Add line wrap logic to box code

It can happen that the text to be displayed in the content box overflows
the terminal width and therefore is difficult to read.

Add line wrap logic to box code, which is enabled by default.

Add option to disable line wrap.

Author: HeavyWombat

box.go

@@ -28,6 +28,7 @@ import (
 	"strings"
 
 	"github.com/gonvenience/bunt"
+	"github.com/gonvenience/term"
 	colorful "github.com/lucasb-eyer/go-colorful"
 )
 
@@ -39,6 +40,7 @@ type boxOptions struct {
 	contentColor       *colorful.Color
 	headlineStyles     []bunt.StyleOption
 	noClosingEndOfLine bool
+	noLineWrap         bool
 }
 
 // HeadlineColor sets the color of the headline text
@@ -69,6 +71,13 @@ func NoFinalEndOfLine() BoxStyle {
 	}
 }
 
+// NoLineWrap disables line wrapping in the content box
+func NoLineWrap() BoxStyle {
+	return func(options *boxOptions) {
+		options.noLineWrap = true
+	}
+}
+
 // ContentBox creates a string for the terminal where content is printed inside
 // a simple box shape.
 func ContentBox(headline string, content string, opts ...BoxStyle) string {
@@ -107,20 +116,55 @@ func Box(out io.Writer, headline string, content io.Reader, opts ...BoxStyle) {
 		headline = bunt.Style(headline, style)
 	}
 
+	var processText = func(text string) []string {
+		if options.noLineWrap {
+			return []string{text}
+		}
+
+		words := strings.Fields(strings.TrimSpace(text))
+		if len(words) == 0 {
+			return []string{text}
+		}
+
+		var (
+			buf       bytes.Buffer
+			lines     = []string{}
+			lineWidth = term.GetTerminalWidth() - len(prefix)
+		)
+
+		buf.WriteString(words[0])
+		for _, word := range words[1:] {
+			if len(word)+1 > lineWidth-buf.Len() {
+				lines = append(lines, buf.String())
+				buf.Reset()
+				buf.WriteString(word)
+
+			} else {
+				fmt.Fprint(&buf, " ", word)
+			}
+		}
+
+		return append(lines, buf.String())
+	}
+
 	// Process each line of the content and apply styles if necessary
 	scanner := bufio.NewScanner(content)
 	for scanner.Scan() {
 		text := scanner.Text()
-		if options.contentColor != nil {
-			text = bunt.Style(text, bunt.Foreground(*options.contentColor))
-		}
 
 		if !linewritten {
 			// Write the headline string including the corner item
 			fmt.Fprintf(out, "%s %s\n", beginning, headline)
 		}
 
-		fmt.Fprintf(out, "%s %s\n", prefix, text)
+		for _, line := range processText(text) {
+			if options.contentColor != nil {
+				line = bunt.Style(line, bunt.Foreground(*options.contentColor))
+			}
+
+			fmt.Fprintf(out, "%s %s\n", prefix, line)
+		}
+
 		linewritten = true
 	}
 

box_test.go

@@ -29,6 +29,7 @@ import (
 
 	. "github.com/gonvenience/bunt"
 	. "github.com/gonvenience/neat"
+	. "github.com/gonvenience/term"
 )
 
 var _ = Describe("content box", func() {
@@ -219,4 +220,52 @@ DimGray{╵}
 			Expect(len(buf.String())).To(BeIdenticalTo(0))
 		})
 	})
+
+	Context("using line wrap", func() {
+		var tmp int
+
+		BeforeEach(func() {
+			tmp = FixedTerminalWidth
+			FixedTerminalWidth = 80
+		})
+
+		AfterEach(func() {
+			FixedTerminalWidth = tmp
+		})
+
+		It("should wrap lines that are too long", func() {
+			Expect("\n" + ContentBox(
+				"headline",
+				"content with a very long first line, that is most likely an error message with a lot of context or similar",
+			)).To(BeEquivalentTo(Sprintf(`
+╭ headline
+│ content with a very long first line, that is most likely an error message
+│ with a lot of context or similar
+╵
+`)))
+		})
+
+		It("should not wrap long lines if wrapping is disabled", func() {
+			Expect("\n" + ContentBox(
+				"headline",
+				"content with a very long first line, that is most likely an error message with a lot of context or similar",
+				NoLineWrap(),
+			)).To(BeEquivalentTo(Sprintf(`
+╭ headline
+│ content with a very long first line, that is most likely an error message with a lot of context or similar
+╵
+`)))
+		})
+
+		It("should not fail with empty lines", func() {
+			Expect("\n" + ContentBox(
+				"headline",
+				" ",
+			)).To(BeEquivalentTo(Sprintf(`
+╭ headline
+│  
+╵
+`)))
+		})
+	})
 })

go.mod

@@ -4,6 +4,7 @@ go 1.12
 
 require (
 	github.com/gonvenience/bunt v1.1.1
+	github.com/gonvenience/term v1.0.0
 	github.com/gonvenience/wrap v1.1.0
 	github.com/lucasb-eyer/go-colorful v1.0.3
 	github.com/onsi/ginkgo v1.12.0