<?php
if (!defined('ABSPATH')) exit;

/**
 * Base class for a healthcheck step.
 *
 * Each step lives in its own file under includes/steps/ with a numeric prefix
 * (e.g. 10-backup.php). The file returns an instance of a subclass of WPH_Step.
 * Drop a new file in that directory and it shows up; delete a file and it
 * disappears. The numeric prefix controls order so re-ordering is a rename.
 *
 * Stable string IDs (returned by id()) are stored in the session, so renaming
 * the file does NOT lose data as long as id() stays the same.
 */
abstract class WPH_Step {

    /** Stable identifier (lowercase slug). NEVER change once shipped. */
    abstract public function id(): string;

    /** Human-readable title shown in the UI and report. */
    abstract public function title(): string;

    /** Intro paragraph shown under the title (plain text or simple inline HTML). */
    public function blurb(): string { return ''; }

    /** Sub-items the technician should tick through (plain strings). */
    public function sub_items(): array { return []; }

    /** "Watch out for" callouts (plain strings). */
    public function watch_outs(): array { return []; }

    /**
     * If this step has a stop/escalate condition (e.g. backup failed → stop),
     * return the guidance string. Rendered as a banner when status=blocked.
     */
    public function escalation(): ?string { return null; }

    /**
     * Phase 3 hook — return structured findings (php version, plugin update
     * intel, etc.) for the technician to verify. Phase 1 returns nothing.
     *
     * @return array<string,mixed>
     */
    public function autocheck(array $session_state): array { return []; }
}