<?php
/**
 * The email notification when somebody sends a form.
 *
 * Without this a form is not usable on a live site, because nobody knows that
 * somebody wrote in until they open the dashboard themselves.
 *
 * The message goes out as a card with a coloured frame, and the same message in
 * plain text travels inside it for a reader that does not draw HTML. The owner
 * picks the colour of the frame and nothing else.
 *
 * 🔴 What a visitor typed NEVER becomes markup. Every answer goes through
 * `esc_html` in `Ranq_Forms_Notification_Template`, and the plain text version
 * carries no markup at all. That was the reason the first version was plain text
 * only, and the reason is answered here rather than avoided.
 *
 * Copyright (c) 2026 Quantum, Serbia. https://2ranq.com
 *
 * This program is free software: you can redistribute it and change it under
 * the terms of the GNU General Public License as published by the Free Software
 * Foundation, either version 2 of the License, or any later version. The full
 * text is in LICENSE.txt, next to this file.
 *
 * @package Ranq_Forms
 */

defined( 'ABSPATH' ) || exit;

/**
 * Ranq_Forms_Notifications
 */
class Ranq_Forms_Notifications {

	/**
	 * Hooks up.
	 *
	 * @return void
	 */
	public static function hooks() {

		add_action( 'ranq_forms_entry_saved', array( __CLASS__, 'send' ), 20, 3 );
	}

	/**
	 * Who the notification goes to.
	 *
	 * @param int $form_id The form id.
	 *
	 * @return array A list of addresses, which may be empty.
	 */
	private static function recipients( $form_id ) {

		$saved = Ranq_Forms_Form_Settings::value( $form_id, 'notify_to' );
		$raw   = is_string( $saved ) && '' !== trim( $saved )
			? $saved
			: (string) get_option( 'ranq_forms_notify_email', get_option( 'admin_email' ) );

		$list = array();

		foreach ( preg_split( '/[,;]/', $raw ) as $address ) {

			$address = sanitize_email( trim( $address ) );

			if ( is_email( $address ) ) {
				$list[] = $address;
			}
		}

		/**
		 * Who the notification about a new entry goes to.
		 *
		 * @param array $list    The addresses.
		 * @param int   $form_id The form id.
		 */
		return apply_filters( 'ranq_forms_notify_recipients', $list, $form_id );
	}

	/**
	 * Sends the notification.
	 *
	 * @param int   $entry_id The entry id.
	 * @param int   $form_id  The form id.
	 * @param array $values   The cleaned fields.
	 *
	 * @return void
	 */
	public static function send( $entry_id, $form_id, $values ) {

		$settings = Ranq_Forms_Form_Settings::get( $form_id );

		if ( ! $settings['notify_enabled'] ) {
			return;
		}

		$to = self::recipients( $form_id );

		// An empty address means the owner wants no notifications. A choice, not a bug.
		if ( ! $to ) {
			return;
		}

		$title = get_the_title( $form_id );
		$site  = wp_specialchars_decode( get_bloginfo( 'name' ), ENT_QUOTES );

		if ( '' !== $settings['notify_subject'] ) {

			$subject = str_replace(
				array( '{form_name}', '{site_name}' ),
				array( $title, $site ),
				$settings['notify_subject']
			);

		} else {

			$subject = sprintf(
				/* translators: 1: form name, 2: site name. */
				__( 'New entry: %1$s (%2$s)', '2ranq-forms' ),
				$title,
				$site
			);
		}

		// 🔴 A subject with a line break in it would let a second header be written
		// into the message. The saved setting is already cleaned, but the form name
		// and the site name come from elsewhere and reach it through the tags, so the
		// break is taken out here, at the last point before sending.
		$subject = self::one_line( $subject );

		$rows   = self::rows( $form_id, $values );
		$text   = self::body( $entry_id, $form_id, $values, $rows );
		$format = isset( $settings['notify_format'] ) ? $settings['notify_format'] : 'html';
		$html   = 'html' === $format ? self::html( $entry_id, $form_id, $rows, $values, $settings, $title, $site ) : '';

		/**
		 * The message headers.
		 *
		 * The sender address is deliberately NOT changed to the visitor's address.
		 * That would make the message fail the origin check and land in the spam
		 * folder. Instead, a reply goes to the visitor's address when they left one.
		 *
		 * @param array $headers The headers.
		 * @param int   $form_id The form id.
		 */
		$headers = apply_filters( 'ranq_forms_notify_headers', self::headers( $values, $settings, '' !== $html ), $form_id );

		if ( '' === $html ) {
			wp_mail( $to, $subject, $text, $headers );

			return;
		}

		// The plain text version travels inside the same message, for a reader that
		// does not draw HTML and for one that refuses to. `wp_mail` cannot carry two
		// bodies on its own, so it is handed to PHPMailer, and only for this send:
		// the listener is taken off the moment the message is out.
		$alternative = static function ( $phpmailer ) use ( $text ) {
			$phpmailer->AltBody = $text;
		};

		add_action( 'phpmailer_init', $alternative );

		wp_mail( $to, $subject, $html, $headers );

		remove_action( 'phpmailer_init', $alternative );
	}

	/**
	 * The message headers.
	 *
	 * @param array $values   The cleaned fields.
	 * @param array $settings The form settings.
	 * @param bool  $as_html  Whether the body is HTML.
	 *
	 * @return array
	 */
	private static function headers( $values, $settings, $as_html = false ) {

		$headers = array( 'Content-Type: ' . ( $as_html ? 'text/html' : 'text/plain' ) . '; charset=UTF-8' );

		$from_email = is_email( $settings['from_email'] ) ? sanitize_email( $settings['from_email'] ) : '';
		$from_name  = '' !== $settings['from_name'] ? self::one_line( $settings['from_name'] ) : '';

		if ( $from_email ) {
			$headers[] = $from_name
				? 'From: ' . $from_name . ' <' . $from_email . '>'
				: 'From: ' . $from_email;
		}

		if ( 'none' === $settings['reply_to'] ) {
			return $headers;
		}

		$reply = self::find_email( $values );

		if ( $reply ) {
			$headers[] = 'Reply-To: ' . $reply;
		}

		return $headers;
	}

	/**
	 * Takes the line breaks out of a string that goes into a header.
	 *
	 * A break in a header is not a cosmetic matter. Everything after it is read as
	 * a new header, so one break in a subject is enough to add a recipient nobody
	 * asked for.
	 *
	 * @param string $value The text.
	 *
	 * @return string
	 */
	private static function one_line( $value ) {

		return trim( preg_replace( '/[\r\n\t]+/', ' ', (string) $value ) );
	}

	/**
	 * Looks for an email address among the answers, so a reply takes one click.
	 *
	 * @param array $values The cleaned fields.
	 *
	 * @return string
	 */
	private static function find_email( $values ) {

		foreach ( $values as $value ) {

			if ( is_scalar( $value ) && is_email( (string) $value ) ) {
				return sanitize_email( (string) $value );
			}
		}

		return '';
	}

	/**
	 * The answers, as label and value pairs.
	 *
	 * Both shapes of the message are built out of this one list, so the card and
	 * the plain text can never say different things.
	 *
	 * @param int   $form_id The form id.
	 * @param array $values  The cleaned fields.
	 *
	 * @return array
	 */
	private static function rows( $form_id, $values ) {

		$rows = array();

		foreach ( Ranq_Forms_Fields::get_form_fields( $form_id ) as $field ) {

			$key    = isset( $field['id'] ) ? $field['id'] : '';
			$object = isset( $field['type'] ) ? Ranq_Forms_Fields::get( $field['type'] ) : null;

			if ( '' === $key || ! $object instanceof Ranq_Forms_Field || ! $object->is_input() ) {
				continue;
			}

			$rows[] = array(
				'label' => isset( $field['label'] ) && '' !== $field['label'] ? $field['label'] : $key,
				'value' => isset( $values[ $key ] ) ? (string) $object->format_value( $values[ $key ], $field ) : '',
			);
		}

		return $rows;
	}

	/**
	 * The address of this one entry in the dashboard.
	 *
	 * The link leads to the entry itself, not to the list, so the owner lands on
	 * the message they were told about. Attached files are opened from there and
	 * only from there: a file link carries a nonce tied to the person opening it,
	 * so a link made at sending time would be dead for the reader.
	 *
	 * @param int $form_id  The form id.
	 * @param int $entry_id The entry id.
	 *
	 * @return string
	 */
	private static function entry_url( $form_id, $entry_id ) {

		return admin_url(
			'admin.php?page=' . Ranq_Forms_Admin::PAGE_ENTRIES
			. '&form_id=' . absint( $form_id )
			. '&entry_id=' . absint( $entry_id )
		);
	}

	/**
	 * The card, as HTML.
	 *
	 * @param int    $entry_id The entry id.
	 * @param int    $form_id  The form id.
	 * @param array  $rows     The answers.
	 * @param array  $values   The cleaned fields.
	 * @param array  $settings The form settings.
	 * @param string $title    The form name.
	 * @param string $site     The site name.
	 *
	 * @return string
	 */
	private static function html( $entry_id, $form_id, $rows, $values, $settings, $title, $site ) {

		$html = Ranq_Forms_Notification_Template::render(
			array(
				'color'    => isset( $settings['notify_color'] ) ? $settings['notify_color'] : '',
				'title'    => $title,
				'site'     => $site,
				'date'     => wp_date( get_option( 'date_format' ) . ', ' . get_option( 'time_format' ) ),
				'rows'     => $rows,
				'url'      => self::entry_url( $form_id, $entry_id ),
				'entry_id' => $entry_id,
				'reply'    => 'none' === $settings['reply_to'] ? '' : self::find_email( $values ),
			)
		);

		/**
		 * The card, as HTML.
		 *
		 * @param string $html    The message.
		 * @param int    $form_id The form id.
		 * @param array  $rows    The answers, as label and value pairs.
		 */
		return apply_filters( 'ranq_forms_notify_html', $html, $form_id, $rows );
	}

	/**
	 * The body of the message, as plain text.
	 *
	 * @param int   $entry_id The entry id.
	 * @param int   $form_id  The form id.
	 * @param array $values   The cleaned fields.
	 * @param array $rows     The answers. Built here when not handed in.
	 *
	 * @return string
	 */
	private static function body( $entry_id, $form_id, $values, $rows = null ) {

		$rows  = is_array( $rows ) ? $rows : self::rows( $form_id, $values );
		$lines = array();

		foreach ( $rows as $row ) {
			$lines[] = $row['label'];
			$lines[] = '' === trim( $row['value'] ) ? '—' : $row['value'];
			$lines[] = '';
		}

		$lines[] = str_repeat( '-', 40 );
		$lines[] = sprintf(
			/* translators: %s: form name. */
			__( 'Form: %s', '2ranq-forms' ),
			get_the_title( $form_id )
		);
		$lines[] = sprintf(
			/* translators: %s: link to this entry in the dashboard. */
			__( 'Open this entry: %s', '2ranq-forms' ),
			self::entry_url( $form_id, $entry_id )
		);
		$lines[] = sprintf(
			/* translators: %d: entry number. */
			__( 'Entry number: %d', '2ranq-forms' ),
			absint( $entry_id )
		);

		/**
		 * The body of the message.
		 *
		 * @param string $body    The text.
		 * @param int    $form_id The form id.
		 * @param array  $values  The cleaned fields.
		 */
		return apply_filters( 'ranq_forms_notify_body', implode( "\n", $lines ), $form_id, $values );
	}
}