<?php
/**
 * Tools → Email Log.
 *
 * @package Adminkeep
 */

namespace Adminkeep\Admin;

use Adminkeep\Feature\EmailLog;
use Adminkeep\Service\EmailLogImporter;
use Adminkeep\Service\EmailLogImport\Source;
use Adminkeep\Service\EmailLogStore;
use Adminkeep\Settings;

defined( 'ABSPATH' ) || exit;

/**
 * Tools → Email Log. Exists only while the feature is on.
 *
 * The log is reachable through this page and WP-CLI and nothing else: no REST route, no AJAX
 * action. The preview is this same page with `?preview=`, behind the same capability and a
 * nonce.
 */
class EmailLogScreen {

	/**
	 * Page slug.
	 */
	const PAGE = 'adminkeep-email-log';

	/**
	 * Capability for the page and for deleting.
	 */
	const CAPABILITY = 'manage_options';

	/**
	 * Nonce action shared by both forms on the page.
	 */
	const NONCE = 'adminkeep_email_log';

	/**
	 * Field name for this screen's own nonce. Not the default `_wpnonce`: the bulk-delete form
	 * also holds core's `WP_List_Table::display_tablenav()`, which prints its own nonce field
	 * named `_wpnonce`. Two fields with the same name in one form collide — the browser submits
	 * both and PHP keeps only the last — so this screen's nonce needs a name of its own.
	 */
	const NONCE_FIELD = '_adminkeep_email_log_nonce';

	/**
	 * Hidden field marking a form on this page as one of ours, and which action it asks for.
	 */
	const ACTION_FIELD = 'adminkeep_email_log_action';

	/**
	 * Query flag the delete redirect carries: how many rows it removed.
	 */
	const DONE_ARG = 'adminkeep_deleted';

	/**
	 * Query flag the import redirect carries: imported, skipped as too old, left out because the
	 * log is full, and failed, joined with dashes.
	 */
	const IMPORT_ARG = 'adminkeep_imported';

	/**
	 * The import source the button copies from, by its EmailLogImporter::sources() name.
	 */
	const IMPORT_SOURCE = 'email-log';

	/**
	 * Id of the GET form that filters and searches. The filter controls live inside the table's
	 * POST form and join this one through their form attribute.
	 */
	const FILTER_FORM = 'adminkeep-email-log-filters';

	/**
	 * Hook suffix of the registered page.
	 *
	 * @var string
	 */
	private $hook = '';

	/**
	 * URL of the screen.
	 *
	 * @return string
	 */
	public static function url() {
		return admin_url( 'tools.php?page=' . self::PAGE );
	}

	/**
	 * Register hooks.
	 *
	 * @return void
	 */
	public function boot() {
		add_action( 'admin_menu', array( $this, 'register_page' ) );
		add_action( 'admin_init', array( $this, 'handle_action' ), 10, 0 );
		add_action( 'admin_enqueue_scripts', array( $this, 'enqueue_assets' ) );
		add_filter( 'removable_query_args', array( $this, 'removable_query_args' ) );
	}

	/**
	 * Let WordPress strip the "N entries deleted" flag out of the address bar.
	 *
	 * The list table builds its pagination, sort and filter links from the current URL, so without
	 * this the notice follows the administrator around the log long after the delete it reported.
	 *
	 * @param array $args Query arguments WordPress removes after the page has loaded.
	 * @return array
	 */
	public function removable_query_args( $args ) {
		$args[] = self::DONE_ARG;
		$args[] = self::IMPORT_ARG;

		return $args;
	}

	/**
	 * Add the page under Tools.
	 *
	 * @return void
	 */
	public function register_page() {
		$this->hook = (string) add_management_page( __( 'Email Log', 'adminkeep' ), __( 'Email Log', 'adminkeep' ), self::CAPABILITY, self::PAGE, array( $this, 'render' ) );

		// The preview document is this screen's own URL with ?preview=, answered before the admin
		// header prints. load-{hook} fires only for this page and only once the user may see it.
		if ( '' !== $this->hook ) {
			add_action( 'load-' . $this->hook, array( $this, 'maybe_preview' ) );
			add_action( 'load-' . $this->hook, array( $this, 'register_columns' ) );
		}
	}

	/**
	 * Screen Options: a show/hide checkbox for every column but Subject, with From off until
	 * someone turns it on. WordPress builds the panel before the table exists, from these filters;
	 * it stores and applies each user's choice itself.
	 *
	 * @return void
	 */
	public function register_columns() {
		$screen = get_current_screen();

		if ( null === $screen ) {
			return;
		}

		add_filter(
			'manage_' . $screen->id . '_columns',
			static function () {
				// Subject opens the preview and is what stays on a narrow screen, so it is not
				// offered for hiding at all.
				return array_diff_key( EmailLogTable::columns(), array( 'subject' => true ) );
			}
		);

		add_filter(
			'default_hidden_columns',
			static function ( $hidden, $for ) use ( $screen ) {
				return $for->id === $screen->id ? array( 'from_email' ) : $hidden;
			},
			10,
			2
		);
	}

	/**
	 * The badge and modal styles and the modal script. Scoped to this screen's hook suffix, the
	 * same way SmtpScreen scopes its own.
	 *
	 * @param string $hook_suffix Current admin page.
	 * @return void
	 */
	public function enqueue_assets( $hook_suffix ) {
		if ( '' === $this->hook || $hook_suffix !== $this->hook ) {
			return;
		}

		wp_enqueue_style( 'adminkeep-email-log', ADMINKEEP_URL . 'assets/css/email-log.css', array( 'dashicons' ), \Adminkeep\Assets::version( 'assets/css/email-log.css' ) );
		wp_enqueue_script( 'adminkeep-email-log', ADMINKEEP_URL . 'assets/js/email-log.js', array(), \Adminkeep\Assets::version( 'assets/js/email-log.js' ), true );
	}

	/**
	 * House shape: marker field, capability, nonce, work, redirect.
	 *
	 * @return void
	 */
	public function handle_action() {
		if ( ! isset( $_POST[ self::ACTION_FIELD ] ) ) { // phpcs:ignore WordPress.Security.NonceVerification.Missing -- Checked below, after the cheap bail.
			return;
		}

		if ( ! current_user_can( self::CAPABILITY ) ) {
			wp_die( esc_html__( 'Sorry, you are not allowed to manage the email log.', 'adminkeep' ), '', 403 );
		}

		check_admin_referer( self::NONCE, self::NONCE_FIELD );

		$action  = sanitize_key( wp_unslash( (string) $_POST[ self::ACTION_FIELD ] ) );
		$deleted = 0;

		if ( 'import' === $action ) {
			$this->handle_import();
		}

		// The list table posts its dropdown as `action` (top) or `action2` (bottom). "Apply" with
		// nothing chosen posts -1 in both, and must delete nothing.
		$bulk = array(
			isset( $_POST['action'] ) ? sanitize_key( wp_unslash( (string) $_POST['action'] ) ) : '',
			isset( $_POST['action2'] ) ? sanitize_key( wp_unslash( (string) $_POST['action2'] ) ) : '',
		);

		if ( 'delete_all' === $action ) {
			$deleted = EmailLogStore::delete_all();
		} elseif ( 'delete' === $action && in_array( 'delete', $bulk, true ) && isset( $_POST['email_log'] ) && is_array( $_POST['email_log'] ) ) {
			$deleted = EmailLogStore::delete( array_map( 'absint', wp_unslash( $_POST['email_log'] ) ) );
		}

		wp_safe_redirect( add_query_arg( self::DONE_ARG, $deleted, self::url() ) );
		exit;
	}

	/**
	 * Run the import the button asks for, then redirect with its counts. Nothing is imported
	 * unless the button would be showing: a stale form posted after the Email Log plugin was
	 * deactivated just comes back to the log.
	 *
	 * @return void
	 */
	private function handle_import() {
		$source = $this->import_source();

		if ( null === $source ) {
			wp_safe_redirect( self::url() );
			exit;
		}

		$result = ( new EmailLogImporter() )->run( $source, false );
		$counts = array( $result['imported'], $result['skipped_old'], $result['left_full'], $result['failed'] );

		wp_safe_redirect( add_query_arg( self::IMPORT_ARG, implode( '-', $counts ), self::url() ) );
		exit;
	}

	/**
	 * Whether the Email Log plugin (wordpress.org/plugins/email-log) is running on this site. Its
	 * main file defines EMAIL_LOG_FILE, which holds whatever folder the plugin was installed in.
	 * Its own method so a test can say yes: a real constant could never be undefined again.
	 *
	 * @return bool
	 */
	protected function email_log_plugin_active() {
		return defined( 'EMAIL_LOG_FILE' );
	}

	/**
	 * The source the button copies from, or null when there should be no button: the Email Log
	 * plugin is not active, or its table is missing or not the shape the importer reads.
	 *
	 * @return Source|null
	 */
	private function import_source() {
		if ( ! $this->email_log_plugin_active() ) {
			return null;
		}

		$sources = EmailLogImporter::sources();
		$source  = $sources[ self::IMPORT_SOURCE ];

		return $source->available() ? $source : null;
	}

	/**
	 * Serve one email's preview document, when asked for one.
	 *
	 * A plain page load with a nonce, not an AJAX action or a REST route: the log keeps its single
	 * guarded way in. Capability first, then the nonce, then the row.
	 *
	 * @return void
	 */
	public function maybe_preview() {
		if ( ! isset( $_GET['preview'] ) ) { // phpcs:ignore WordPress.Security.NonceVerification.Recommended -- Checked below, after the cheap bail.
			return;
		}

		if ( ! current_user_can( self::CAPABILITY ) ) {
			wp_die( esc_html__( 'Sorry, you are not allowed to view the email log.', 'adminkeep' ), '', 403 );
		}

		$nonce = isset( $_GET['_wpnonce'] ) ? sanitize_text_field( wp_unslash( (string) $_GET['_wpnonce'] ) ) : '';

		if ( ! wp_verify_nonce( $nonce, EmailLogPreview::NONCE ) ) {
			wp_die( esc_html__( 'This preview link has expired. Reload the email log and try again.', 'adminkeep' ), '', 403 );
		}

		$row = EmailLogStore::get( absint( $_GET['preview'] ) );

		if ( null === $row ) {
			wp_die( esc_html__( 'That email is no longer in the log.', 'adminkeep' ), '', 404 );
		}

		$view = isset( $_GET['view'] ) && in_array( $_GET['view'], array( 'text', 'source' ), true ) ? ( 'text' === $_GET['view'] ? 'text' : 'source' ) : 'preview';

		$this->emit( EmailLogPreview::headers(), EmailLogPreview::document( $row, $view ) );
	}

	/**
	 * Send the document and stop. Its own method so tests can capture it instead of exiting.
	 *
	 * @param string[] $headers Header lines.
	 * @param string   $body    Document.
	 * @return void
	 */
	protected function emit( array $headers, $body ) {
		nocache_headers();

		foreach ( $headers as $header ) {
			header( $header );
		}

		echo $body; // phpcs:ignore WordPress.Security.EscapeOutput.OutputNotEscaped -- A standalone document under a CSP sandbox; EmailLogPreview::document() escapes everything that is not the logged HTML itself.
		exit;
	}

	/**
	 * Render the screen.
	 *
	 * @return void
	 */
	public function render() {
		if ( ! current_user_can( self::CAPABILITY ) ) {
			wp_die( esc_html__( 'Sorry, you are not allowed to view the email log.', 'adminkeep' ), '', 403 );
		}

		$table = new EmailLogTable();
		$table->prepare_items();

		echo '<div class="wrap"><h1>' . Brand::heading_mark() . esc_html__( 'Email Log', 'adminkeep' ) . '</h1>'; // phpcs:ignore WordPress.Security.EscapeOutput.OutputNotEscaped -- heading_mark() returns escaped markup.

		if ( isset( $_GET[ self::DONE_ARG ] ) ) { // phpcs:ignore WordPress.Security.NonceVerification.Recommended -- Read-only flag choosing a static notice.
			$count = absint( $_GET[ self::DONE_ARG ] ); // phpcs:ignore WordPress.Security.NonceVerification.Recommended

			/* translators: %d: number of log entries. */
			echo '<div class="notice notice-success inline"><p>' . esc_html( sprintf( _n( '%d entry deleted.', '%d entries deleted.', $count, 'adminkeep' ), $count ) ) . '</p></div>';
		}

		$source    = $this->import_source();
		$retention = EmailLog::resolve( Settings::get( 'email_log' ) )['retention_days'];

		$this->render_import_result( null !== $source, $retention );

		if ( null !== $source ) {
			$this->render_import_box( $retention );
		}

		// Filters and search read, so they travel by GET and can be bookmarked. Deleting writes, so
		// the table sits in its own POST form. One form for both would put the nonce in the URL.
		// The filters print inside the table's top bar (EmailLogTable::extra_tablenav()) and join
		// this form by its id.
		echo '<form method="get" id="' . esc_attr( self::FILTER_FORM ) . '"><input type="hidden" name="page" value="' . esc_attr( self::PAGE ) . '" />';
		$table->search_box( __( 'Search email', 'adminkeep' ), 'adminkeep-email-log' );
		echo '</form>';

		echo '<form method="post">';
		wp_nonce_field( self::NONCE, self::NONCE_FIELD );
		echo '<input type="hidden" name="' . esc_attr( self::ACTION_FIELD ) . '" value="delete" />';
		$table->display();
		echo '</form>';

		echo '<form method="post" onsubmit="return confirm(\'' . esc_js( __( 'Delete every entry in the email log?', 'adminkeep' ) ) . '\');">';
		wp_nonce_field( self::NONCE, self::NONCE_FIELD );
		echo '<input type="hidden" name="' . esc_attr( self::ACTION_FIELD ) . '" value="delete_all" />';
		submit_button( __( 'Delete all', 'adminkeep' ), 'delete', 'adminkeep_email_log_delete_all', false );
		echo '</form>';

		$this->render_dialog();

		echo '</div>';
	}

	/**
	 * The box offering to copy the Email Log plugin's log into this one. A form of its own, so
	 * pressing it never carries the table's bulk-delete fields along.
	 *
	 * @param int $retention Days the log keeps an email.
	 * @return void
	 */
	private function render_import_box( $retention ) {
		echo '<div class="notice notice-info inline adminkeep-email-log-import">';
		echo '<p><strong>' . esc_html__( 'The Email Log plugin is active.', 'adminkeep' ) . '</strong> ';
		echo esc_html(
			sprintf(
				/* translators: %d: number of days the email log keeps an entry. */
				_n(
					'Copy its log into this one. Emails older than %d day are skipped, as this log would already have deleted them, and sign-in links are removed. Running it again copies only new emails. The Email Log plugin\'s own log is not changed.',
					'Copy its log into this one. Emails older than %d days are skipped, as this log would already have deleted them, and sign-in links are removed. Running it again copies only new emails. The Email Log plugin\'s own log is not changed.',
					$retention,
					'adminkeep'
				),
				$retention
			)
		);
		echo '</p>';

		echo '<form method="post" id="adminkeep-email-log-import">';
		wp_nonce_field( self::NONCE, self::NONCE_FIELD );
		echo '<input type="hidden" name="' . esc_attr( self::ACTION_FIELD ) . '" value="import" />';
		submit_button( __( 'Copy from Email Log', 'adminkeep' ), 'secondary', 'adminkeep_email_log_import', false );
		echo '</form></div>';
	}

	/**
	 * What the last import did, read from the redirect's flag.
	 *
	 * @param bool $plugin_active Whether the Email Log plugin is still active.
	 * @param int  $retention     Days the log keeps an email.
	 * @return void
	 */
	private function render_import_result( $plugin_active, $retention ) {
		$flag = isset( $_GET[ self::IMPORT_ARG ] ) ? sanitize_text_field( wp_unslash( (string) $_GET[ self::IMPORT_ARG ] ) ) : ''; // phpcs:ignore WordPress.Security.NonceVerification.Recommended -- Read-only flag choosing a static notice.

		if ( ! preg_match( '/^(\d+)-(\d+)-(\d+)-(\d+)$/', $flag, $counts ) ) {
			return;
		}

		list( , $imported, $skipped, $full, $failed ) = array_map( 'intval', $counts );

		/* translators: %d: number of emails. */
		$parts = array( sprintf( _n( '%d email copied from Email Log.', '%d emails copied from Email Log.', $imported, 'adminkeep' ), $imported ) );

		if ( $skipped > 0 ) {
			/* translators: 1: number of emails, 2: number of days. */
			$parts[] = sprintf( _n( '%1$d older than %2$d days was skipped.', '%1$d older than %2$d days were skipped.', $skipped, 'adminkeep' ), $skipped, $retention );
		}

		if ( $full > 0 ) {
			/* translators: %d: number of emails. */
			$parts[] = sprintf( _n( '%d was left out because the log is full.', '%d were left out because the log is full.', $full, 'adminkeep' ), $full );
		}

		if ( $failed > 0 ) {
			/* translators: %d: number of emails. */
			$parts[] = sprintf( _n( '%d could not be saved.', '%d could not be saved.', $failed, 'adminkeep' ), $failed );
		}

		if ( $plugin_active ) {
			$parts[] = __( 'While both plugins are active, every email is logged twice, so you can deactivate Email Log now.', 'adminkeep' );
		}

		$class = $failed > 0 || $full > 0 ? 'notice-warning' : 'notice-success';

		echo '<div class="notice ' . esc_attr( $class ) . ' inline"><p>' . esc_html( implode( ' ', $parts ) ) . '</p></div>';
	}

	/**
	 * The preview dialog, printed once and filled by assets/js/email-log.js from the row clicked.
	 * Every label is here, translated; the script only ever sets textContent.
	 *
	 * @return void
	 */
	private function render_dialog() {
		$rows = array(
			'from'        => __( 'From', 'adminkeep' ),
			'to'          => __( 'To', 'adminkeep' ),
			'reply-to'    => __( 'Reply-To', 'adminkeep' ),
			'cc'          => __( 'Cc', 'adminkeep' ),
			'bcc'         => __( 'Bcc', 'adminkeep' ),
			'date'        => __( 'Date', 'adminkeep' ),
			'attachments' => __( 'Attachments', 'adminkeep' ),
		);

		echo '<dialog id="adminkeep-email-log-preview" class="adminkeep-email-preview" aria-labelledby="adminkeep-email-preview-title" data-no-subject="' . esc_attr__( '(no subject)', 'adminkeep' ) . '">';
		echo '<div class="adminkeep-email-preview__inner">';

		echo '<div class="adminkeep-email-preview__header">';
		echo '<h2 id="adminkeep-email-preview-title" data-field="subject"></h2>';
		echo '<span class="adminkeep-email-log-status" data-field="status"></span>';
		echo '<div class="adminkeep-email-preview__nav">';
		echo '<button type="button" class="button" data-action="prev" aria-label="' . esc_attr__( 'Previous email', 'adminkeep' ) . '">&lsaquo;</button>';
		echo '<button type="button" class="button" data-action="next" aria-label="' . esc_attr__( 'Next email', 'adminkeep' ) . '">&rsaquo;</button>';
		echo '<button type="button" class="adminkeep-email-preview__close" data-action="close" aria-label="' . esc_attr__( 'Close', 'adminkeep' ) . '"><span class="dashicons dashicons-no-alt" aria-hidden="true"></span></button>';
		echo '</div></div>';

		echo '<div class="adminkeep-email-preview__error" data-field="error" hidden><strong>' . esc_html__( 'Error', 'adminkeep' ) . ':</strong> <span></span></div>';

		echo '<dl class="adminkeep-email-preview__meta">';
		foreach ( $rows as $key => $label ) {
			printf( '<div data-row="%1$s" hidden><dt>%2$s</dt><dd data-field="%1$s"></dd></div>', esc_attr( $key ), esc_html( $label ) );
		}
		echo '</dl>';

		echo '<div class="adminkeep-email-preview__tabs" role="tablist">';
		echo '<button type="button" role="tab" aria-selected="true" data-tab="preview" data-label-html="' . esc_attr__( 'HTML', 'adminkeep' ) . '" data-label-text="' . esc_attr__( 'Plain text', 'adminkeep' ) . '">' . esc_html__( 'HTML', 'adminkeep' ) . '</button>';
		echo '<button type="button" role="tab" aria-selected="false" data-tab="text" hidden>' . esc_html__( 'Plain text', 'adminkeep' ) . '</button>';
		echo '<button type="button" role="tab" aria-selected="false" data-tab="source">' . esc_html__( 'Source', 'adminkeep' ) . '</button>';
		echo '</div>';

		echo '<div class="adminkeep-email-preview__body">';
		echo '<div class="adminkeep-email-preview__loading"><span class="spinner is-active"></span>' . esc_html__( 'Loading email…', 'adminkeep' ) . '</div>';
		echo '<iframe data-pane="preview" title="' . esc_attr__( 'Email preview', 'adminkeep' ) . '" sandbox="" referrerpolicy="no-referrer"></iframe>';
		echo '<iframe data-pane="text" title="' . esc_attr__( 'Email plain text', 'adminkeep' ) . '" sandbox="" referrerpolicy="no-referrer" hidden></iframe>';
		echo '<iframe data-pane="source" title="' . esc_attr__( 'Email source', 'adminkeep' ) . '" sandbox="" referrerpolicy="no-referrer" hidden></iframe>';
		echo '</div>';

		echo '<p class="adminkeep-email-preview__note">' . esc_html__( 'Remote images are blocked in this preview.', 'adminkeep' ) . '</p>';
		echo '</div></dialog>';
	}
}