From a4e2383b30189c028ae35d2f587b084803e5d888 Mon Sep 17 00:00:00 2001
From: Ian Jackson <ian@liberator.relativity.greenend.org.uk>
Date: Wed, 26 Aug 2009 02:15:16 +0100
Subject: [PATCH] Fix circular routes (including arbitrage complications)

---
 yarrg/TODO           |  3 ---
 yarrg/web/routetrade | 13 +++++++++----
 2 files changed, 9 insertions(+), 7 deletions(-)

diff --git a/yarrg/TODO b/yarrg/TODO
index e3ecc68..8a22088 100644
--- a/yarrg/TODO
+++ b/yarrg/TODO
@@ -23,9 +23,6 @@ commodity mass/volume in live database
 WEBSITE
 -------
 
-circular routes are treated as complex eg
-   eta, jorvik, zeta, turtle, alpha, papaya, eta
-
 onload thing broken, need proper framework
 
 dropdowns are broken sometimes
diff --git a/yarrg/web/routetrade b/yarrg/web/routetrade
index 9fde77e..80fc2b1 100644
--- a/yarrg/web/routetrade
+++ b/yarrg/web/routetrade
@@ -85,10 +85,12 @@ foreach my $src_i (0..$#islandids) {
 
 		if ($specific && !$confusing &&
 		    # With a circular route, do not carry goods round the loop
-		    !($src_i==0 && $dst_i==$#islandids &&
+		    !(($src_i==0 || $src_i==$#islandids) &&
+		      $dst_i==$#islandids &&
 		      $src_isle == $islandids[$dst_i])) {
 			if ($islandpair{$src_isle,$dst_isle}) {
 				$confusing= 1;
+print "confusing $src_i $src_isle  $dst_i $dst_isle\n";
 			} else {
 				$islandpair{$src_isle,$dst_isle}=
 					[ $src_i, $dst_i ];
@@ -580,6 +582,11 @@ Sail to <% $islandname |h %>
 		next if $f->{Suppress};
 		next unless $f->{"${od}_id"} == $islandids[$i];
 		next unless $f->{OptQty};
+		my $arbitrage= $f->{'org_id'} == $f->{'dst_id'};
+		my $loop= $islandids[0] == $islandids[-1] &&
+			  ($i==0 || $i==$#islandids);
+		next if $loop and ($arbitrage ? $i :
+			!!$i == !!($od eq 'org'));
 		my $price= $f->{"${od}_price"};
 		my $stallname= $f->{"${od}_stallname"};
 		my $todo= \$flowlists{$od}{
@@ -600,9 +607,7 @@ Sail to <% $islandname |h %>
 		$$todo->{Qty} += $f->{OptQty};
 		$$todo->{Total}= $$todo->{Price} * $$todo->{Qty};
 		$$todo->{Stalls}= $f->{"${od}Stalls"};
-		if ($f->{'org_id'} == $f->{'dst_id'}) {
-			$$todo->{"${od}Arbitrage"}= 1;
-		}
+		$$todo->{"${od}Arbitrage"}= 1 if $arbitrage;
 	}
      }
 
-- 
2.30.2