package termenv

import (
	"fmt"
	"strings"

	"github.com/mattn/go-runewidth"
)

const (
	ResetSeq     = "0"
	BoldSeq      = "1"
	FaintSeq     = "2"
	ItalicSeq    = "3"
	UnderlineSeq = "4"
	BlinkSeq     = "5"
	ReverseSeq   = "7"
	CrossOutSeq  = "9"
	OverlineSeq  = "53"
)

// Style is a string that various rendering styles can be applied to.
type Style struct {
	string
	styles []string
}

// String returns a new Style.
func String(s ...string) Style {
	return Style{
		string: strings.Join(s, " "),
	}
}

func (t Style) String() string {
	return t.Styled(t.string)
}

// Styled renders s with all applied styles.
func (t Style) Styled(s string) string {
	if len(t.styles) == 0 {
		return s
	}

	seq := strings.Join(t.styles, ";")
	if seq == "" {
		return s
	}

	return fmt.Sprintf("%s%sm%s%sm", CSI, seq, s, CSI+ResetSeq)
}

// Foreground sets a foreground color.
func (t Style) Foreground(c Color) Style {
	if c != nil {
		t.styles = append(t.styles, c.Sequence(false))
	}
	return t
}

// Background sets a background color.
func (t Style) Background(c Color) Style {
	if c != nil {
		t.styles = append(t.styles, c.Sequence(true))
	}
	return t
}

// Bold enables bold rendering.
func (t Style) Bold() Style {
	t.styles = append(t.styles, BoldSeq)
	return t
}

// Faint enables faint rendering.
func (t Style) Faint() Style {
	t.styles = append(t.styles, FaintSeq)
	return t
}

// Italic enables italic rendering.
func (t Style) Italic() Style {
	t.styles = append(t.styles, ItalicSeq)
	return t
}

// Underline enables underline rendering.
func (t Style) Underline() Style {
	t.styles = append(t.styles, UnderlineSeq)
	return t
}

// Overline enables overline rendering.
func (t Style) Overline() Style {
	t.styles = append(t.styles, OverlineSeq)
	return t
}

// Blink enables blink mode.
func (t Style) Blink() Style {
	t.styles = append(t.styles, BlinkSeq)
	return t
}

// Reverse enables reverse color mode.
func (t Style) Reverse() Style {
	t.styles = append(t.styles, ReverseSeq)
	return t
}

// CrossOut enables crossed-out rendering.
func (t Style) CrossOut() Style {
	t.styles = append(t.styles, CrossOutSeq)
	return t
}

// Width returns the width required to print all runes in Style.
func (t Style) Width() int {
	return runewidth.StringWidth(t.string)
}