<?php

require_once __DIR__.'/../bootstrap.php';

use App\Classes\BaseHandler;

class SearchHandler extends BaseHandler
{
    protected int $cacheTTL = 300;

    public function __construct()
    {
        parent::__construct();
        $this->initializeCache();
    }

    public function handleRequest(): void
    {
        try {
            $query = $this->validateAndSanitizeQuery($_GET['q'] ?? null);
            $sections = $this->validateAndSanitizeSections($_GET['section'] ?? '');
            $page = isset($_GET['page']) ? intval($_GET['page']) : 1;
            $pageSize = isset($_GET['pageSize']) ? intval($_GET['pageSize']) : 10;
            $offset = ($page - 1) * $pageSize;
            $cacheKey = $this->generateCacheKey($query, $sections, $page, $pageSize);
            $results = [];
            $results = $this->getCachedResults($cacheKey) ?? $this->fetchSearchResults($query, $sections, $pageSize, $offset);

            if (empty($results) || empty($results['data'])) {
                $this->sendResponse(['results' => [], 'total' => 0, 'page' => $page, 'pageSize' => $pageSize], 200);

                return;
            }

            $this->cacheResults($cacheKey, $results);
            $this->sendResponse(
                [
                    'results' => $results['data'],
                    'total' => $results['total'],
                    'page' => $page,
                    'pageSize' => $pageSize,
                ],
                200
            );
        } catch (\Exception $e) {
            error_log('Search API Error: '.$e->getMessage());
            $this->sendErrorResponse('Invalid request. Please check your query and try again.', 400);
        }
    }

    private function validateAndSanitizeQuery(?string $query): string
    {
        if (empty($query) || ! is_string($query)) {
            throw new \Exception("Invalid 'q' parameter. Must be a non-empty string.");
        }

        $query = trim($query);

        if (strlen($query) > 255) {
            throw new \Exception("Invalid 'q' parameter. Exceeds maximum length of 255 characters.");
        }
        if (! preg_match('/^[a-zA-Z0-9\s\-_\'"]+$/', $query)) {
            throw new \Exception("Invalid 'q' parameter. Contains unsupported characters.");
        }

        $query = preg_replace("/\s+/", ' ', $query);

        return $query;
    }

    private function validateAndSanitizeSections(string $rawSections): ?array
    {
        $allowedSections = ['post', 'artist', 'genre', 'book', 'movie', 'show'];

        if (empty($rawSections)) {
            return null;
        }

        $sections = array_map(
            fn ($section) => strtolower(
                trim(htmlspecialchars($section, ENT_QUOTES, 'UTF-8'))
            ),
            explode(',', $rawSections)
        );
        $invalidSections = array_diff($sections, $allowedSections);

        if (! empty($invalidSections)) {
            throw new Exception("Invalid 'section' parameter. Unsupported sections: ".implode(', ', $invalidSections));
        }

        return $sections;
    }

    private function fetchSearchResults(
        string $query,
        ?array $sections,
        int $pageSize,
        int $offset
    ): array {
        $sectionsParam = $sections && count($sections) > 0 ? '%7B'.implode(',', $sections).'%7D' : '';
        $endpoint = 'rpc/search_optimized_index';
        $queryString =
          'search_query='.
          urlencode($query).
          "&page_size={$pageSize}&page_offset={$offset}".
          ($sectionsParam ? "&sections={$sectionsParam}" : '');
        $data = $this->makeRequest('GET', "{$endpoint}?{$queryString}");
        $total = count($data) > 0 ? $data[0]['total_count'] : 0;
        $results = array_map(function ($item) {
            unset($item['total_count']);

            if (! empty($item['description'])) {
                $item['description'] = truncateText(strip_tags(parseMarkdown($item['description'])), 225);
            }

            return $item;

        }, $data);

        return ['data' => $results, 'total' => $total];
    }

    private function generateCacheKey(
        string $query,
        ?array $sections,
        int $page,
        int $pageSize
    ): string {
        $sectionsKey = $sections ? implode(',', $sections) : 'all';

        return sprintf(
            'search:%s:sections:%s:page:%d:pageSize:%d',
            md5($query),
            $sectionsKey,
            $page,
            $pageSize
        );
    }

    private function getCachedResults(string $cacheKey): ?array
    {
        if ($this->cache instanceof \Redis) {
            $cachedData = $this->cache->get($cacheKey);

            return $cachedData ? json_decode($cachedData, true) : null;
        } elseif (is_array($this->cache)) {
            return $this->cache[$cacheKey] ?? null;
        }

        return null;
    }

    private function cacheResults(string $cacheKey, array $results): void
    {
        if ($this->cache instanceof \Redis) {
            $this->cache->set($cacheKey, json_encode($results));
            $this->cache->expire($cacheKey, $this->cacheTTL);
        } elseif (is_array($this->cache)) {
            $this->cache[$cacheKey] = $results;
        }
    }
}

$handler = new SearchHandler();
$handler->handleRequest();