PHP: ensure 5.3 compatibility, refactor timezone utilities

Relates to #250

Modifications
 - supported version
   - bump required version from 5.1.0 to 5.3.x
   - update README
   - add PHP 5.3 to Travis environments
 - rewrite array declarations: explicitely use array() instead of []
 - move checkPHPVersion to application/Utils.php
 - move timezone functions to application/TimeZone.php
   - cleanup code
   - improve test coverage

Signed-off-by: VirtualTam <virtualtam@flibidi.net>

1 files changed, 110 insertions, 0 deletions

diff --git a/application/TimeZone.php b/application/TimeZone.php
new file mode 100644
index 00000000..ccbef918
--- /dev/null
+++ b/application/TimeZone.php
@@ -0,0 +1,110 @@
+<?php
+/**
+ * Generates the timezone selection form and JavaScript.
+ *
+ * Note: 'UTC/UTC' is mapped to 'UTC' to form a valid option
+ *
+ * Example: preselect Europe/Paris
+ *  list($htmlform, $js) = templateTZform('Europe/Paris');
+ *
+ * @param string $preselected_timezone preselected timezone (optional)
+ *
+ * @return an array containing the generated HTML form and Javascript code
+ **/
+function generateTimeZoneForm($preselected_timezone='')
+{
+    // Select the first available timezone if no preselected value is passed
+    if ($preselected_timezone == '') {
+        $l = timezone_identifiers_list();
+        $preselected_timezone = $l[0];
+    }
+
+    // Try to split the provided timezone
+    $spos = strpos($preselected_timezone, '/');
+    $pcontinent = substr($preselected_timezone, 0, $spos);
+    $pcity = substr($preselected_timezone, $spos+1);
+
+    // Display config form:
+    $timezone_form = '';
+    $timezone_js = '';
+
+    // The list is in the form 'Europe/Paris', 'America/Argentina/Buenos_Aires'...
+    // We split the list in continents/cities.
+    $continents = array();
+    $cities = array();
+
+    // TODO: use a template to generate the HTML/Javascript form
+
+    foreach (timezone_identifiers_list() as $tz) {
+        if ($tz == 'UTC') {
+            $tz = 'UTC/UTC';
+        }
+        $spos = strpos($tz, '/');
+
+        if ($spos !== false) {
+            $continent = substr($tz, 0, $spos);
+            $city = substr($tz, $spos+1);
+            $continents[$continent] = 1;
+
+            if (!isset($cities[$continent])) {
+                $cities[$continent] = '';
+            }
+            $cities[$continent] .= '<option value="'.$city.'"';
+            if ($pcity == $city) {
+                $cities[$continent] .= ' selected="selected"';
+            }
+            $cities[$continent] .= '>'.$city.'</option>';
+        }
+    }
+
+    $continents_html = '';
+    $continents = array_keys($continents);
+
+    foreach ($continents as $continent) {
+        $continents_html .= '<option  value="'.$continent.'"';
+        if ($pcontinent == $continent) {
+            $continents_html .= ' selected="selected"';
+        }
+        $continents_html .= '>'.$continent.'</option>';
+    }
+
+    // Timezone selection form
+    $timezone_form = 'Continent:';
+    $timezone_form .= '<select name="continent" id="continent" onChange="onChangecontinent();">';
+    $timezone_form .= $continents_html.'</select>';
+    $timezone_form .= '&nbsp;&nbsp;&nbsp;&nbsp;City:';
+    $timezone_form .= '<select name="city" id="city">'.$cities[$pcontinent].'</select><br />';
+
+    // Javascript handler - updates the city list when the user selects a continent
+    $timezone_js = '<script>';
+    $timezone_js .= 'function onChangecontinent() {';
+    $timezone_js .= 'document.getElementById("city").innerHTML =';
+    $timezone_js .= ' citiescontinent[document.getElementById("continent").value]; }';
+    $timezone_js .= 'var citiescontinent = '.json_encode($cities).';';
+    $timezone_js .= '</script>';
+
+    return array($timezone_form, $timezone_js);
+}
+
+/**
+ * Tells if a continent/city pair form a valid timezone
+ *
+ * Note: 'UTC/UTC' is mapped to 'UTC'
+ *
+ * @param string $continent the timezone continent
+ * @param string $city      the timezone city
+ *
+ * @return whether continent/city is a valid timezone
+ */
+function isTimeZoneValid($continent, $city)
+{
+    if ($continent == 'UTC' && $city == 'UTC') {
+        return true;
+    }
+
+    return in_array(
+        $continent.'/'.$city,
+        timezone_identifiers_list()
+    );
+}
+?>