view.go

package view

import (
	"log"

	termbox "github.com/nsf/termbox-go"
)

type Render interface {
	Draw()
}

type Layer struct {
	win       *Window
	cursorPos *Position
	drawPos   *Position
}

func NewLayer(x, y, width, height int) *Layer {
	return &Layer{
		win:       newWindow(x, y, width, height),
		cursorPos: newPosition(0, 0),
		drawPos:   newPosition(0, 0),
	}
}

func (l *Layer) Resize(x, y, width, height int) {
	l.win.Resize(x, y, width, height)
}

func (l *Layer) getCursorY() int {
	return l.win.DrawY(l.cursorPos.Y) - l.drawPos.Y
}

func (l *Layer) getDrawY(i int) int {
	return l.win.DrawY(i) - l.drawPos.Y
}

func (l *Layer) DrawBackGround(fg, bg termbox.Attribute) {
	for i := 0; i < l.win.Box.Height; i++ {
		drawStr := PadRight("", l.win.Box.Width, " ")
		drawX := l.win.DrawX(0)
		drawY := l.win.DrawY(i)
		tbPrint(drawX, drawY, fg, bg, drawStr)
	}
}

func (l *Layer) DrawContents(
	lines []string,
	cursorFG, cursorBG termbox.Attribute,
	defaultFG, defaultBG termbox.Attribute,
) {
	for i, line := range lines {
		if i >= l.drawPos.Y {
			drawStr := PadRight(line, l.win.Box.Width, " ")
			drawX := l.win.DrawX(0)
			drawY := l.getDrawY(i)
			var fg, bg termbox.Attribute
			if drawY == l.getCursorY() {
				fg = cursorFG
				bg = cursorBG
			} else {
				fg = defaultFG
				bg = defaultBG
			}
			tbPrint(drawX, drawY, fg, bg, drawStr)
		}
	}
}

func (l *Layer) UpCursor(val int) int {
	l.cursorPos.Y -= val
	if l.cursorPos.Y < 0 {
		l.cursorPos.Y = 0
	}
	if l.cursorPos.Y < l.drawPos.Y {
		l.drawPos.Y = l.cursorPos.Y
	}
	log.Printf("Up detail. CursorPosition:%d, DrawPosition:%d", l.cursorPos.Y, l.drawPos.Y)
	return l.cursorPos.Y
}

func (l *Layer) DownCursor(val int, contentNum int) int {
	l.cursorPos.Y += val
	if l.cursorPos.Y > (contentNum - 1) {
		l.cursorPos.Y = contentNum - 1
	}
	if l.cursorPos.Y > (l.drawPos.Y + l.win.Box.Height - 1) {
		l.drawPos.Y = l.cursorPos.Y - l.win.Box.Height + 1
	}
	log.Printf("Down detail. CursorPosition:%d, DrawPosition:%d", l.cursorPos.Y, l.drawPos.Y)
	return l.cursorPos.Y
}

func (l *Layer) HalfPageUpCursor() int {
	_, height := termbox.Size()
	halfPage := height / 2
	return l.UpCursor(halfPage)
}

func (l *Layer) HalfPageDownCursor(contentNum int) int {
	_, height := termbox.Size()
	halfPage := height / 2
	return l.DownCursor(halfPage, contentNum)
}

type Position struct {
	X, Y int
}

func newPosition(x, y int) *Position {
	return &Position{x, y}
}

type Box struct {
	Width, Height int
}

type Window struct {
	Pos *Position
	Box *Box
}

func newWindow(x, y, width, height int) *Window {
	return &Window{
		Pos: &Position{
			X: x,
			Y: y,
		},
		Box: &Box{
			Width:  width,
			Height: height,
		},
	}
}

func (w *Window) Resize(x, y, width, height int) {
	w.Pos.X = x
	w.Pos.Y = y
	w.Box.Width = width
	w.Box.Height = height
}

func (w *Window) DrawX(x int) int {
	return w.Pos.X + x
}

func (w *Window) DrawY(y int) int {
	return w.Pos.Y + y
}