copy langext & termext from ffsclient

termext/termcolor.go

@@ -0,0 +1,90 @@
+package termext
+
+import (
+	"golang.org/x/term"
+	"os"
+	"regexp"
+	"strconv"
+	"strings"
+)
+
+// -> partly copied from [ https://github.com/jwalton/go-supportscolor/tree/master ]
+
+func SupportsColors() bool {
+
+	if isatty := term.IsTerminal(int(os.Stdout.Fd())); !isatty {
+		return false
+	}
+
+	termenv := os.Getenv("TERM")
+
+	if termenv == "dumb" {
+		return false
+	}
+
+	if osColorEnabled := enableColor(); !osColorEnabled {
+		return false
+	}
+
+	if _, ci := os.LookupEnv("CI"); ci {
+		var ciEnvNames = []string{"TRAVIS", "CIRCLECI", "APPVEYOR", "GITLAB_CI", "GITHUB_ACTIONS", "BUILDKITE", "DRONE"}
+		for _, ciEnvName := range ciEnvNames {
+			_, exists := os.LookupEnv(ciEnvName)
+			if exists {
+				return true
+			}
+		}
+
+		if os.Getenv("CI_NAME") == "codeship" {
+			return true
+		}
+
+		return false
+	}
+
+	if teamCityVersion, isTeamCity := os.LookupEnv("TEAMCITY_VERSION"); isTeamCity {
+		versionRegex := regexp.MustCompile(`^(9\.(0*[1-9]\d*)\.|\d{2,}\.)`)
+		if versionRegex.MatchString(teamCityVersion) {
+			return true
+		}
+		return false
+	}
+
+	if os.Getenv("COLORTERM") == "truecolor" {
+		return true
+	}
+
+	if termProgram, termProgramPreset := os.LookupEnv("TERM_PROGRAM"); termProgramPreset {
+		switch termProgram {
+		case "iTerm.app":
+			termProgramVersion := strings.Split(os.Getenv("TERM_PROGRAM_VERSION"), ".")
+			version, err := strconv.ParseInt(termProgramVersion[0], 10, 64)
+			if err == nil && version >= 3 {
+				return true
+			}
+			return true
+		case "Apple_Terminal":
+			return true
+
+		default:
+			// No default
+		}
+	}
+
+	var term256Regex = regexp.MustCompile("(?i)-256(color)?$")
+	if term256Regex.MatchString(termenv) {
+		return true
+	}
+
+	var termBasicRegex = regexp.MustCompile("(?i)^screen|^xterm|^vt100|^vt220|^rxvt|color|ansi|cygwin|linux")
+
+	if termBasicRegex.MatchString(termenv) {
+		return true
+	}
+
+	if _, colorTerm := os.LookupEnv("COLORTERM"); colorTerm {
+		return true
+	}
+
+	return false
+}