<?php

namespace App\SearchDisplace;

use App\SearchDisplace\Searchers\Searcher;

class SearchAndDisplace
{
    protected $documentContent;
    protected $info;

    public function __construct($documentContent, $info)
    {
        $this->documentContent = $documentContent;
        $this->info = $info;
    }

    public function execute()
    {
        $searchResult = $this->search();

        return $this->displace($searchResult);
    }

    /**
     *
     * @return mixed
     * @throws \Exception
     */
    protected function search()
    {
        $searcher = new Searcher($this->info['searchers'], $this->documentContent);

        return $searcher->execute();
    }

    protected function displace($searchResult)
    {
        $replacementIndexes = [];
        $replacements = [];

        foreach ($this->info['searchers'] as $searcher) {
            $replacements[$searcher['key']] = $searcher['replace_with'];
        }

        $searchers = [];

        foreach ($searchResult as $searcher => $searcherResults) {
            $replacementIndexes[$searcher] = [];

            foreach ($searcherResults as $searcherResult) {
                $searchers[$searcherResult['start']] = array_merge($searcherResult, [
                    'searcher' => $searcher
                ]);
            }
        }

        ksort($searchers);

        $updatedDocumentContent = '';
        $currentIndex = 0;

        foreach ($searchers as $start => $searcherItem) {
            $partialContent = substr($this->documentContent, $currentIndex, $searcherItem['start'] - $currentIndex);

            $updatedDocumentContent = $updatedDocumentContent . $partialContent;

            $start = strlen($updatedDocumentContent);

            $updatedDocumentContent = $updatedDocumentContent . $replacements[$searcherItem['searcher']];

            $end = strlen($updatedDocumentContent) - 1;

            if ($start <= $end) {
                $replacementIndexes[$searcherItem['searcher']][] = [
                    'start' => $start,
                    'end' => $end,
                ];
            }

            $currentIndex = $searcherItem['end'] + 1;
        }

        if ($currentIndex < strlen($this->documentContent) - 1) {
            $updatedDocumentContent = $updatedDocumentContent . substr($this->documentContent, $currentIndex);
        }

        return [
            'content' => $updatedDocumentContent,
            'indexes' => $replacementIndexes,
        ];
    }
}