<?php
namespace ActiveTwist\SEO\Utils;

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

class Helpers
{
    const META_KEY = '_at_seo_meta';

    const SOURCE_EXPLICIT = 'explicit';
    const SOURCE_INHERITED = 'inherited'; // From Global Default
    const SOURCE_AUTO = 'auto'; // From Excerpt or Content
    const SOURCE_MISSING = 'missing';

    public static function get_post_meta($post_id)
    {
        $meta = get_post_meta($post_id, self::META_KEY, true);
        return is_array($meta) ? $meta : [];
    }

    public static function get_seo_title($post)
    {
        $result = self::get_seo_title_with_source($post);
        return $result['value'];
    }

    public static function get_seo_title_with_source($post)
    {
        $meta = self::get_post_meta($post->ID);

        // 1. Manual SEO title
        if (!empty($meta['title'])) {
            return ['value' => $meta['title'], 'source' => self::SOURCE_EXPLICIT];
        }

        // 2. Post title (Auto)
        $title = get_the_title($post);
        $suffix = \ActiveTwist\SEO\Settings\Options::get('seo_title_suffix', get_bloginfo('name'));

        if (!empty($suffix)) {
            return ['value' => $title . ' - ' . $suffix, 'source' => self::SOURCE_AUTO];
        }

        return ['value' => $title, 'source' => self::SOURCE_AUTO];
    }

    public static function get_seo_description($post)
    {
        $result = self::get_seo_description_with_source($post);
        return $result['value'];
    }

    public static function get_seo_description_with_source($post)
    {
        $meta = self::get_post_meta($post->ID);
        // 1. Manual SEO description
        if (!empty($meta['description'])) {
            return ['value' => $meta['description'], 'source' => self::SOURCE_EXPLICIT];
        }

        // 2. Post excerpt
        if (has_excerpt($post)) {
            return ['value' => get_the_excerpt($post), 'source' => self::SOURCE_AUTO];
        }

        // 3. Global Default Description (Fallback)
        $default_desc = \ActiveTwist\SEO\Settings\Options::get('default_description');
        if (!empty($default_desc)) {
            return ['value' => $default_desc, 'source' => self::SOURCE_INHERITED];
        }

        // 4. Auto-generated summary (HTML stripped, ~25 words)
        $content = strip_shortcodes($post->post_content);
        $content = wp_strip_all_tags($content);
        $result = wp_trim_words($content, 25);

        if (!empty($result)) {
            return ['value' => $result, 'source' => self::SOURCE_AUTO];
        }

        return ['value' => '', 'source' => self::SOURCE_MISSING];
    }

    public static function get_canonical_url($post)
    {
        $result = self::get_canonical_url_with_source($post);
        return $result['value'];
    }

    public static function get_canonical_url_with_source($post)
    {
        $meta = self::get_post_meta($post->ID);
        // 1. Manual canonical override
        if (!empty($meta['canonical'])) {
            return ['value' => $meta['canonical'], 'source' => self::SOURCE_EXPLICIT];
        }
        // 2. get_permalink()
        return ['value' => get_permalink($post), 'source' => self::SOURCE_AUTO];
    }

    public static function get_robots($post)
    {
        $result = self::get_robots_with_source($post);
        return $result['value'];
    }

    public static function get_robots_with_source($post)
    {
        $meta = self::get_post_meta($post->ID);
        // 1. Manual robots
        if (!empty($meta['robots'])) {
            return ['value' => $meta['robots'], 'source' => self::SOURCE_EXPLICIT];
        }
        // 2. Default
        return ['value' => 'index, follow', 'source' => self::SOURCE_AUTO];
    }

    public static function get_og_title($post)
    {
        $result = self::get_og_title_with_source($post);
        return $result['value'];
    }

    public static function get_og_title_with_source($post)
    {
        $meta = self::get_post_meta($post->ID);
        if (!empty($meta['og_title'])) {
            return ['value' => $meta['og_title'], 'source' => self::SOURCE_EXPLICIT];
        }
        // Inherit from SEO Title
        $seo_title = self::get_seo_title_with_source($post);
        return ['value' => $seo_title['value'], 'source' => self::SOURCE_INHERITED];
    }

    public static function get_og_description($post)
    {
        $result = self::get_og_description_with_source($post);
        return $result['value'];
    }

    public static function get_og_description_with_source($post)
    {
        $meta = self::get_post_meta($post->ID);
        if (!empty($meta['og_description'])) {
            return ['value' => $meta['og_description'], 'source' => self::SOURCE_EXPLICIT];
        }
        // Inherit from SEO Description
        $seo_desc = self::get_seo_description_with_source($post);
        return ['value' => $seo_desc['value'], 'source' => self::SOURCE_INHERITED];
    }

    public static function get_og_image($post)
    {
        $result = self::get_og_image_with_source($post);
        return $result['value'];
    }

    public static function get_og_image_with_source($post)
    {
        $meta = self::get_post_meta($post->ID);

        // 1. Manual OG image
        if (!empty($meta['og_image'])) {
            return ['value' => $meta['og_image'], 'source' => self::SOURCE_EXPLICIT];
        }

        // 2. Featured image
        if (has_post_thumbnail($post)) {
            return ['value' => get_the_post_thumbnail_url($post, 'full'), 'source' => self::SOURCE_AUTO];
        }

        // 3. Global Default
        $default_image = \ActiveTwist\SEO\Settings\Options::get('default_og_image');
        if (!empty($default_image)) {
            return ['value' => $default_image, 'source' => self::SOURCE_INHERITED];
        }

        return ['value' => '', 'source' => self::SOURCE_MISSING];
    }

    public static function get_twitter_title($post)
    {
        $result = self::get_twitter_title_with_source($post);
        return $result['value'];
    }

    public static function get_twitter_title_with_source($post)
    {
        $meta = self::get_post_meta($post->ID);
        if (!empty($meta['twitter_title'])) {
            return ['value' => $meta['twitter_title'], 'source' => self::SOURCE_EXPLICIT];
        }
        // Inherit from OG Title
        $og_title = self::get_og_title_with_source($post);
        return ['value' => $og_title['value'], 'source' => self::SOURCE_INHERITED];
    }

    public static function get_twitter_description($post)
    {
        $result = self::get_twitter_description_with_source($post);
        return $result['value'];
    }

    public static function get_twitter_description_with_source($post)
    {
        $meta = self::get_post_meta($post->ID);
        if (!empty($meta['twitter_description'])) {
            return ['value' => $meta['twitter_description'], 'source' => self::SOURCE_EXPLICIT];
        }
        // Inherit from OG Description
        $og_desc = self::get_og_description_with_source($post);
        return ['value' => $og_desc['value'], 'source' => self::SOURCE_INHERITED];
    }

    public static function get_twitter_image($post)
    {
        $result = self::get_twitter_image_with_source($post);
        return $result['value'];
    }

    public static function get_twitter_image_with_source($post)
    {
        $meta = self::get_post_meta($post->ID);
        if (!empty($meta['twitter_image'])) {
            return ['value' => $meta['twitter_image'], 'source' => self::SOURCE_EXPLICIT];
        }
        // Inherit from OG Image
        $og_img = self::get_og_image_with_source($post);
        return ['value' => $og_img['value'], 'source' => self::SOURCE_INHERITED];
    }
}