<?php

namespace Lib\Google;

include_once 'lib/google/oauth2.php';
include_once 'config.php';

class GoogleDrive {
    private const DRIVE_API_BASE = 'https://www.googleapis.com/drive/v3';
    private GoogleOAuth2 $oauth;
    
    // Required scopes for Drive API
    private const DRIVE_SCOPES = [
        'https://www.googleapis.com/auth/drive.file'
    ];

    public function __construct(GoogleOAuth2 $oauth) {
        $this->oauth = $oauth;
        $this->oauth->addScopes(self::DRIVE_SCOPES);
    }

    /**
     * List files and folders in Google Drive
     * @param string|null $folderId Parent folder ID (null for root)
     * @param array $options Additional query parameters
     * @return array
     * @throws \Exception
     */
    public function listFiles(?string $folderId = null, array $options = []): array {
        try {
            $query = [];
            
            if ($folderId) {
                $query[] = "'{$folderId}' in parents";
            } else {
                $query[] = "'root' in parents";
            }
            
            // Add trashed=false to exclude deleted files
            $query[] = "trashed=false";
            
            // Handle mime type filtering through options
            if (isset($options['mimeTypes'])) {
                $mimeTypes = array_map(function($type) {
                    return "mimeType='" . $type . "'";
                }, $options['mimeTypes']);
                $query[] = '(' . implode(' or ', $mimeTypes) . ')';
                unset($options['mimeTypes']); // Remove from options to avoid duplication in params
            }
            
            $params = array_merge([
                'fields' => 'files(id, name, mimeType, size, modifiedTime, parents)',
                'orderBy' => 'folder,name', // Sort folders first, then by name
                'q' => implode(' and ', $query)
            ], $options);

            $response = $this->oauth->makeAuthenticatedRequest(
                self::DRIVE_API_BASE . '/files?' . http_build_query($params)
            );

            return $response;
        } catch (\Exception $e) {
            if ($this->isAuthenticationError($e)) {
                throw new \Exception('Authentication required. Use getAuthorizationUrl() to start the auth flow.', 401);
            }
            throw $e;
        }
    }

    /**
     * Download a file by its ID
     * @param string $fileId
     * @param string|null $mimeType Optional mime type for export (useful for Google Docs)
     * @return string File content
     * @throws \Exception
     */
    public function downloadFile(string $fileId, ?string $mimeType = null): string {
        try {
            // First, get file metadata to determine if it's a Google Workspace file
            $file = $this->getFile($fileId);
            $isGoogleWorkspaceFile = substr($file['mimeType'], 0, 23) === 'application/vnd.google-apps';

            // For Google Sheets, always use export
            if ($file['mimeType'] === 'application/vnd.google-apps.spreadsheet') {
                $endpoint = self::DRIVE_API_BASE . '/files/' . $fileId . '/export';
                $endpoint .= '?mimeType=' . urlencode('text/csv');
                
                return $this->oauth->makeAuthenticatedRequest(
                    $endpoint,
                    'GET',
                    ['Accept: text/csv'],
                    null,
                    true
                );
            }
            
            // For other files, use regular download
            $endpoint = self::DRIVE_API_BASE . '/files/' . $fileId;
            if ($isGoogleWorkspaceFile && $mimeType) {
                $endpoint .= '/export';
                $endpoint .= '?mimeType=' . urlencode($mimeType);
            } else {
                $endpoint .= '?alt=media';
            }

            return $this->oauth->makeAuthenticatedRequest(
                $endpoint,
                'GET',
                ['Accept: */*'],
                null,
                true
            );
        } catch (\Exception $e) {
            if ($this->isAuthenticationError($e)) {
                throw new \Exception('Authentication required. Use getAuthorizationUrl() to start the auth flow.', 401);
            }
            throw $e;
        }
    }

    /**
     * Get file metadata
     * @param string $fileId
     * @return array
     * @throws \Exception
     */
    public function getFile(string $fileId): array {
        try {
            return $this->oauth->makeAuthenticatedRequest(
                self::DRIVE_API_BASE . '/files/' . $fileId . '?fields=id,name,mimeType,size,modifiedTime,parents'
            );
        } catch (\Exception $e) {
            if ($this->isAuthenticationError($e)) {
                throw new \Exception('Authentication required. Use getAuthorizationUrl() to start the auth flow.', 401);
            }
            throw $e;
        }
    }

    /**
     * Get authorization URL to start OAuth flow
     * @param array $additionalParams
     * @return string
     */
    public function getAuthorizationUrl(array $additionalParams = []): string {
        return $this->oauth->getAuthorizationUrl($additionalParams);
    }

    /**
     * Check if the error is related to authentication
     * @param \Exception $e
     * @return bool
     */
    private function isAuthenticationError(\Exception $e): bool {
        return $e->getCode() === 401 || $e->getCode() === 403;
    }

    /**
     * Get common MIME types for Google Workspace files
     * @return array
     */
    public static function getCommonExportMimeTypes(): array {
        return [
            'application/vnd.google-apps.spreadsheet' => [
                'xlsx' => 'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet',
                'csv' => 'text/csv',
                'pdf' => 'application/pdf'
            ],
            'application/vnd.google-apps.document' => [
                'docx' => 'application/vnd.openxmlformats-officedocument.wordprocessingml.document',
                'pdf' => 'application/pdf',
                'txt' => 'text/plain'
            ],
            'application/vnd.google-apps.presentation' => [
                'pptx' => 'application/vnd.openxmlformats-officedocument.presentationml.presentation',
                'pdf' => 'application/pdf'
            ]
        ];
    }
}

// Initialize the service
// $oauth = new GoogleOAuth2($clientId, $clientSecret, $redirectUri);
// $drive = new GoogleDrive($oauth);