<?php
/**
 * Accessibility statement generator.
 *
 * This is the free hook: the European Accessibility Act requires a statement,
 * and the commercial plugins keep theirs behind a paywall. Here it stays free
 * and unlimited, because it costs nothing to produce and it earns the install.
 *
 * Deliberately avoided: "compliant", "certified", "prevents lawsuits".
 * The statement says "partially conformant" and lists what is still broken.
 *
 * @package Siftra
 */

if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

/**
 * Class Siftra_Statement
 */
class Siftra_Statement {

	/**
	 * Turn the latest scan into a plain list of known limitations.
	 *
	 * @param int $scan_id Scan id.
	 * @return array
	 */
	public static function known_issues_from_scan( $scan_id ) {
		$lines  = array();
		$counts = Siftra_DB::counts_by_rule( (int) $scan_id );
		$rules  = Siftra_Scanner::rules();

		foreach ( $rules as $key => $meta ) {
			if ( empty( $counts[ $key ] ) ) {
				continue;
			}
			$total = (int) $counts[ $key ]['total'];
			if ( $total < 1 ) {
				continue;
			}

			$line = $meta['label'] . ' (' . sprintf(
				/* translators: %d: number of findings. */
				_n( '%d instance', '%d instances', $total, 'siftra' ),
				$total
			) . ')';

			if ( '' !== $meta['wcag'] ) {
				$line .= ' — WCAG ' . $meta['wcag'];
			}

			$lines[] = $line;
		}

		return $lines;
	}

	/**
	 * Whether an address can actually receive a complaint.
	 *
	 * admin_email is not always a real inbox. A fresh install on a test host
	 * hands back admin@localhost.com or admin@example.com, and a statement
	 * that sends visitors to a dead address is worse than one that sends them
	 * nowhere: the visitor believes there is a feedback route and there is not.
	 *
	 * @param string $email Email address.
	 * @return bool
	 */
	public static function is_usable_email( $email ) {
		$email = trim( (string) $email );

		if ( '' === $email || ! is_email( $email ) ) {
			return false;
		}

		$parts = explode( '@', $email );
		$host  = strtolower( (string) end( $parts ) );

		/*
		 * Playground and several one-click installers ship admin@localhost.com,
		 * admin@localhost.localdomain and friends. They all start with
		 * "localhost": matching the bare word only was not enough, because
		 * localhost.com slipped straight through.
		 */
		if ( 0 === strpos( $host, 'localhost' ) || false !== strpos( $host, '.localhost' ) ) {
			return false;
		}

		$placeholders = array( 'example.com', 'example.org', 'example.net', 'example.edu' );
		if ( in_array( $host, $placeholders, true ) ) {
			return false;
		}

		foreach ( array( '.local', '.test', '.invalid', '.example', '.localhost', '.localdomain' ) as $suffix ) {
			if ( substr( $host, -strlen( $suffix ) ) === $suffix ) {
				return false;
			}
		}

		return true;
	}

	/**
	 * Build the statement text.
	 *
	 * @param array $args Inputs from the form.
	 * @return string
	 */
	public static function build( $args ) {
		$defaults = array(
			'org'             => get_bloginfo( 'name' ),
			'site'            => home_url( '/' ),
			'email'           => get_option( 'admin_email' ),
			'phone'           => '',
			'standard'        => 'WCAG 2.1 level AA',
			'conformance'     => 'partially conformant',
			'date'            => date_i18n( get_option( 'date_format' ) ),
			'response_days'   => 5,
			'known_issues'    => array(),
			'manual'          => '',
			'scan_date'       => '',
			'pages_checked'   => 0,
			'pages_attempted' => 0,
		);

		$a = array_merge( $defaults, is_array( $args ) ? $args : array() );

		$org      = trim( (string) $a['org'] );
		$site     = trim( (string) $a['site'] );
		$email    = trim( (string) $a['email'] );
		$email_ok = self::is_usable_email( $email );
		$phone    = trim( (string) $a['phone'] );
		$date     = trim( (string) $a['date'] );
		$days     = max( 1, (int) $a['response_days'] );
		$issues   = is_array( $a['known_issues'] ) ? $a['known_issues'] : array();
		$manual   = trim( (string) $a['manual'] );

		$checked   = max( 0, (int) $a['pages_checked'] );
		$attempted = max( $checked, (int) $a['pages_attempted'] );

		if ( '' === $org ) {
			$org = get_bloginfo( 'name' );
		}

		// An empty field would otherwise leave a blank in the middle of a sentence.
		if ( '' === $site ) {
			$site = home_url( '/' );
		}

		if ( '' === $date ) {
			$date = date_i18n( get_option( 'date_format' ) );
		}

		$conformance = (string) $a['conformance'];
		if ( ! in_array( $conformance, array( 'fully conformant', 'partially conformant', 'not conformant' ), true ) ) {
			$conformance = 'partially conformant';
		}

		$lines = array();

		$lines[] = 'Accessibility Statement for ' . $org;
		$lines[] = '';
		$lines[] = sprintf( 'This statement applies to %1$s and was last reviewed on %2$s.', $site, $date );
		$lines[] = '';
		$lines[] = sprintf(
			'%1$s wants this website to be usable by as many people as possible, including people who use screen readers, keyboard navigation, screen magnification, or speech input.',
			$org
		);
		$lines[] = '';

		$lines[] = 'Conformance status';
		$lines[] = sprintf( 'This website is %1$s with %2$s.', $conformance, $a['standard'] );
		if ( 'partially conformant' === $conformance ) {
			$lines[] = '"Partially conformant" means that some parts of the content do not fully meet the standard. The known gaps are listed below.';
		} elseif ( 'not conformant' === $conformance ) {
			$lines[] = '"Not conformant" means that the content does not meet the standard yet. The known gaps are listed below.';
		}
		$lines[] = '';

		$lines[] = 'Known limitations';
		if ( empty( $issues ) ) {
			if ( $checked > 0 ) {
				$lines[] = 'We are not aware of any known limitations at this time.';
			} else {
				$lines[] = 'This site has not been assessed yet, so no limitations can be listed here.';
			}
		} else {
			foreach ( $issues as $issue ) {
				$issue = trim( (string) $issue );
				if ( '' !== $issue ) {
					$lines[] = '- ' . $issue;
				}
			}
		}
		$lines[] = '';
		$lines[] = 'These findings come from automated testing, which can detect only a share of accessibility problems. This list is therefore not a complete picture of the site.';

		if ( $checked > 0 ) {
			if ( $attempted > $checked ) {
				$lines[] = sprintf(
					'The scan read %1$d of %2$d pages; the remaining %3$d could not be fetched and were not checked.',
					$checked,
					$attempted,
					$attempted - $checked
				);
			} else {
				$lines[] = sprintf( 'The scan read %d pages.', $checked );
			}
		}
		$lines[] = '';

		$lines[] = 'Feedback';
		if ( $email_ok ) {
			$contact = 'If you meet a barrier on this site, please tell us at ' . $email . '.';
			if ( '' !== $phone ) {
				$contact .= ' You can also call ' . $phone . '.';
			}
			$lines[] = $contact;
		} elseif ( '' !== $phone ) {
			$lines[] = 'If you meet a barrier on this site, please call ' . $phone . '.';
		} else {
			$lines[] = 'If you meet a barrier on this site, please use the contact details on our contact page so that we can fix it.';
		}
		$lines[] = sprintf( 'We aim to reply within %d business days.', $days );
		$lines[] = '';

		$lines[] = 'Assessment approach';
		if ( '' !== $manual ) {
			$lines[] = $org . ' assessed this website with automated scanning plus manual checks: ' . $manual;
		} else {
			$lines[] = $org . ' assessed this website with automated scanning. Manual testing has not been carried out yet.';
		}
		$lines[] = '';

		$lines[] = 'Enforcement procedure';
		$lines[] = 'If you are not satisfied with our response, you can contact the authority responsible for accessibility in your country.';
		$lines[] = '';

		$lines[] = 'Date of this statement: ' . $date;
		$lines[] = 'Created with Siftra, the free accessibility statement generator.';

		return implode( "\n", $lines );
	}
}