From b4bf8f6c5a77c409f1532057768b767103aa4c66 Mon Sep 17 00:00:00 2001
From: Brian Picciano <mediocregopher@gmail.com>
Date: Thu, 2 Nov 2017 16:45:10 -0600
Subject: [PATCH] basic box drawing and moving in gim

---
 gim/main.go | 280 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 280 insertions(+)
 create mode 100644 gim/main.go

diff --git a/gim/main.go b/gim/main.go
new file mode 100644
index 0000000..6b61378
--- /dev/null
+++ b/gim/main.go
@@ -0,0 +1,280 @@
+package main
+
+import (
+	"fmt"
+	"math/rand"
+	"os"
+	"os/signal"
+	"strings"
+	"time"
+
+	"github.com/buger/goterm"
+)
+
+const (
+	// Reset all custom styles
+	ansiReset = "\033[0m"
+
+	// Reset to default color
+	ansiResetColor = "\033[32m"
+
+	// Return curor to start of line and clean it
+	ansiResetLine = "\r\033[K"
+)
+
+// List of possible colors
+const (
+	black = iota
+	red
+	green
+	yellow
+	blue
+	magenta
+	cyan
+	white
+)
+
+func getFgColor(code int) string {
+	return fmt.Sprintf("\033[3%dm", code)
+}
+
+func getBgColor(code int) string {
+	return fmt.Sprintf("\033[4%dm", code)
+}
+
+func fgColor(str string, color int) string {
+	return fmt.Sprintf("%s%s%s", getFgColor(color), str, ansiReset)
+}
+
+func bgColor(str string, color int) string {
+	return fmt.Sprintf("%s%s%s", getBgColor(color), str, ansiReset)
+}
+
+type xy [2]int
+
+func (p xy) x() int {
+	return p[0]
+}
+
+func (p xy) y() int {
+	return p[1]
+}
+
+func (p xy) add(p2 xy) xy {
+	p[0] += p2[0]
+	p[1] += p2[1]
+	return p
+}
+
+////////////////////////////////////////////////////////////////////////////////
+
+type terminal struct {
+	cursorPos xy
+}
+
+func (t *terminal) moveAbs(to xy) {
+	t.cursorPos = to
+	goterm.MoveCursor(to.x()+1, to.y()+1)
+}
+
+func (t *terminal) size() xy {
+	return xy{goterm.Width(), goterm.Height()}
+}
+
+////////////////////////////////////////////////////////////////////////////////
+
+const (
+	boxBorderHoriz = iota
+	boxBorderVert
+	boxBorderTL
+	boxBorderTR
+	boxBorderBL
+	boxBorderBR
+)
+
+var boxDefault = []string{
+	"─",
+	"│",
+	"┌",
+	"┐",
+	"└",
+	"┘",
+}
+
+type box struct {
+	pos  xy
+	size xy // if unset, auto-determined
+	body string
+
+	transparent bool
+}
+
+func (b box) lines() []string {
+	lines := strings.Split(b.body, "\n")
+	// if the last line is empty don't include it, it means there was a trailing
+	// newline (or the whole string is empty)
+	if lines[len(lines)-1] == "" {
+		lines = lines[:len(lines)-1]
+	}
+	return lines
+}
+
+func (b box) getSize() xy {
+	if b.size != (xy{}) {
+		return b.size
+	}
+	var size xy
+	for _, line := range b.lines() {
+		size[1]++
+		if l := len(line); l > size[0] {
+			size[0] = l
+		}
+	}
+	return size
+}
+
+func (b box) draw(term *terminal) {
+	chars := boxDefault
+	pos := b.pos
+	size := b.getSize()
+	w, h := size.x(), size.y()
+
+	// draw top line
+	term.moveAbs(pos)
+	goterm.Print(chars[boxBorderTL])
+	for i := 0; i < w; i++ {
+		goterm.Print(chars[boxBorderHoriz])
+	}
+	goterm.Print(chars[boxBorderTR])
+
+	drawLine := func(line string) {
+		pos[1]++
+		term.moveAbs(pos)
+		goterm.Print(chars[boxBorderVert])
+		if len(line) > w {
+			line = line[:w]
+		}
+		goterm.Print(line)
+		if b.transparent {
+			term.moveAbs(pos.add(xy{w + 1, 0}))
+		} else {
+			goterm.Print(strings.Repeat(" ", w-len(line)))
+		}
+		goterm.Print(chars[boxBorderVert])
+	}
+
+	// truncate lines if necessary
+	lines := b.lines()
+	if len(lines) > h {
+		lines = lines[:h]
+	}
+
+	// draw body
+	for _, line := range lines {
+		drawLine(line)
+	}
+
+	// draw empty lines
+	for i := 0; i < h-len(lines); i++ {
+		drawLine("")
+	}
+
+	// draw bottom line
+	pos[1]++
+	term.moveAbs(pos)
+	goterm.Print(chars[boxBorderBL])
+	for i := 0; i < w; i++ {
+		goterm.Print(chars[boxBorderHoriz])
+	}
+	goterm.Print(chars[boxBorderBR])
+}
+
+////////////////////////////////////////////////////////////////////////////////
+
+const (
+	framerate   = 30
+	frameperiod = time.Second / time.Duration(framerate)
+)
+
+func debugf(str string, args ...interface{}) {
+	fmt.Fprintf(os.Stderr, str, args...)
+}
+
+func main() {
+	rand.Seed(time.Now().UnixNano())
+	{ // exit signal handling, cause ctrl-c doesn't work with goterm otherwise
+		c := make(chan os.Signal, 1)
+		signal.Notify(c, os.Interrupt)
+		go func() {
+			<-c
+			goterm.Clear()
+			goterm.Flush()
+			os.Stdout.Sync()
+			os.Exit(0)
+		}()
+	}
+
+	term := new(terminal)
+
+	type movingBox struct {
+		box
+		xRight bool
+		yDown  bool
+	}
+
+	randBox := func() movingBox {
+		tsize := term.size()
+		return movingBox{
+			box: box{
+				pos: xy{rand.Intn(tsize[0]), rand.Intn(tsize[1])},
+			},
+			xRight: rand.Intn(1) == 0,
+			yDown:  rand.Intn(1) == 0,
+		}
+	}
+
+	boxes := []movingBox{
+		randBox(),
+		randBox(),
+		randBox(),
+		randBox(),
+		randBox(),
+	}
+
+	for range time.Tick(frameperiod) {
+		goterm.Clear()
+
+		termSize := term.size()
+		now := time.Now()
+		for i := range boxes {
+			b := &boxes[i]
+			b.body = fmt.Sprintf("%d\n%s", now.Unix(), now.String())
+
+			size := b.getSize()
+			if b.pos[0] <= 0 {
+				b.xRight = true
+			} else if b.pos[0]+size[0]+2 > termSize[0] {
+				b.xRight = false
+			}
+			if b.pos[1] <= 0 {
+				b.yDown = true
+			} else if b.pos[1]+size[1]+2 > termSize[1] {
+				b.yDown = false
+			}
+
+			if b.xRight {
+				b.pos[0] += 3
+			} else {
+				b.pos[0] -= 3
+			}
+			if b.yDown {
+				b.pos[1]++
+			} else {
+				b.pos[1]--
+			}
+
+			b.draw(term)
+		}
+		goterm.Flush()
+	}
+}