re-structured project again and added CLI arguments

package main

import (

	"flag"

	"fmt"

	"strconv"

	"time"

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

	"repositories.muehmer.net/bsmrgo/wator"

)

func main() {

	// check terminal size

	width, height := 0, 0

	var err error

	if terminal.IsTerminal(0) {

		width, height, err = terminal.GetSize(0)

		if err != nil {

			panic(err)

		}

		fmt.Printf("Terminal: %d * %d\n", width, height)

	}

	// setup environment

	w := &wator.Wator{

		Debug:             false, //true,

		Width:             72,    //32,

		Height:            36,    //14,

		InitialFishes:     400,   //200,

		InitialSharks:     40,    //20,

		BreedFish:         3,

		BreedShark:        30,

		StarveShark:       2,

		SleepMilliseconds: 50 * time.Millisecond,

	}

	if width > 0 {

		w.Width = width

	}

	if height > 5 {

		w.Height = height - 5

	}

	flag.BoolVar(&w.Debug, "debug", false, "enable debug mode")

	flag.IntVar(&w.Width, "width", w.Width, "wator width")

	flag.IntVar(&w.Height, "height", w.Height, "wator height")

	flag.IntVar(&w.InitialFishes, "fish-count", 400, "initial number of fish")

	flag.IntVar(&w.InitialSharks, "shark-count", 40, "initial number of sharks")

	flag.IntVar(&w.BreedFish, "fish-breed", 3, "chronos for fish to breed")

	flag.IntVar(&w.BreedShark, "shark-breed", 30, "chronos for sharks to breed")

	flag.IntVar(&w.StarveShark, "shark-starve", 2, "chronos for sharks to starve")

	//flag.IntVar(&w.MaxAgeFishes, "fish-max-age", )

	flag.Parse()

	initialize(w)

	print(w)

	repl(w)

}

func repl(w *wator.Wator) {

	cycles := read()

	if cycles == 0 {

		return

	}

	for i := 0; i < cycles; i++ {

		if i > 0 {

			time.Sleep(w.SleepMilliseconds)

		}

		evaluate(w)

		print(w)

	}

	repl(w)

}

func initialize(w *wator.Wator) {

	if err := w.Populate(); err != nil {

		panic(err)

	}

}

func print(w *wator.Wator) {

	fmt.Printf("\033[H\033[2J") // TBD: remove this hack

	if err := w.Display(); err != nil {

		panic(err)

	}

	fmt.Printf("%s\n", w)

}

func evaluate(w *wator.Wator) {

	if err := w.Next(); err != nil {

		panic(err)

	}

}

func read() int {

	cycles := 1

	done := false

	for !done {

		fmt.Printf("Command: ")

		var s string

		n, err := fmt.Scanf("%s", &s)

		if n == 0 {

			s = "n"

			err = nil

		}

		if err != nil {

			panic(err)

		}

		if num, err := strconv.Atoi(s); (err == nil) && (num > 0) && (num <= 100000) {

			done = true

			cycles = num

		}

		if !done {

			switch s {

			case "?", "h", "help":

				usage()

			case "n", "next":

				done = true

			case "q", "quit":

				cycles = 0

				done = true

			default:

				fmt.Printf("Unknown command \"%s\"\n", s)

			}

		}

	}

	return cycles

}

func usage() {

	fmt.Println("--- Commands ---")

	fmt.Println("?, h, help: show this usage information")

	fmt.Println("n, next   : calculate next iteration")

	fmt.Println("<number>  : do <number> iterations")

	fmt.Println("q, quit   : terminate wator")

}

module repositories.muehmer.net/bsmrgo/wator

go 1.12

go 1.13

require golang.org/x/crypto v0.0.0-20200117160349-530e935923ad

golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=

golang.org/x/crypto v0.0.0-20200117160349-530e935923ad h1:Jh8cai0fqIK+f6nG0UgPW5wFk8wmiMhM3AyciDBdtQg=

golang.org/x/crypto v0.0.0-20200117160349-530e935923ad/go.mod h1:LzIPMQfyMNhhGPhUkYOs5KpL4U8rLKemX1yGLhDgUto=

golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=

golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=

golang.org/x/sys v0.0.0-20190412213103-97732733099d h1:+R4KGOnez64A81RvjARKc4UT5/tI9ujCIVX+P5KiHuI=

golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=

golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=