<?php
/**
 * Per-site delivery options: PDF attachment, secure link, review, incomplete reports.
 *
 * @package TurtleReport
 */

namespace TurtleReport\Policy;

defined( 'ABSPATH' ) || exit;

/**
 * Cleans and defaults a site's delivery settings.
 *
 * Incomplete reports are held for an administrator by default. PDF attachments
 * and plain-English highlights are included; public share links are opt-in.
 */
final class Options {

	const MODE_AUTO   = 'auto';
	const MODE_REVIEW = 'review';

	const INCOMPLETE_SEND = 'send';
	const INCOMPLETE_HOLD = 'hold';

	const MIN_LINK_DAYS     = 1;
	const MAX_LINK_DAYS     = 90;
	const DEFAULT_LINK_DAYS = 30;

	/**
	 * Settings for a new site and missing stored fields.
	 *
	 * @return array
	 */
	public static function defaults() {
		return array(
			'mode'       => self::MODE_AUTO,
			'attach_pdf' => true,
			'share_link' => false,
			'link_days'  => self::DEFAULT_LINK_DAYS,
			'incomplete' => self::INCOMPLETE_HOLD,
			'insights'   => true,
			'link_key'   => '',
		);
	}

	/**
	 * Cleans stored or posted options over a base.
	 *
	 * @param array      $raw  Stored or posted values.
	 * @param array|null $base Defaults for missing keys; defaults() when null.
	 * @return array
	 */
	public static function normalize( array $raw, $base = null ) {
		$base = is_array( $base ) ? $base : self::defaults();
		$get  = static function ( $key ) use ( $raw, $base ) {
			return array_key_exists( $key, $raw ) ? $raw[ $key ] : $base[ $key ];
		};
		$days = is_scalar( $get( 'link_days' ) ) ? (int) $get( 'link_days' ) : 0;
		$key  = is_string( $get( 'link_key' ) ) ? $get( 'link_key' ) : '';
		return array(
			'mode'       => self::MODE_REVIEW === $get( 'mode' ) ? self::MODE_REVIEW : self::MODE_AUTO,
			'attach_pdf' => is_scalar( $get( 'attach_pdf' ) ) && (bool) $get( 'attach_pdf' ),
			'share_link' => is_scalar( $get( 'share_link' ) ) && (bool) $get( 'share_link' ),
			'link_days'  => $days >= self::MIN_LINK_DAYS ? min( self::MAX_LINK_DAYS, $days ) : self::DEFAULT_LINK_DAYS,
			'incomplete' => self::INCOMPLETE_HOLD === $get( 'incomplete' ) ? self::INCOMPLETE_HOLD : self::INCOMPLETE_SEND,
			'insights'   => is_scalar( $get( 'insights' ) ) && (bool) $get( 'insights' ),
			'link_key'   => preg_match( '/^[A-Za-z0-9]{16,64}$/', $key ) ? $key : '',
		);
	}

	/**
	 * Reads posted checkbox-style values: an unticked box is absent from the form.
	 *
	 * @param array $posted  Posted delivery fields.
	 * @param array $current Current options (keeps the link key).
	 * @return array
	 */
	public static function from_form( array $posted, array $current ) {
		return self::normalize(
			array(
				'mode'       => isset( $posted['mode'] ) ? $posted['mode'] : self::MODE_AUTO,
				'attach_pdf' => ! empty( $posted['attach_pdf'] ) && is_scalar( $posted['attach_pdf'] ),
				'share_link' => ! empty( $posted['share_link'] ) && is_scalar( $posted['share_link'] ),
				'link_days'  => isset( $posted['link_days'] ) ? $posted['link_days'] : self::DEFAULT_LINK_DAYS,
				'incomplete' => isset( $posted['incomplete'] ) ? $posted['incomplete'] : self::INCOMPLETE_HOLD,
				'insights'   => ! empty( $posted['insights'] ) && is_scalar( $posted['insights'] ),
				'link_key'   => isset( $current['link_key'] ) ? $current['link_key'] : '',
			),
			$current
		);
	}

	/**
	 * A fresh secret used to sign this site's share links. Changing it revokes every
	 * link issued before.
	 *
	 * @return string
	 */
	public static function new_link_key() {
		return wp_generate_password( 32, false, false );
	}

	/**
	 * The signing key after a settings save. Turning links on (again), a missing key
	 * or "Revoke links" starts a new key, so links sent before can never come back.
	 *
	 * @param array $delivery      Normalised options from from_form().
	 * @param bool  $links_were_on Whether links were on before this save.
	 * @param bool  $revoke        Whether "Revoke links" was ticked.
	 * @return array
	 */
	public static function with_link_key( array $delivery, $links_were_on, $revoke ) {
		if ( $delivery['share_link'] && ( ! $links_were_on || '' === $delivery['link_key'] || $revoke ) ) {
			$delivery['link_key'] = self::new_link_key();
		} elseif ( $revoke ) {
			$delivery['link_key'] = '';
		}
		return $delivery;
	}
}