doorgo/door/line.go

package door

import (
	"bytes"
	"log"
	"unicode"
)

/*
door.Line - Display a line of text

Example:

	    var basicLine door.Line = {Text: "Welcome",
		    DefaultColor: door.Color("BRIGHT YELLOW"),
		}

	    d.Write(basicLine.Output() + door.Reset + door.CRNL)

This outputs Welcome in Bright/Bold Yellow.

Example Render:

	    var renderAlphaDigit ColorRender = func(text string) string {
			var r door.Render{Text: text}
			var alpha string = door.ColorText("BOLD YELLOW")
			var digit string = door.ColorText("BOLD GREEN")
			var other string = door.Reset
			for _, letter := range text {
				if unicode.IsAlpha(letter) {
					r.Append(alpha, 1)
				} else {
					if unicode.IsDigit(letter) {
						r.Append(digit, 1)
					} else {
						r.Append(other, 1)
					}
				}
			}
			return r.Result
		}
		var renderLine door.Line = {Text: "Render - 12345",
			RenderF: renderAlphaDigit,
		}
		d.Write(renderLine.Output() + door.Reset + door.CRNL)

This outputs "Render" in Yellow, "12345" in Green, and " - " in White.

Example Update:

		var updateTime() string {
			var now time.Time = time.Now()
			var result string = now.Format("3:04:05 PM")
	        return result
		}
		var timeLine door.Line = {Text: updateTime(),
			UpdateF: updateTime,
		}
		d.Write(timeLine.Output() + door.CRNL)
		time.Sleep(time.Second)

		// Check timeLine for update
		if timeLine.Update() {
			// Yes, there's an update to the time, output it.
			d.Write(timeLine.Output() + door.CRNL)
		}

		if timeLine.Update() {
			// This isn't called.  There were no changes.
			d.Write(timeLine.Output() + door.CRNL)
		}

This outputs the Current time in 12 hour format.  It pauses for a second,
and outputs the new time.
*/

/*
Line of text to display.
*/
type Line struct {
	Text         *bytes.Buffer // Text to be displayed
	update       *bytes.Buffer // Buffer for updates
	DefaultColor string        // Default Color to use
	RenderF      ColorRender   // Render function (displays string with colors)
	render       *bytes.Buffer // Buffer for rendering
	UpdateF      Updater       // Update function updates the text
	Width        int           // Line length
}

func NewLine(text string) Line {
	return Line{Text: bytes.NewBuffer([]byte(text))}
}

/*
Line Update - This calls the UpdateF if present.

Returns true if the line has been updated, and there's an Update function.
*/
func (l *Line) Update() bool {
	if l.Text == nil {
		l.Text = &bytes.Buffer{}
	}
	if l.UpdateF == nil {
		return false
	}
	if l.update == nil {
		l.update = &bytes.Buffer{}
	}
	l.update.Reset()
	l.UpdateF(l.update)

	l.LineLength(l.update)
	if bytes.Compare(l.update.Bytes(), l.Text.Bytes()) != 0 {
		l.Text.Reset()
		l.Text.Write(l.update.Bytes())
		return true
	}
	return false
}

// If a line Width has been set, make sure we match it.
func (l *Line) LineLength(text *bytes.Buffer) {
	if l.Width == 0 {
		return
	}
	var length int

	if Unicode {
		var ubuff *bytes.Buffer = bytes.NewBuffer(text.Bytes())
		var e error
		var r rune
		for {
			r, _, e = ubuff.ReadRune()
			if e != nil {
				break
			}
			length += UnicodeWidth(r)
		}
	} else {
		length = text.Len()
	}

	if length > l.Width {
		log.Printf("ERROR: Line Width %d: Have %d\n", l.Width, length)
	} else {
		for length < l.Width {
			text.WriteByte(' ')
			length++
		}
		// *text += strings.Repeat(" ", l.Width-length)
	}
}

/*
Line Output - returns a string with ANSI Color codes.

If there is no RenderF, we use the DefaultColor.  Otherwise we pass the text
to RenderF and return what it returns.
*/
func (l *Line) Output() []byte {
	if l.UpdateF == nil {
		l.LineLength(l.Text)
	}
	if l.render == nil {
		l.render = &bytes.Buffer{}
	}
	if l.RenderF == nil {
		l.render.Reset()
		l.render.WriteString(l.DefaultColor)
		l.render.Write(l.Text.Bytes())
		return l.render.Bytes()
		// return l.DefaultColor + l.Text
	} else {
		return l.RenderF(l.render, l.Text.Bytes())
	}
}

func RenderBlueYellow(output *bytes.Buffer, text []byte) []byte {
	output.Reset()

	// var output = RenderPool.Get().(*strings.Builder)
	// output.Reset()

	var blue string = ColorText("BOLD BLUE")
	var yellow string = ColorText("BOLD YELLOW")
	var last *string

	for _, letter := range text {
		if unicode.IsUpper(rune(letter)) {
			if last != &blue {
				output.WriteString(blue)
				last = &blue
			}
		} else {
			if last != &yellow {
				output.WriteString(yellow)
				last = &yellow
			}
		}
		output.WriteByte(letter)
	}

	// var result = output.String()
	// RenderPool.Put(output)
	// return result
	return output.Bytes()
}