1 files changed, 89 insertions, 0 deletions
diff --git a/library/intl/src/LocaleResolverTrait.php b/library/intl/src/LocaleResolverTrait.php
new file mode 100644
index 000000000..21c463c7e
--- /dev/null
+++ b/library/intl/src/LocaleResolverTrait.php
@@ -0,0 +1,89 @@
+<?php
+
+namespace CommerceGuys\Intl;
+
+use CommerceGuys\Intl\Exception\UnknownLocaleException;
+
+trait LocaleResolverTrait
+{
+    /**
+     * The path where per-locale definitions are stored.
+     */
+    protected $definitionPath;
+
+    /**
+     * Determines which locale should be used for loading definitions.
+     *
+     * If the "bs-Cyrl-BA" locale is requested, with an "en" fallback,
+     * the system will try to find the definitions for:
+     * 1) bs-Cyrl-BA
+     * 2) bs-Cyrl
+     * 3) bs
+     * 4) en
+     * The first locale for which a definition file is found, wins.
+     * Otherwise, an exception is thrown.
+     *
+     * @param string $locale         The desired locale (i.e. fr-FR).
+     * @param string $fallbackLocale A fallback locale (i.e "en").
+     *
+     * @return string
+     *
+     * @throws UnknownLocaleException
+     */
+    protected function resolveLocale($locale = null, $fallbackLocale = null)
+    {
+        if (is_null($locale)) {
+            // Use the default locale if none was provided.
+            // @todo Provide a way to override this.
+            $locale = 'en';
+        }
+        // Normalize the locale. Allows en_US to work the same as en-US, etc.
+        $locale = str_replace('_', '-', $locale);
+        // List all possible variants (i.e. en-US gives "en-US" and "en").
+        $localeVariants = $this->getLocaleVariants($locale);
+        // A fallback locale was provided, add it to the end of the chain.
+        if (isset($fallbackLocale)) {
+            $localeVariants[] = $fallbackLocale;
+        }
+
+        // Try to resolve a locale by finding a matching definition file.
+        $resolvedLocale = null;
+        foreach ($localeVariants as $localeVariant) {
+            $path = $this->definitionPath . $localeVariant . '.json';
+            if (file_exists($path)) {
+                $resolvedLocale = $localeVariant;
+                break;
+            }
+        }
+        // No locale could be resolved, stop here.
+        if (!$resolvedLocale) {
+            throw new UnknownLocaleException($locale);
+        }
+
+        return $resolvedLocale;
+    }
+
+    /**
+     * Returns all variants of a locale.
+     *
+     * For example, "bs-Cyrl-BA" has the following variants:
+     * 1) bs-Cyrl-BA
+     * 2) bs-Cyrl
+     * 3) bs
+     *
+     * @param string $locale The locale (i.e. fr-FR).
+     *
+     * @return array An array of all variants of a locale.
+     */
+    protected function getLocaleVariants($locale)
+    {
+        $localeVariants = array();
+        $localeParts = explode('-', $locale);
+        while (!empty($localeParts)) {
+            $localeVariants[] = implode('-', $localeParts);
+            array_pop($localeParts);
+        }
+
+        return $localeVariants;
+    }
+}