package style

import (
	"fmt"
	"os"
	"strings"
)

var noColor = os.Getenv("NO_COLOR") != "" || os.Getenv("TERM") == "dumb"

type Style struct {
	codes []string
}

func New() *Style {
	return &Style{}
}

func (s *Style) clone() *Style {
	c := &Style{codes: make([]string, len(s.codes))}
	copy(c.codes, s.codes)
	return c
}

func (s *Style) Bold() *Style {
	c := s.clone()
	c.codes = append(c.codes, "1")
	return c
}

func (s *Style) Dim() *Style {
	c := s.clone()
	c.codes = append(c.codes, "2")
	return c
}

func (s *Style) Italic() *Style {
	c := s.clone()
	c.codes = append(c.codes, "3")
	return c
}

func (s *Style) Underline() *Style {
	c := s.clone()
	c.codes = append(c.codes, "4")
	return c
}

func (s *Style) Fg(c Color) *Style {
	n := s.clone()
	n.codes = append(n.codes, fmt.Sprintf("%d", c))
	return n
}

func (s *Style) Bg(c Color) *Style {
	n := s.clone()
	n.codes = append(n.codes, fmt.Sprintf("%d", c+10))
	return n
}

func (s *Style) FgHex(hex string) *Style {
	n := s.clone()
	r, g, b := hexToRGB(hex)
	n.codes = append(n.codes, fmt.Sprintf("38;2;%d;%d;%d", r, g, b))
	return n
}

func (s *Style) BgHex(hex string) *Style {
	n := s.clone()
	r, g, b := hexToRGB(hex)
	n.codes = append(n.codes, fmt.Sprintf("48;2;%d;%d;%d", r, g, b))
	return n
}

func hexToRGB(hex string) (r, g, b int) {
	hex = strings.TrimPrefix(hex, "#")
	if len(hex) != 6 {
		return 255, 255, 255
	}
	r = parseHex(hex[0:2])
	g = parseHex(hex[2:4])
	b = parseHex(hex[4:6])
	return
}

func parseHex(s string) int {
	v := 0
	for _, c := range s {
		v *= 16
		switch {
		case c >= '0' && c <= '9':
			v += int(c - '0')
		case c >= 'a' && c <= 'f':
			v += int(c - 'a' + 10)
		case c >= 'A' && c <= 'F':
			v += int(c - 'A' + 10)
		}
	}
	return v
}

func (s *Style) Render(text string) string {
	if noColor || len(s.codes) == 0 {
		return text
	}
	return "\033[" + strings.Join(s.codes, ";") + "m" + text + "\033[0m"
}

type Color int

const (
	ColorBlack   Color = 30
	ColorRed     Color = 31
	ColorGreen   Color = 32
	ColorYellow  Color = 33
	ColorBlue    Color = 34
	ColorMagenta Color = 35
	ColorCyan    Color = 36
	ColorWhite   Color = 37
)

var (
	Red     = New().Fg(ColorRed)
	Green   = New().Fg(ColorGreen)
	Yellow  = New().Fg(ColorYellow)
	Cyan    = New().Fg(ColorCyan)
	Blue    = New().Fg(ColorBlue)
	Magenta = New().Fg(ColorMagenta)
	White   = New().Fg(ColorWhite)
	Bold    = New().Bold()
	Dim     = New().Dim()
)