<?php
/**
 * Export ALPEG Forms templates to a file and import them on another website.
 *
 * @package ALPEG\Forms
 */

namespace ALPEG\Forms\Admin;

use ALPEG\Forms\Fields;

defined( 'ABSPATH' ) || exit;

/**
 * Templates are unsynced patterns that contain an "ALPEG Form" block.
 * The export file is plain JSON: title + block attributes. On import every
 * value is validated again exactly like a form saved in the editor.
 */
class Template_Transfer {

	const FORMAT = 'alpeg-forms-templates';

	/**
	 * Largest accepted import file (bytes).
	 */
	const MAX_BYTES = 1048576;

	/**
	 * Saved templates (patterns containing the block).
	 *
	 * @return array[] id, title, attributes.
	 */
	public static function templates() {
		$posts = get_posts(
			array(
				'post_type'      => 'wp_block',
				'post_status'    => 'publish',
				'posts_per_page' => 200,
				'orderby'        => 'title',
				'order'          => 'ASC',
				's'              => 'wp:alpeg-forms/form',
			)
		);
		$out = array();
		foreach ( $posts as $post ) {
			foreach ( parse_blocks( $post->post_content ) as $block ) {
				if ( 'alpeg-forms/form' === $block['blockName'] ) {
					$out[] = array(
						'id'         => (int) $post->ID,
						'title'      => $post->post_title,
						'attributes' => (array) $block['attrs'],
					);
					break;
				}
			}
		}
		return $out;
	}

	/**
	 * Download the selected templates as a JSON file (admin-post).
	 */
	public static function export() {
		if ( ! current_user_can( 'manage_options' ) ) {
			wp_die( esc_html__( 'You are not allowed to do this.', 'alpeg-forms' ), 403 );
		}
		check_admin_referer( 'alpeg_forms_template_export' );
		$wanted = isset( $_POST['af_templates'] ) ? array_map( 'absint', (array) wp_unslash( $_POST['af_templates'] ) ) : array();
		$items  = array();
		foreach ( self::templates() as $t ) {
			if ( in_array( $t['id'], $wanted, true ) ) {
				$attrs = $t['attributes'];
				// A new form ID is created on the target site; recipients belong to this website only.
				unset( $attrs['formId'], $attrs['notifyEmail'] );
				$items[] = array(
					'title'      => $t['title'],
					'attributes' => $attrs,
				);
			}
		}
		if ( ! $items ) {
			wp_safe_redirect( admin_url( 'admin.php?page=alpeg-forms-import#templates' ) );
			exit;
		}
		$json = wp_json_encode(
			array(
				'format'    => self::FORMAT,
				'version'   => 1,
				'plugin'    => ALPEG_FORMS_VERSION,
				'exported'  => gmdate( 'c' ),
				'templates' => $items,
			),
			JSON_PRETTY_PRINT | JSON_UNESCAPED_UNICODE | JSON_UNESCAPED_SLASHES
		);
		nocache_headers();
		header( 'Content-Type: application/json; charset=utf-8' );
		header( 'Content-Disposition: attachment; filename="alpeg-forms-templates-' . gmdate( 'Y-m-d' ) . '.json"' );
		header( 'X-Content-Type-Options: nosniff' );
		echo $json; // phpcs:ignore WordPress.Security.EscapeOutput.OutputNotEscaped -- JSON file download.
		exit;
	}

	/**
	 * Import templates from an uploaded JSON file (admin-post).
	 */
	public static function import() {
		if ( ! current_user_can( 'manage_options' ) ) {
			wp_die( esc_html__( 'You are not allowed to do this.', 'alpeg-forms' ), 403 );
		}
		check_admin_referer( 'alpeg_forms_template_import' );
		$result = self::import_file( isset( $_FILES['af_template_file'] ) ? $_FILES['af_template_file'] : array() ); // phpcs:ignore WordPress.Security.ValidatedSanitizedInput -- Validated in import_file().
		set_transient( 'alpeg_forms_template_notice_' . get_current_user_id(), $result, 60 );
		wp_safe_redirect( admin_url( 'admin.php?page=alpeg-forms-import#templates' ) );
		exit;
	}

	/**
	 * Read and validate an uploaded file.
	 *
	 * @param array $file Entry from $_FILES.
	 * @return array done (titles), error (message).
	 */
	public static function import_file( $file ) {
		$fail = static function ( $msg ) {
			return array(
				'done'  => array(),
				'error' => $msg,
			);
		};
		if ( empty( $file['tmp_name'] ) || ! empty( $file['error'] ) || ! is_uploaded_file( $file['tmp_name'] ) ) {
			return $fail( __( 'Please choose a template file.', 'alpeg-forms' ) );
		}
		if ( (int) $file['size'] > self::MAX_BYTES ) {
			return $fail( __( 'The file is too large for a template file.', 'alpeg-forms' ) );
		}
		$data = json_decode( (string) file_get_contents( $file['tmp_name'] ), true ); // phpcs:ignore WordPress.WP.AlternativeFunctions.file_get_contents_file_get_contents -- Local temporary upload.
		return self::import_data( $data );
	}

	/**
	 * Create templates from decoded file data.
	 *
	 * @param mixed $data Decoded JSON.
	 * @return array done (titles), error (message).
	 */
	public static function import_data( $data ) {
		if ( ! is_array( $data ) || ! isset( $data['format'] ) || self::FORMAT !== $data['format'] || empty( $data['templates'] ) || ! is_array( $data['templates'] ) ) {
			return array(
				'done'  => array(),
				'error' => __( 'This is not an ALPEG Forms template file.', 'alpeg-forms' ),
			);
		}
		$done = array();
		foreach ( array_slice( $data['templates'], 0, 50 ) as $t ) {
			if ( ! is_array( $t ) || empty( $t['attributes'] ) || ! is_array( $t['attributes'] ) ) {
				continue;
			}
			$attrs = self::clean_attributes( $t['attributes'] );
			if ( ! $attrs['fields'] ) {
				continue;
			}
			$title = sanitize_text_field( isset( $t['title'] ) && is_scalar( $t['title'] ) ? $t['title'] : '' );
			$title = '' !== $title ? $title : __( 'Imported form', 'alpeg-forms' );
			$id    = wp_insert_post(
				array(
					'post_type'    => 'wp_block',
					'post_status'  => 'publish',
					'post_title'   => $title,
					'post_content' => wp_slash( '<!-- wp:alpeg-forms/form ' . serialize_block_attributes( $attrs ) . ' /-->' ),
				),
				true
			);
			if ( ! is_wp_error( $id ) ) {
				update_post_meta( $id, 'wp_pattern_sync_status', 'unsynced' );
				$done[] = $title;
			}
		}
		return array(
			'done'  => $done,
			'error' => $done ? '' : __( 'The file does not contain any usable form.', 'alpeg-forms' ),
		);
	}

	/**
	 * Only known block attributes, each validated.
	 *
	 * @param array $in Attributes from the file.
	 * @return array
	 */
	private static function clean_attributes( array $in ) {
		$out    = array( 'fields' => Fields::normalize( isset( $in['fields'] ) && is_array( $in['fields'] ) ? $in['fields'] : array() ) );
		$texts  = array( 'formTitle', 'submitLabel', 'notifySubject', 'confirmationSubject', 'firstStepTitle' );
		$areas  = array( 'successMessage', 'confirmationMessage' );
		$bools  = array( 'sendConfirmation', 'attachFiles' );
		foreach ( $texts as $k ) {
			if ( isset( $in[ $k ] ) && is_scalar( $in[ $k ] ) ) {
				$out[ $k ] = sanitize_text_field( (string) $in[ $k ] );
			}
		}
		foreach ( $areas as $k ) {
			if ( isset( $in[ $k ] ) && is_scalar( $in[ $k ] ) ) {
				$out[ $k ] = sanitize_textarea_field( (string) $in[ $k ] );
			}
		}
		foreach ( $bools as $k ) {
			if ( isset( $in[ $k ] ) ) {
				$out[ $k ] = (bool) $in[ $k ];
			}
		}
		if ( isset( $in['accentColor'] ) && is_string( $in['accentColor'] ) && sanitize_hex_color( $in['accentColor'] ) ) {
			$out['accentColor'] = sanitize_hex_color( $in['accentColor'] );
		}
		// The recipient address is deliberately not taken over: it belongs to the source website.
		return $out;
	}

	/**
	 * Section on the import page.
	 */
	public static function render() {
		$notice    = get_transient( 'alpeg_forms_template_notice_' . get_current_user_id() );
		delete_transient( 'alpeg_forms_template_notice_' . get_current_user_id() );
		$templates = self::templates();
		?>
		<h2 id="templates"><?php esc_html_e( 'Share templates between websites', 'alpeg-forms' ); ?></h2>
		<?php if ( is_array( $notice ) ) : ?>
			<?php if ( $notice['done'] ) : ?>
				<div class="notice notice-success is-dismissible"><p>
					<?php
					/* translators: %s: list of template titles */
					echo esc_html( sprintf( __( 'Templates added: %s. You will find them under "My templates" when inserting an "ALPEG Form" block.', 'alpeg-forms' ), implode( ', ', $notice['done'] ) ) );
					?>
				</p></div>
			<?php endif; ?>
			<?php if ( ! empty( $notice['error'] ) ) : ?>
				<div class="notice notice-error"><p><?php echo esc_html( $notice['error'] ); ?></p></div>
			<?php endif; ?>
		<?php endif; ?>
		<p class="alpeg-lead"><?php esc_html_e( 'Export your saved templates as a file and import them on another website – handy for agencies and for moving from a staging site. Recipient addresses are not included in the file.', 'alpeg-forms' ); ?></p>
		<div class="alpeg-columns">
			<div class="alpeg-card">
				<h3><?php esc_html_e( 'Export', 'alpeg-forms' ); ?></h3>
				<?php if ( ! $templates ) : ?>
					<p class="alpeg-muted"><?php esc_html_e( 'No saved templates yet. In the editor, select an ALPEG Form block and click "Save as template".', 'alpeg-forms' ); ?></p>
				<?php else : ?>
					<form method="post" action="<?php echo esc_url( admin_url( 'admin-post.php' ) ); ?>">
						<?php wp_nonce_field( 'alpeg_forms_template_export' ); ?>
						<input type="hidden" name="action" value="alpeg_forms_template_export">
						<fieldset>
							<legend class="screen-reader-text"><?php esc_html_e( 'Templates to export', 'alpeg-forms' ); ?></legend>
							<?php foreach ( $templates as $t ) : ?>
								<label class="alpeg-check"><input type="checkbox" name="af_templates[]" value="<?php echo esc_attr( $t['id'] ); ?>" checked> <?php echo esc_html( $t['title'] ); ?></label>
							<?php endforeach; ?>
						</fieldset>
						<?php submit_button( __( 'Download template file', 'alpeg-forms' ), 'secondary', 'submit', false ); ?>
					</form>
				<?php endif; ?>
			</div>
			<div class="alpeg-card">
				<h3><?php esc_html_e( 'Import', 'alpeg-forms' ); ?></h3>
				<form method="post" enctype="multipart/form-data" action="<?php echo esc_url( admin_url( 'admin-post.php' ) ); ?>">
					<?php wp_nonce_field( 'alpeg_forms_template_import' ); ?>
					<input type="hidden" name="action" value="alpeg_forms_template_import">
					<p>
						<label for="af-template-file"><?php esc_html_e( 'Template file (.json)', 'alpeg-forms' ); ?></label><br>
						<input type="file" id="af-template-file" name="af_template_file" accept=".json,application/json" required>
					</p>
					<?php submit_button( __( 'Import templates', 'alpeg-forms' ), 'secondary', 'submit', false ); ?>
				</form>
			</div>
		</div>
		<?php
	}
}