doorgo/door/line.go

package door

import (
	"unicode"
)

type Line struct {
	Text         string
	DefaultColor string
	RenderF      func(string) string
	UpdateF      func() string
}

func (l *Line) Update() bool {
	if l.UpdateF == nil {
		return false
	}
	NewText := l.UpdateF()
	if NewText != l.Text {
		l.Text = NewText
		return true
	}
	return false
}

func (l *Line) Output() string {
	if l.RenderF == nil {
		return l.DefaultColor + l.Text
	} else {
		return l.RenderF(l.Text)
	}
}

// Sample RenderF function
// Upcase is BOLD Blue, everything else is Yellow
func RenderBlueYellow(text string) string {
	var output string
	var lastColor string

	blue := ColorText("BOLD BLUE")
	yellow := ColorText("BOLD YELLOW")

	for _, letter := range text {
		if unicode.IsUpper(letter) {
			if lastColor != blue {
				lastColor = blue
				output += blue
			}
			output += string(letter)
		} else {
			if lastColor != yellow {
				lastColor = yellow
				output += yellow
			}
			output += string(letter)
		}
	}
	return output
}

type Render struct {
	Line      string
	Result    string
	Pos       int
	LastColor string
}

func (r *Render) Append(color string, len int) {
	if color != r.LastColor {
		r.LastColor = color
		r.Result += color
	}
	r.Result += r.Line[r.Pos : r.Pos+len]
	r.Pos += len
}