<?php

declare(strict_types=1);

namespace UserAccessManager\Object;

use UserAccessManager\Cache\Cache;
use UserAccessManager\Database\Database;

class ObjectMapHandler
{
    public const TREE_MAP_PARENTS = 'PARENT';
    public const TREE_MAP_CHILDREN = 'CHILDREN';
    public const POST_TREE_MAP_CACHE_KEY = 'uamPostTreeMap';
    public const TERM_TREE_MAP_CACHE_KEY = 'uamTermTreeMap';
    public const TERM_POST_MAP_CACHE_KEY = 'uamTermPostMap';
    public const POST_TERM_MAP_CACHE_KEY = 'uamPostTermMap';

    private ?array $termPostMap = null;
    private ?array $postTermMap = null;
    private ?array $termTreeMap = null;
    private ?array $postTreeMap = null;

    public function __construct(
        private Database $database,
        private Cache $cache
    ) {
    }

    private function processTreeMapElements(array &$map, ?array $subMap = null, array &$processed = []): array
    {
        $processMap = ($subMap === null) ? $map : $subMap;

        foreach ($processMap as $id => $subIds) {
            foreach ($subIds as $subId => $type) {
                if (isset($map[$subId]) === true && isset($processed[$id][$subId]) === false) {
                    $map[$id] += $this->processTreeMapElements($map, [$subId => $map[$subId]], $processed)[$subId];
                    $processed[$id][$subId] = $subId;
                }
            }
        }

        return $map;
    }

    private function getTreeMap(string $select, string $generalType): array
    {
        $treeMap = [
            self::TREE_MAP_CHILDREN => [
                $generalType => []
            ],
            self::TREE_MAP_PARENTS => [
                $generalType => []
            ]
        ];
        $results = (array) $this->database->getResults($select);

        foreach ($results as $result) {
            $treeMap[self::TREE_MAP_CHILDREN][$generalType][$result->parentId][$result->id] = $result->type;
            $treeMap[self::TREE_MAP_CHILDREN][$result->type][$result->parentId][$result->id] = $result->type;
            $treeMap[self::TREE_MAP_PARENTS][$generalType][$result->id][$result->parentId] = $result->type;
            $treeMap[self::TREE_MAP_PARENTS][$result->type][$result->id][$result->parentId] = $result->type;
        }

        foreach ($treeMap as $mapType => $mapsByObjectType) {
            foreach ($mapsByObjectType as $objectType => $map) {
                $treeMap[$mapType][(string) $objectType] = $this->processTreeMapElements($map);
            }
        }

        return $treeMap;
    }

    private function getCachedTreeMap(string $cacheKey, string $generalType, string $query): array
    {
        $map = $this->cache->get($cacheKey);

        if ($map === null) {
            $map = $this->getTreeMap($query, $generalType);
            $this->cache->add($cacheKey, $map);
        }

        return $map;
    }

    public function getPostTreeMap(): array
    {
        if ($this->postTreeMap === null) {
            $query = "SELECT ID AS id, post_parent AS parentId, post_type AS type 
                FROM {$this->database->getPostsTable()}
                WHERE post_parent != 0 AND post_type != 'revision'";

            $this->postTreeMap = $this->getCachedTreeMap(
                self::POST_TREE_MAP_CACHE_KEY,
                ObjectHandler::GENERAL_POST_OBJECT_TYPE,
                $query
            );
        }

        return $this->postTreeMap;
    }

    public function getTermTreeMap(): array
    {
        if ($this->termTreeMap === null) {
            $query = "SELECT term_id AS id, parent AS parentId, taxonomy AS type
                FROM {$this->database->getTermTaxonomyTable()}
                WHERE parent != 0";

            $this->termTreeMap = $this->getCachedTreeMap(
                self::TERM_TREE_MAP_CACHE_KEY,
                ObjectHandler::GENERAL_TERM_OBJECT_TYPE,
                $query
            );
        }

        return $this->termTreeMap;
    }

    private function getCachedMap(string $cacheKey, string $query): array
    {
        $map = $this->cache->get($cacheKey);

        if ($map === null) {
            $map = [];
            $results = (array) $this->database->getResults($query);

            foreach ($results as $result) {
                $map[$result->parentId][$result->objectId] = $result->type;
            }

            $this->cache->add($cacheKey, $map);
        }

        return $map;
    }

    public function getTermPostMap(): array
    {
        if ($this->termPostMap === null) {
            $select = "
                SELECT tr.object_id AS objectId, tt.term_id AS parentId, p.post_type AS type
                FROM {$this->database->getTermRelationshipsTable()} AS tr
                  LEFT JOIN {$this->database->getPostsTable()} AS p
                   ON (tr.object_id = p.ID)
                  LEFT JOIN {$this->database->getTermTaxonomyTable()} AS tt
                    ON (tr.term_taxonomy_id = tt.term_taxonomy_id)";

            $this->termPostMap = $this->getCachedMap(self::TERM_POST_MAP_CACHE_KEY, $select);
        }

        return $this->termPostMap;
    }

    public function getPostTermMap(): array
    {
        if ($this->postTermMap === null) {
            $select = "
                SELECT tr.object_id AS parentId, tt.term_id AS objectId, tt.taxonomy AS type
                FROM {$this->database->getTermRelationshipsTable()} AS tr 
                  LEFT JOIN {$this->database->getTermTaxonomyTable()} AS tt
                    ON (tr.term_taxonomy_id = tt.term_taxonomy_id)";

            $this->postTermMap = $this->getCachedMap(self::POST_TERM_MAP_CACHE_KEY, $select);
        }

        return $this->postTermMap;
    }
}