From e7464f34818f20377ca73fab72c7b3214e0f5e1c Mon Sep 17 00:00:00 2001
From: Brian Wolff <bawolff+wn@gmail.com>
Date: Sat, 29 Oct 2016 08:29:11 +0000
Subject: [PATCH] Make NumericUppercaseCollation use localized digit transforms

This will cause the numeric collation to sort localized digits
for the current content language the same as how 0-9 are.

This only deals with the localized digit numbers, commas
and other number formatting are still not handled. Weird
"numerical" unicode characters are also not handled.

I was unsure if to make a "family" of numeric collations
where you specify numeric-<lang code>, or if it should
just use $wgContLang. Given that $wgContLang effectively
never changes, and also affects all other digit handling,
I opted to just use $wgContLang.

Any wikis currently using the 'numeric' collation will
have to have updateCollation.php --force run after this
change is deployed. At the moment that includes:
bnwiki, bnwikisource and hewiki

Bug: T148873
Change-Id: I9eda52a8a9752a91134d1118546b0a80d3980ccf
---
 includes/collation/Collation.php              |  4 +-
 .../collation/NumericUppercaseCollation.php   | 57 +++++++++++++++++--
 2 files changed, 55 insertions(+), 6 deletions(-)

diff --git a/includes/collation/Collation.php b/includes/collation/Collation.php
index 881c8c23fe..9950a11a6f 100644
--- a/includes/collation/Collation.php
+++ b/includes/collation/Collation.php
@@ -46,11 +46,13 @@ abstract class Collation {
 	 * @return Collation
 	 */
 	public static function factory( $collationName ) {
+		global $wgContLang;
+
 		switch ( $collationName ) {
 			case 'uppercase':
 				return new UppercaseCollation;
 			case 'numeric':
-				return new NumericUppercaseCollation;
+				return new NumericUppercaseCollation( $wgContLang );
 			case 'identity':
 				return new IdentityCollation;
 			case 'uca-default':
diff --git a/includes/collation/NumericUppercaseCollation.php b/includes/collation/NumericUppercaseCollation.php
index d15daec505..2d2ca47bcf 100644
--- a/includes/collation/NumericUppercaseCollation.php
+++ b/includes/collation/NumericUppercaseCollation.php
@@ -24,12 +24,37 @@
  * Note that this only works in terms of sequences of digits, and the behavior for decimal fractions
  * or pretty-formatted numbers may be unexpected.
  *
+ * Digits will be based on the wiki's content language settings. If
+ * you change the content langauge of a wiki you will need to run
+ * updateCollation.php --force. Only English (ASCII 0-9) and the
+ * localized version will be counted. Localized digits from other languages
+ * or weird unicode digit equivalents (e.g. ４, 𝟜, ⓸ , ⁴, etc) will not count.
+ *
  * @since 1.28
  */
 class NumericUppercaseCollation extends UppercaseCollation {
+
+	/**
+	 * @var $digitTransformLang Language How to convert digits (usually $wgContLang)
+	 */
+	private $digitTransformLang;
+
+	/**
+	 * Constructor
+	 *
+	 * @param $lang Language How to convert digits.
+	 *  For example, if given language "my" than ၇ is treated like 7.
+	 *
+	 * It is expected that usually this is given $wgContLang.
+	 */
+	public function __construct( Language $lang ) {
+		$this->digitTransformLang = $lang;
+		parent::__construct();
+	}
+
 	public function getSortKey( $string ) {
 		$sortkey = parent::getSortKey( $string );
-
+		$sortkey = $this->convertDigits( $sortkey );
 		// For each sequence of digits, insert the digit '0' and then the length of the sequence
 		// (encoded in two bytes) before it. That's all folks, it sorts correctly now! The '0' ensures
 		// correct position (where digits would normally sort), then the length will be compared putting
@@ -48,11 +73,33 @@ class NumericUppercaseCollation extends UppercaseCollation {
 		return $sortkey;
 	}
 
+	/**
+	 * Convert localized digits to english digits.
+	 *
+	 * based on Language::parseFormattedNumber but without commas.
+	 *
+	 * @param $string String sortkey to unlocalize digits of
+	 * @return String Sortkey with all localized digits replaced with ASCII digits.
+	 */
+	private function convertDigits( $string ) {
+		$table = $this->digitTransformLang->digitTransformTable();
+		if ( $table ) {
+			$table = array_filter( $table );
+			$flipped = array_flip( $table );
+			// Some languages seem to also have commas in this table.
+			$flipped = array_filter( $flipped, 'is_numeric' );
+			$string = strtr( $string, $flipped );
+		}
+		return $string;
+	}
+
 	public function getFirstLetter( $string ) {
-		if ( preg_match( '/^\d/', $string ) ) {
-			// Note that we pass 0 and 9 as normal params, not numParams(). This only works for 0-9
-			// and not localised digits, so we don't want them to be converted.
-			return wfMessage( 'category-header-numerals' )->params( 0, 9 )->text();
+		$convertedString = $this->convertDigits( $string );
+
+		if ( preg_match( '/^\d/', $convertedString ) ) {
+			return wfMessage( 'category-header-numerals' )
+				->numParams( 0, 9 )
+				->text();
 		} else {
 			return parent::getFirstLetter( $string );
 		}
-- 
2.20.1