reorganize package for a more idomatic go

3 files changed, 371 insertions, 0 deletions

diff --git a/util/text/left_padded.go b/util/text/left_padded.go
new file mode 100644
index 00000000..a38dfba5
--- /dev/null
+++ b/util/text/left_padded.go
@@ -0,0 +1,20 @@
+package text
+
+import (
+	"strings"
+	"unicode/utf8"
+)
+
+// LeftPaddedString pads a string on the left by a specified amount and pads the string on the right to fill the maxLength
+func LeftPaddedString(value string, maxValueLength, padAmount int) string {
+	valueLength := utf8.RuneCountInString(value)
+	if maxValueLength-padAmount >= valueLength {
+		return strings.Repeat(" ", padAmount) + value + strings.Repeat(" ", maxValueLength-valueLength-padAmount)
+	} else if maxValueLength-padAmount < valueLength {
+		tmp := strings.Trim(value[0:maxValueLength-padAmount-3], " ") + "..."
+		tmpLength := utf8.RuneCountInString(tmp)
+		return strings.Repeat(" ", padAmount) + tmp + strings.Repeat(" ", maxValueLength-tmpLength-padAmount)
+	}
+
+	return value
+}
diff --git a/util/text/text.go b/util/text/text.go
new file mode 100644
index 00000000..10b70b01
--- /dev/null
+++ b/util/text/text.go
@@ -0,0 +1,160 @@
+package text
+
+import (
+	"bytes"
+	"strings"
+)
+
+// Wrap a text for an exact line size
+// Handle properly terminal color escape code
+func Wrap(text string, lineWidth int) (string, int) {
+	return WrapLeftPadded(text, lineWidth, 0)
+}
+
+// Wrap a text for an exact line size with a left padding
+// Handle properly terminal color escape code
+func WrapLeftPadded(text string, lineWidth int, leftPad int) (string, int) {
+	var textBuffer bytes.Buffer
+	var lineBuffer bytes.Buffer
+	nbLine := 1
+	firstLine := true
+	pad := strings.Repeat(" ", leftPad)
+
+	// tabs are formatted as 4 spaces
+	text = strings.Replace(text, "\t", "    ", 4)
+
+	for _, line := range strings.Split(text, "\n") {
+		spaceLeft := lineWidth - leftPad
+
+		if !firstLine {
+			textBuffer.WriteString("\n")
+			nbLine++
+		}
+
+		firstWord := true
+
+		for _, word := range strings.Split(line, " ") {
+			wordLength := wordLen(word)
+
+			if !firstWord {
+				lineBuffer.WriteString(" ")
+				spaceLeft -= 1
+
+				if spaceLeft <= 0 {
+					textBuffer.WriteString(pad + strings.TrimRight(lineBuffer.String(), " "))
+					textBuffer.WriteString("\n")
+					lineBuffer.Reset()
+					spaceLeft = lineWidth - leftPad
+					nbLine++
+					firstLine = false
+				}
+			}
+
+			// Word fit in the current line
+			if spaceLeft >= wordLength {
+				lineBuffer.WriteString(word)
+				spaceLeft -= wordLength
+				firstWord = false
+			} else {
+				// Break a word longer than a line
+				if wordLength > lineWidth {
+					for wordLength > 0 && len(word) > 0 {
+						l := minInt(spaceLeft, wordLength)
+						part, leftover := splitWord(word, l)
+						word = leftover
+						wordLength = wordLen(word)
+
+						lineBuffer.WriteString(part)
+						textBuffer.WriteString(pad)
+						textBuffer.Write(lineBuffer.Bytes())
+						lineBuffer.Reset()
+
+						spaceLeft -= l
+
+						if spaceLeft <= 0 {
+							textBuffer.WriteString("\n")
+							nbLine++
+							spaceLeft = lineWidth - leftPad
+						}
+					}
+				} else {
+					// Normal break
+					textBuffer.WriteString(pad + strings.TrimRight(lineBuffer.String(), " "))
+					textBuffer.WriteString("\n")
+					lineBuffer.Reset()
+					lineBuffer.WriteString(word)
+					firstWord = false
+					spaceLeft = lineWidth - wordLength
+					nbLine++
+				}
+			}
+		}
+
+		textBuffer.WriteString(pad + strings.TrimRight(lineBuffer.String(), " "))
+		lineBuffer.Reset()
+		firstLine = false
+	}
+
+	return textBuffer.String(), nbLine
+}
+
+func wordLen(word string) int {
+	length := 0
+	escape := false
+
+	for _, char := range word {
+		if char == '\x1b' {
+			escape = true
+		}
+
+		if !escape {
+			length++
+		}
+
+		if char == 'm' {
+			escape = false
+		}
+	}
+
+	return length
+}
+
+func splitWord(word string, length int) (string, string) {
+	result := ""
+	added := 0
+	escape := false
+
+	if length == 0 {
+		return "", word
+	}
+
+	for _, char := range word {
+		if char == '\x1b' {
+			escape = true
+		}
+
+		result += string(char)
+
+		if !escape {
+			added++
+			if added == length {
+				break
+			}
+		}
+
+		if char == 'm' {
+			escape = false
+		}
+	}
+
+	leftover := word[len(result):]
+
+	return result, leftover
+}
+
+func minInt(a, b int) int {
+	if a > b {
+		return b
+	}
+	return a
+}
diff --git a/util/text/text_test.go b/util/text/text_test.go
new file mode 100644
index 00000000..96234464
--- /dev/null
+++ b/util/text/text_test.go
@@ -0,0 +1,191 @@
+package text
+
+import (
+	"strings"
+	"testing"
+)
+
+func TestWrap(t *testing.T) {
+	cases := []struct {
+		Input, Output string
+		Lim           int
+	}{
+		// A simple word passes through.
+		{
+			"foo",
+			"foo",
+			4,
+		},
+		// Word breaking
+		{
+			"foobarbaz",
+			"foob\narba\nz",
+			4,
+		},
+		// Lines are broken at whitespace.
+		{
+			"foo bar baz",
+			"foo\nbar\nbaz",
+			4,
+		},
+		// Word breaking
+		{
+			"foo bars bazzes",
+			"foo\nbars\nbazz\nes",
+			4,
+		},
+		// A word that would run beyond the width is wrapped.
+		{
+			"fo sop",
+			"fo\nsop",
+			4,
+		},
+		// A tab counts as 4 characters.
+		{
+			"foo\nb\t r\n baz",
+			"foo\nb\n  r\n baz",
+			4,
+		},
+		// Trailing whitespace is removed after used for wrapping.
+		// Runs of whitespace on which a line is broken are removed.
+		{
+			"foo    \nb   ar   ",
+			"foo\n\nb\nar\n",
+			4,
+		},
+		// An explicit line break at the end of the input is preserved.
+		{
+			"foo bar baz\n",
+			"foo\nbar\nbaz\n",
+			4,
+		},
+		// Explicit break are always preserved.
+		{
+			"\nfoo bar\n\n\nbaz\n",
+			"\nfoo\nbar\n\n\nbaz\n",
+			4,
+		},
+		// Ignore complete words with terminal color sequence
+		{
+			"foo \x1b[31mbar\x1b[0m baz",
+			"foo\n\x1b[31mbar\x1b[0m\nbaz",
+			4,
+		},
+		// Handle words with colors sequence inside the word
+		{
+			"foo b\x1b[31mbar\x1b[0mr baz",
+			"foo\nb\x1b[31mbar\n\x1b[0mr\nbaz",
+			4,
+		},
+		// Break words with colors sequence inside the word
+		{
+			"foo bb\x1b[31mbar\x1b[0mr baz",
+			"foo\nbb\x1b[31mba\nr\x1b[0mr\nbaz",
+			4,
+		},
+		// Complete example:
+		{
+			" This is a list: \n\n\t* foo\n\t* bar\n\n\n\t* baz  \nBAM    ",
+			" This\nis a\nlist:\n\n\n    *\nfoo\n    *\nbar\n\n\n    *\nbaz\nBAM\n",
+			6,
+		},
+	}
+
+	for i, tc := range cases {
+		actual, lines := Wrap(tc.Input, tc.Lim)
+		if actual != tc.Output {
+			t.Fatalf("Case %d Input:\n\n`%s`\n\nExpected Output:\n\n`%s`\n\nActual Output:\n\n`%s`",
+				i, tc.Input, tc.Output, actual)
+		}
+
+		expected := len(strings.Split(tc.Output, "\n"))
+		if expected != lines {
+			t.Fatalf("Case %d Nb lines mismatch\nExpected:%d\nActual:%d",
+				i, expected, lines)
+		}
+	}
+}
+
+func TestWordLen(t *testing.T) {
+	cases := []struct {
+		Input  string
+		Length int
+	}{
+		// A simple word
+		{
+			"foo",
+			3,
+		},
+		// A simple word with colors
+		{
+			"\x1b[31mbar\x1b[0m",
+			3,
+		},
+		// Handle prefix and suffix properly
+		{
+			"foo\x1b[31mfoobarHoy\x1b[0mbaaar",
+			17,
+		},
+	}
+
+	for i, tc := range cases {
+		l := wordLen(tc.Input)
+		if l != tc.Length {
+			t.Fatalf("Case %d Input:\n\n`%s`\n\nExpected Output:\n\n`%d`\n\nActual Output:\n\n`%d`",
+				i, tc.Input, tc.Length, l)
+		}
+	}
+}
+
+func TestSplitWord(t *testing.T) {
+	cases := []struct {
+		Input            string
+		Length           int
+		Result, Leftover string
+	}{
+		// A simple word passes through.
+		{
+			"foo",
+			4,
+			"foo", "",
+		},
+		// Cut at the right place
+		{
+			"foobarHoy",
+			4,
+			"foob", "arHoy",
+		},
+		// A simple word passes through with colors
+		{
+			"\x1b[31mbar\x1b[0m",
+			4,
+			"\x1b[31mbar\x1b[0m", "",
+		},
+		// Cut at the right place with colors
+		{
+			"\x1b[31mfoobarHoy\x1b[0m",
+			4,
+			"\x1b[31mfoob", "arHoy\x1b[0m",
+		},
+		// Handle prefix and suffix properly
+		{
+			"foo\x1b[31mfoobarHoy\x1b[0mbaaar",
+			4,
+			"foo\x1b[31mf", "oobarHoy\x1b[0mbaaar",
+		},
+		// Cut properly with length = 0
+		{
+			"foo",
+			0,
+			"", "foo",
+		},
+	}
+
+	for i, tc := range cases {
+		result, leftover := splitWord(tc.Input, tc.Length)
+		if result != tc.Result || leftover != tc.Leftover {
+			t.Fatalf("Case %d Input:\n\n`%s`\n\nExpected Output:\n\n`%s` - `%s`\n\nActual Output:\n\n`%s` - `%s`",
+				i, tc.Input, tc.Result, tc.Leftover, result, leftover)
+		}
+	}
+}