From d8a1378e8bfd1915ab4386b63130d16c3acdfec7 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 | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/rules.js b/rules.js
index e6dd4e8..18c1367 100644
--- a/rules.js
+++ b/rules.js
@@ -261,6 +261,10 @@ const 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);
@@ -367,7 +371,7 @@ function gen_action(view, action, argument) {
 }
 
 function roll_d6() {
-	return Math.floor(Math.random() * 6) + 1;
+	return random(6) + 1;
 }
 
 function reshuffle_discard(draw, discard) {
@@ -377,14 +381,14 @@ function reshuffle_discard(draw, discard) {
 
 function draw_cards(hand, draw, n) {
 	for (let i = 0; i < n; ++i) {
-		let c = Math.floor(Math.random() * draw.length);
+		let c = random(draw.length);
 		hand.push(draw[c]);
 		draw.splice(c, 1);
 	}
 }
 
 function discard_random_card(hand, discard) {
-	let i = Math.floor(Math.random() * hand.length);
+	let i = random(hand.length);
 	let c = hand[i];
 	discard.push(c);
 	hand.splice(i, 1);
@@ -2758,8 +2762,9 @@ exports.ready = function (scenario, players) {
 	return players.length === 2;
 }
 
-exports.setup = function (scenario) {
+exports.setup = function (seed, scenario) {
 	game = {
+		seed: seed,
 		state: null,
 		year: 1801,
 		season: 0,
-- 
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