<?php
// chatbot/rag_api.php
require_once($_SERVER['DOCUMENT_ROOT'] . "/session.php");
// JSON 응답을 위해 에러 출력 방지
error_reporting(0);
ini_set('display_errors', 0);
// Increase memory limit for API context
ini_set('memory_limit', '512M');
ob_start();

header('Content-Type: application/json; charset=utf-8');

if ($_SERVER['REQUEST_METHOD'] !== 'POST') {
    ob_clean();
    echo json_encode(['error' => 'Invalid request method']);
    exit;
}

$input = json_decode(file_get_contents('php://input'), true);
$userMessage = $input['message'] ?? '';
$history = $input['history'] ?? [];

if (empty($userMessage)) {
    ob_clean();
    echo json_encode(['error' => 'Empty message']);
    exit;
}

$googleApiKeyPath = $_SERVER['DOCUMENT_ROOT'] . "/apikey/google_vertex_api.txt";
if (!file_exists($googleApiKeyPath)) {
    ob_clean();
    echo json_encode(['reply' => "API Key not found."]);
    exit;
}
$googleApiKey = trim(file_get_contents($googleApiKeyPath));

require_once __DIR__ . '/rag/search.php';

try {
    // 1. Vector Search (Semantic Search)
    // 기존 NotionClient->search() 대신 VectorSearch 사용
    $vectorSearch = new VectorSearch();
    $results = $vectorSearch->search($userMessage, $googleApiKey, 5); // 상위 5개
    
    $context = "";
    if (empty($results)) {
        $context = "관련된 내부 문서를 찾을 수 없습니다. (벡터 데이터가 없거나 매칭 실패)";
    } else {
        // Deduplicate documents (Group text by URL)
        $processedDocs = [];
        foreach ($results as $doc) {
            $url = $doc['url'];
            if (!isset($processedDocs[$url])) {
                $processedDocs[$url] = [
                    'title' => $doc['title'],
                    'score' => $doc['score'],
                    'text' => $doc['text']
                ];
            } else {
                // Determine if this text chunk is already in the compiled text to avoid exact duplication
                // (Simple check, can be improved)
                if (strpos($processedDocs[$url]['text'], $doc['text']) === false) {
                    $processedDocs[$url]['text'] .= "\n[...추가 내용...]\n" . $doc['text'];
                }
            }
        }

        foreach ($processedDocs as $url => $doc) {
            $score = round($doc['score'] * 100, 1);
            $context .= "문서 제목: [{$doc['title']}] (유사도: {$score}%)\nURL: {$url}\n내용:\n{$doc['text']}\n---\n";
        }
    }

    // 2. Gemini Answer Generation
    $url = "https://generativelanguage.googleapis.com/v1beta/models/gemini-2.0-flash:generateContent?key=" . $googleApiKey;
    $headers = ['Content-Type: application/json'];
    
    $historyText = "";
    if (!empty($history)) {
        foreach ($history as $msg) {
            $role = $msg['role'] === 'user' ? "User" : "Assistant";
            $text = is_array($msg['parts']) ? $msg['parts'][0]['text'] : $msg['parts'];
            $historyText .= "$role: $text\n";
        }
    }

    $systemInstruction = "You are a helpful customer support agent for 'codebridge-x.com'. 
    Use the provided [Context] (retrieved via Semantic Vector Search) to answer the user's question. 
    If you cannot find the answer in the context, say so.
    
    [Conversation History]
    $historyText

    IMPORTANT: List the used documents at the bottom.
    
    Format:
    [Answer]
    
    관련 문서 (Vector Search Result):
    - [Title](URL)
    
    [Context]
    $context";
    $data = [
        'contents' => [['parts' => [['text' => $userMessage]]]],
        'systemInstruction' => ['parts' => [['text' => $systemInstruction]]]
    ];

    $ch = curl_init($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, $headers);
    $response = curl_exec($ch);
    
    if (curl_errno($ch)) throw new Exception(curl_error($ch));
    curl_close($ch);
    
    $responseData = json_decode($response, true);
    
    // Check for standard text response
    $reply = $responseData['candidates'][0]['content']['parts'][0]['text'] ?? null;
    
    // If empty, check for finishReason
    if (!$reply) {
        $finishReason = $responseData['candidates'][0]['finishReason'] ?? 'UNKNOWN';
        if ($finishReason === 'SAFETY') {
            $reply = "죄송합니다. 해당 질문에 대한 답변은 안전 정책상 제공해드릴 수 없습니다.";
        } else {
             $reply = "답변 생성 실패 (Finish Reason: $finishReason). Raw Response를 확인해주세요.";
        }
    }

    // Debug File Status
    $vectorFile = __DIR__ . '/rag/data/vectors.json';
    $fileStatus = [
        'path' => $vectorFile,
        'exists' => file_exists($vectorFile),
        'size' => file_exists($vectorFile) ? filesize($vectorFile) : -1,
        'memory_limit' => ini_get('memory_limit')
    ];

    ob_clean();
    echo json_encode([
        'reply' => $reply,
        'debug' => [
            'refinedQuery' => $userMessage,
            'vectorCount' => $vectorSearch->getVectorCount(),
            'loadError' => $vectorSearch->getLastError(),
            'fileStatus' => $fileStatus,
            'context' => $context,
            'systemInstruction' => $systemInstruction,
            'rawResponse' => $responseData
        ]
    ]);

} catch (Exception $e) {
    ob_clean();
    echo json_encode(['reply' => "Error: " . $e->getMessage()]);
}
?>