 		return utils.OpenInBrowser(openURL)
 	}
 
+	opts.IO.DetectTerminalTheme()
+
 	err = opts.IO.StartPager()
 	if err != nil {
 		return err
 	}
 	defer opts.IO.StopPager()
 
 	if connectedToTerminal {
-		return printHumanPrPreview(opts.IO.Out, pr)
+		return printHumanPrPreview(opts.IO, pr)
 	}
 	return printRawPrPreview(opts.IO.Out, pr)
 }
@@ -134,7 +137,9 @@ func printRawPrPreview(out io.Writer, pr *api.PullRequest) error {
 	return nil
 }
 
-func printHumanPrPreview(out io.Writer, pr *api.PullRequest) error {
+func printHumanPrPreview(io *iostreams.IOStreams, pr *api.PullRequest) error {
+	out := io.Out
+
 	// Header (Title and State)
 	fmt.Fprintln(out, utils.Bold(pr.Title))
 	fmt.Fprintf(out, "%s", shared.StateTitleWithColor(*pr))
@@ -172,7 +177,8 @@ func printHumanPrPreview(out io.Writer, pr *api.PullRequest) error {
 	// Body
 	if pr.Body != "" {
 		fmt.Fprintln(out)
-		md, err := utils.RenderMarkdown(pr.Body)
+		style := markdown.GetStyle(io.TerminalTheme())
+		md, err := markdown.Render(pr.Body, style)
 		if err != nil {
 			return err
 		}

@@ -12,6 +12,7 @@ import (
 	"github.com/cli/cli/pkg/cmd/release/shared"
 	"github.com/cli/cli/pkg/cmdutil"
 	"github.com/cli/cli/pkg/iostreams"
+	"github.com/cli/cli/pkg/markdown"
 	"github.com/cli/cli/utils"
 	"github.com/spf13/cobra"
 )
@@ -122,7 +123,8 @@ func renderReleaseTTY(io *iostreams.IOStreams, release *shared.Release) error {
 		fmt.Fprintf(w, "%s\n", iofmt.Gray(fmt.Sprintf("%s released this %s", release.Author.Login, utils.FuzzyAgo(time.Since(release.PublishedAt)))))
 	}
 
-	renderedDescription, err := utils.RenderMarkdown(release.Body)
+	style := markdown.GetStyle(io.DetectTerminalTheme())
+	renderedDescription, err := markdown.Render(release.Body, style)
 	if err != nil {
 		return err
 	}

@@ -14,6 +14,7 @@ import (
 	"github.com/cli/cli/internal/ghrepo"
 	"github.com/cli/cli/pkg/cmdutil"
 	"github.com/cli/cli/pkg/iostreams"
+	"github.com/cli/cli/pkg/markdown"
 	"github.com/cli/cli/utils"
 	"github.com/enescakir/emoji"
 	"github.com/spf13/cobra"
@@ -114,6 +115,8 @@ func viewRun(opts *ViewOptions) error {
 		return err
 	}
 
+	opts.IO.DetectTerminalTheme()
+
 	err = opts.IO.StartPager()
 	if err != nil {
 		return err
@@ -153,7 +156,8 @@ func viewRun(opts *ViewOptions) error {
 		readmeContent = utils.Gray("This repository does not have a README")
 	} else if isMarkdownFile(readme.Filename) {
 		var err error
-		readmeContent, err = utils.RenderMarkdown(readme.Content)
+		style := markdown.GetStyle(opts.IO.TerminalTheme())
+		readmeContent, err = markdown.Render(readme.Content, style)
 		if err != nil {
 			return fmt.Errorf("error rendering markdown: %w", err)
 		}

@@ -15,6 +15,7 @@ import (
 	"github.com/google/shlex"
 	"github.com/mattn/go-colorable"
 	"github.com/mattn/go-isatty"
+	"github.com/muesli/termenv"
 	"golang.org/x/crypto/ssh/terminal"
 )
 
@@ -24,9 +25,10 @@ type IOStreams struct {
 	ErrOut io.Writer
 
 	// the original (non-colorable) output stream
-	originalOut  io.Writer
-	colorEnabled bool
-	is256enabled bool
+	originalOut   io.Writer
+	colorEnabled  bool
+	is256enabled  bool
+	terminalTheme string
 
 	progressIndicatorEnabled bool
 	progressIndicator        *spinner.Spinner
@@ -52,6 +54,40 @@ func (s *IOStreams) ColorSupport256() bool {
 	return s.is256enabled
 }
 
+func (s *IOStreams) DetectTerminalTheme() string {
+	if !s.ColorEnabled() {
+		s.terminalTheme = "none"
+		return "none"
+	}
+
+	if s.pagerProcess != nil {
+		s.terminalTheme = "none"
+		return "none"
+	}
+
+	style := os.Getenv("GLAMOUR_STYLE")
+	if style != "" && style != "auto" {
+		s.terminalTheme = "none"
+		return "none"
+	}
+
+	if termenv.HasDarkBackground() {
+		s.terminalTheme = "dark"
+		return "dark"
+	}
+
+	s.terminalTheme = "light"
+	return "light"
+}
+
+func (s *IOStreams) TerminalTheme() string {
+	if s.terminalTheme == "" {
+		return "none"
+	}
+
+	return s.terminalTheme
+}
+
 func (s *IOStreams) SetStdinTTY(isTTY bool) {
 	s.stdinTTYOverride = true
 	s.stdinIsTTY = isTTY

@@ -0,0 +1,42 @@
+package markdown
+
+import (
+	"os"
+	"strings"
+
+	"github.com/charmbracelet/glamour"
+)
+
+func Render(text, style string) (string, error) {
+	// Glamour rendering preserves carriage return characters in code blocks, but
+	// we need to ensure that no such characters are present in the output.
+	text = strings.ReplaceAll(text, "\r\n", "\n")
+
+	tr, err := glamour.NewTermRenderer(
+		glamour.WithStylePath(style),
+		// glamour.WithBaseURL(""),  // TODO: make configurable
+		// glamour.WithWordWrap(80), // TODO: make configurable
+	)
+	if err != nil {
+		return "", err
+	}
+
+	return tr.Render(text)
+}
+
+func GetStyle(defaultStyle string) string {
+	style := fromEnv()
+	if style != "" && style != "auto" {
+		return style
+	}
+
+	if defaultStyle == "light" || defaultStyle == "dark" {
+		return defaultStyle
+	}
+
+	return "notty"
+}
+
+var fromEnv = func() string {
+	return os.Getenv("GLAMOUR_STYLE")
+}