Add util to render table

util/padding.go

+package util
+
+import (
+	"math"
+	"strings"
+	"unicode/utf8"
+)
+
+const (
+	ALIGN_LEFT   = 0
+	ALIGN_CENTER = 1
+	ALIGN_RIGHT  = 2
+)
+
+func Pad(s, pad string, width int, align int) string {
+	switch align {
+	case ALIGN_CENTER:
+		return PadCenter(s, pad, width)
+	case ALIGN_RIGHT:
+		return PadLeft(s, pad, width)
+	default:
+		return PadRight(s, pad, width)
+	}
+}
+
+func PadRight(s, pad string, width int) string {
+	gap := width - utf8.RuneCountInString(s)
+	if gap > 0 {
+		return s + strings.Repeat(string(pad), gap)
+	}
+	return s
+}
+
+func PadLeft(s, pad string, width int) string {
+	gap := width - utf8.RuneCountInString(s)
+	if gap > 0 {
+		return strings.Repeat(string(pad), gap) + s
+	}
+	return s
+}
+
+func PadCenter(s, pad string, width int) string {
+	gap := width - utf8.RuneCountInString(s)
+	if gap > 0 {
+		gapLeft := int(math.Ceil(float64(gap / 2)))
+		gapRight := gap - gapLeft
+		return strings.Repeat(string(pad), gapLeft) + s + strings.Repeat(string(pad), gapRight)
+	}
+	return s
+}

util/table.go

+package util
+
+import (
+	"fmt"
+	"io"
+	"unicode/utf8"
+)
+
+// const (
+// 	ALIGN_LEFT   = 0
+// 	ALIGN_CENTER = 1
+// 	ALIGN_RIGHT  = 2
+// )
+
+type Table struct {
+	Out          io.Writer
+	Rows         [][]string
+	ColumnWidths []int
+	ColumnAlign  []int
+	Separator    string
+}
+
+func CreateTable(out io.Writer) Table {
+	return Table{
+		Out:       out,
+		Separator: " ",
+	}
+}
+
+// Clear removes all rows while preserving the layout
+func (t *Table) Clear() {
+	t.Rows = [][]string{}
+}
+
+// AddRow adds a new row to the table
+func (t *Table) AddRow(col ...string) {
+	t.Rows = append(t.Rows, col)
+}
+
+func (t *Table) Render() {
+	// lets figure out the max widths of each column
+	for _, row := range t.Rows {
+		for ci, col := range row {
+			l := utf8.RuneCountInString(col)
+			t.ColumnWidths = ensureArrayCanContain(t.ColumnWidths, ci)
+			if l > t.ColumnWidths[ci] {
+				t.ColumnWidths[ci] = l
+			}
+		}
+	}
+
+	out := t.Out
+	for _, row := range t.Rows {
+		lastColumn := len(row) - 1
+		for ci, col := range row {
+			if ci > 0 {
+				fmt.Fprint(out, t.Separator)
+			}
+			l := t.ColumnWidths[ci]
+			align := t.GetColumnAlign(ci)
+			if ci >= lastColumn && align != ALIGN_CENTER && align != ALIGN_RIGHT {
+				fmt.Fprint(out, col)
+			} else {
+				fmt.Fprint(out, Pad(col, " ", l, align))
+			}
+		}
+		fmt.Fprint(out, "\n")
+	}
+}
+
+// SetColumnsAligns sets the alignment of the columns
+func (t *Table) SetColumnsAligns(colAligns []int) {
+	t.ColumnAlign = colAligns
+}
+
+// GetColumnAlign return the column alignment
+func (t *Table) GetColumnAlign(i int) int {
+	t.ColumnAlign = ensureArrayCanContain(t.ColumnAlign, i)
+	return t.ColumnAlign[i]
+}
+
+// SetColumnAlign sets the column alignment for the given column index
+func (t *Table) SetColumnAlign(i int, align int) {
+	t.ColumnAlign = ensureArrayCanContain(t.ColumnAlign, i)
+	t.ColumnAlign[i] = align
+}
+
+func ensureArrayCanContain(array []int, idx int) []int {
+	diff := idx + 1 - len(array)
+	for i := 0; i < diff; i++ {
+		array = append(array, 0)
+	}
+	return array
+}