<?php
/**
 * The check registry: pure logic over post snapshots. No WordPress calls here.
 *
 * Snapshot shape:
 * [
 *   id, title, type, status, date,
 *   excerpt_set => bool, tags_count => int, categories_count => int,
 *   word_count => int, has_thumbnail => bool, images_missing_alt => int,
 *   duplicate_title => bool,
 * ]
 */
defined('ABSPATH') || exit;

class Postlint_Checks {

    /** @return string[] code => label */
    public static function all_checks() {
        return [
            'featured-image' => 'Missing featured image',
            'excerpt' => 'Missing excerpt',
            'tags' => 'Missing tags',
            'categories' => 'Missing categories',
            'alt-text' => 'Images without alt text',
            'thin-content' => 'Thin content',
            'duplicate-title' => 'Duplicate title',
        ];
    }

    /** Default-enabled checks (thin-content off by default to avoid noise). */
    public static function default_enabled() {
        return ['featured-image', 'excerpt', 'tags', 'categories', 'alt-text', 'duplicate-title'];
    }

    /**
     * @param array $snapshot  one post snapshot
     * @param array $settings  normalized settings (checks, thin_content_words)
     * @return string[] issue codes present on this post, in registry order
     */
    public static function evaluate(array $snapshot, array $settings) {
        $enabled = isset($settings['checks']) && is_array($settings['checks'])
            ? $settings['checks']
            : self::default_enabled();
        $issues = [];
        foreach (array_keys(self::all_checks()) as $code) {
            if (!in_array($code, $enabled, true)) {
                continue;
            }
            $method = 'check_' . str_replace('-', '_', $code);
            if (self::$method($snapshot, $settings)) {
                $issues[] = $code;
            }
        }
        return $issues;
    }

    /** Pages have no tags, categories or excerpts in core; flagging them would be a false alarm. */
    private static function supports(array $s, $feature) {
        return !isset($s['supports'][$feature]) || $s['supports'][$feature];
    }

    public static function check_featured_image(array $s, array $settings) {
        return self::supports($s, 'thumbnail') && empty($s['has_thumbnail']);
    }

    public static function check_excerpt(array $s, array $settings) {
        return self::supports($s, 'excerpt') && empty($s['excerpt_set']);
    }

    public static function check_tags(array $s, array $settings) {
        return self::supports($s, 'tags') && (int) $s['tags_count'] === 0;
    }

    public static function check_categories(array $s, array $settings) {
        return self::supports($s, 'categories') && (int) $s['categories_count'] === 0;
    }

    public static function check_alt_text(array $s, array $settings) {
        return (int) $s['images_missing_alt'] > 0;
    }

    public static function check_thin_content(array $s, array $settings) {
        $threshold = max(1, (int) ($settings['thin_content_words'] ?? 150));
        return (int) $s['word_count'] < $threshold;
    }

    public static function check_duplicate_title(array $s, array $settings) {
        return !empty($s['duplicate_title']);
    }
}