From 3aec639f39c1d035a5a2aa6f12e139d70e58c9fa Mon Sep 17 00:00:00 2001
From: Tor Andersson <tor@ccxvii.net>
Date: Sat, 23 Oct 2021 23:15:45 +0200
Subject: Add PRNG seed to game state.

Log all game actions to a table so they can be replayed.
---
 rules.js | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

(limited to 'rules.js')

diff --git a/rules.js b/rules.js
index 337f982..5d507df 100644
--- a/rules.js
+++ b/rules.js
@@ -37,6 +37,10 @@ let states = {};
 
 let game = null;
 
+function random(n) {
+	return Math.floor(((game.seed = game.seed * 48271 % 0x7fffffff) / 0x7fffffff) * n);
+}
+
 function log(...args) {
 	let s = Array.from(args).join(" ");
 	game.log.push(s);
@@ -144,7 +148,7 @@ function gen_action(view, action, argument) {
 }
 
 function roll_d6() {
-	return Math.floor(Math.random() * 6) + 1;
+	return random(6) + 1;
 }
 
 function shuffle_deck() {
@@ -157,7 +161,7 @@ function shuffle_deck() {
 function deal_cards(deck, n) {
 	let hand = [];
 	for (let i = 0; i < n; ++i) {
-		let k = Math.floor(Math.random() * deck.length);
+		let k = random(deck.length);
 		hand.push(deck[k]);
 		deck.splice(k, 1);
 	}
@@ -631,7 +635,7 @@ function draw_from_bag(bag, exclude_list) {
 		if (game.location[b] === bag)
 			list.push(b);
 	}
-	return list[Math.floor(Math.random() * list.length)];
+	return list[random(list.length)];
 }
 
 function deploy_english(count) {
@@ -640,7 +644,7 @@ function deploy_english(count) {
 		if (game.location[b] === E_BAG)
 			list.push(b);
 	for (let i = 0; i < count; ++i) {
-		let x = Math.floor(Math.random() * list.length);
+		let x = random(list.length);
 		let b = list[x];
 		list.splice(x,1);
 		game.location[b] = ENGLAND;
@@ -2827,8 +2831,9 @@ exports.ready = function (scenario, players) {
 	return players.length === 2;
 }
 
-exports.setup = function (scenario) {
+exports.setup = function (seed, scenario) {
 	game = {
+		seed: seed,
 		attacker: {},
 		border_limit: {},
 		last_used: {},
-- 
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