From c798b7fa59579eea4c5823925e43b15658a30095 Mon Sep 17 00:00:00 2001
From: Tor Andersson <tor@ccxvii.net>
Date: Sun, 13 Feb 2022 00:37:29 +0100
Subject: Add "Iron Bridge" optional rule.

---
 create.html | 10 ++++++++++
 data.js     |  3 ++-
 rules.js    | 21 +++++++++++++++++----
 3 files changed, 29 insertions(+), 5 deletions(-)

diff --git a/create.html b/create.html
index e69de29..a9b870a 100644
--- a/create.html
+++ b/create.html
@@ -0,0 +1,10 @@
+<p>
+Optional rules:
+<dl>
+<dt>
+<label>
+<input type="checkbox" name="iron_bridge" value="true">
+Iron Bridge
+</label>
+<dd>The road between Antioch and Harim has a move limit of 3.
+</dl>
diff --git a/data.js b/data.js
index de6cacb..56a1d85 100644
--- a/data.js
+++ b/data.js
@@ -337,10 +337,11 @@ const PORTS = [];
 		TOWNS[B].exits.push(A);
 	}
 
+	function iron_bridge(A,B) { road(A,B,"iron-bridge"); }
 	function major(A,B) { road(A,B,"major"); }
 	function minor(A,B) { road(A,B,"minor"); }
 
-	major("Antioch", "Harim");
+	iron_bridge("Antioch", "Harim");
 	major("Harim", "Artah");
 	major("Artah", "Aleppo");
 	major("Aleppo", "Zerdana");
diff --git a/rules.js b/rules.js
index 890120d..ae5b47b 100644
--- a/rules.js
+++ b/rules.js
@@ -659,13 +659,24 @@ function is_pinned(who, from) {
 function can_block_use_road(from, to) {
 	if (game.active === game.guide) {
 		switch (road_type(from, to)) {
-		case 'major': return road_limit(from, to) < 8;
-		case 'minor': return road_limit(from, to) < 4;
+		case 'iron-bridge':
+			// https://boardgamegeek.com/thread/744750/20-rules-iron-bridge-question
+		case 'major':
+			return road_limit(from, to) < 8;
+		case 'minor':
+			return road_limit(from, to) < 4;
 		}
 	} else {
 		switch (road_type(from, to)) {
-		case 'major': return road_limit(from, to) < 4;
-		case 'minor': return road_limit(from, to) < 2;
+		case 'iron-bridge':
+			if (game.iron_bridge)
+				return road_limit(from, to) < 3;
+			else
+				return road_limit(from, to) < 4;
+		case 'major':
+			return road_limit(from, to) < 4;
+		case 'minor':
+			return road_limit(from, to) < 2;
 		}
 	}
 	return false;
@@ -3752,6 +3763,8 @@ exports.setup = function (seed, scenario, options) {
 		where: null,
 		undo: [],
 	}
+	if (options && options.iron_bridge)
+		game.iron_bridge = 1;
 	setup_game();
 	return game;
 }
-- 
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