package main

import (
	"flag"
	"fmt"
	"os"
	"time"
)

import (
	. "github.com/meatballhat/box-o-sand/conway"
)

var (
	height  = flag.Int("height", 40, "Game height")
	width   = flag.Int("width", 80, "Game width")
	mutate  = flag.Bool("mutate", false, "Mutate every other generation")
	sleepMs = flag.Int("sleep.ms", 200,
		"Millisecond sleep interval per generation")
)

func pushChecksum(checksum string, checksums []string) {
	head := make([]string, 3)
	copy(head, checksums[:3])
	checksums[0] = checksum
	checksums[1] = head[0]
	checksums[2] = head[1]
	checksums[3] = head[2]
}

func main() {
	flag.Parse()

	game := NewGameOfLife(*height, *width)
	err := game.ImportRandomState()
	if err != nil {
		fmt.Fprintf(os.Stderr, "WHAT IN FAIL?: %v\n", err)
		os.Exit(2)
	}

	checksums := make([]string, 4)
	checksums[0], checksums[1], checksums[2], checksums[3] = "foo", "bar", "baz", "qwx"
	ck, err := game.Checksum()
	if err != nil {
		fmt.Fprintf(os.Stderr, "NAY NAY: %v\n", err)
		os.Exit(3)
	}
	pushChecksum(ck, checksums)

	ticks := time.Tick(time.Duration(*sleepMs) * time.Millisecond)
	generations := 0
	for now := range ticks {
		fmt.Printf("\nGeneration %v\n%v\n", generations, now)
		fmt.Println(game)

		game.EvaluateGeneration()

		curChecksum, err := game.Checksum()
		if err != nil {
			fmt.Fprintf(os.Stderr, "Failed to calculate current game checksum: %v\n", err)
			os.Exit(4)
		}

		if checksums[0] == curChecksum || checksums[1] == curChecksum {
			fmt.Println("Stasis!")
			os.Exit(0)
		}

		if checksums[2] == curChecksum {
			fmt.Println("Checksum found 2 periods ago")
			fmt.Println("Stasis with 2-period oscillator(s)!")
			os.Exit(0)
		}

		if checksums[3] == curChecksum {
			fmt.Println("Checksum found 3 periods ago")
			fmt.Println("Stasis with 3-period oscillator(s)!")
			os.Exit(0)
		}

		pushChecksum(curChecksum, checksums)

		if *mutate && generations%2 == 0 {
			game.Mutate()
		}

		generations++
	}
}