package main

import (
	"math"
	"math/rand"
	"os"

	"github.com/tfriedel6/canvas/sdlcanvas"
	"strconv"
)

var (
	squareSize int
	sizeX      int
	sizeY      int
	gameWidth  int
	gameHeight int
)

func initTable(sizeX, sizeY int) map[int]map[int]int {
	table := make(map[int]map[int]int)

	for x := 0; x < sizeX; x++ {
		table[x] = make(map[int]int)

		for y := 0; y < sizeY; y++ {
			table[x][y] = rand.Intn(2)
		}
	}

	return table
}

func updateTable(table map[int]map[int]int) map[int]map[int]int {
	sum := 0
	newTable := make(map[int]map[int]int)

	for x := 0; x < sizeX; x++ {
		newTable[x] = make(map[int]int)

		for y := 0; y < sizeY; y++ {
			sum = getSum(table, x, y)

			if sum == 3 {
				newTable[x][y] = 1
			} else if sum > 3 || sum < 2 {
				newTable[x][y] = 0
			} else {
				newTable[x][y] = table[x][y]
			}
		}
	}

	return newTable
}

func getSum(table map[int]map[int]int, x, y int) int {
	sum := 0

	sum += table[(sizeX+x-1)%sizeX][(sizeY+y-1)%sizeY]
	sum += table[x][(sizeY+y-1)%sizeY]
	sum += table[(sizeX+x+1)%sizeX][(sizeY+y-1)%sizeY]
	sum += table[(sizeX+x-1)%sizeX][y]
	sum += table[(sizeX+x+1)%sizeX][y]
	sum += table[(sizeX+x-1)%sizeX][(sizeY+y+1)%sizeY]
	sum += table[x][(sizeY+y+1)%sizeY]
	sum += table[(sizeX+x+1)%sizeX][(sizeY+y+1)%sizeY]

	return sum
}

func main() {
	squareSize, _ = strconv.Atoi(os.Args[1])
	sizeX, _ = strconv.Atoi(os.Args[2])
	sizeY, _ = strconv.Atoi(os.Args[3])
	gameWidth = squareSize * sizeX
	gameHeight = squareSize * sizeY

	table := initTable(sizeX, sizeY)

	wnd, cv, err := sdlcanvas.CreateWindow(gameWidth, gameHeight, "Game of life")

	if err != nil {
		panic(err)
	}

	defer wnd.Destroy()
	w, h := float64(cv.Width()), float64(cv.Height())

	wnd.MainLoop(func() {
		cv.SetFillStyle("#3f4b7e")
		cv.FillRect(0, 0, w, h)

		for x := 0; x < sizeX; x++ {
			for y := 0; y < sizeY; y++ {
				if table[x][y] == 1 {
					cv.SetFillStyle(255, 255, 255)
					cv.BeginPath()
					// cv.Rect(float64(x*squareSize), float64(y*squareSize), float64(squareSize), float64(squareSize))
					cv.Arc(float64(x*squareSize), float64(y*squareSize), float64(squareSize)/2, 0, math.Pi*2, false)
					cv.ClosePath()
					cv.Fill()
				}
			}
		}

		table = updateTable(table)
	})
}