<?php

namespace App\Services;

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

class RecordFileService
{
    /**
     * The storage disk to use for file operations
     */
    private $disk;

    /**
     * Allowed file extensions for record attachments
     */
    private const ALLOWED_EXTENSIONS = ['jpg', 'jpeg', 'png', 'pdf', 'doc', 'docx', 'xml', 'txt', 'csv', 'xls', 'xlsx'];

    /**
     * Maximum file size in KB
     */
    private const MAX_FILE_SIZE = 10240; // 10MB

    /**
     * Constructor
     */
    public function __construct()
    {
        $this->disk = Storage::disk('s3');
    }

    /**
     * Upload record attachment file
     *
     * @param UploadedFile $attachmentFile
     * @param int $recordId
     * @param string $recordType ('IN' or 'OUT')
     * @return string
     * @throws Exception
     */
    public function uploadAttachment(UploadedFile $attachmentFile, int $recordId, string $recordType = 'OUT'): string
    {
        try {
            $currentClient = session('currentClient', 'iao');

            // Validate file
            $this->validateAttachmentFile($attachmentFile);

            // Create filename
            $originalName = pathinfo($attachmentFile->getClientOriginalName(), PATHINFO_FILENAME);
            $extension = strtolower($attachmentFile->getClientOriginalExtension());
            $timestamp = time();
            $filename = 'attachment_' . $recordId . '_' . $timestamp . '_' . substr(md5($originalName), 0, 8) . '.' . $extension;

            // Upload to S3
            $s3Path = $currentClient . '/records/' . strtolower($recordType) . '/' . $recordId . '/attachments/' . $filename;

            $uploaded = $this->disk->putFileAs(
                $currentClient . '/records/' . strtolower($recordType) . '/' . $recordId . '/attachments',
                $attachmentFile,
                $filename,
                'private'
            );

            if (!$uploaded) {
                throw new Exception('Failed to upload attachment to S3: ' . $originalName);
            }

            Log::info("Record attachment uploaded", [
                'record_id' => $recordId,
                'record_type' => $recordType,
                'path' => $s3Path,
                'original_name' => $attachmentFile->getClientOriginalName(),
                'size' => $attachmentFile->getSize()
            ]);

            return $s3Path;

        } catch (Exception $e) {
            Log::error("Error uploading record attachment", [
                'record_id' => $recordId,
                'record_type' => $recordType,
                'error' => $e->getMessage()
            ]);
            throw $e;
        }
    }

    /**
     * Upload XML receipt file (for electronic invoice imports)
     *
     * @param UploadedFile $xmlFile
     * @param int $recordId
     * @param string $recordType
     * @return string
     * @throws Exception
     */
    public function uploadXmlReceipt(UploadedFile $xmlFile, int $recordId, string $recordType = 'OUT'): string
    {
        try {
            $currentClient = session('currentClient', 'iao');

            // Validate XML file
            $this->validateXmlFile($xmlFile);

            // Create filename
            $originalName = pathinfo($xmlFile->getClientOriginalName(), PATHINFO_FILENAME);
            $extension = strtolower($xmlFile->getClientOriginalExtension());
            $timestamp = time();
            $filename = 'xml_receipt_' . $recordId . '_' . $timestamp . '_' . substr(md5($originalName), 0, 8) . '.' . $extension;

            // Upload to S3
            $s3Path = $currentClient . '/records/' . strtolower($recordType) . '/' . $recordId . '/xml/' . $filename;

            $uploaded = $this->disk->putFileAs(
                $currentClient . '/records/' . strtolower($recordType) . '/' . $recordId . '/xml',
                $xmlFile,
                $filename,
                'private'
            );

            if (!$uploaded) {
                throw new Exception('Failed to upload XML receipt to S3: ' . $originalName);
            }

            Log::info("XML receipt uploaded", [
                'record_id' => $recordId,
                'record_type' => $recordType,
                'path' => $s3Path,
                'original_name' => $xmlFile->getClientOriginalName(),
                'size' => $xmlFile->getSize()
            ]);

            return $s3Path;

        } catch (Exception $e) {
            Log::error("Error uploading XML receipt", [
                'record_id' => $recordId,
                'record_type' => $recordType,
                'error' => $e->getMessage()
            ]);
            throw $e;
        }
    }

    /**
     * Get attachment file URL for display/download
     *
     * @param string $filePath
     * @param string $expiresIn
     * @return string|null
     */
    public function getAttachmentUrl(string $filePath, string $expiresIn = '+1 hour'): ?string
    {
        if (!$filePath) {
            return null;
        }

        // Handle legacy local paths - return asset URL
        if (!$this->isS3Path($filePath)) {
            return asset('storage/' . $filePath);
        }

        try {
            if (!$this->disk->exists($filePath)) {
                Log::warning("Attachment file not found", ['path' => $filePath]);
                return null;
            }

            return $this->disk->temporaryUrl($filePath, now()->add($expiresIn));

        } catch (Exception $e) {
            Log::error("Error generating attachment URL", [
                'path' => $filePath,
                'error' => $e->getMessage()
            ]);
            return null;
        }
    }

    /**
     * Delete attachment file from S3
     *
     * @param string $filePath
     * @return bool
     */
    public function deleteAttachment(string $filePath): bool
    {
        // Don't try to delete local files
        if (!$this->isS3Path($filePath)) {
            return false;
        }

        try {
            if ($this->disk->exists($filePath)) {
                $this->disk->delete($filePath);
                Log::info("Attachment file deleted", ['path' => $filePath]);
                return true;
            }
            return false;

        } catch (Exception $e) {
            Log::error("Error deleting attachment file", [
                'path' => $filePath,
                'error' => $e->getMessage()
            ]);
            return false;
        }
    }

    /**
     * Check if path is S3 path
     */
    private function isS3Path(string $path): bool
    {
        return strpos($path, '/records/') !== false ||
               strpos($path, session('currentClient', 'iao')) === 0;
    }

    /**
     * Validate the uploaded attachment file
     *
     * @param UploadedFile $attachmentFile
     * @throws Exception
     */
    private function validateAttachmentFile(UploadedFile $attachmentFile): void
    {
        // Check if file is valid
        if (!$attachmentFile->isValid()) {
            throw new Exception('Invalid file upload');
        }

        // Check file size
        if ($attachmentFile->getSize() > (self::MAX_FILE_SIZE * 1024)) {
            throw new Exception('File size exceeds maximum allowed size of ' . self::MAX_FILE_SIZE . 'KB');
        }

        // Check file extension
        $extension = strtolower($attachmentFile->getClientOriginalExtension());
        if (!in_array($extension, self::ALLOWED_EXTENSIONS)) {
            throw new Exception('File type not allowed. Allowed types: ' . implode(', ', self::ALLOWED_EXTENSIONS));
        }

        // Check mime type for additional security
        $mimeType = $attachmentFile->getMimeType();
        $allowedMimeTypes = [
            'image/jpeg', 'image/png',
            'application/pdf',
            'application/msword',
            'application/vnd.openxmlformats-officedocument.wordprocessingml.document',
            'application/xml', 'text/xml',
            'text/plain',
            'text/csv',
            'application/vnd.ms-excel',
            'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet'
        ];

        if (!in_array($mimeType, $allowedMimeTypes)) {
            throw new Exception('Invalid file type');
        }
    }

    /**
     * Validate XML file specifically
     *
     * @param UploadedFile $xmlFile
     * @throws Exception
     */
    private function validateXmlFile(UploadedFile $xmlFile): void
    {
        // Check if file is valid
        if (!$xmlFile->isValid()) {
            throw new Exception('Invalid XML file upload');
        }

        // Check file size
        if ($xmlFile->getSize() > (self::MAX_FILE_SIZE * 1024)) {
            throw new Exception('XML file size exceeds maximum allowed size of ' . self::MAX_FILE_SIZE . 'KB');
        }

        // Check file extension
        $extension = strtolower($xmlFile->getClientOriginalExtension());
        if ($extension !== 'xml') {
            throw new Exception('Only XML files are allowed for receipt uploads');
        }

        // Check mime type
        $mimeType = $xmlFile->getMimeType();
        $allowedMimeTypes = ['application/xml', 'text/xml'];

        if (!in_array($mimeType, $allowedMimeTypes)) {
            throw new Exception('Invalid XML file type');
        }
    }

    /**
     * Create record folder structure in S3
     *
     * @param int $recordId
     * @param string $recordType
     */
    public function createRecordFolders(int $recordId, string $recordType = 'OUT'): void
    {
        try {
            $currentClient = session('currentClient', 'iao');

            $folders = [
                $currentClient . '/records/' . strtolower($recordType) . '/' . $recordId . '/attachments/.gitkeep',
                $currentClient . '/records/' . strtolower($recordType) . '/' . $recordId . '/xml/.gitkeep'
            ];

            foreach ($folders as $folder) {
                if (!$this->disk->exists($folder)) {
                    $this->disk->put($folder, '');
                }
            }

            Log::info("Created record folder structure", [
                'record_id' => $recordId,
                'record_type' => $recordType
            ]);

        } catch (Exception $e) {
            Log::error("Error creating record folders", [
                'record_id' => $recordId,
                'record_type' => $recordType,
                'error' => $e->getMessage()
            ]);
        }
    }

    /**
     * Get attachment file info
     *
     * @param string $filePath
     * @return array|null
     */
    public function getAttachmentInfo(string $filePath): ?array
    {
        if (!$filePath) {
            return null;
        }

        // Handle legacy local paths
        if (!$this->isS3Path($filePath)) {
            $localPath = storage_path('app/public/' . $filePath);
            if (file_exists($localPath)) {
                return [
                    'path' => $filePath,
                    'name' => basename($filePath),
                    'size' => filesize($localPath),
                    'last_modified' => filemtime($localPath),
                    'url' => $this->getAttachmentUrl($filePath),
                    'exists' => true,
                    'storage_type' => 'local'
                ];
            }
            return null;
        }

        if (!$this->disk->exists($filePath)) {
            return null;
        }

        try {
            return [
                'path' => $filePath,
                'name' => basename($filePath),
                'size' => $this->disk->size($filePath),
                'last_modified' => $this->disk->lastModified($filePath),
                'url' => $this->getAttachmentUrl($filePath),
                'exists' => true,
                'storage_type' => 's3'
            ];

        } catch (Exception $e) {
            Log::error("Error getting attachment info", [
                'path' => $filePath,
                'error' => $e->getMessage()
            ]);
            return null;
        }
    }

    /**
     * List all attachments for a record
     *
     * @param int $recordId
     * @param string $recordType
     * @return array
     */
    public function listRecordAttachments(int $recordId, string $recordType = 'OUT'): array
    {
        try {
            $currentClient = session('currentClient', 'iao');
            $attachmentPath = $currentClient . '/records/' . strtolower($recordType) . '/' . $recordId . '/attachments';

            $files = $this->disk->files($attachmentPath);

            return array_filter($files, function($file) {
                $filename = basename($file);
                return strpos($filename, 'attachment_') === 0;
            });

        } catch (Exception $e) {
            Log::error("Error listing record attachments", [
                'record_id' => $recordId,
                'record_type' => $recordType,
                'error' => $e->getMessage()
            ]);
            return [];
        }
    }

    /**
     * Store XML receipt files for batch import
     *
     * @param array $xmlFiles
     * @param string $batchId
     * @return array
     */
    public function storeXmlBatch(array $xmlFiles, string $batchId): array
    {
        $storedFiles = [];
        $currentClient = session('currentClient', 'iao');

        foreach ($xmlFiles as $index => $xmlFile) {
            try {
                $this->validateXmlFile($xmlFile);

                $originalName = pathinfo($xmlFile->getClientOriginalName(), PATHINFO_FILENAME);
                $extension = strtolower($xmlFile->getClientOriginalExtension());
                $timestamp = time();
                $filename = 'batch_' . $batchId . '_' . $index . '_' . $timestamp . '_' . substr(md5($originalName), 0, 8) . '.' . $extension;

                $s3Path = $currentClient . '/imports/xml_batch/' . $batchId . '/' . $filename;

                $uploaded = $this->disk->putFileAs(
                    $currentClient . '/imports/xml_batch/' . $batchId,
                    $xmlFile,
                    $filename,
                    'private'
                );

                if ($uploaded) {
                    $storedFiles[] = [
                        'original_name' => $xmlFile->getClientOriginalName(),
                        's3_path' => $s3Path,
                        'local_path' => $xmlFile->getRealPath(),
                        'index' => $index
                    ];

                    Log::info("XML file stored for batch processing", [
                        'batch_id' => $batchId,
                        'original_name' => $xmlFile->getClientOriginalName(),
                        's3_path' => $s3Path
                    ]);
                }

            } catch (Exception $e) {
                Log::error("Error storing XML file for batch", [
                    'batch_id' => $batchId,
                    'file_name' => $xmlFile->getClientOriginalName(),
                    'error' => $e->getMessage()
                ]);
            }
        }

        return $storedFiles;
    }
}