shimmie2/core/config.php

<?php

/**
 * Interface Config
 *
 * An abstract interface for altering a name:value pair list.
 */
interface Config {
	/**
	 * Save the list of name:value pairs to wherever they came from,
	 * so that the next time a page is loaded it will use the new
	 * configuration.
	 */
	public function save(string $name=null): void;

	//@{ /*--------------------------------- SET ------------------------------------------------------*/
	/**
	 * Set a configuration option to a new value, regardless of what the value is at the moment.
	 */
	public function set_int(string $name, ?int $value): void;

	/**
	 * Set a configuration option to a new value, regardless of what the value is at the moment.
	 */
	public function set_string(string $name, ?string $value): void;

	/**
	 * Set a configuration option to a new value, regardless of what the value is at the moment.
	 * @param null|bool|string $value
	 */
	public function set_bool(string $name, $value): void;

	/**
	 * Set a configuration option to a new value, regardless of what the value is at the moment.
	 */
	public function set_array(string $name, array $value): void;
	//@} /*--------------------------------------------------------------------------------------------*/

	//@{ /*-------------------------------- SET DEFAULT -----------------------------------------------*/
	/**
	 * Set a configuration option to a new value, if there is no value currently.
	 *
	 * Extensions should generally call these from their InitExtEvent handlers.
	 * This has the advantage that the values will show up in the "advanced" setup
	 * page where they can be modified, while calling get_* with a "default"
	 * parameter won't show up.
	 */
	public function set_default_int(string $name, int $value): void;

	/**
	 * Set a configuration option to a new value, if there is no value currently.
	 *
	 * Extensions should generally call these from their InitExtEvent handlers.
	 * This has the advantage that the values will show up in the "advanced" setup
	 * page where they can be modified, while calling get_* with a "default"
	 * parameter won't show up.
	 */
	public function set_default_string(string $name, string $value): void;

	/**
	 * Set a configuration option to a new value, if there is no value currently.
	 *
	 * Extensions should generally call these from their InitExtEvent handlers.
	 * This has the advantage that the values will show up in the "advanced" setup
	 * page where they can be modified, while calling get_* with a "default"
	 * parameter won't show up.
	 */
	public function set_default_bool(string $name, bool $value): void;

	/**
	 * Set a configuration option to a new value, if there is no value currently.
	 *
	 * Extensions should generally call these from their InitExtEvent handlers.
	 * This has the advantage that the values will show up in the "advanced" setup
	 * page where they can be modified, while calling get_* with a "default"
	 * parameter won't show up.
	 */
	public function set_default_array(string $name, array $value): void;
	//@} /*--------------------------------------------------------------------------------------------*/

	//@{ /*--------------------------------- GET ------------------------------------------------------*/
	/**
	 * Pick a value out of the table by name, cast to the appropriate data type.
	 */
	public function get_int(string $name, ?int $default=null): ?int;

	/**
	 * Pick a value out of the table by name, cast to the appropriate data type.
	 */
	public function get_string(string $name, ?string $default=null): ?string;

	/**
	 * Pick a value out of the table by name, cast to the appropriate data type.
	 */
	public function get_bool(string $name, ?bool $default=null): ?bool;

	/**
	 * Pick a value out of the table by name, cast to the appropriate data type.
	 */
	public function get_array(string $name, ?array $default=array()): ?array;
	//@} /*--------------------------------------------------------------------------------------------*/
}


/**
 * Class BaseConfig
 *
 * Common methods for manipulating the list, loading and saving is
 * left to the concrete implementation
 */
abstract class BaseConfig implements Config {
	public $values = array();

	public function set_int(string $name, $value) {
		$this->values[$name] = parse_shorthand_int($value);
		$this->save($name);
	}

	public function set_string(string $name, $value) {
		$this->values[$name] = $value;
		$this->save($name);
	}

	public function set_bool(string $name, $value) {
		$this->values[$name] = bool_escape($value) ? 'Y' : 'N';
		$this->save($name);
	}

	public function set_array(string $name, array $value) {
		$this->values[$name] = implode(",", $value);
		$this->save($name);
	}

	public function set_default_int(string $name, int $value) {
		if(is_null($this->get($name))) {
			$this->values[$name] = $value;
		}
	}

	public function set_default_string(string $name, string $value) {
		if(is_null($this->get($name))) {
			$this->values[$name] = $value;
		}
	}

	public function set_default_bool(string $name, bool $value) {
		if(is_null($this->get($name))) {
			$this->values[$name] = $value ? 'Y' : 'N';
		}
	}

	public function set_default_array(string $name, array $value) {
		if(is_null($this->get($name))) {
			$this->values[$name] = implode(",", $value);
		}
	}

	public function get_int(string $name, $default=null) {
		return (int)($this->get($name, $default));
	}

	public function get_string(string $name, $default=null) {
		return $this->get($name, $default);
	}

	public function get_bool(string $name, $default=null) {
		return bool_escape($this->get($name, $default));
	}

	public function get_array(string $name, array $default=array()): array {
		return explode(",", $this->get($name, ""));
	}

	private function get(string $name, $default=null) {
		if(isset($this->values[$name])) {
			return $this->values[$name];
		}
		else {
			return $default;
		}
	}
}


/**
 * Class HardcodeConfig
 *
 * For testing, mostly.
 */
class HardcodeConfig extends BaseConfig {
	public function __construct(array $dict) {
		$this->values = $dict;
	}

	public function save(string $name=null) {
		// static config is static
	}
}


/**
 * Class StaticConfig
 *
 * Loads the config list from a PHP file; the file should be in the format:
 *
 *  <?php
 *  $config['foo'] = "bar";
 *  $config['baz'] = "qux";
 *  ?>
 */
class StaticConfig extends BaseConfig {
	public function __construct(string $filename) {
		if(file_exists($filename)) {
			$config = array();
			require_once $filename;
			if(!empty($config)) {
				$this->values = $config;
			}
			else {
				throw new Exception("Config file '$filename' doesn't contain any config");
			}
		}
		else {
			throw new Exception("Config file '$filename' missing");
		}
	}

	public function save(string $name=null) {
		// static config is static
	}
}


/**
 * Class DatabaseConfig
 *
 * Loads the config list from a table in a given database, the table should
 * be called config and have the schema:
 *
 * \code
 *  CREATE TABLE config(
 *      name VARCHAR(255) NOT NULL,
 *      value TEXT
 *  );
 * \endcode
 */
class DatabaseConfig extends BaseConfig {
	/** @var Database  */
	private $database = null;

	public function __construct(Database $database) {
		$this->database = $database;

		$cached = $this->database->cache->get("config");
		if($cached) {
			$this->values = $cached;
		}
		else {
			$this->values = array();
			foreach($this->database->get_all("SELECT name, value FROM config") as $row) {
				$this->values[$row["name"]] = $row["value"];
			}
			$this->database->cache->set("config", $this->values);
		}
	}

	public function save(string $name=null) {
		if(is_null($name)) {
			reset($this->values); // rewind the array to the first element
			foreach($this->values as $name => $value) {
				$this->save($name);
			}
		}
		else {
			$this->database->Execute("DELETE FROM config WHERE name = :name", array("name"=>$name));
			$this->database->Execute("INSERT INTO config VALUES (:name, :value)", array("name"=>$name, "value"=>$this->values[$name]));
		}
		// rather than deleting and having some other request(s) do a thundering
		// herd of race-conditioned updates, just save the updated version once here
		$this->database->cache->set("config", $this->values);
	}
}

/**
 * Class MockConfig
 */
class MockConfig extends HardcodeConfig {
	public function __construct(array $config=array()) {
		$config["db_version"] = "999";
		$config["anon_id"] = "0";
		parent::__construct($config);
	}
}