<?php

namespace App\Http\Controllers\Front;

use App\Http\Requests\Front\Search\SearchAjaxRequest;
use App\Http\Requests\Front\Search\SearchRequest;
use App\Models\Document;
use App\Models\DynamicPage;
use App\Models\News;
use App\Enums\Document\DocumentStatusEnum;
use App\Enums\News\NewsStatusEnum;
use App\Enums\DynamicPages\PageStatusEnum;
use Illuminate\Http\Request;
use Illuminate\Support\Str;
use Illuminate\Database\Eloquent\Builder;
use Mcamara\LaravelLocalization\LaravelLocalization;
use Uwil\LaravelCommon\Controllers\Controller;
use Uwil\LaravelCommon\Helpers\CollectionHelper;

class SearchController extends Controller
{
    /**
     * Access to the search page.
     *
     * @param \App\Http\Requests\Front\Search\SearchRequest $request
     * @return \Illuminate\Contracts\View\View
     */
    public function search(SearchRequest $request)
    {
        $queryKey   = trans('front.search.query');
        $searchTerm = $request->validated()[$queryKey];

        return view('front.pages.search', compact('searchTerm'));
    }

    /**
     * Load results from search.
     *
     * @param \App\Http\Requests\Front\Search\SearchAjaxRequest $request
     * @return \Illuminate\Http\JsonResponse
     */
    public function ajaxSearchLoadResults(SearchAjaxRequest $request): \Illuminate\Http\JsonResponse
    {
        $class         = $request->validated()['class'];
        $searchTerm    = $request->validated()['search'];
        $currentPage   = (int) $request->validated()['page'];
        $currentLocale = $request->validated()['locale'];
        $perPage       = 5;
    
        app()->setLocale($currentLocale);
        $searchQuery = $this->buildExactSearchQuery($searchTerm);
    
        $models = $class::search($searchQuery, function ($engine, $query, $options) use ($class, $currentLocale) {
            $options['attributesToSearchOn'] = $class::searchTransFields($currentLocale);
            return $engine->search($query, $options);
        })
        ->where('status', $class::searchStatusEnum())
        ->paginateRaw(perPage: $perPage, page: $currentPage);
    
        // Render items.
        $itemsHtml = collect($models['hits'])->map(fn ($result) =>
            view('components.front.search.card', [
                'class'             => $class,
                'result'            => $result,
                'mainField'         => $class::searchMainField(),
                'routeName'         => $class::searchRouteName($result['id_key'] ?? null),
                'customBreadcrumbs' => true,
                'searchTerm'        => $searchTerm,
                'currentLocale'     => $currentLocale,
            ])->render()
        )->implode('');
    
        // Pagination.
        $paginationHtml = view('components.front.search.pagination', [
            'models' => $models,
        ])->render();
    
        return response()->json([
            'items'      => $itemsHtml,
            'pagination' => $paginationHtml,
            'totalHits'  => $models['totalHits'],
        ]);
    }
    
    /**
     * Set strict search term.
     * 
     * @return string
     */
    private function buildExactSearchQuery(string $searchTerm): string
    {
        $words = preg_split('/\s+/', trim($searchTerm), -1, PREG_SPLIT_NO_EMPTY);
        
        if (count($words) === 1) {
            return '"' . $words[0] . '"';
        }
        
        $exactTerms = array_map(function($word) {
            return $word . '*';
        }, $words);
        
        return '+' . implode(' +', $exactTerms);
    }

    /**
     * Highlights all search terms in a text.
     *
     * @param string $text
     * @param string $searchTerm
     * @return string
     */
    public static function highlightTerms(string $text, string $searchTerm, int $contextLength = 150): string
    {
        if (trim($searchTerm) === '') {
            return $text;
        }
    
        // Clean terms list.
        $words = preg_split('/\s+/', $searchTerm, -1, PREG_SPLIT_NO_EMPTY);
        if (empty($words)) {
            return $text;
        }
    
        $fullText   = strip_tags($text);
        $textLength = strlen($fullText);
        $ranges     = [];
    
        // Collection of relevant ranges around each word.
        foreach ($words as $word) {
            $pattern = '/(?<!\w)' . preg_quote($word, '/') . '(?!\w)/iu';
            // Check if current word match exactly with terms.
            if (preg_match_all($pattern, $fullText, $matches, PREG_OFFSET_CAPTURE)) {
                foreach ($matches[0] as $match) {
                    $matchPos = $match[1];
                    $matchLen = strlen($match[0]);
                    $ranges[] = [
                        'start' => max(0, $matchPos - $contextLength),
                        'end'   => min($textLength, $matchPos + $matchLen + $contextLength),
                    ];
                }
            }
        }
    
        // Return the entire text if there isn't matches.
        if (empty($ranges)) {
            return $text;
        }
    
        // Merging overlapping intervals.
        usort($ranges, fn($a, $b) => $a['start'] <=> $b['start']);
        $merged = [];
        foreach ($ranges as $r) {
            if (empty($merged) || $r['start'] > $merged[array_key_last($merged)]['end']) {
                $merged[] = $r;
            } else {
                $merged[array_key_last($merged)]['end'] = max(
                    $merged[array_key_last($merged)]['end'],
                    $r['end']
                );
            }
        }
    
        $snippets = [];
    
        foreach ($merged as $r) {
            $snippet = substr($fullText, $r['start'], $r['end'] - $r['start']);
    
            // Cut cleanly without breaking the words
            if ($r['start'] > 0) {
                $snippet = preg_replace('/^\S*\s/', '…', $snippet, 1);
            }
            if ($r['end'] < $textLength) {
                $snippet = preg_replace('/\s\S*$/', '…', $snippet, 1);
            }
    
            // Highlighting searched words
            foreach ($words as $word) {
                $pattern = '/(?<!\w)' . preg_quote($word, '/') . '(?!\w)/iu';
                $snippet = preg_replace(
                    $pattern,
                    '<span class="search-highlight">$0</span>',
                    $snippet
                );
            }
    
            $snippets[] = trim($snippet);
            if (count($snippets) >= 3) break;
        }
    
        $result = implode('… ', $snippets);
        $result = preg_replace('/\s*…\s*(?:…\s*)+/', ' … ', $result);
    
        return trim($result);
    }
}