From 50cf1a0f6c220ac9bf5f246468739eddf73248e8 Mon Sep 17 00:00:00 2001
From: Alessandro Cifani <alessandro.cifani@adevinta.com>
Date: Mon, 13 Nov 2023 23:38:02 +0100
Subject: [PATCH] lib/game: custom life-like rules

---
 cmd/vita/main.go  | 32 +++++++++++++++++++++++++-------
 lib/game/rules.go | 36 ++++++++++++++++++++++++++++++++++++
 2 files changed, 61 insertions(+), 7 deletions(-)

diff --git a/cmd/vita/main.go b/cmd/vita/main.go
index 22e7991..57317e4 100644
--- a/cmd/vita/main.go
+++ b/cmd/vita/main.go
@@ -3,6 +3,7 @@ package main
 import (
 	"flag"
 	"fmt"
+	"strconv"
 	"sync"
 
 	"github.com/acifani/vita/lib/game"
@@ -15,6 +16,8 @@ var (
 	population  = flag.Int("pop", 45, "initial population percent of the universe")
 	number      = flag.Int("n", 1, "number of universes to run in parallel")
 	rules       = flag.String("rules", "conway", "rules to use for the universe")
+	b           = flag.String("B", "3", "born")
+	s           = flag.String("S", "23", "survive")
 )
 
 func main() {
@@ -35,11 +38,13 @@ func runSingleUniverse() {
 	universe := game.NewUniverse(uint32(*height), uint32(*width))
 	switch *rules {
 	case "dayandnight":
-		universe.Rules = game.DayAndNightRules
+		universe.Rules = universe.DayAndNightRules
 	case "seeds":
-		universe.Rules = game.SeedsRules
+		universe.Rules = universe.SeedsRules
 	case "wrap":
-		universe.Rules = game.ConwayRulesWrap
+		universe.Rules = universe.ConwayRulesWrap
+	case "custom":
+		universe.Rules = universe.NewLifeLikeRules(convertStringToUint8(*b), convertStringToUint8(*s), true)
 	default:
 		// just use conway
 	}
@@ -76,10 +81,10 @@ func createParallelUniverses() []*game.ParallelUniverse {
 		for col := 0; col < *number; col++ {
 			u := game.NewParallelUniverse(uint32(*height), uint32(*width))
 			switch *rules {
-			case "dayandnight":
-				u.Rules = game.DayAndNightRules
-			case "seeds":
-				u.Rules = game.SeedsRules
+			// case "dayandnight":
+			// 	u.Rules = game.DayAndNightRules
+			// case "seeds":
+			// 	u.Rules = game.SeedsRules
 			default:
 				// just use conway
 			}
@@ -160,3 +165,16 @@ func callMultiTick(wg *sync.WaitGroup, u *game.ParallelUniverse) {
 		wg.Done()
 	}()
 }
+
+func convertStringToUint8(input string) []uint8 {
+	output := make([]uint8, len(input))
+	for i, c := range input {
+		n, err := strconv.Atoi(string(c))
+		if err != nil {
+			panic(err)
+		}
+		output[i] = uint8(n)
+	}
+
+	return output
+}
diff --git a/lib/game/rules.go b/lib/game/rules.go
index 07de8fc..83eb4b7 100644
--- a/lib/game/rules.go
+++ b/lib/game/rules.go
@@ -1,5 +1,41 @@
 package game
 
+func (u *Universe) NewLifeLikeRules(B, S []uint8, wraps bool) func(cell uint8, row, column uint32) uint8 {
+	rule := NewRule(B, S)
+	return func(cell uint8, row, column uint32) uint8 {
+		var neighbors uint8
+		if wraps {
+			neighbors = u.MooreNeighbors(row, column)
+		} else {
+			neighbors = u.MooreNeighborsWrap(row, column)
+		}
+		return rule(cell, neighbors)
+	}
+}
+
+func NewRule(B, S []uint8) func(cell uint8, liveNeighbors uint8) uint8 {
+	return func(cell uint8, liveNeighbors uint8) uint8 {
+		if cell == Dead && contains(B, liveNeighbors) {
+			return Alive
+		}
+
+		if cell == Alive && contains(S, liveNeighbors) {
+			return Alive
+		}
+
+		return Dead
+	}
+}
+
+func contains(slice []uint8, candidate uint8) bool {
+	for _, element := range slice {
+		if element == candidate {
+			return true
+		}
+	}
+	return false
+}
+
 // ConwayRules implements the classic Game of Life rules.
 func (u *Universe) ConwayRules(cell uint8, row, column uint32) uint8 {
 	return RuleB3S23(cell, u.MooreNeighbors(row, column))