<?php

namespace SilverStripe\Control;

use SilverStripe\ORM\FieldType\DBDatetime;
use LogicException;

/**
 * A default backend for the setting and getting of cookies
 *
 * This backend allows one to better test Cookie setting and separate cookie
 * handling from the core
 *
 * @todo Create a config array for defaults (eg: httpOnly, secure, path, domain, expiry)
 * @todo A getter for cookies that haven't been sent to the browser yet
 * @todo Tests / a way to set the state without hacking with $_COOKIE
 * @todo Store the meta information around cookie setting (path, domain, secure, etc)
 */
class CookieJar implements Cookie_Backend {

	/**
	 * Hold the cookies that were existing at time of instantiation (ie: The ones
	 * sent to PHP by the browser)
	 *
	 * @var array Existing cookies sent by the browser
	 */
	protected $existing = array();

	/**
	 * Hold the current cookies (ie: a mix of those that were sent to us and we
	 * have set without the ones we've cleared)
	 *
	 * @var array The state of cookies once we've sent the response
	 */
	protected $current = array();

	/**
	 * Hold any NEW cookies that were set by the application and will be sent
	 * in the next response
	 *
	 * @var array New cookies set by the application
	 */
	protected $new = array();

	/**
	 * When creating the backend we want to store the existing cookies in our
	 * "existing" array. This allows us to distinguish between cookies we received
	 * or we set ourselves (and didn't get from the browser)
	 *
	 * @param array $cookies The existing cookies to load into the cookie jar.
	 * Omit this to default to $_COOKIE
	 */
	public function __construct($cookies = array()) {
		$this->current = $this->existing = func_num_args()
			? ($cookies ?: array()) // Convert empty values to blank arrays
			: $_COOKIE;
	}

	/**
	 * Set a cookie
	 *
	 * @param string $name The name of the cookie
	 * @param string $value The value for the cookie to hold
	 * @param int $expiry The number of days until expiry; 0 indicates a cookie valid for the current session
	 * @param string $path The path to save the cookie on (falls back to site base)
	 * @param string $domain The domain to make the cookie available on
	 * @param boolean $secure Can the cookie only be sent over SSL?
	 * @param boolean $httpOnly Prevent the cookie being accessible by JS
	 */
	public function set($name, $value, $expiry = 90, $path = null, $domain = null, $secure = false, $httpOnly = true) {
		//are we setting or clearing a cookie? false values are reserved for clearing cookies (see PHP manual)
		$clear = false;
		if ($value === false || $value === '' || $expiry < 0) {
			$clear = true;
			$value = false;
		}

		//expiry === 0 is a special case where we set a cookie for the current user session
		if ($expiry !== 0) {
			//don't do the maths if we are clearing
			$expiry = $clear ? -1 : DBDatetime::now()->Format('U') + (86400 * $expiry);
		}
		//set the path up
		$path = $path ? $path : Director::baseURL();
		//send the cookie
		$this->outputCookie($name, $value, $expiry, $path, $domain, $secure, $httpOnly);
		//keep our variables in check
		if ($clear) {
			unset ($this->new[$name], $this->current[$name]);
		}
		else {
			$this->new[$name] = $this->current[$name] = $value;
		}

	}

	/**
	 * Get the cookie value by name
	 *
	 * Cookie names are normalised to work around PHP's behaviour of replacing incoming variable name . with _
	 *
	 * @param string $name The name of the cookie to get
	 * @param boolean $includeUnsent Include cookies we've yet to send when fetching values
	 *
	 * @return string|null The cookie value or null if unset
	 */
	public function get($name, $includeUnsent = true) {
		$cookies = $includeUnsent ? $this->current : $this->existing;
		if (isset($cookies[$name])) {
			return $cookies[$name];
		}

		//Normalise cookie names by replacing '.' with '_'
		$safeName = str_replace('.', '_', $name);
		if (isset($cookies[$safeName])) {
			return $cookies[$safeName];
		}
		return null;
	}

	/**
	 * Get all the cookies
	 *
	 * @param boolean $includeUnsent Include cookies we've yet to send
	 * @return array All the cookies
	 */
	public function getAll($includeUnsent = true) {
		return $includeUnsent ? $this->current : $this->existing;
	}

	/**
	 * Force the expiry of a cookie by name
	 *
	 * @param string $name The name of the cookie to expire
	 * @param string $path The path to save the cookie on (falls back to site base)
	 * @param string $domain The domain to make the cookie available on
	 * @param boolean $secure Can the cookie only be sent over SSL?
	 * @param boolean $httpOnly Prevent the cookie being accessible by JS
	 */
	public function forceExpiry($name, $path = null, $domain = null, $secure = false, $httpOnly = true) {
		$this->set($name, false, -1, $path, $domain, $secure, $httpOnly);
	}

	/**
	 * The function that actually sets the cookie using PHP
	 *
	 * @see http://uk3.php.net/manual/en/function.setcookie.php
	 *
	 * @param string $name The name of the cookie
	 * @param string|array $value The value for the cookie to hold
	 * @param int $expiry The number of days until expiry
	 * @param string $path The path to save the cookie on (falls back to site base)
	 * @param string $domain The domain to make the cookie available on
	 * @param boolean $secure Can the cookie only be sent over SSL?
	 * @param boolean $httpOnly Prevent the cookie being accessible by JS
	 * @return boolean If the cookie was set or not; doesn't mean it's accepted by the browser
	 */
	protected function outputCookie(
		$name, $value, $expiry = 90, $path = null, $domain = null, $secure = false, $httpOnly = true
	) {
		// if headers aren't sent, we can set the cookie
		if(!headers_sent($file, $line)) {
			return setcookie($name, $value, $expiry, $path, $domain, $secure, $httpOnly);
		}

		if(Cookie::config()->get('report_errors')) {
			throw new LogicException(
				"Cookie '$name' can't be set. The site started outputting content at line $line in $file"
			);
		}
		return false;
	}

}