Translations

class Translations {
	var $entries = array();
	var $headers = array();

	/**
	 * Add entry to the PO structure
	 *
	 * @param array|Translation_Entry $entry
	 * @return bool true on success, false if the entry doesn't have a key
	 */
	function add_entry($entry) {
		if (is_array($entry)) {
			$entry = new Translation_Entry($entry);
		}
		$key = $entry->key();
		if (false === $key) return false;
		$this->entries[$key] = &$entry;
		return true;
	}

	/**
	 * @param array|Translation_Entry $entry
	 * @return bool
	 */
	function add_entry_or_merge($entry) {
		if (is_array($entry)) {
			$entry = new Translation_Entry($entry);
		}
		$key = $entry->key();
		if (false === $key) return false;
		if (isset($this->entries[$key]))
			$this->entries[$key]->merge_with($entry);
		else
			$this->entries[$key] = &$entry;
		return true;
	}

	/**
	 * Sets $header PO header to $value
	 *
	 * If the header already exists, it will be overwritten
	 *
	 * TODO: this should be out of this class, it is gettext specific
	 *
	 * @param string $header header name, without trailing :
	 * @param string $value header value, without trailing \n
	 */
	function set_header($header, $value) {
		$this->headers[$header] = $value;
	}

	/**
	 * @param array $headers
	 */
	function set_headers($headers) {
		foreach($headers as $header => $value) {
			$this->set_header($header, $value);
		}
	}

	/**
	 * @param string $header
	 */
	function get_header($header) {
		return isset($this->headers[$header])? $this->headers[$header] : false;
	}

	/**
	 * @param Translation_Entry $entry
	 */
	function translate_entry(&$entry) {
		$key = $entry->key();
		return isset($this->entries[$key])? $this->entries[$key] : false;
	}

	/**
	 * @param string $singular
	 * @param string $context
	 * @return string
	 */
	function translate($singular, $context=null) {
		$entry = new Translation_Entry(array('singular' => $singular, 'context' => $context));
		$translated = $this->translate_entry($entry);
		return ($translated && !empty($translated->translations))? $translated->translations[0] : $singular;
	}

	/**
	 * Given the number of items, returns the 0-based index of the plural form to use
	 *
	 * Here, in the base Translations class, the common logic for English is implemented:
	 * 	0 if there is one element, 1 otherwise
	 *
	 * This function should be overridden by the sub-classes. For example MO/PO can derive the logic
	 * from their headers.
	 *
	 * @param integer $count number of items
	 */
	function select_plural_form($count) {
		return 1 == $count? 0 : 1;
	}

	/**
	 * @return int
	 */
	function get_plural_forms_count() {
		return 2;
	}

	/**
	 * @param string $singular
	 * @param string $plural
	 * @param int    $count
	 * @param string $context
	 */
	function translate_plural($singular, $plural, $count, $context = null) {
		$entry = new Translation_Entry(array('singular' => $singular, 'plural' => $plural, 'context' => $context));
		$translated = $this->translate_entry($entry);
		$index = $this->select_plural_form($count);
		$total_plural_forms = $this->get_plural_forms_count();
		if ($translated && 0 <= $index && $index < $total_plural_forms &&
				is_array($translated->translations) &&
				isset($translated->translations[$index]))
			return $translated->translations[$index];
		else
			return 1 == $count? $singular : $plural;
	}

	/**
	 * Merge $other in the current object.
	 *
	 * @param Object $other Another Translation object, whose translations will be merged in this one (passed by reference).
	 * @return void
	 **/
	function merge_with(&$other) {
		foreach( $other->entries as $entry ) {
			$this->entries[$entry->key()] = $entry;
		}
	}

	/**
	 * @param object $other
	 */
	function merge_originals_with(&$other) {
		foreach( $other->entries as $entry ) {
			if ( !isset( $this->entries[$entry->key()] ) )
				$this->entries[$entry->key()] = $entry;
			else
				$this->entries[$entry->key()]->merge_with($entry);
		}
	}
}