<?php

/**
 * Class MC4WP_Form
 *
 * Represents a Form object.
 *
 * To get a form instance, use `mc4wp_get_form( $id );` where `$id` is the post ID.
 *
 * @access public
 * @since 3.0
 */
class MC4WP_Form {


	/**
	 * @var array Array of instantiated form objects.
	 */
	public static $instances = array();

	/**
	 * @param int $post_id
	 * @throws Exception
	 */
	public static function throw_not_found_exception( $post_id ) {
		$message = sprintf( __( 'There is no form with ID %d, perhaps it was deleted?', 'mailchimp-for-wp' ), $post_id );
		throw new Exception( $message );
	}

	/**
	 * Get a shared form instance.
	 *
	 * @param WP_Post|int $post Post instance or post ID.
	 * @return MC4WP_Form
	 * @throws Exception
	 */
	public static function get_instance( $post = 0 ) {
		if ( $post instanceof WP_Post ) {
			$post_id = $post->ID;
		} else {
			$post_id = (int) $post;

			if ( $post_id === 0 ) {
				$post_id = (int) get_option( 'mc4wp_default_form_id', 0 );
			}
		}

		if ( $post_id === 0 ) {
			self::throw_not_found_exception( $post_id );
		}

		if ( isset( self::$instances[ $post_id ] ) ) {
			return self::$instances[ $post_id ];
		}

		// get post object if we don't have it by now
		if ( ! $post instanceof WP_Post ) {
			$post = get_post( $post_id );
		}

		// check post object
		if ( ! $post instanceof WP_Post || $post->post_type !== 'mc4wp-form' ) {
			self::throw_not_found_exception( $post_id );
		}

		// get all post meta in single call for performance
		$post_meta = (array) get_post_meta( $post_id );
		$form      = new MC4WP_Form( $post_id, $post, $post_meta );

		// store instance
		self::$instances[ $post_id ] = $form;

		return $form;
	}

	/**
	 * @var int The form ID, matches the underlying post its ID
	 */
	public $ID = 0;

	/**
	 * @var string The form name
	 */
	public $name = 'Default Form';

	/**
	 * @var string The form HTML content
	 */
	public $content = '';

	/**
	 * @var array Array of settings
	 */
	public $settings = array();

	/**
	 * @var array Array of messages
	 */
	public $messages = array();

	/**
	 * @var array Array of notices to be shown when this form is rendered
	 */
	public $notices = array();

	/**
	 * @var array Array of error codes
	 */
	public $errors = array();

	/**
	 * @var bool Was this form submitted?
	 */
	public $is_submitted = false;

	/**
	 * @var array Array of the data that was submitted, in name => value pairs.
	 *
	 * Keys in this array are uppercased and keys starting with _ are stripped.
	 */
	private $data = array();

	/**
	 * @var array Array of the raw form data that was submitted.
	 */
	public $raw_data = array();

	/**
	 * @var array
	 */
	public $config = array(
		'action'     => 'subscribe',
		'lists'      => array(),
		'email_type' => '',
		'element_id' => '',
	);

	/**
	* @var string
	*/
	public $last_event = '';

	/**
	* @var string
	*/
	public $status;

	/**
	 * @param int $id The post ID
	 * @param WP_Post $post
	 * @param array $post_meta
	 */
	public function __construct( $id, WP_Post $post, array $post_meta = array() ) {
		$this->ID       = (int) $id;
		$this->name     = $post->post_title;
		$this->content  = $post->post_content;
		$this->status   = $post->post_status;
		$this->settings = $this->load_settings( $post_meta );
		$this->messages = $this->load_messages( $post_meta );

		// update config from settings
		$this->config['lists'] = $this->settings['lists'];
	}

	/**
	 * @param string $name
	 *
	 * @return mixed
	 */
	public function __get( $name ) {
		$method_name = sprintf( 'get_%s', $name );
		if ( method_exists( $this, $method_name ) ) {
			return $this->$method_name();
		}
	}


	/**
	 * Gets the form response string
	 *
	 * This does not take the submitted form element into account.
	 *
	 * @see MC4WP_Form_Element::get_response_html()
	 *
	 * @return string
	 */
	public function get_response_html() {
		return $this->get_element()->get_response_html( true );
	}

	/**
	 * @param string $element_id
	 * @param array $config
	 * @return MC4WP_Form_element
	 */
	public function get_element( $element_id = 'mc4wp-form', array $config = array() ) {
		return new MC4WP_Form_Element( $this, $element_id, $config );
	}

	/**
	 * Get HTML string for this form.
	 *
	 * If you want to output a form, use `mc4wp_show_form` instead as it.
	 *
	 * @param string $element_id
	 * @param array $config
	 *
	 * @return string
	 */
	public function get_html( $element_id = 'mc4wp-form', array $config = array() ) {
		$element = $this->get_element( $element_id, $config );
		$html    = $element->generate_html();
		return $html;
	}


	/**
	 * @param array $post_meta
	 * @return array
	 */
	protected function load_settings( array $post_meta = array() ) {
		$form             = $this;
		$default_settings = include MC4WP_PLUGIN_DIR . '/config/default-form-settings.php';

		// start with defaults
		$settings = $default_settings;

		// get custom settings from meta
		if ( ! empty( $post_meta['_mc4wp_settings'] ) ) {
			$meta = $post_meta['_mc4wp_settings'][0];
			$meta = (array) maybe_unserialize( $meta );

			// ensure lists is an array
			if ( empty( $meta['lists'] ) ) {
				$meta['lists'] = array();
			}

			// merge with current settings (defaults)
			$settings = array_merge( $settings, $meta );
		}

		/**
		 * Filters the form settings
		 *
		 * @since 3.0
		 *
		 * @param array $settings
		 * @param MC4WP_Form $form
		 */
		$settings = (array) apply_filters( 'mc4wp_form_settings', $settings, $form );

		return $settings;
	}

	/**
	 * @param array $post_meta
	 * @return array
	 */
	protected function load_messages( array $post_meta = array() ) {
		$form = $this;

		// get default messages
		$default_messages = include MC4WP_PLUGIN_DIR . '/config/default-form-messages.php';

		// start with default messages
		$messages = $default_messages;

		/**
		 * Filters the form messages
		 *
		 * @since 3.0
		 *
		 * @param array $registered_messages
		 * @param MC4WP_Form $form
		 */
		$messages = (array) apply_filters( 'mc4wp_form_messages', $messages, $form );

		// for backwards compatiblity, grab text of each message (if is array)
		foreach ( $messages as $key => $message ) {
			if ( is_array( $message ) && isset( $message['text'] ) ) {
				$messages[ $key ] = $message['text'];
			}
		}

		foreach ( $messages as $key => $message_text ) {

			// overwrite default text with text in form meta.
			if ( isset( $post_meta[ 'text_' . $key ][0] ) ) {
				$message_text = $post_meta[ 'text_' . $key ][0];
			}

			$messages[ $key ] = $message_text;
		}

		return $messages;
	}

	/**
	 * Does this form has a field of the given type?
	 *
	 * @param string $type
	 *
	 * @return bool
	 */
	public function has_field_type( $type ) {
		return in_array( strtolower( $type ), $this->get_field_types(), true );
	}

	/**
	 * Get an array of field types which are present in this form.
	 *
	 * @return array
	 */
	public function get_field_types() {
		preg_match_all( '/type=\"(\w+)?\"/', strtolower( $this->content ), $result );
		$field_types = $result[1];
		return $field_types;
	}

	/**
	* Add notice to this form when it is rendered
	* @param string $text
	* @param string $type
	*/
	public function add_notice( $text, $type = 'notice' ) {
		$this->notices[] = new MC4WP_Form_Notice( $text, $type );
	}

	/**
	 * Output this form
	 *
	 * @return string
	 */
	public function __toString() {
		return mc4wp_show_form( $this->ID, array(), false );
	}

	/**
	 * Get "redirect to url after success" setting for this form
	 *
	 * @return string
	 */
	public function get_redirect_url() {
		$form = $this;
		$url  = trim( $this->settings['redirect'] );

		/**
		 * Filters the redirect URL setting
		 *
		 * @since 3.0
		 *
		 * @param string $url
		 * @param MC4WP_Form $form
		 */
		$url = (string) apply_filters( 'mc4wp_form_redirect_url', $url, $form );
		return $url;
	}

	/**
	 * Is this form valid?
	 *
	 * Will always return true if the form is not yet submitted. Otherwise, it will run validation and store any errors.
	 * This method should be called before `get_errors()`
	 *
	 * @return bool
	 */
	public function validate() {
		if ( ! $this->is_submitted ) {
			return true;
		}

		$form   = $this;
		$errors = array();

		if ( empty( $this->config['lists'] ) ) {
			$errors[] = 'no_lists_selected';
		}

		if ( ! isset( $this->raw_data['_mc4wp_timestamp'] ) || $this->raw_data['_mc4wp_timestamp'] > ( time() - 2 ) ) {
			$errors[] = 'spam';
		} elseif ( ! isset( $this->raw_data['_mc4wp_honeypot'] ) || ! empty( $this->raw_data['_mc4wp_honeypot'] ) ) {
			$errors[] = 'spam';
		}

		if ( empty( $errors ) ) {
			// validate email field
			if ( empty( $this->data['EMAIL'] ) || ! is_email( $this->data['EMAIL'] ) ) {
				$errors[] = 'invalid_email';
			}

			// validate other required fields
			foreach ( $this->get_required_fields() as $field ) {
				$value = mc4wp_array_get( $this->data, $field );

				// check for empty string or array here instead of empty() since we want to allow for "0" values.
				if ( $value === '' || $value === array() ) {
					$errors[] = 'required_field_missing';
					break;
				}
			}
		}

		/**
		 * Filters whether this form has errors. Runs only when a form is submitted.
		 * Expects an array of message keys with an error type (string).
		 *
		 * Beware: all non-string values added to this array will be filtered out.
		 *
		 * @since 3.0
		 *
		 * @param array $errors
		 * @param MC4WP_Form $form
		 */
		$errors = (array) apply_filters( 'mc4wp_form_errors', $errors, $form );

		/**
		 * @ignore
		 * @deprecated 3.0 Use `mc4wp_form_errors` instead
		 */
		$form_validity = apply_filters( 'mc4wp_valid_form_request', true, $this->data );
		if ( is_string( $form_validity ) ) {
			$errors[] = $form_validity;
		}

		// filter out all non-string values
		$errors = array_filter( $errors, 'is_string' );

		// set property on self
		$this->errors = $errors;

		// return whether we have errors
		return ! $this->has_errors();
	}

	/**
	 * Handle an incoming request. Should be called before calling validate() method.
	 *
	 * @see MC4WP_Form::validate
	 * @param array $data
	 * @return void
	 */
	public function handle_request( array $data ) {
		$this->is_submitted = true;
		$this->raw_data     = $data;
		$this->data         = $this->parse_request_data( $data );
		$this->last_event   = '';

		// update form configuration from given data
		$config = array();
		$map    = array(
			'_mc4wp_lists'           => 'lists',
			'_mc4wp_action'          => 'action',
			'_mc4wp_form_element_id' => 'element_id',
			'_mc4wp_email_type'      => 'email_type',
		);

		// use isset here to allow empty lists (which should show a notice)
		foreach ( $map as $param_key => $config_key ) {
			if ( isset( $this->raw_data[ $param_key ] ) ) {
				$value = $this->raw_data[ $param_key ];
				if ( is_array( $value ) ) {
					$value = array_filter( $value );
				}

				$config[ $config_key ] = $value;
			}
		}

		if ( ! empty( $config ) ) {
			$this->set_config( $config );
		}
	}

	/**
	 * Parse a request for data which should be binded to `$data` property.
	 *
	 * This does the following on all post data.
	 *
	 * - Removes fields starting with an underscore.
	 * - Remove fields which are set to be ignored.
	 * - Uppercase all field names
	 *
	 * @param array $data
	 *
	 * @return array
	 */
	protected function parse_request_data( array $data ) {
		$form                = $this;
		$filtered            = array();
		$ignored_field_names = array();

		/**
		* Filters field names which should be ignored when showing data.
		*
		* @since 3.0
		*
		* @param array $ignored_field_names Array of ignored field names
		* @param MC4WP_Form $form The form instance.
		*/
		$ignored_field_names = apply_filters( 'mc4wp_form_ignored_field_names', $ignored_field_names, $form );

		foreach ( $data as $key => $value ) {
			// skip fields in ignored field names
			if ( $key[0] === '_' || in_array( $key, $ignored_field_names, true ) ) {
				continue;
			}

			// uppercase key
			$key = strtoupper( $key );

			// filter empty array values
			if ( is_array( $value ) ) {
				$value = array_filter( $value );
			}

			$filtered[ $key ] = $value;
		}

		return $filtered;
	}

	/**
	 * Update configuration for this form
	 *
	 * @param array $config
	 * @return array
	 */
	public function set_config( array $config ) {
		$this->config = array_merge( $this->config, $config );

		// make sure lists is an array
		if ( ! is_array( $this->config['lists'] ) ) {
			$this->config['lists'] = array_map( 'trim', explode( ',', $this->config['lists'] ) );
		}

		// make sure action is valid
		if ( ! in_array( $this->config['action'], array( 'subscribe', 'unsubscribe' ), true ) ) {
			$this->config['action'] = 'subscribe';
		}

		// email_type should be a valid value
		if ( ! in_array( $this->config['email_type'], array( 'html', 'text' ), true ) ) {
			$this->config['email_type'] = '';
		}

		return $this->config;
	}

	/**
	 * Get Mailchimp lists this form subscribes to
	 *
	 * @return array
	 */
	public function get_lists() {
		$lists = $this->config['lists'];
		$form  = $this;

		/**
		 * Filters Mailchimp lists new subscribers should be added to.
		 *
		 * @param array $lists
		 */
		$lists = (array) apply_filters( 'mc4wp_lists', $lists );

		/**
		 * Filters Mailchimp lists new subscribers coming from this form should be added to.
		 *
		 * @param array $lists
		 * @param MC4WP_Form $form
		 */
		$lists = (array) apply_filters( 'mc4wp_form_lists', $lists, $form );

		// filter out empty array elements
		$lists = array_filter( $lists );

		return $lists;
	}

	/**
	 * Does this form have errors?
	 *
	 * Should always evaluate to false when form has not been submitted.
	 *
	 * @see `mc4wp_form_errors` filter.
	 * @return bool
	 */
	public function has_errors() {
		return count( $this->errors ) > 0;
	}

	/**
	 * Add an error to this form
	 *
	 * @param string $error_code
	 */
	public function add_error( $error_code ) {
		// only add each error once
		if ( ! in_array( $error_code, $this->errors, true ) ) {
			$this->errors[] = $error_code;
		}
	}

	/**
	 * Get the form action
	 *
	 * Valid return values are "subscribe" and "unsubscribe"
	 *
	 * @return string
	 */
	public function get_action() {
		return $this->config['action'];
	}

	/**
	 * @return array
	 */
	public function get_data() {
		$data = $this->data;
		$form = $this;

		/**
		 * Filters the form data.
		 *
		 * @param array $data
		 * @param MC4WP_Form $form
		 */
		$data = apply_filters( 'mc4wp_form_data', $data, $form );

		return $data;
	}

	/**
	 * @return array
	 */
	public function get_raw_data() {
		return $this->raw_data;
	}

	/**
	 * Get array of name attributes for the required fields in this form.
	 *
	 * @return array
	 */
	public function get_required_fields() {
		$form = $this;

		// explode required fields (generated in JS) to an array (uppercased)
		$required_fields_string = strtoupper( $this->settings['required_fields'] );

		// remove array-formatted fields
		// workaround for #261 (https://github.com/ibericode/mailchimp-for-wordpress/issues/261)
		$required_fields_string = preg_replace( '/\[\w+\]/', '', $required_fields_string );

		// turn into an array
		$required_fields = explode( ',', $required_fields_string );

		// EMAIL is not a required field as it has its own validation rules
		$required_fields = array_diff( $required_fields, array( 'EMAIL' ) );

		// filter duplicate & empty values
		$required_fields = array_unique( $required_fields );
		$required_fields = array_filter( $required_fields );

		// fix uppercased subkeys, see https://github.com/ibericode/mailchimp-for-wordpress/issues/516
		foreach ( $required_fields as $key => $value ) {
			$pos = strpos( $value, '.' );
			if ( $pos > 0 ) {
				$required_fields[ $key ] = substr( $value, 0, $pos ) . strtolower( substr( $value, $pos ) );
			}
		}

		/**
		 * Filters the required fields for a form
		 *
		 * By default, this holds the following fields.
		 *
		 * - All fields which are required for the selected Mailchimp lists
		 * - All fields in the form with a `required` attribute.
		 *
		 * @param array $required_fields
		 * @param MC4WP_Form $form
		 */
		$required_fields = (array) apply_filters( 'mc4wp_form_required_fields', $required_fields, $form );

		return $required_fields;
	}

	/**
	 * Get "email_type" setting for new Mailchimp subscribers added by this form.
	 *
	 * @return string
	 */
	public function get_email_type() {
		$email_type = $this->config['email_type'];

		if ( empty( $email_type ) ) {
			$email_type = mc4wp_get_email_type();
		}

		return $email_type;
	}

	/**
	 * Gets the filename of the stylesheet to load for this form.
	 *
	 * @return string
	 */
	public function get_stylesheet() {
		$stylesheet = $this->settings['css'];

		if ( empty( $stylesheet ) ) {
			return '';
		}

		// form themes live in the same stylesheet
		if ( strpos( $stylesheet, 'theme-' ) !== false ) {
			$stylesheet = 'themes';
		}

		return $stylesheet;
	}

	/**
	* @param string $key
	* @return string
	*/
	public function get_message( $key ) {
		$message = isset( $this->messages[ $key ] ) ? $this->messages[ $key ] : $this->messages['error'];

		if ( $key === 'no_lists_selected' && current_user_can( 'manage_options' ) ) {
			$message .= sprintf( ' (<a href="%s">%s</a>)', mc4wp_get_edit_form_url( $this->ID, 'settings' ), 'edit form settings' );
		}

		return $message;
	}

	/**
	 * Get HTML string for a message, including wrapper element.
	 *
	 * @deprecated 3.1
	 *
	 * @param string $key
	 *
	 * @return string
	 */
	public function get_message_html( $key ) {
		_deprecated_function( __METHOD__, '3.2' );
		return '';
	}

	/**
	* Add a notice to this form
	*/
	public function add_message( $key ) {
		_deprecated_function( __METHOD__, '3.3' );
		$this->add_notice( $this->get_message( $key ) );
	}

	/**
	 * @since 4.4
	 * @return array
	 */
	public function get_subscriber_tags() {
		if ( empty( $this->settings['subscriber_tags'] ) ) {
			return array();
		}

		$tags = explode( ',', $this->settings['subscriber_tags'] );
		$tags = array_map( 'trim', $tags );

		// remove empty tag values
		foreach ( $tags as $i => $tag ) {
			if ( $tag === '' ) {
				unset( $tags[ $i ] );
			}
		}

		return array_values( $tags );
	}
}
