<?php

namespace SilverStripe\Core;

use SilverStripe\Control\Director;
use SilverStripe\Core\Manifest\SS_ClassLoader;
use SilverStripe\Dev\Deprecation;
use SilverStripe\ORM\ArrayLib;
use SilverStripe\ORM\DB;
use SilverStripe\ORM\DataObject;
use ReflectionClass;

/**
 * Provides introspection information about the class tree.
 *
 * It's a cached wrapper around the built-in class functions.  SilverStripe uses
 * class introspection heavily and without the caching it creates an unfortunate
 * performance hit.
 */
class ClassInfo {

	/**
	 * Wrapper for classes getter.
	 *
	 * @return array
	 */
	public static function allClasses() {
		return SS_ClassLoader::instance()->getManifest()->getClasses();
	}

	/**
	 * Returns true if a class or interface name exists.
	 *
	 * @param  string $class
	 * @return bool
	 */
	public static function exists($class) {
		return class_exists($class, false) || interface_exists($class, false) || SS_ClassLoader::instance()->getItemPath($class);
	}

	/**
	 * Cache for {@link hasTable()}
	 */
	private static $_cache_all_tables = array();

	/**
	 * @var array Cache for {@link ancestry()}.
	 */
	private static $_cache_ancestry = array();

	/**
	 * @todo Move this to SS_Database or DB
	 *
	 * @param string $tableName
	 * @return bool
	 */
	public static function hasTable($tableName) {
		// Cache the list of all table names to reduce on DB traffic
		if(empty(self::$_cache_all_tables) && DB::is_active()) {
			self::$_cache_all_tables = DB::get_schema()->tableList();
		}
		return !empty(self::$_cache_all_tables[strtolower($tableName)]);
	}

	public static function reset_db_cache() {
		self::$_cache_all_tables = null;
		self::$_cache_ancestry = array();
	}

	/**
	 * Returns the manifest of all classes which are present in the database.
	 *
	 * @param string $class Class name to check enum values for ClassName field
	 * @param boolean $includeUnbacked Flag indicating whether or not to include
	 * types that don't exist as implemented classes. By default these are excluded.
	 * @return array List of subclasses
	 */
	public static function getValidSubClasses($class = 'SilverStripe\\CMS\\Model\\SiteTree', $includeUnbacked = false) {
		if(is_string($class) && !class_exists($class)) return array();

		$class = self::class_name($class);
		if ($includeUnbacked) {
			$table = DataObject::getSchema()->tableName($class);
			$classes = DB::get_schema()->enumValuesForField($table, 'ClassName');
		} else {
			$classes = static::subclassesFor($class);
		}
		return $classes;
	}

	/**
	 * Returns an array of the current class and all its ancestors and children
	 * which require a DB table.
	 *
	 * @todo Move this into {@see DataObjectSchema}
	 *
	 * @param string|object $nameOrObject Class or object instance
	 * @return array
	 */
	public static function dataClassesFor($nameOrObject) {
		if(is_string($nameOrObject) && !class_exists($nameOrObject)) {
			return array();
		}

		$result = array();

		$class = self::class_name($nameOrObject);

		$classes = array_merge(
			self::ancestry($class),
			self::subclassesFor($class)
		);

		foreach ($classes as $class) {
			if (DataObject::has_own_table($class)) {
				$result[$class] = $class;
			}
		}

		return $result;
	}

	/**
	 * @deprecated 4.0..5.0
	 */
	public static function baseDataClass($class) {
		Deprecation::notice('5.0', 'Use DataObject::getSchema()->baseDataClass()');
		return DataObject::getSchema()->baseDataClass($class);
	}

	/**
	 * Returns a list of classes that inherit from the given class.
	 * The resulting array includes the base class passed
	 * through the $class parameter as the first array value.
	 *
	 * Example usage:
	 * <code>
	 * ClassInfo::subclassesFor('BaseClass');
	 * 	array(
	 * 	'BaseClass' => 'BaseClass',
	 * 	'ChildClass' => 'ChildClass',
	 * 	'GrandChildClass' => 'GrandChildClass'
	 * )
	 * </code>
	 *
	 * @param string|object $nameOrObject The classname or object
	 * @return array Names of all subclasses as an associative array.
	 */
	public static function subclassesFor($nameOrObject) {
		if(is_string($nameOrObject) && !class_exists($nameOrObject)) {
			return [];
		}

		//normalise class case
		$className = self::class_name($nameOrObject);
		$descendants = SS_ClassLoader::instance()->getManifest()->getDescendantsOf($className);
		$result      = array($className => $className);

		if ($descendants) {
			return $result + ArrayLib::valuekey($descendants);
		} else {
			return $result;
		}
	}

	/**
	 * Convert a class name in any case and return it as it was defined in PHP
	 *
	 * eg: self::class_name('dataobJEct'); //returns 'DataObject'
	 *
	 * @param string|object $nameOrObject The classname or object you want to normalise
	 * @return string The normalised class name
	 */
	public static function class_name($nameOrObject) {
		if (is_object($nameOrObject)) {
			return get_class($nameOrObject);
		}
		$reflection = new ReflectionClass($nameOrObject);
		return $reflection->getName();
	}

	/**
	 * Returns the passed class name along with all its parent class names in an
	 * array, sorted with the root class first.
	 *
	 * @param string|object $nameOrObject Class or object instance
	 * @param bool $tablesOnly Only return classes that have a table in the db.
	 * @return array
	 */
	public static function ancestry($nameOrObject, $tablesOnly = false) {
		if(is_string($nameOrObject) && !class_exists($nameOrObject)) {
			return array();
		}

		$class = self::class_name($nameOrObject);

		$lClass = strtolower($class);

		$cacheKey = $lClass . '_' . (string)$tablesOnly;
		$parent = $class;
		if(!isset(self::$_cache_ancestry[$cacheKey])) {
			$ancestry = array();
			do {
				if (!$tablesOnly || DataObject::has_own_table($parent)) {
					$ancestry[$parent] = $parent;
				}
			} while ($parent = get_parent_class($parent));
			self::$_cache_ancestry[$cacheKey] = array_reverse($ancestry);
		}

		return self::$_cache_ancestry[$cacheKey];
	}

	/**
	 * @param string $interfaceName
	 * @return array A self-keyed array of class names. Note that this is only available with Silverstripe
	 * classes and not built-in PHP classes.
	 */
	public static function implementorsOf($interfaceName) {
		return SS_ClassLoader::instance()->getManifest()->getImplementorsOf($interfaceName);
	}

	/**
	 * Returns true if the given class implements the given interface
	 *
	 * @param string $className
	 * @param string $interfaceName
	 * @return bool
	 */
	public static function classImplements($className, $interfaceName) {
		return in_array($className, self::implementorsOf($interfaceName));
	}

	/**
	 * Get all classes contained in a file.
	 * @uses ManifestBuilder
	 *
	 * @todo Doesn't return additional classes that only begin
	 *  with the filename, and have additional naming separated through underscores.
	 *
	 * @param string $filePath Path to a PHP file (absolute or relative to webroot)
	 * @return array
	 */
	public static function classes_for_file($filePath) {
		$absFilePath    = Director::getAbsFile($filePath);
		$matchedClasses = array();
		$manifest       = SS_ClassLoader::instance()->getManifest()->getClasses();

		foreach($manifest as $class => $compareFilePath) {
			if($absFilePath == $compareFilePath) $matchedClasses[] = $class;
		}

		return $matchedClasses;
	}

	/**
	 * Returns all classes contained in a certain folder.
	 *
	 * @todo Doesn't return additional classes that only begin
	 *  with the filename, and have additional naming separated through underscores.
	 *
	 * @param string $folderPath Relative or absolute folder path
	 * @return array Array of class names
	 */
	public static function classes_for_folder($folderPath) {
		$absFolderPath  = Director::getAbsFile($folderPath);
		$matchedClasses = array();
		$manifest       = SS_ClassLoader::instance()->getManifest()->getClasses();

		foreach($manifest as $class => $compareFilePath) {
			if(stripos($compareFilePath, $absFolderPath) === 0) $matchedClasses[] = $class;
		}

		return $matchedClasses;
	}

	private static $method_from_cache = array();

	public static function has_method_from($class, $method, $compclass) {
		$lClass = strtolower($class);
		$lMethod = strtolower($method);
		$lCompclass = strtolower($compclass);
		if (!isset(self::$method_from_cache[$lClass])) self::$method_from_cache[$lClass] = array();

		if (!array_key_exists($lMethod, self::$method_from_cache[$lClass])) {
			self::$method_from_cache[$lClass][$lMethod] = false;

			$classRef = new ReflectionClass($class);

			if ($classRef->hasMethod($method)) {
				$methodRef = $classRef->getMethod($method);
				self::$method_from_cache[$lClass][$lMethod] = $methodRef->getDeclaringClass()->getName();
			}
		}

		return strtolower(self::$method_from_cache[$lClass][$lMethod]) == $lCompclass;
	}

	/**
	 * @deprecated 4.0..5.0
	 */
	public static function table_for_object_field($candidateClass, $fieldName) {
		Deprecation::notice('5.0', 'Use DataObject::getSchema()->tableForField()');
		return DataObject::getSchema()->tableForField($candidateClass, $fieldName);
	}

	/**
	 * Strip namespace from class
	 *
	 * @param string|object $nameOrObject Name of class, or instance
	 * @return string Name of class without namespace
	 */
	public static function shortName($nameOrObject) {
		$reflection = new ReflectionClass($nameOrObject);
		return $reflection->getShortName();
	}
}