<?php

namespace App\Services;

use Illuminate\Support\Facades\Http;
use Illuminate\Support\Facades\Log;
use Illuminate\Support\Facades\Storage;

/**
 * Google Cloud 서비스 (Storage, Speech-to-Text)
 */
class GoogleCloudService
{
    private ?array $serviceAccount = null;

    private ?string $accessToken = null;

    private ?int $tokenExpiry = null;

    public function __construct()
    {
        $this->loadServiceAccount();
    }

    /**
     * 서비스 계정 로드
     */
    private function loadServiceAccount(): void
    {
        $path = config('services.google.credentials_path');

        if ($path && file_exists($path)) {
            $this->serviceAccount = json_decode(file_get_contents($path), true);
        }
    }

    /**
     * OAuth 토큰 발급
     */
    private function getAccessToken(): ?string
    {
        // 캐시된 토큰이 유효하면 재사용
        if ($this->accessToken && $this->tokenExpiry && time() < $this->tokenExpiry - 60) {
            return $this->accessToken;
        }

        if (! $this->serviceAccount) {
            Log::error('Google Cloud: 서비스 계정 파일이 없습니다.');

            return null;
        }

        try {
            $now = time();
            $jwtHeader = base64_encode(json_encode(['alg' => 'RS256', 'typ' => 'JWT']));
            $jwtClaim = base64_encode(json_encode([
                'iss' => $this->serviceAccount['client_email'],
                'scope' => 'https://www.googleapis.com/auth/cloud-platform',
                'aud' => 'https://oauth2.googleapis.com/token',
                'exp' => $now + 3600,
                'iat' => $now,
            ]));

            $privateKey = openssl_pkey_get_private($this->serviceAccount['private_key']);
            if (! $privateKey) {
                Log::error('Google Cloud: 개인 키 읽기 실패');

                return null;
            }

            openssl_sign($jwtHeader.'.'.$jwtClaim, $signature, $privateKey, OPENSSL_ALGO_SHA256);

            $jwt = $jwtHeader.'.'.$jwtClaim.'.'.base64_encode($signature);

            $response = Http::asForm()->post('https://oauth2.googleapis.com/token', [
                'grant_type' => 'urn:ietf:params:oauth:grant-type:jwt-bearer',
                'assertion' => $jwt,
            ]);

            if ($response->successful()) {
                $data = $response->json();
                $this->accessToken = $data['access_token'];
                $this->tokenExpiry = $now + ($data['expires_in'] ?? 3600);

                return $this->accessToken;
            }

            Log::error('Google Cloud: OAuth 토큰 발급 실패', ['response' => $response->body()]);

            return null;
        } catch (\Exception $e) {
            Log::error('Google Cloud: OAuth 토큰 발급 예외', ['error' => $e->getMessage()]);

            return null;
        }
    }

    /**
     * GCS에 파일 업로드
     */
    public function uploadToStorage(string $localPath, string $objectName): ?string
    {
        $token = $this->getAccessToken();
        if (! $token) {
            return null;
        }

        $bucket = config('services.google.storage_bucket');
        if (! $bucket) {
            Log::error('Google Cloud: Storage 버킷 설정 없음');

            return null;
        }

        try {
            $fileContent = file_get_contents($localPath);
            $mimeType = mime_content_type($localPath) ?: 'audio/webm';

            $uploadUrl = 'https://storage.googleapis.com/upload/storage/v1/b/'.
                urlencode($bucket).'/o?uploadType=media&name='.
                urlencode($objectName);

            $response = Http::withToken($token)
                ->withHeaders(['Content-Type' => $mimeType])
                ->withBody($fileContent, $mimeType)
                ->post($uploadUrl);

            if ($response->successful()) {
                return 'gs://'.$bucket.'/'.$objectName;
            }

            Log::error('Google Cloud: Storage 업로드 실패', ['response' => $response->body()]);

            return null;
        } catch (\Exception $e) {
            Log::error('Google Cloud: Storage 업로드 예외', ['error' => $e->getMessage()]);

            return null;
        }
    }

    /**
     * Base64 오디오를 GCS에 업로드
     */
    public function uploadBase64Audio(string $base64Audio, string $objectName): ?string
    {
        // Base64 데이터 파싱
        $audioData = $base64Audio;
        if (preg_match('/^data:audio\/\w+;base64,(.+)$/', $base64Audio, $matches)) {
            $audioData = $matches[1];
        }

        // 임시 파일 생성
        $tempPath = storage_path('app/temp/'.uniqid('audio_').'.webm');
        $tempDir = dirname($tempPath);

        if (! is_dir($tempDir)) {
            mkdir($tempDir, 0755, true);
        }

        file_put_contents($tempPath, base64_decode($audioData));

        // GCS 업로드
        $gcsUri = $this->uploadToStorage($tempPath, $objectName);

        // 임시 파일 삭제
        @unlink($tempPath);

        return $gcsUri;
    }

    /**
     * Speech-to-Text API 호출
     */
    public function speechToText(string $gcsUri, string $languageCode = 'ko-KR'): ?string
    {
        $token = $this->getAccessToken();
        if (! $token) {
            return null;
        }

        try {
            // 긴 오디오는 비동기 처리 (LongRunningRecognize)
            $response = Http::withToken($token)
                ->post('https://speech.googleapis.com/v1/speech:longrunningrecognize', [
                    'config' => [
                        'encoding' => 'WEBM_OPUS',
                        'sampleRateHertz' => 48000,
                        'languageCode' => $languageCode,
                        'enableAutomaticPunctuation' => true,
                        'model' => 'latest_long',
                    ],
                    'audio' => [
                        'uri' => $gcsUri,
                    ],
                ]);

            if (! $response->successful()) {
                Log::error('Google Cloud: STT 요청 실패', ['response' => $response->body()]);

                return null;
            }

            $operation = $response->json();
            $operationName = $operation['name'] ?? null;

            if (! $operationName) {
                Log::error('Google Cloud: STT 작업 이름 없음');

                return null;
            }

            // 작업 완료 대기 (폴링)
            return $this->waitForSttOperation($operationName);
        } catch (\Exception $e) {
            Log::error('Google Cloud: STT 예외', ['error' => $e->getMessage()]);

            return null;
        }
    }

    /**
     * STT 작업 완료 대기
     */
    private function waitForSttOperation(string $operationName, int $maxAttempts = 60): ?string
    {
        $token = $this->getAccessToken();
        if (! $token) {
            return null;
        }

        for ($i = 0; $i < $maxAttempts; $i++) {
            sleep(5); // 5초 대기

            $response = Http::withToken($token)
                ->get("https://speech.googleapis.com/v1/operations/{$operationName}");

            if (! $response->successful()) {
                continue;
            }

            $result = $response->json();

            if (isset($result['done']) && $result['done']) {
                if (isset($result['error'])) {
                    Log::error('Google Cloud: STT 작업 실패', ['error' => $result['error']]);

                    return null;
                }

                // 결과 텍스트 추출
                $transcript = '';
                $results = $result['response']['results'] ?? [];

                foreach ($results as $res) {
                    $alternatives = $res['alternatives'] ?? [];
                    if (! empty($alternatives)) {
                        $transcript .= $alternatives[0]['transcript'] ?? '';
                    }
                }

                return $transcript;
            }
        }

        Log::error('Google Cloud: STT 작업 타임아웃');

        return null;
    }

    /**
     * GCS 파일 삭제
     */
    public function deleteFromStorage(string $objectName): bool
    {
        $token = $this->getAccessToken();
        if (! $token) {
            return false;
        }

        $bucket = config('services.google.storage_bucket');
        if (! $bucket) {
            return false;
        }

        try {
            $deleteUrl = 'https://storage.googleapis.com/storage/v1/b/'.
                urlencode($bucket).'/o/'.urlencode($objectName);

            $response = Http::withToken($token)->delete($deleteUrl);

            return $response->successful();
        } catch (\Exception $e) {
            Log::error('Google Cloud: Storage 삭제 예외', ['error' => $e->getMessage()]);

            return false;
        }
    }

    /**
     * 서비스 사용 가능 여부
     */
    public function isAvailable(): bool
    {
        return $this->serviceAccount !== null && $this->getAccessToken() !== null;
    }
}