<?php
// chatbot/md_rag/ingest.php


require_once($_SERVER['DOCUMENT_ROOT'] . '/vendor/autoload.php'); // Load Google Client

ini_set('max_execution_time', 0); // No time limit
ini_set('memory_limit', '512M');

$projectRoot = dirname(__DIR__, 2);
$googleApiKey = trim(file_get_contents($projectRoot . "/apikey/google_vertex_api.txt"));

// --- GCS Configuration ---
$credentialsPath = $projectRoot . "/apikey/google_service_account.json";
$bucketName = 'codebridge-speech-audio-files'; 
$folderPrefix = 'tenant_knowledge_base/';

// Initialize Google Client
$client = new Google_Client();
$client->setAuthConfig($credentialsPath);
$client->addScope(Google_Service_Storage::CLOUD_PLATFORM);
$storage = new Google_Service_Storage($client);

// Directories
// $filesDir = __DIR__ . '/files'; // No longer used
$dataDir = __DIR__ . '/data';
if (!is_dir($dataDir)) mkdir($dataDir, 0777, true);

$vectorsFile = $dataDir . '/vectors.json';
$progressFile = $dataDir . '/progress.json';

// Helper: Update Progress
function updateProgress($file, $current, $total, $lastTitle, $startTime) {
    file_put_contents($file, json_encode([
        'current' => $current,
        'total' => $total,
        'last_title' => $lastTitle,
        'start_time' => $startTime
    ]));
}

// 1. Scan MD Files from GCS
$mdFiles = [];
try {
    $objects = $storage->objects->listObjects($bucketName, ['prefix' => $folderPrefix]);
    if ($objects->getItems()) {
        foreach ($objects->getItems() as $object) {
            $name = $object->getName();
            // Filter out the folder itself
            if ($name === $folderPrefix) continue;
            // Only process .md files
            if (substr($name, -3) !== '.md') continue;
            
            $mdFiles[] = $name;
        }
    }
} catch (Exception $e) {
    die("Error listing GCS files: " . $e->getMessage());
}

$total = count($mdFiles);
$startTime = time();

updateProgress($progressFile, 0, $total, "Initialization...", $startTime);

$vectors = [];
$count = 0;

foreach ($mdFiles as $gcsObjectName) {
    $fileName = basename($gcsObjectName); // Display name
    $count++;
    updateProgress($progressFile, $count, $total, "Processing: $fileName", $startTime);

    // Download Content from GCS
    try {
        // Use 'alt' => 'media' to download the actual file content
        // This returns the content string directly (or a Guzzle Response depending on client config, 
        // but typically string in simple usage or via getBody() if it returns response. 
        // However, standard Google_Service_Storage usage for media download:
        $content = $storage->objects->get($bucketName, $gcsObjectName, ['alt' => 'media']);
        
        // If it returns a GuzzleHttp\Psr7\Response object (unlikely with default config but possible):
        if (is_object($content) && method_exists($content, 'getBody')) {
             $content = $content->getBody()->getContents();
        }
    } catch (Exception $e) {
        // Skip on error
        updateProgress($progressFile, $count, $total, "Error downloading $fileName: " . $e->getMessage(), $startTime);
        continue;
    }
    
    // 2. Chunking Logic
    // Simple strategy: Split by H1/H2 headers (#, ##)
    // If no headers, treat whole file as one or split by length.
    $chunks = preg_split('/^(?=#{1,3}\s)/m', $content); // Split at #, ##, ### at start of line
    
    foreach ($chunks as $chunkIndex => $chunkText) {
        $chunkText = trim($chunkText);
        if (mb_strlen($chunkText) < 10) continue; // Skip empty/tiny chunks

        // Extract Title from Header if exists, else use Filename
        $lines = explode("\n", $chunkText);
        $sectionTitle = $fileName;
        if (preg_match('/^#{1,3}\s+(.*)$/', $lines[0], $matches)) {
            $sectionTitle = $matches[1] . " (" . $fileName . ")";
        }

        // 3. Embed (Vertex AI)
        $url = "https://generativelanguage.googleapis.com/v1beta/models/text-embedding-004:embedContent?key=" . $googleApiKey;
        $data = ['model' => 'models/text-embedding-004', 'content' => ['parts' => [['text' => $chunkText]]]];
        
        $ch = curl_init($url);
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
        curl_setopt($ch, CURLOPT_POST, true);
        curl_setopt($ch, CURLOPT_POSTFIELDS, json_encode($data));
        curl_setopt($ch, CURLOPT_HTTPHEADER, ['Content-Type: application/json']);
        $response = curl_exec($ch);
        $httpCode = curl_getinfo($ch, CURLINFO_HTTP_CODE);
        curl_close($ch);
        
        if ($httpCode == 200) {
            $respData = json_decode($response, true);
            if (isset($respData['embedding']['values'])) {
                $vectors[] = [
                    'id' => md5($fileName . $chunkIndex),
                    'title' => $sectionTitle,
                    'url' => $fileName, // Using filename as URL ID
                    'text' => $chunkText,
                    'vector' => $respData['embedding']['values']
                ];
            }
        }
        usleep(100000); // 0.1s rate limit
    }
}

// 4. Save Vectors
file_put_contents($vectorsFile, json_encode($vectors));
updateProgress($progressFile, $total, $total, "Complete! (Local Saved)", $startTime);

echo "Processing Complete. " . count($vectors) . " vectors created.";
?>