<?php

namespace SilverStripe\Dev\Install;

use InvalidArgumentException;

/**
 * This class keeps track of the available database adapters
 * and provides a meaning of registering community built
 * adapters in to the installer process.
 *
 * @author Tom Rix
 */
class DatabaseAdapterRegistry {

	/**
	 * Default database connector registration fields
	 *
	 * @var array
	 */
	private static $default_fields = array(
		'server' => array(
			'title' => 'Database server',
			'envVar' => 'SS_DATABASE_SERVER',
			'default' => 'localhost'
		),
		'username' => array(
			'title' => 'Database username',
			'envVar' => 'SS_DATABASE_USERNAME',
			'default' => 'root'
		),
		'password' => array(
			'title' => 'Database password',
			'envVar' => 'SS_DATABASE_PASSWORD',
			'default' => 'password'
		),
		'database' => array(
			'title' => 'Database name',
			'default' => 'SS_mysite',
			'attributes' => array(
				"onchange" => "this.value = this.value.replace(/[\/\\:*?&quot;<>|. \t]+/g,'');"
			)
		),
	);

	/**
	 * Internal array of registered database adapters
	 *
	 * @var array
	 */
	private static $adapters = array();

	/**
	 * Add new adapter to the registry
	 *
	 * @param array $config Associative array of configuration details. This must include:
	 *  - title
	 *  - class
	 *  - helperClass
	 *  - supported
	 * This SHOULD include:
	 *  - fields
	 *  - helperPath (if helperClass can't be autoloaded via psr-4/-0)
	 *  - missingExtensionText
	 *  - module OR missingModuleText
	 */
	public static function register($config) {
		// Validate config
		$missing = array_diff(['title', 'class', 'helperClass', 'supported'], array_keys($config));
		if($missing) {
			throw new InvalidArgumentException(
				"Missing database helper config keys: '" . implode("', '", $missing) . "'"
			);
		}

		// Guess missing module text if not given
		if (empty($config['missingModuleText'])) {
			if (empty($config['module'])) {
				$moduleText = 'Module for database connector ' . $config['title'] . 'is missing.';
			} else {
				$moduleText = "The SilverStripe module '" . $config['module'] . "' is missing.";
			}
			$config['missingModuleText'] = $moduleText
				. ' Please install it via composer or from http://addons.silverstripe.org/.';
		}

		// Set missing text
		if (empty($config['missingExtensionText'])) {
			$config['missingExtensionText'] = 'The PHP extension is missing, please enable or install it.';
		}

		// set default fields if none are defined already
		if(!isset($config['fields'])) {
			$config['fields'] = self::$default_fields;
		}

		self::$adapters[$config['class']] = $config;
	}

	/**
	 * Unregisters a database connector by classname
	 *
	 * @param string $class
	 */
	public static function unregister($class) {
		unset(self::$adapters[$class]);
	}

	/**
	 * Detects all _register_database.php files and invokes them
	 */
	public static function autodiscover() {
		foreach(glob(dirname(__FILE__) . '/../../../*', GLOB_ONLYDIR) as $directory) {
			if(file_exists($directory . '/_register_database.php')) {
				include_once($directory . '/_register_database.php');
			}
		}
	}

	/**
	 * Detects all _configure_database.php files and invokes them
	 * Called by ConfigureFromEnv.php
	 */
	public static function autoconfigure() {
		foreach(glob(dirname(__FILE__) . '/../../../*', GLOB_ONLYDIR) as $directory) {
			if(file_exists($directory . '/_configure_database.php')) {
				include_once($directory . '/_configure_database.php');
			}
		}
	}

	/**
	 * Return all registered adapters
	 *
	 * @return array
	 */
	public static function get_adapters() {
		return self::$adapters;
	}

	/**
	 * Returns registry data for a class
	 *
	 * @param string $class
	 * @return array List of adapter properties
	 */
	public static function get_adapter($class) {
		if(isset(self::$adapters[$class])) {
			return self::$adapters[$class];
		}
		return null;
	}

	/**
	 * Retrieves default field configuration
	 *
	 * @return array
	 */
	public static function get_default_fields() {
		return self::$default_fields;
	}

	/**
	 * Build configuration helper for a given class
	 *
	 * @param string $databaseClass Name of class
	 * @return DatabaseConfigurationHelper|null Instance of helper, or null if cannot be loaded
	 */
	public static function getDatabaseConfigurationHelper($databaseClass) {
		$adapters = static::get_adapters();
		if(empty($adapters[$databaseClass]) || empty($adapters[$databaseClass]['helperClass'])) {
			return null;
		}

		// Load if path given
		if (isset($adapters[$databaseClass]['helperPath'])) {
			include_once $adapters[$databaseClass]['helperPath'];
		}

		// Construct
		$class = $adapters[$databaseClass]['helperClass'];
		return (class_exists($class)) ? new $class() : null;
	}

}