<?php

namespace SilverStripe\FullTextSearch\Search\Processors;

use SilverStripe\FullTextSearch\Search\Services\SearchableService;
use SilverStripe\FullTextSearch\Search\Variants\SearchVariantVersioned;
use SilverStripe\ORM\DataObject;
use SilverStripe\ORM\DB;
use SilverStripe\FullTextSearch\Search\Variants\SearchVariant;
use SilverStripe\FullTextSearch\Search\FullTextSearch;
use SilverStripe\Versioned\Versioned;

abstract class SearchUpdateProcessor
{
    /**
     * List of dirty records to process in format
     *
     * array(
     *   '$BaseClass' => array(
     *     '$State Key' => array(
     *       'state' => array(
     *         'key1' => 'value',
     *         'key2' => 'value'
     *       ),
     *       'ids' => array(
     *         '*id*' => array(
     *           '*Index Name 1*',
     *           '*Index Name 2*'
     *         )
     *       )
     *     )
     *   )
     * )
     *
     * @var array
     */
    protected $dirty;

    public function __construct()
    {
        $this->dirty = array();
    }

    public function addDirtyIDs($class, $statefulids, $index)
    {
        $base = DataObject::getSchema()->baseDataClass($class);
        $forclass = isset($this->dirty[$base]) ? $this->dirty[$base] : array();

        foreach ($statefulids as $statefulid) {
            $id = $statefulid['id'];
            $state = $statefulid['state'];
            $statekey = serialize($state);

            if (!isset($forclass[$statekey])) {
                $forclass[$statekey] = array('state' => $state, 'ids' => array($id => array($index)));
            } elseif (!isset($forclass[$statekey]['ids'][$id])) {
                $forclass[$statekey]['ids'][$id] = array($index);
            } elseif (array_search($index, $forclass[$statekey]['ids'][$id] ?? []) === false) {
                $forclass[$statekey]['ids'][$id][] = $index;
                // dirty count stays the same
            }
        }

        $this->dirty[$base] = $forclass;
    }

    /**
     * Generates the list of indexes to process for the dirty items
     *
     * @return array
     */
    protected function prepareIndexes()
    {
        $originalState = SearchVariant::current_state();
        $dirtyIndexes = array();
        $dirty = $this->getSource();
        $indexes = FullTextSearch::get_indexes();
        $searchableService = SearchableService::singleton();

        foreach ($dirty as $base => $statefulids) {
            if (!$statefulids) {
                continue;
            }

            foreach ($statefulids as $statefulid) {
                $state = $statefulid['state'];
                $ids = $statefulid['ids'];

                SearchVariant::activate_state($state);

                // Ensure that indexes for all new / updated objects are included
                $objs = DataObject::get($base)->byIDs(array_keys($ids ?? []));

                /** @var DataObject $obj */
                foreach ($objs as $obj) {
                    foreach ($ids[$obj->ID] as $index) {
                        if (!$searchableService->variantStateExcluded($state) &&
                            !$indexes[$index]->variantStateExcluded($state)
                        ) {
                            // Remove any existing data from index if the object is no longer indexable
                            if (!$searchableService->isIndexable($obj)) {
                                $indexes[$index]->delete($base, $obj->ID, $state);
                            } else {
                                $indexes[$index]->add($obj);
                            }
                            $dirtyIndexes[$index] = $indexes[$index];
                        }
                    }
                    unset($ids[$obj->ID]);
                }

                // Generate list of records that do not exist and should be removed
                foreach ($ids as $id => $fromindexes) {
                    foreach ($fromindexes as $index) {
                        if (!$searchableService->variantStateExcluded($state) &&
                            !$indexes[$index]->variantStateExcluded($state)
                        ) {
                            $indexes[$index]->delete($base, $id, $state);
                            $dirtyIndexes[$index] = $indexes[$index];
                        }
                    }
                }
            }
        }

        SearchVariant::activate_state($originalState);
        return $dirtyIndexes;
    }

    /**
     * Commits the specified index to the Solr service
     *
     * @param SolrIndex $index Index object
     * @return bool Flag indicating success
     */
    protected function commitIndex($index)
    {
        return $index->commit() !== false;
    }

    /**
     * Gets the record data source to process
     *
     * @return array
     */
    protected function getSource()
    {
        return $this->dirty;
    }

    /**
     * Process all indexes, returning true if successful
     *
     * @return bool Flag indicating success
     */
    public function process()
    {
        if (!DB::is_active()) {
            return false;
        }
        // Generate and commit all instances
        $indexes = $this->prepareIndexes();
        foreach ($indexes as $index) {
            if (!$this->commitIndex($index)) {
                return false;
            }
        }
        return true;
    }

    abstract public function triggerProcessing();
}