<?php

namespace RoosterLMS\Events;

use RoosterLMS\Content\ObjectType;
use RoosterLMS\Data\Db;
use RoosterLMS\Data\SqlPart;
use RoosterLMS\Domain\Services;
use RoosterLMS\I18n\Providers;
use RoosterLMS\I18n\Switcher;
use RoosterLMS\Live\Placement;
use RoosterLMS\Routing\Urls;

defined( 'ABSPATH' ) || exit;

final class EventPosts {

	public static function of( array $events, string $lang = '' ): array {
		if ( array() === $events ) {
			return array();
		}
		$lang    = '' !== $lang ? $lang : Switcher::current();
		$courses = array();
		$units   = array();
		$own     = array();
		foreach ( $events as $e ) {
			$courses[ $e->course_id ] = true;
			if ( $e->session->unit_id > 0 ) {
				$units[ $e->session->unit_id ] = true;
			}
			if ( Placement::LESSON !== $e->session->placement ) {
				$own[ $e->session->id ] = $e->session;
			}
		}
		$posts  = self::read( array_keys( $courses ), array_keys( $units ), $lang );
		$titles = array() === $own ? array() : Services::live_session_repo()->titles( array_values( $own ), $lang );
		$out    = array();
		foreach ( $events as $e ) {
			$course          = $posts[ ObjectType::COURSE->value ][ $e->course_id ] ?? null;
			$unit            = $posts[ ObjectType::UNIT->value ][ $e->session->unit_id ] ?? null;
			$course_url      = null === $course ? '' : Services::posts()->permalink( (int) $course['ID'] );
			$url             = null === $course || null === $unit ? '' : Urls::build( (int) $course['ID'], (int) $unit['ID'] );
			$course_t        = null === $course ? '' : self::title( (string) $course['post_title'] );
			$title           = isset( $titles[ $e->session->id ] ) ? (string) $titles[ $e->session->id ] : ( null === $unit ? '' : self::title( (string) $unit['post_title'] ) );
			$out[ $e->id() ] = array(
				'title'        => '' !== $title ? $title : ( '' !== $course_t ? $course_t : __( 'Live lesson', 'rooster-lms' ) ),
				'course_title' => $course_t,
				'url'          => '' !== $url ? $url : $course_url,
				'course_url'   => $course_url,
				'image'        => self::image( $unit ) ?? self::image( $course ),
			);
		}
		return $out;
	}

	private static function read( array $courses, array $units, string $lang ): array {
		global $wpdb;
		$or = array();
		if ( array() !== $courses ) {
			$or[] = SqlPart::of( '( op.object_type = %d AND op.object_id IN (' . implode( ',', array_fill( 0, count( $courses ), '%d' ) ) . ') )', array_merge( array( ObjectType::COURSE->value ), $courses ) );
		}
		if ( array() !== $units ) {
			$or[] = SqlPart::of( '( op.object_type = %d AND op.object_id IN (' . implode( ',', array_fill( 0, count( $units ), '%d' ) ) . ') )', array_merge( array( ObjectType::UNIT->value ), $units ) );
		}
		$rows    = Db::rows(
			SqlPart::of(
				"SELECT /* outside-tx */ op.object_type AS rl_type, op.object_id AS rl_object, op.lang AS rl_lang, ( op.post_id = COALESCE( cc.home_post_id, uu.home_post_id ) ) AS rl_home, p.*, th.meta_value AS rl_thumb, af.meta_value AS rl_file, am.meta_value AS rl_meta, al.meta_value AS rl_alt
				FROM %i op
				JOIN %i p ON p.ID = op.post_id AND p.post_status = 'publish'
				LEFT JOIN %i cc ON op.object_type = %d AND cc.id = op.object_id
				LEFT JOIN %i uu ON op.object_type = %d AND uu.id = op.object_id
				LEFT JOIN %i th ON th.post_id = p.ID AND th.meta_key = '_thumbnail_id'
				LEFT JOIN %i af ON af.post_id = CAST( th.meta_value AS UNSIGNED ) AND af.meta_key = '_wp_attached_file'
				LEFT JOIN %i am ON am.post_id = CAST( th.meta_value AS UNSIGNED ) AND am.meta_key = '_wp_attachment_metadata'
				LEFT JOIN %i al ON al.post_id = CAST( th.meta_value AS UNSIGNED ) AND al.meta_key = '_wp_attachment_image_alt'
				WHERE ",
				Db::table( 'object_posts' ),
				$wpdb->posts,
				Db::table( 'courses' ),
				ObjectType::COURSE->value,
				Db::table( 'units' ),
				ObjectType::UNIT->value,
				$wpdb->postmeta,
				$wpdb->postmeta,
				$wpdb->postmeta,
				$wpdb->postmeta
			)->add( '( ' )->add( SqlPart::join( ' OR ', $or ) )->add( ' )' )
		);
		$default = Providers::current()->default_language();
		$by      = array();
		foreach ( $rows as $row ) {
			$type   = (int) $row['rl_type'];
			$object = (int) $row['rl_object'];
			$key    = (string) $row['rl_lang'];
			if ( ! isset( $by[ $type ][ $object ][ $key ] ) ) {
				$by[ $type ][ $object ][ $key ] = $row;
			}
			if ( 1 === (int) $row['rl_home'] ) {
				$by[ $type ][ $object ]['@home'] = $row;
			}
		}
		$out   = array();
		$cache = array();
		foreach ( $by as $type => $objects ) {
			foreach ( $objects as $object => $langs ) {
				$row = $langs[ $lang ] ?? $langs[ $default ] ?? $langs['@home'] ?? reset( $langs );
				if ( ! is_array( $row ) ) {
					continue;
				}
				$out[ $type ][ $object ] = $row;
				$post                    = $row;
				foreach ( array_keys( $post ) as $column ) {
					if ( str_starts_with( (string) $column, 'rl_' ) ) {
						unset( $post[ $column ] );
					}
				}
				$cache[] = (object) $post;
			}
		}
		if ( array() !== $cache ) {
			update_post_cache( $cache );
		}
		return $out;
	}

	private static function image( ?array $row ): ?array {
		$file = null === $row ? '' : (string) ( $row['rl_file'] ?? '' );
		if ( '' === $file ) {
			return null;
		}
		$id      = (int) $row['rl_thumb'];
		$uploads = wp_get_upload_dir();
		$base    = trailingslashit( (string) $uploads['baseurl'] );
		$full    = str_starts_with( $file, 'http://' ) || str_starts_with( $file, 'https://' ) ? $file : $base . ltrim( $file, '/' );
		$full = (string) apply_filters( 'wp_get_attachment_url', $full, $id ); // phpcs:ignore WordPress.NamingConventions.PrefixAllGlobals.NonPrefixedHooknameFound -- WordPress's own filter, applied as wp_get_attachment_url() does.
		$meta = maybe_unserialize( (string) ( $row['rl_meta'] ?? '' ) );
		$meta = is_array( $meta ) ? $meta : array();
		$src  = $full;
		$w    = (int) ( $meta['width'] ?? 0 );
		$h    = (int) ( $meta['height'] ?? 0 );
		foreach ( array( 'medium_large', 'large', 'medium' ) as $size ) {
			$one = $meta['sizes'][ $size ] ?? null;
			if ( is_array( $one ) && '' !== (string) ( $one['file'] ?? '' ) ) {
				$src = str_replace( wp_basename( $full ), (string) $one['file'], $full );
				$w   = (int) ( $one['width'] ?? 0 );
				$h   = (int) ( $one['height'] ?? 0 );
				break;
			}
		}
		return array(
			'src'    => $src,
			'width'  => $w,
			'height' => $h,
			'alt'    => trim( wp_strip_all_tags( (string) ( $row['rl_alt'] ?? '' ) ) ),
		);
	}

	private static function title( string $title ): string {
		return trim( wp_strip_all_tags( html_entity_decode( $title, ENT_QUOTES | ENT_HTML5, 'UTF-8' ) ) );
	}
}