package color

import (
	"strconv"
	"strings"
)

const (
	csi   = "\x1b["
	Clear = "\x1b[0m"
)

type Attribute int

// https://en.wikipedia.org/wiki/ANSI_escape_code
const (
	Reset Attribute = iota
	Bold
	Faint
	Italic
	Underline
	SlowBlink
	RapidBlink
	ReverseVideo
	Conceal
	CrossedOut
)

const (
	重置 Attribute = iota
	加粗
	弱化
	斜体
	下划线
	缓慢闪烁
	快速闪烁
	反显
	消隐
	划除
)

type Color int

const (
	Black Color = iota + 30
	Red
	Green
	Yellow
	Blue
	Magenta
	Cyan
	White
)

type Sequence []Attribute

func (seq Sequence) String() string {
	var b strings.Builder
	b.WriteString(csi)
	if len(seq) > 0 {
		b.WriteString(strconv.Itoa(int(seq[0])))
	}
	for _, v := range seq[1:] {
		b.WriteRune(';')
		b.WriteString(strconv.Itoa(int(v)))
	}
	b.WriteRune('m')
	return b.String()
}

func (seq Sequence) Base(attrs ...Attribute) Sequence {
	return append(seq, attrs...)
}

func (seq Sequence) Bg(c Color) Sequence {
	return append(seq, add(c, 10))
}

func (seq Sequence) Fg(c Color) Sequence {
	return append(seq, Attribute(c))
}

func (seq Sequence) Hi(c Color) Sequence {
	return append(seq, add(c, 60))
}

func (seq Sequence) HiBg(c Color) Sequence {
	return append(seq, add(c, 70))
}

func (seq Sequence) BgRGB(r, g, b int) Sequence {
	return append(seq, Sequence{48, 2, Attribute(r), Attribute(g), Attribute(b)}...)
}

func (seq Sequence) FgRGB(r, g, b int) Sequence {
	return append(seq, Sequence{38, 2, Attribute(r), Attribute(g), Attribute(b)}...)
}

func Base(attrs ...Attribute) Sequence {
	return Sequence(attrs)
}

func Bg(c Color) Sequence {
	return []Attribute{add(c, 10)}
}

func Fg(c Color) Sequence {
	return []Attribute{Attribute(c)}
}

func Hi(c Color) Sequence {
	return []Attribute{add(c, 60)}
}

func HiBg(c Color) Sequence {
	return []Attribute{add(c, 70)}
}

func add(c Color, offset int) Attribute {
	return Attribute(c) + Attribute(offset)
}