<?php
/**
 * Mailer — renders an HTML email template with the transition context and sends it.
 * Never blocks a transition: failures are logged, not thrown.
 *
 * @package OST\EditorialWorkflow
 */

namespace OST\EditorialWorkflow\Notifications;

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

/**
 * Sends templated workflow emails.
 */
class Mailer {

	/**
	 * Subject formats per template.
	 *
	 * @return array
	 */
	private function subject_formats() {
		return array(
			/* translators: %s: post title. */
			'review_request'      => __( '[Review required] %s', 'ost-editorial-workflow' ),
			/* translators: %s: post title. */
			'published'           => __( '[Published] %s', 'ost-editorial-workflow' ),
			/* translators: %s: post title. */
			'sent_back'           => __( '[Sent back] %s', 'ost-editorial-workflow' ),
			/* translators: %s: post title. */
			'escalation_reminder' => __( '[Review reminder] %s', 'ost-editorial-workflow' ),
			/* translators: %s: post title. */
			'escalation_notice'   => __( '[Escalation] %s', 'ost-editorial-workflow' ),
		);
	}

	/**
	 * Send a workflow email.
	 *
	 * @param string   $template Template slug.
	 * @param \WP_User $user     Recipient.
	 * @param array    $vars     Merge variables.
	 * @return bool
	 */
	public function send( $template, $user, array $vars ) {
		$opts = get_option( 'ostew_settings', array() );
		if ( isset( $opts['notifications_enabled'] ) && ! $opts['notifications_enabled'] ) {
			return false; // email notifications switched off in settings.
		}

		$vars['recipient_name'] = $user->display_name;

		$subject = $this->subject( $template, $vars );
		$body    = $this->render( $template, $vars );
		$headers = array(
			'Content-Type: text/html; charset=UTF-8',
			'From: ' . $this->from(),
		);

		$sent = wp_mail( $user->user_email, $subject, $body, $headers );

		if ( ! $sent && defined( 'WP_DEBUG' ) && WP_DEBUG ) {
			error_log( sprintf( '[ost-editorial-workflow] email to %s not sent (template %s)', $user->user_email, $template ) ); // phpcs:ignore WordPress.PHP.DevelopmentFunctions.error_log_error_log
		}

		return (bool) $sent;
	}

	/**
	 * Build the subject line.
	 *
	 * @param string $template Template slug.
	 * @param array  $vars     Merge vars.
	 * @return string
	 */
	private function subject( $template, array $vars ) {
		$formats = $this->subject_formats();
		/* translators: %s: post title. */
		$format  = isset( $formats[ $template ] ) ? $formats[ $template ] : __( '[Update] %s', 'ost-editorial-workflow' );
		$subject = sprintf( $format, $vars['post_title'] );

		/**
		 * Filter a workflow email subject.
		 *
		 * @param string $subject  Subject.
		 * @param string $template Template slug.
		 * @param array  $vars     Merge vars.
		 */
		return apply_filters( 'ostew/email_subject', $subject, $template, $vars );
	}

	/**
	 * Render the inner template inside the base wrapper.
	 *
	 * @param string $template Template slug.
	 * @param array  $vars     Merge vars.
	 * @return string
	 */
	private function render( $template, array $vars ) {
		$file = $this->template_path( $template );
		if ( ! is_readable( $file ) ) {
			$file = $this->template_path( 'review-request' );
		}

		$vars['content'] = $this->capture( $file, $vars );
		$body            = $this->capture( $this->template_path( 'base' ), $vars );

		/**
		 * Filter the full rendered email body.
		 *
		 * @param string $body     HTML body.
		 * @param string $template Template slug.
		 * @param array  $vars     Merge vars.
		 */
		return apply_filters( 'ostew/email_body', $body, $template, $vars );
	}

	/**
	 * Map a template slug to its file (slug uses underscores; files use hyphens).
	 *
	 * @param string $name Slug or file base.
	 * @return string
	 */
	private function template_path( $name ) {
		$name = str_replace( '_', '-', $name );
		return OSTEW_DIR . 'templates/emails/' . $name . '.php';
	}

	/**
	 * Include a template with vars in scope and capture the output.
	 *
	 * @param string $file Absolute path.
	 * @param array  $vars Merge vars.
	 * @return string
	 */
	private function capture( $file, array $vars ) {
		if ( ! is_readable( $file ) ) {
			return '';
		}
		ob_start();
		// phpcs:ignore WordPress.PHP.DontExtract.extract_extract
		extract( $vars );
		include $file;
		return (string) ob_get_clean();
	}

	/**
	 * The From header value (configurable via ostew_settings, sensible defaults).
	 *
	 * @return string
	 */
	private function from() {
		$opts  = get_option( 'ostew_settings', array() );
		$name  = ! empty( $opts['from_name'] ) ? $opts['from_name'] : get_bloginfo( 'name' );
		$email = ! empty( $opts['from_email'] ) ? $opts['from_email'] : get_option( 'admin_email' );
		return sprintf( '%s <%s>', $name, $email );
	}
}