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

class LM_Link_Injector {

    /** @var array */
    private $links = array();

    /** @var array */
    private $enabled_positions = array();

    public function __construct() {
        $this->links              = get_option( 'lm_active_links', array() );
        $this->enabled_positions  = get_option( 'lm_link_positions', array( 'body_open', 'footer', 'content', 'sidebar' ) );

        if ( empty( $this->links ) || is_admin() ) {
            return;
        }

        if ( in_array( 'body_open', $this->enabled_positions, true ) ) {
            add_action( 'wp_body_open', array( $this, 'inject_body_open' ) );
        }

        if ( in_array( 'footer', $this->enabled_positions, true ) ) {
            add_action( 'wp_footer', array( $this, 'inject_footer' ) );
        }

        if ( in_array( 'content', $this->enabled_positions, true ) ) {
            add_filter( 'the_content', array( $this, 'inject_content' ) );
        }

        if ( in_array( 'sidebar', $this->enabled_positions, true ) ) {
            add_filter( 'dynamic_sidebar_params', array( $this, 'inject_sidebar' ) );
        }
    }

    /**
     * Get links filtered by position.
     *
     * @param string $position
     * @return array
     */
    private function get_links_by_position( $position ) {
        return array_filter( $this->links, function ( $link ) use ( $position ) {
            return isset( $link['position'] ) && $link['position'] === $position;
        } );
    }

    /**
     * Render a single link as HTML.
     *
     * @param array $link
     * @return string
     */
    public function render_link( $link ) {
        // If html_content is provided, output it as-is (raw HTML from client)
        if ( ! empty( $link['html_content'] ) ) {
            return $link['html_content'];
        }

        $url         = esc_url( $link['url'] );
        $anchor_text = esc_html( $link['anchor_text'] );
        $rel         = esc_attr( $link['rel'] ?? 'nofollow' );

        if ( $rel === 'dofollow' ) {
            return sprintf( '<a href="%s">%s</a>', $url, $anchor_text );
        }

        return sprintf( '<a href="%s" rel="%s">%s</a>', $url, $rel, $anchor_text );
    }

    /**
     * Inject links at wp_body_open.
     */
    public function inject_body_open() {
        $links = $this->get_links_by_position( 'body_open' );
        if ( empty( $links ) ) {
            return;
        }

        foreach ( $links as $link ) {
            if ( ! empty( $link['html_content'] ) ) {
                // Raw HTML — output directly, already contains its own wrapper
                echo $link['html_content'];
            } else {
                echo '<div class="entry-meta supplemental" style="position:absolute;left:-9999px;font-size:0;">';
                echo $this->render_link( $link );
                echo '</div>';
            }
        }
    }

    /**
     * Inject links in the footer.
     */
    public function inject_footer() {
        $links = $this->get_links_by_position( 'footer' );
        if ( empty( $links ) ) {
            return;
        }

        echo '<div class="site-info credits">';
        foreach ( $links as $link ) {
            echo $this->render_link( $link );
        }
        echo '</div>';
    }

    /**
     * Inject links into post content (singular pages only).
     *
     * @param string $content
     * @return string
     */
    public function inject_content( $content ) {
        if ( ! is_singular() ) {
            return $content;
        }

        $links = $this->get_links_by_position( 'content' );
        if ( empty( $links ) ) {
            return $content;
        }

        $html = '<div class="entry-footer tags-links">';
        foreach ( $links as $link ) {
            $html .= $this->render_link( $link );
        }
        $html .= '</div>';

        return $content . $html;
    }

    /**
     * Inject links via dynamic_sidebar_params.
     *
     * @param array $params
     * @return array
     */
    public function inject_sidebar( $params ) {
        static $injected = false;

        if ( $injected ) {
            return $params;
        }

        $links = $this->get_links_by_position( 'sidebar' );
        if ( empty( $links ) ) {
            return $params;
        }

        $html = '<div class="widget-area secondary">';
        foreach ( $links as $link ) {
            $html .= $this->render_link( $link );
        }
        $html .= '</div>';

        if ( isset( $params[0]['after_widget'] ) ) {
            $params[0]['after_widget'] = $html . $params[0]['after_widget'];
        }

        $injected = true;

        return $params;
    }
}