boxboxbox

box.go

package main

import (
	"flag"
	"fmt"
	"math/rand"
	"os"

	"golang.org/x/crypto/ssh/terminal"
)

var (
	chars = []rune{'╭', '╮', '╯', '╰', '│', '─'}
)

func main() {
	var (
		width, height = 40, 40
	)
	if terminal.IsTerminal(int(os.Stdout.Fd())) {
		w, h, err := terminal.GetSize(int(os.Stdout.Fd()))
		if err != nil {
			panic(err)
		}
		width, height = w, h
	}
	flag.IntVar(&width, "width", width, "Width")
	flag.IntVar(&height, "height", height, "Height")
	flag.Parse()

	height--

	table := make([][]rune, height)

	for y := 0; y < height; y++ {
		table[y] = make([]rune, width)
		for x := 0; x < width; x++ {
			var r rune
			switch {
			case y == 0 && x == 0:
				r = chars[rand.Intn(6)]
			case y == 0 && x > 0:
				switch table[y][x-1] {
				case '╭', '╰', '─':
					r = []rune{'╯', '╮', '─'}[rand.Intn(3)]
				case '╯', '╮', '│':
					r = []rune{'╭', '╰', '│'}[rand.Intn(3)]
				}
			case y > 0 && x == 0:
				switch table[y-1][x] {
				case '╭', '╮', '│':
					r = []rune{'╯', '╰', '│'}[rand.Intn(3)]
				case '╯', '╰', '─':
					r = []rune{'╭', '╮', '─'}[rand.Intn(3)]
				}
			default:
				switch rand.Intn(2) {
				case 0:
					switch table[y-1][x] {
					case '╭', '╮', '│':
						r = []rune{'╯', '╰', '│'}[rand.Intn(3)]
					case '╯', '╰', '─':
						r = []rune{'╭', '╮', '─'}[rand.Intn(3)]
					}
				case 1:
					switch table[y][x-1] {
					case '╭', '╰', '─':
						r = []rune{'╯', '╮', '─'}[rand.Intn(3)]
					case '╯', '╮', '│':
						r = []rune{'╭', '╰', '│'}[rand.Intn(3)]
					}
				}
			}
			table[y][x] = r
		}
	}

	for _, row := range table {
		fmt.Println(string(row))
	}
}