(refactor): prepare breaking v2 API

- rename package to sneklog and move module to /v2
- replace text output flags with writer formatters
- remove external color dependencies
- update migration notes and coverage

colors.go

@@ -0,0 +1,181 @@
+package sneklog
+
+import (
+	"fmt"
+	"strings"
+)
+
+type FgColor uint8
+type BgColor uint8
+type Attribute uint8
+
+const (
+	Reset Attribute = iota
+	Bold
+	Faint
+	Italic
+	Underline
+	BlinkSlow
+	BlinkRapid
+	Invert
+	Conceal
+	CrossedOut
+)
+const (
+	DoubleUnderline Attribute = iota + 21 // Can be disable bold on some terminals
+	DisableBold
+	DisableItalic
+	DisableUnderline
+	DisableBlink
+	DisableInvert
+	DisableConceal
+	DisableCrossedOut
+)
+const (
+	FgBlack FgColor = iota + 30
+	FgRed
+	FgGreen
+	FgYellow
+	FgBlue
+	FgMagenta
+	FgCyan
+	FgWhite
+	FgDefault FgColor = 39
+)
+const (
+	BgBlack BgColor = iota + 40
+	BgRed
+	BgGreen
+	BgYellow
+	BgBlue
+	BgMagenta
+	BgCyan
+	BgWhite
+	BgDefault BgColor = 49
+)
+const (
+	FgHiBlack FgColor = iota + 90
+	FgHiRed
+	FgHiGreen
+	FgHiYellow
+	FgHiBlue
+	FgHiMagenta
+	FgHiCyan
+	FgHiWhite
+)
+const (
+	BgHiBlack BgColor = iota + 100
+	BgHiRed
+	BgHiGreen
+	BgHiYellow
+	BgHiBlue
+	BgHiMagenta
+	BgHiCyan
+	BgHiWhite
+)
+
+// This attributes rarely used and not supported by all terminals.
+const (
+	Border Attribute = iota + 51
+	Outline
+	Upperline
+	DisableBorderOutline
+	DisableUpperline
+)
+
+type ColorStringBuilder struct {
+	str string
+}
+
+func NewColorStringBuilder() *ColorStringBuilder {
+	return &ColorStringBuilder{str: ""}
+}
+func (builder *ColorStringBuilder) AddAttribute(attr Attribute) *ColorStringBuilder {
+	builder.str += attr.String()
+	return builder
+}
+func (builder *ColorStringBuilder) AddFgColor(color FgColor) *ColorStringBuilder {
+	if color == 0 {
+		return builder
+	}
+	builder.str += color.String()
+	return builder
+}
+func (builder *ColorStringBuilder) AddBgColor(color BgColor) *ColorStringBuilder {
+	if color == 0 {
+		return builder
+	}
+	builder.str += color.String()
+	return builder
+}
+func (builder *ColorStringBuilder) AddColor256Fg(color uint8) *ColorStringBuilder {
+	builder.str += color256Fg(color)
+	return builder
+}
+func (builder *ColorStringBuilder) AddColor256Bg(color uint8) *ColorStringBuilder {
+	builder.str += color256Bg(color)
+	return builder
+}
+func (builder *ColorStringBuilder) AddColorRgbFg(r, g, b uint8) *ColorStringBuilder {
+	builder.str += colorRgbFg(r, g, b)
+	return builder
+}
+func (builder *ColorStringBuilder) AddColorRgbBg(r, g, b uint8) *ColorStringBuilder {
+	builder.str += colorRgbBg(r, g, b)
+	return builder
+}
+func (builder *ColorStringBuilder) AddReset() *ColorStringBuilder {
+	builder.str += "\x1b[0m"
+	return builder
+}
+func (builder *ColorStringBuilder) AddText(text string) *ColorStringBuilder {
+	builder.str += text
+	return builder
+}
+func (builder *ColorStringBuilder) String() string {
+	if strings.Contains(builder.str, "\x1b[") && !strings.HasSuffix(builder.str, "\x1b[0m") {
+		builder.AddReset()
+	}
+	return builder.str
+}
+
+func (a Attribute) String() string {
+	return fmt.Sprintf("\x1b[%dm", a)
+}
+func (a Attribute) Uint8() uint8 {
+	return uint8(a)
+}
+func (a Attribute) Int() int {
+	return int(a)
+}
+func (c FgColor) String() string {
+	return fmt.Sprintf("\x1b[%dm", c)
+}
+func (c FgColor) Uint8() uint8 {
+	return uint8(c)
+}
+func (c FgColor) Int() int {
+	return int(c)
+}
+func (c BgColor) String() string {
+	return fmt.Sprintf("\x1b[%dm", c)
+}
+func (c BgColor) Uint8() uint8 {
+	return uint8(c)
+}
+func (c BgColor) Int() int {
+	return int(c)
+}
+
+func color256Fg(color uint8) string {
+	return fmt.Sprintf("\x1b[38;5;%dm", color)
+}
+func color256Bg(color uint8) string {
+	return fmt.Sprintf("\x1b[48;5;%dm", color)
+}
+func colorRgbFg(r, g, b uint8) string {
+	return fmt.Sprintf("\x1b[38;2;%d;%d;%dm", r, g, b)
+}
+func colorRgbBg(r, g, b uint8) string {
+	return fmt.Sprintf("\x1b[48;2;%d;%d;%dm", r, g, b)
+}