<?php

namespace AcademicCrew\PageGenerator;

use AcademicCrew\Core\Loader;
use AcademicCrew\Members\RoleRegistry;

/**
 * Creates and links a WP page for each published academiccrew_member post.
 *
 * On first publish: generates a page at /members/{slug} and stores cross-references.
 * On subsequent saves: syncs post_content bidirectionally.
 * On trash/delete: mirrors the action on the linked page and cleans nav menus.
 */
class MemberPageGenerator extends PageGeneratorBase {

    private static bool $syncing = false;

    public function register( Loader $loader ): void {
        $loader->add_action( 'save_post_academiccrew_member', $this, 'on_member_saved',      20, 2 );
        $loader->add_action( 'save_post_page',             $this, 'on_linked_page_saved', 20, 2 );
        $loader->add_action( 'trashed_post',               $this, 'on_cpt_trashed'           );
        $loader->add_action( 'untrashed_post',             $this, 'on_cpt_untrashed'          );
        $loader->add_action( 'before_delete_post',         $this, 'on_cpt_before_delete', 10, 2 );
        $loader->add_action( 'before_delete_post',         $this, 'on_page_before_delete',10, 2 );
    }

    // ---------------------------------------------------------------
    // Save hooks
    // ---------------------------------------------------------------

    public function on_member_saved( int $post_id, \WP_Post $post ): void {
        if ( defined( 'DOING_AUTOSAVE' ) && DOING_AUTOSAVE ) return;
        if ( wp_is_post_revision( $post_id ) ) return;
        if ( 'publish' !== $post->post_status ) return;
        if ( self::$syncing ) return;

        $existing_page_id = (int) get_post_meta( $post_id, '_academiccrew_linked_page_id', true );
        if ( $existing_page_id && get_post( $existing_page_id ) ) {
            $this->sync_to_page( $post->post_content, $existing_page_id );
            return;
        }

        $this->generate_page( $post_id );
    }

    public function on_linked_page_saved( int $page_id, \WP_Post $page ): void {
        if ( defined( 'DOING_AUTOSAVE' ) && DOING_AUTOSAVE ) return;
        if ( wp_is_post_revision( $page_id ) ) return;
        if ( self::$syncing ) return;
        if ( 'publish' !== $page->post_status && 'private' !== $page->post_status ) return;

        $member_id = (int) get_post_meta( $page_id, '_academiccrew_member_id', true );
        if ( ! $member_id ) return;

        self::$syncing = true;
        wp_update_post( [ 'ID' => $member_id, 'post_content' => $page->post_content ] );
        self::$syncing = false;
    }

    private function sync_to_page( string $content, int $page_id ): void {
        if ( self::$syncing ) return;
        self::$syncing = true;
        wp_update_post( [ 'ID' => $page_id, 'post_content' => $content ] );
        self::$syncing = false;
    }

    // ---------------------------------------------------------------
    // Lifecycle hooks — trash / delete
    // ---------------------------------------------------------------

    public function on_cpt_trashed( int $post_id ): void {
        if ( 'academiccrew_member' !== get_post_type( $post_id ) ) return;
        $page_id = (int) get_post_meta( $post_id, '_academiccrew_linked_page_id', true );
        if ( ! $page_id || 'publish' !== get_post_status( $page_id ) ) return;

        self::$syncing = true;
        wp_trash_post( $page_id );
        self::$syncing = false;
    }

    public function on_cpt_untrashed( int $post_id ): void {
        if ( 'academiccrew_member' !== get_post_type( $post_id ) ) return;
        $page_id = (int) get_post_meta( $post_id, '_academiccrew_linked_page_id', true );
        if ( ! $page_id || 'trash' !== get_post_status( $page_id ) ) return;

        self::$syncing = true;
        wp_untrash_post( $page_id );
        // wp_untrash_post may restore to 'draft' depending on WP config; ensure publish.
        if ( 'publish' !== get_post_status( $page_id ) ) {
            wp_update_post( [ 'ID' => $page_id, 'post_status' => 'publish' ] );
        }
        self::$syncing = false;
    }

    public function on_cpt_before_delete( int $post_id, \WP_Post $post ): void {
        if ( 'academiccrew_member' !== $post->post_type ) return;

        // Delete the linked profile page.
        $page_id = (int) get_post_meta( $post_id, '_academiccrew_linked_page_id', true );
        if ( $page_id && get_post( $page_id ) ) {
            self::$syncing = true;
            $this->remove_nav_menu_items_for_page( $page_id );
            wp_delete_post( $page_id, true );
            self::$syncing = false;
        }

        // Remove publication links and orphaned publications.
        $this->purge_member_publications( $post_id );
    }

    /**
     * Removes the member's rows from academiccrew_member_publications, then
     * permanently deletes any publication that has no remaining member links.
     */
    private function purge_member_publications( int $member_id ): void {
        global $wpdb;
        $rel_table = esc_sql( $wpdb->prefix . 'academiccrew_member_publications' );
        $pub_table = esc_sql( $wpdb->prefix . 'academiccrew_publications' );

        // Collect all publication IDs linked to this member.
        $pub_ids = $wpdb->get_col( $wpdb->prepare( // phpcs:ignore WordPress.DB
            "SELECT publication_id FROM {$rel_table} WHERE member_id = %d",
            $member_id
        ) );

        // Remove the member's relation rows.
        $wpdb->delete( $rel_table, [ 'member_id' => $member_id ], [ '%d' ] ); // phpcs:ignore WordPress.DB

        if ( empty( $pub_ids ) ) {
            return;
        }

        // Delete publications that are now unlinked (no remaining member).
        $placeholders = implode( ',', array_fill( 0, count( $pub_ids ), '%d' ) );
        $orphans      = $wpdb->get_col( $wpdb->prepare( // phpcs:ignore WordPress.DB
            "SELECT p.id FROM {$pub_table} p
             WHERE p.id IN ({$placeholders})
               AND NOT EXISTS (
                   SELECT 1 FROM {$rel_table} r WHERE r.publication_id = p.id
               )",
            ...$pub_ids
        ) );

        foreach ( $orphans as $pub_id ) {
            $wpdb->delete( $pub_table, [ 'id' => (int) $pub_id ], [ '%d' ] ); // phpcs:ignore WordPress.DB
        }
    }

    /**
     * When the linked WP page is permanently deleted from the Pages screen,
     * clear the cross-reference so next CPT save regenerates it.
     */
    public function on_page_before_delete( int $post_id, \WP_Post $post ): void {
        if ( 'page' !== $post->post_type ) return;
        if ( self::$syncing ) return;

        $member_id = (int) get_post_meta( $post_id, '_academiccrew_member_id', true );
        if ( ! $member_id ) return;

        delete_post_meta( $member_id, '_academiccrew_linked_page_id' );
    }

    // ---------------------------------------------------------------
    // Page generation
    // ---------------------------------------------------------------

    public function generate_page( int $member_id ): int {
        $member = get_post( $member_id );
        if ( ! $member ) {
            return 0;
        }

        $content = '';

        $archive_page_id = (int) get_option( 'academiccrew_members_archive_page_id', 0 );
        if ( ! $archive_page_id ) {
            MembersArchivePageGenerator::generate_if_needed();
            $archive_page_id = (int) get_option( 'academiccrew_members_archive_page_id', 0 );
        }

        $role_key    = (string) ( get_post_meta( $member_id, '_acc_member_role', true ) ?: '' );
        $rank        = (int) ( get_post_meta( $member_id, '_acc_role_rank', true ) ?: 0 );
        $role_order  = array_keys( RoleRegistry::all() );
        $found       = array_search( $role_key, $role_order, true );
        $role_pos    = $found !== false ? (int) $found : 99;
        $menu_order  = $role_pos * 1000 + ( $rank > 0 ? min( $rank, 998 ) : 999 );

        $page_id = $this->create_page( [
            'post_title'   => $member->post_title,
            'post_content' => $content,
            'post_status'  => 'publish',
            'post_type'    => 'page',
            'post_name'    => $member->post_name,
            'post_parent'  => $archive_page_id ?: 0,
            'menu_order'   => $menu_order,
            'meta_input'   => [
                '_academiccrew_is_member_page' => 1,
                '_academiccrew_member_id'      => $member_id,
                'pyre_page_title'           => 'no',
                'pyre_sidebar_position'     => 'none',
            ],
        ] );

        if ( ! $page_id ) {
            return 0;
        }

        update_post_meta( $member_id, '_academiccrew_linked_page_id', $page_id );

        return $page_id;
    }
}