From b939ad368af00f2265a915d259041b8e2cb303c4 Mon Sep 17 00:00:00 2001
From: Ian Jackson <ian@liberator.relativity.greenend.org.uk>
Date: Wed, 19 Aug 2009 23:37:10 +0100
Subject: [PATCH] Show medians etc.

---
 yarrg/web/query_commod | 64 +++++++++++++++++++++++++++++++++---------
 1 file changed, 50 insertions(+), 14 deletions(-)

diff --git a/yarrg/web/query_commod b/yarrg/web/query_commod
index aeee3ce..9a7d2bc 100644
--- a/yarrg/web/query_commod
+++ b/yarrg/web/query_commod
@@ -91,16 +91,26 @@ $someresults->();
 foreach my $bs (split /_/, $ARGS{BuySell}) {
 	$bs =~ m/^(buy|sell)$/ or die;
 	$bs= $1;
+	my ($ascdesc) = ($bs eq 'buy')
+		? ('DESC')
+		: ('ASC');
+
+	my $islands= $dbh->prepare(
+	"SELECT islandid, archipelago, islandname, sum(qty) as tqty
+		FROM $bs NATURAL JOIN islands
+		WHERE commodid = ?
+		GROUP BY islandid,
+		ORDER BY archipelago, islandname"
+		);
 
-	my $sth= $dbh->prepare(
-	"SELECT archipelago, islandname, stallname, price, qty
-		FROM $bs NATURAL JOIN stalls NATURAL JOIN islands
-		WHERE commodid = ?"
+	my $offers= $dbh->prepare(
+	"SELECT stallname, price, qty
+		FROM $bs NATURAL JOIN stalls
+		WHERE commodid = ? AND islandid = ?
+		ORDER BY price $ascdesc"
 		);
 	# fixme this query is utterly wrong
 
-	$sth->execute($commodid);
-
 </%perl>
 
 <h2>Offers to <% uc $bs |h %> <% $commodname |h %></h2>
@@ -109,17 +119,43 @@ foreach my $bs (split /_/, $ARGS{BuySell}) {
 <tr>
 <th>Archipelago
 <th>Island
-<th>Best stall
+<th>Unique best stall
 <th>Best price
 <th>Qty at best
+<th>Median price
+<th>Total qty
 </tr>
-%	my $row;
-%	while ($row=$sth->fetchrow_hashref) {
-<tr> <td><% $row->{'archipelago'} %>
-     <td><% $row->{'islandname'} %>
-     <td><% $row->{'stallname'} %>
-     <td><% $row->{'price'} %>
-     <td><% $row->{'qty'} %>
+%	$islands->execute($commodid);
+%	my $island;
+%	while ($island= $islands->fetchrow_hashref) {
+%		my $islandid= $island->{'islandid'};
+%		$offers->execute($commodid, $islandid);
+%		my ($offer, $best, $median);
+%		my $tqty= $island->{'tqty'};
+%		my $cqty= 0;
+%		while ($offer= $offers->fetchrow_hashref) {
+%			if (!$best) {
+%				$best= { 'price' => $offer->{'price'} };
+%			}
+%			if ($offer->{'price'} == $best->{'price'}) {
+%				$best->{'qty'} += $offer->{'qty'};
+%				push @{ $best->{'stalls'} },
+%					$offer->{'stallname'};
+%			}
+%			$cqty += $offer->{'qty'};
+%			if ($cqty*2 >= $tqty && !defined $median) {
+%				$median= $offer->{'price'};
+%			}
+%		}
+%		$cqty == $tqty or die "$bs $cqty $tqty $commodid $islandid ";
+%		my $nstalls= @{ $best->{'stalls'} };
+<tr> <td><% $island->{'archipelago'} |h %>
+     <td><% $island->{'islandname'} |h %>
+     <td><% $nstalls==1 ? $best->{'stalls'}[0] : "$nstalls offers" |h %>
+     <td><% $best->{'price'} %>
+     <td><% $best->{'qty'} %>
+     <td><% $median %>
+     <td><% $tqty %>
 </tr>
 %	}
 </table>
-- 
2.30.2