<?php
/**
 * Search API - Meilisearch-powered full-text search
 * 
 * GET /api/search.php
 * 
 * Parameters:
 * - q: Search query (required)
 * - category: Filter by category
 * - duration: Filter by duration range (under_1min, 1_5min, 5_10min, 10_20min, over_20min)
 * - content_type: video or live
 * - date_from: Unix timestamp
 * - date_to: Unix timestamp
 * - sort: upload_date, view_count, like_count (desc by default)
 * - page: Page number (default 1)
 * - limit: Results per page (default 20, max 100)
 */

require_once dirname(__DIR__) . '/f_core/config.boot.php';
require_once dirname(__DIR__) . '/f_core/f_classes/class.logger.php';

header('Content-Type: application/json');

class SearchAPI {
    private $meili_host;
    private $meili_key;
    private $logger;
    
    public function __construct() {
        $this->meili_host = getenv('MEILI_HOST') ?: 'http://meilisearch:7700';
        $this->meili_key = getenv('MEILI_MASTER_KEY') ?: 'changeme_meilisearch_master_key';
        $this->logger = new VLogger('search_api');
    }
    
    public function search() {
        // Validate query
        $query = $_GET['q'] ?? '';
        
        if (empty(trim($query))) {
            return $this->error('Search query is required', 400);
        }
        
        // Build search parameters
        $params = [
            'q' => $query,
            'limit' => min(intval($_GET['limit'] ?? 20), 100),
            'offset' => (intval($_GET['page'] ?? 1) - 1) * min(intval($_GET['limit'] ?? 20), 100)
        ];
        
        // Build filters
        $filters = [];
        
        if (!empty($_GET['category'])) {
            $filters[] = 'category = "' . $this->escapeFilter($_GET['category']) . '"';
        }
        
        if (!empty($_GET['duration'])) {
            $filters[] = 'duration_range = "' . $this->escapeFilter($_GET['duration']) . '"';
        }
        
        if (!empty($_GET['content_type'])) {
            $filters[] = 'content_type = "' . $this->escapeFilter($_GET['content_type']) . '"';
        }
        
        if (!empty($_GET['date_from'])) {
            $filters[] = 'upload_date >= ' . intval($_GET['date_from']);
        }
        
        if (!empty($_GET['date_to'])) {
            $filters[] = 'upload_date <= ' . intval($_GET['date_to']);
        }
        
        // Only show public/approved content
        $filters[] = 'privacy = "public"';
        
        if (!empty($filters)) {
            $params['filter'] = implode(' AND ', $filters);
        }
        
        // Sorting
        if (!empty($_GET['sort'])) {
            $sort_field = $_GET['sort'];
            $sort_order = $_GET['order'] ?? 'desc';
            $params['sort'] = ["$sort_field:$sort_order"];
        }
        
        // Facets for filter options
        $params['facets'] = ['category', 'content_type', 'duration_range'];
        
        // Execute search
        $response = $this->apiRequest('POST', '/indexes/videos/search', $params);
        
        if ($response === null) {
            return $this->error('Search service unavailable', 503);
        }
        
        // Track search query for trending
        $this->trackQuery($query);
        
        // Format response
        return $this->success([
            'query' => $query,
            'results' => $this->formatResults($response['hits'] ?? []),
            'total' => $response['estimatedTotalHits'] ?? 0,
            'page' => intval($_GET['page'] ?? 1),
            'limit' => intval($_GET['limit'] ?? 20),
            'facets' => $response['facetDistribution'] ?? [],
            'processing_time_ms' => $response['processingTimeMs'] ?? 0
        ]);
    }
    
    private function formatResults($hits) {
        return array_map(function($hit) {
            return [
                'video_id' => $hit['video_id'],
                'title' => $hit['title'],
                'description' => $hit['description'],
                'category' => $hit['category'],
                'username' => $hit['username'],
                'duration' => $hit['duration'],
                'view_count' => $hit['view_count'],
                'like_count' => $hit['like_count'],
                'upload_date' => $hit['upload_date'],
                'is_live' => $hit['is_live'],
                'thumbnail' => $this->getThumbnailUrl($hit['video_id']),
                'url' => '/watch?v=' . $hit['video_id']
            ];
        }, $hits);
    }
    
    private function getThumbnailUrl($video_id) {
        // Use existing thumbnail logic from the platform
        return "/thumbs/$video_id.jpg";
    }
    
    private function trackQuery($query) {
        global $db;
        
        // Store in trending queries table (create if doesn't exist)
        $query_escaped = $db->escape($query);
        
        $sql = "INSERT INTO db_search_queries (query, search_count, last_searched) 
                VALUES ('$query_escaped', 1, NOW())
                ON DUPLICATE KEY UPDATE 
                search_count = search_count + 1, 
                last_searched = NOW()";
        
        $db->execute($sql);
    }
    
    private function escapeFilter($value) {
        return addslashes($value);
    }
    
    private function apiRequest($method, $endpoint, $data = null) {
        $url = $this->meili_host . $endpoint;
        
        $ch = curl_init($url);
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
        curl_setopt($ch, CURLOPT_CUSTOMREQUEST, $method);
        curl_setopt($ch, CURLOPT_HTTPHEADER, [
            'Authorization: Bearer ' . $this->meili_key,
            'Content-Type: application/json'
        ]);
        
        if ($data !== null) {
            curl_setopt($ch, CURLOPT_POSTFIELDS, json_encode($data));
        }
        
        $response = curl_exec($ch);
        $http_code = curl_getinfo($ch, CURLINFO_HTTP_CODE);
        curl_close($ch);
        
        if ($http_code >= 200 && $http_code < 300) {
            return json_decode($response, true);
        }
        
        $this->logger->error("Meilisearch API error: HTTP $http_code - " . $response);
        return null;
    }
    
    private function success($data) {
        echo json_encode([
            'success' => true,
            'data' => $data
        ]);
        exit;
    }
    
    private function error($message, $code = 400) {
        http_response_code($code);
        echo json_encode([
            'success' => false,
            'error' => $message
        ]);
        exit;
    }
}

// Execute search
$api = new SearchAPI();
$api->search();