import { supabaseAdmin } from './supabase';
import { env as publicEnv } from '$env/dynamic/public';
import {
	S3Client,
	PutObjectCommand,
	GetObjectCommand,
	DeleteObjectCommand,
	DeleteObjectsCommand,
	ListObjectsV2Command,
	HeadBucketCommand
} from '@aws-sdk/client-s3';
import { getSignedUrl as getS3SignedUrl } from '@aws-sdk/s3-request-presigner';

export type StorageBucket = 'documents' | 'avatars' | 'event-images';

/**
 * Magic byte signatures for common file types.
 * Used to validate that file content matches the declared MIME type.
 */
const MAGIC_BYTES: Record<string, { offset: number; bytes: number[] }[]> = {
	'image/png': [{ offset: 0, bytes: [0x89, 0x50, 0x4e, 0x47] }],
	'image/jpeg': [{ offset: 0, bytes: [0xff, 0xd8, 0xff] }],
	'image/gif': [{ offset: 0, bytes: [0x47, 0x49, 0x46] }],
	'application/pdf': [{ offset: 0, bytes: [0x25, 0x50, 0x44, 0x46] }],
	'image/webp': [
		{ offset: 0, bytes: [0x52, 0x49, 0x46, 0x46] }, // RIFF
		{ offset: 8, bytes: [0x57, 0x45, 0x42, 0x50] }  // WEBP
	]
};

/**
 * MIME type to expected file extensions mapping.
 * Used to validate that file content matches the declared extension.
 */
const MIME_TO_EXTENSIONS: Record<string, string[]> = {
	'application/pdf': ['pdf'],
	'application/msword': ['doc'],
	'application/vnd.openxmlformats-officedocument.wordprocessingml.document': ['docx'],
	'application/vnd.ms-excel': ['xls'],
	'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet': ['xlsx'],
	'application/vnd.ms-powerpoint': ['ppt'],
	'application/vnd.openxmlformats-officedocument.presentationml.presentation': ['pptx'],
	'text/plain': ['txt', 'text', 'log'],
	'text/csv': ['csv'],
	'application/json': ['json'],
	'image/jpeg': ['jpg', 'jpeg'],
	'image/png': ['png'],
	'image/webp': ['webp'],
	'image/gif': ['gif']
};

/**
 * Sanitize a filename to prevent path traversal and other attacks.
 * Removes directory separators, null bytes, and other dangerous characters.
 */
export function sanitizeFilename(filename: string): string {
	return filename
		// Remove null bytes
		.replace(/\0/g, '')
		// Remove directory separators
		.replace(/[\/\\]/g, '_')
		// Remove leading dots (hidden files / directory traversal)
		.replace(/^\.+/, '')
		// Replace non-safe characters
		.replace(/[^a-zA-Z0-9._-]/g, '_')
		// Collapse multiple underscores
		.replace(/_+/g, '_')
		// Limit length
		.substring(0, 255)
		// Ensure not empty
		|| 'unnamed_file';
}

/**
 * Validate that file extension matches the declared MIME type.
 */
export function validateExtensionMatchesMime(filename: string, mimeType: string): boolean {
	const ext = filename.split('.').pop()?.toLowerCase();
	if (!ext) return false;

	const allowedExtensions = MIME_TO_EXTENSIONS[mimeType];
	if (!allowedExtensions) return true; // Unknown MIME type - allow

	return allowedExtensions.includes(ext);
}

/**
 * Validate that a file's magic bytes match the declared MIME type.
 * Returns true if the magic bytes match, or if the type has no known magic byte signature
 * (e.g., office documents). Returns false if magic bytes are checked and don't match.
 */
export function validateFileMagicBytes(buffer: ArrayBuffer, declaredType: string): boolean {
	const signatures = MAGIC_BYTES[declaredType];
	if (!signatures) {
		// No magic byte check for this type — allow it
		return true;
	}

	const view = new Uint8Array(buffer);

	for (const sig of signatures) {
		if (view.length < sig.offset + sig.bytes.length) {
			return false;
		}
		for (let i = 0; i < sig.bytes.length; i++) {
			if (view[sig.offset + i] !== sig.bytes[i]) {
				return false;
			}
		}
	}

	return true;
}

/**
 * Generate a browser-accessible public URL for Supabase Storage
 * This uses PUBLIC_SUPABASE_URL instead of the internal Docker URL
 */
function getBrowserAccessibleUrl(bucket: StorageBucket, path: string): string {
	return `${publicEnv.PUBLIC_SUPABASE_URL}/storage/v1/object/public/${bucket}/${path}`;
}

export interface UploadResult {
	success: boolean;
	path?: string;
	publicUrl?: string;
	localUrl?: string;
	s3Url?: string;
	error?: string;
}

export interface S3Config {
	endpoint: string;
	bucket: string;
	accessKey: string;
	secretKey: string;
	region: string;
	useSSL: boolean;
	forcePathStyle: boolean;
	enabled: boolean;
}

let s3ClientCache: S3Client | null = null;
let s3ConfigCache: S3Config | null = null;
let s3ConfigCacheTime: number = 0;
const S3_CONFIG_CACHE_TTL = 60000; // 1 minute cache

/**
 * Get S3 configuration from app_settings table
 */
export async function getS3Config(): Promise<S3Config | null> {
	// Check cache
	if (s3ConfigCache && Date.now() - s3ConfigCacheTime < S3_CONFIG_CACHE_TTL) {
		return s3ConfigCache;
	}

	const { data: settings } = await supabaseAdmin
		.from('app_settings')
		.select('setting_key, setting_value')
		.eq('category', 'storage');

	if (!settings || settings.length === 0) {
		return null;
	}

	const config: Record<string, any> = {};
	for (const s of settings) {
		let value = s.setting_value;
		if (typeof value === 'string') {
			// Remove surrounding quotes if present (from JSON stringified values)
			value = value.replace(/^"|"$/g, '');
		}
		config[s.setting_key] = value;
	}

	// Check if S3 is enabled - handle both boolean true and string 'true'
	const isEnabled = config.s3_enabled === true || config.s3_enabled === 'true';

	// Check if S3 is enabled and configured
	if (!isEnabled || !config.s3_endpoint || !config.s3_access_key || !config.s3_secret_key) {
		console.log('S3 config check failed:', {
			isEnabled,
			hasEndpoint: !!config.s3_endpoint,
			hasAccessKey: !!config.s3_access_key,
			hasSecretKey: !!config.s3_secret_key
		});
		return null;
	}

	s3ConfigCache = {
		endpoint: config.s3_endpoint,
		bucket: config.s3_bucket || 'monacousa-documents',
		accessKey: config.s3_access_key,
		secretKey: config.s3_secret_key,
		region: config.s3_region || 'us-east-1',
		useSSL: config.s3_use_ssl === true || config.s3_use_ssl === 'true',
		forcePathStyle: config.s3_force_path_style === true || config.s3_force_path_style === 'true' || config.s3_force_path_style === undefined,
		enabled: true
	};
	s3ConfigCacheTime = Date.now();

	return s3ConfigCache;
}

/**
 * Get or create S3 client
 */
export async function getS3Client(): Promise<S3Client | null> {
	const config = await getS3Config();
	if (!config) {
		return null;
	}

	// Return cached client if config hasn't changed
	if (s3ClientCache && s3ConfigCache) {
		return s3ClientCache;
	}

	s3ClientCache = new S3Client({
		endpoint: config.endpoint,
		region: config.region,
		credentials: {
			accessKeyId: config.accessKey,
			secretAccessKey: config.secretKey
		},
		forcePathStyle: config.forcePathStyle
	});

	return s3ClientCache;
}

/**
 * Clear S3 client cache (call when settings change)
 */
export function clearS3ClientCache(): void {
	s3ClientCache = null;
	s3ConfigCache = null;
	s3ConfigCacheTime = 0;
}

/**
 * Test S3 connection
 */
export async function testS3Connection(): Promise<{ success: boolean; error?: string }> {
	const config = await getS3Config();
	if (!config) {
		return { success: false, error: 'S3 not configured. Please configure and enable S3 storage settings first.' };
	}

	const client = await getS3Client();
	if (!client) {
		return { success: false, error: 'Failed to create S3 client' };
	}

	try {
		await client.send(new HeadBucketCommand({ Bucket: config.bucket }));
		return { success: true };
	} catch (error) {
		const errorMessage = error instanceof Error ? error.message : 'Unknown error';
		console.error('S3 connection test error:', error);
		return { success: false, error: `S3 connection failed: ${errorMessage}` };
	}
}

/**
 * Check if S3 storage is enabled
 */
export async function isS3Enabled(): Promise<boolean> {
	const config = await getS3Config();
	return config !== null && config.enabled;
}

/**
 * Get the S3 key with bucket prefix for organization
 */
function getS3Key(bucket: StorageBucket, path: string): string {
	return `${bucket}/${path}`;
}

/**
 * Upload a file to S3
 */
async function uploadToS3(
	bucket: StorageBucket,
	path: string,
	file: File | ArrayBuffer | Buffer,
	options?: {
		contentType?: string;
	}
): Promise<UploadResult> {
	const config = await getS3Config();
	const client = await getS3Client();

	if (!config || !client) {
		return { success: false, error: 'S3 not configured' };
	}

	try {
		const key = getS3Key(bucket, path);
		let body: Buffer;

		if (file instanceof ArrayBuffer) {
			body = Buffer.from(file);
		} else if (Buffer.isBuffer(file)) {
			body = file;
		} else {
			// It's a File object
			body = Buffer.from(await file.arrayBuffer());
		}

		await client.send(
			new PutObjectCommand({
				Bucket: config.bucket,
				Key: key,
				Body: body,
				ContentType: options?.contentType
			})
		);

		// Construct public URL
		const protocol = config.useSSL ? 'https' : 'http';
		let publicUrl: string;
		if (config.forcePathStyle) {
			publicUrl = `${config.endpoint}/${config.bucket}/${key}`;
		} else {
			publicUrl = `${protocol}://${config.bucket}.${new URL(config.endpoint).host}/${key}`;
		}

		return {
			success: true,
			path: key,
			publicUrl
		};
	} catch (error) {
		const errorMessage = error instanceof Error ? error.message : 'Unknown error';
		console.error('S3 upload error:', error);
		return { success: false, error: errorMessage };
	}
}

/**
 * Get a signed URL from S3
 */
async function getS3PresignedUrl(
	bucket: StorageBucket,
	path: string,
	expiresIn: number = 3600
): Promise<{ url: string | null; error: string | null }> {
	const config = await getS3Config();
	const client = await getS3Client();

	if (!config || !client) {
		return { url: null, error: 'S3 not configured' };
	}

	try {
		const key = getS3Key(bucket, path);
		const command = new GetObjectCommand({
			Bucket: config.bucket,
			Key: key
		});

		const url = await getS3SignedUrl(client, command, { expiresIn });
		return { url, error: null };
	} catch (error) {
		const errorMessage = error instanceof Error ? error.message : 'Unknown error';
		console.error('S3 signed URL error:', error);
		return { url: null, error: errorMessage };
	}
}

/**
 * Delete a file from S3
 */
async function deleteFromS3(
	bucket: StorageBucket,
	path: string
): Promise<{ success: boolean; error?: string }> {
	const config = await getS3Config();
	const client = await getS3Client();

	if (!config || !client) {
		return { success: false, error: 'S3 not configured' };
	}

	try {
		const key = getS3Key(bucket, path);
		await client.send(
			new DeleteObjectCommand({
				Bucket: config.bucket,
				Key: key
			})
		);
		return { success: true };
	} catch (error) {
		const errorMessage = error instanceof Error ? error.message : 'Unknown error';
		console.error('S3 delete error:', error);
		return { success: false, error: errorMessage };
	}
}

/**
 * Delete multiple files from S3
 */
async function deleteMultipleFromS3(
	bucket: StorageBucket,
	paths: string[]
): Promise<{ success: boolean; error?: string }> {
	const config = await getS3Config();
	const client = await getS3Client();

	if (!config || !client) {
		return { success: false, error: 'S3 not configured' };
	}

	try {
		const objects = paths.map((p) => ({ Key: getS3Key(bucket, p) }));
		await client.send(
			new DeleteObjectsCommand({
				Bucket: config.bucket,
				Delete: { Objects: objects }
			})
		);
		return { success: true };
	} catch (error) {
		const errorMessage = error instanceof Error ? error.message : 'Unknown error';
		console.error('S3 delete multiple error:', error);
		return { success: false, error: errorMessage };
	}
}

/**
 * List files from S3
 */
async function listFilesFromS3(
	bucket: StorageBucket,
	folder?: string,
	options?: {
		limit?: number;
	}
): Promise<{ files: any[]; error: string | null }> {
	const config = await getS3Config();
	const client = await getS3Client();

	if (!config || !client) {
		return { files: [], error: 'S3 not configured' };
	}

	try {
		const prefix = folder ? `${bucket}/${folder}/` : `${bucket}/`;
		const response = await client.send(
			new ListObjectsV2Command({
				Bucket: config.bucket,
				Prefix: prefix,
				MaxKeys: options?.limit || 100
			})
		);

		const files = (response.Contents || []).map((obj) => ({
			name: obj.Key?.replace(prefix, '') || '',
			size: obj.Size,
			updated_at: obj.LastModified?.toISOString(),
			created_at: obj.LastModified?.toISOString()
		}));

		return { files, error: null };
	} catch (error) {
		const errorMessage = error instanceof Error ? error.message : 'Unknown error';
		console.error('S3 list error:', error);
		return { files: [], error: errorMessage };
	}
}

// ===========================================
// PUBLIC API - Uses S3 or Supabase based on settings
// ===========================================

/**
 * Upload a file to storage (S3 or Supabase)
 */
export async function uploadFile(
	bucket: StorageBucket,
	path: string,
	file: File | ArrayBuffer,
	options?: {
		contentType?: string;
		cacheControl?: string;
		upsert?: boolean;
	}
): Promise<UploadResult> {
	// Check if S3 is enabled
	if (await isS3Enabled()) {
		return uploadToS3(bucket, path, file, options);
	}

	// Fall back to Supabase Storage
	try {
		const { data, error } = await supabaseAdmin.storage.from(bucket).upload(path, file, {
			contentType: options?.contentType,
			cacheControl: options?.cacheControl || '3600',
			upsert: options?.upsert || false
		});

		if (error) {
			console.error('Storage upload error:', error);
			return { success: false, error: error.message };
		}

		// Generate browser-accessible public URL (not the internal Docker URL)
		const publicUrl = getBrowserAccessibleUrl(bucket, path);

		return {
			success: true,
			path: data.path,
			publicUrl
		};
	} catch (error) {
		const errorMessage = error instanceof Error ? error.message : 'Unknown error';
		console.error('Storage upload exception:', error);
		return { success: false, error: errorMessage };
	}
}

/**
 * Get the public URL for a file in storage
 */
export async function getPublicUrl(bucket: StorageBucket, path: string): Promise<string> {
	// Check if S3 is enabled
	if (await isS3Enabled()) {
		const config = await getS3Config();
		if (config) {
			const key = getS3Key(bucket, path);
			if (config.forcePathStyle) {
				return `${config.endpoint}/${config.bucket}/${key}`;
			}
			const protocol = config.useSSL ? 'https' : 'http';
			return `${protocol}://${config.bucket}.${new URL(config.endpoint).host}/${key}`;
		}
	}

	// Fall back to Supabase Storage - use browser-accessible URL
	return getBrowserAccessibleUrl(bucket, path);
}

/**
 * Get a signed URL for private file access
 */
export async function getSignedUrl(
	bucket: StorageBucket,
	path: string,
	expiresIn: number = 3600
): Promise<{ url: string | null; error: string | null }> {
	// Check if S3 is enabled
	if (await isS3Enabled()) {
		return getS3PresignedUrl(bucket, path, expiresIn);
	}

	// Fall back to Supabase Storage
	const { data, error } = await supabaseAdmin.storage
		.from(bucket)
		.createSignedUrl(path, expiresIn);

	if (error) {
		return { url: null, error: error.message };
	}

	return { url: data.signedUrl, error: null };
}

/**
 * Delete a file from storage
 */
export async function deleteFile(
	bucket: StorageBucket,
	path: string
): Promise<{ success: boolean; error?: string }> {
	// Check if S3 is enabled
	if (await isS3Enabled()) {
		return deleteFromS3(bucket, path);
	}

	// Fall back to Supabase Storage
	const { error } = await supabaseAdmin.storage.from(bucket).remove([path]);

	if (error) {
		console.error('Storage delete error:', error);
		return { success: false, error: error.message };
	}

	return { success: true };
}

/**
 * Delete multiple files from storage
 */
export async function deleteFiles(
	bucket: StorageBucket,
	paths: string[]
): Promise<{ success: boolean; error?: string }> {
	// Check if S3 is enabled
	if (await isS3Enabled()) {
		return deleteMultipleFromS3(bucket, paths);
	}

	// Fall back to Supabase Storage
	const { error } = await supabaseAdmin.storage.from(bucket).remove(paths);

	if (error) {
		console.error('Storage delete error:', error);
		return { success: false, error: error.message };
	}

	return { success: true };
}

/**
 * List files in a bucket/folder
 */
export async function listFiles(
	bucket: StorageBucket,
	folder?: string,
	options?: {
		limit?: number;
		offset?: number;
		sortBy?: { column: string; order: 'asc' | 'desc' };
	}
): Promise<{ files: any[]; error: string | null }> {
	// Check if S3 is enabled
	if (await isS3Enabled()) {
		return listFilesFromS3(bucket, folder, options);
	}

	// Fall back to Supabase Storage
	const { data, error } = await supabaseAdmin.storage.from(bucket).list(folder || '', {
		limit: options?.limit || 100,
		offset: options?.offset || 0,
		sortBy: options?.sortBy || { column: 'created_at', order: 'desc' }
	});

	if (error) {
		return { files: [], error: error.message };
	}

	return { files: data || [], error: null };
}

/**
 * Generate a unique filename with timestamp
 */
export function generateUniqueFilename(originalName: string): string {
	const timestamp = Date.now();
	const randomStr = Math.random().toString(36).substring(2, 8);
	const safeName = sanitizeFilename(originalName).substring(0, 50);
	const ext = safeName.split('.').pop() || '';
	const nameWithoutExt = safeName.replace(`.${ext}`, '');
	return `${timestamp}-${randomStr}-${nameWithoutExt}.${ext}`;
}

/**
 * Upload an avatar image for a member
 * Returns both S3 and local URLs for storage flexibility
 */
export async function uploadAvatar(
	memberId: string,
	file: File,
	userSupabase?: ReturnType<typeof import('@supabase/supabase-js').createClient>
): Promise<UploadResult> {
	// Validate file type
	const allowedTypes = ['image/jpeg', 'image/png', 'image/webp', 'image/gif'];
	if (!allowedTypes.includes(file.type)) {
		return { success: false, error: 'Invalid image type. Allowed: JPEG, PNG, WebP, GIF' };
	}

	// Validate file size (max 5MB)
	const maxSize = 5 * 1024 * 1024;
	if (file.size > maxSize) {
		return { success: false, error: 'Image size must be less than 5MB' };
	}

	// Generate path - memberId must match auth.uid() for RLS
	const ext = file.name.split('.').pop() || 'jpg';
	const path = `${memberId}/avatar.${ext}`;

	// Convert to ArrayBuffer
	const arrayBuffer = await file.arrayBuffer();

	// Validate magic bytes match declared MIME type
	if (!validateFileMagicBytes(arrayBuffer, file.type)) {
		return { success: false, error: 'File content does not match declared type. The file may be corrupted or mislabeled.' };
	}

	// Check if S3 is enabled
	const s3Enabled = await isS3Enabled();

	// Result object
	const result: UploadResult = {
		success: false,
		path
	};

	// Upload to S3 if enabled
	if (s3Enabled) {
		const s3Result = await uploadToS3('avatars', path, arrayBuffer, {
			contentType: file.type
		});

		if (!s3Result.success) {
			return s3Result;
		}

		result.s3Url = s3Result.publicUrl;
		result.publicUrl = s3Result.publicUrl;
		result.success = true;
	}

	// Always upload to Supabase Storage as well (for fallback)
	try {
		// First try to delete existing avatar (ignore errors)
		await supabaseAdmin.storage.from('avatars').remove([path]);

		const { data, error } = await supabaseAdmin.storage.from('avatars').upload(path, arrayBuffer, {
			contentType: file.type,
			cacheControl: '3600',
			upsert: true
		});

		if (error) {
			// If S3 succeeded, this is okay - just log
			if (result.success) {
				console.warn('Local storage upload failed (S3 succeeded):', error);
			} else {
				console.error('Avatar upload error:', error);
				return { success: false, error: error.message };
			}
		} else {
			// Generate browser-accessible public URL (not the internal Docker URL)
			result.localUrl = getBrowserAccessibleUrl('avatars', path);

			// If S3 is not enabled, use local URL as the public URL
			if (!s3Enabled) {
				result.publicUrl = result.localUrl;
				result.success = true;
			}
		}
	} catch (error) {
		// If S3 succeeded, this is okay
		if (!result.success) {
			const errorMessage = error instanceof Error ? error.message : 'Unknown error';
			console.error('Avatar upload exception:', error);
			return { success: false, error: errorMessage };
		}
	}

	return result;
}

/**
 * Delete a member's avatar from ALL storage backends
 * Always attempts to delete from both S3 and Supabase Storage
 */
export async function deleteAvatar(
	memberId: string,
	avatarPath?: string
): Promise<{ success: boolean; error?: string }> {
	// If we have a specific path, use it; otherwise try common extensions
	let paths: string[];
	if (avatarPath) {
		paths = [avatarPath];
	} else {
		const extensions = ['jpg', 'jpeg', 'png', 'webp', 'gif'];
		paths = extensions.map((ext) => `${memberId}/avatar.${ext}`);
	}

	const errors: string[] = [];

	// Always try to delete from S3 (in case it was uploaded when S3 was enabled)
	try {
		const s3Config = await getS3Config();
		if (s3Config) {
			const result = await deleteMultipleFromS3('avatars', paths);
			if (!result.success && result.error) {
				console.warn('S3 avatar delete warning:', result.error);
			}
		}
	} catch (error) {
		console.warn('S3 avatar delete error (non-critical):', error);
	}

	// Always try to delete from Supabase Storage
	try {
		await supabaseAdmin.storage.from('avatars').remove(paths);
	} catch (error) {
		console.warn('Local storage avatar delete error (non-critical):', error);
	}

	return { success: true };
}

/**
 * Get the appropriate avatar URL based on current storage settings
 * Useful for getting the right URL when storage setting is toggled
 */
export async function getActiveAvatarUrl(member: {
	avatar_url_s3?: string | null;
	avatar_url_local?: string | null;
	avatar_url?: string | null;
}): Promise<string | null> {
	// Check if S3 is enabled
	if (await isS3Enabled()) {
		return member.avatar_url_s3 || member.avatar_url || null;
	}
	return member.avatar_url_local || member.avatar_url || null;
}

/**
 * Upload a document to storage
 * Returns both S3 and local URLs for storage flexibility (same pattern as avatars)
 */
export async function uploadDocument(
	file: File,
	options?: {
		folder?: string;
	}
): Promise<UploadResult> {
	// Validate file type
	const allowedTypes = [
		'application/pdf',
		'application/msword',
		'application/vnd.openxmlformats-officedocument.wordprocessingml.document',
		'application/vnd.ms-excel',
		'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet',
		'application/vnd.ms-powerpoint',
		'application/vnd.openxmlformats-officedocument.presentationml.presentation',
		'text/plain',
		'text/csv',
		'application/json',
		'image/jpeg',
		'image/png',
		'image/webp',
		'image/gif'
	];

	if (!allowedTypes.includes(file.type)) {
		return {
			success: false,
			error:
				'File type not allowed. Supported: PDF, DOC, DOCX, XLS, XLSX, PPT, PPTX, TXT, CSV, JSON, JPG, PNG, WebP, GIF'
		};
	}

	// Validate file extension matches declared MIME type
	if (!validateExtensionMatchesMime(file.name, file.type)) {
		return { success: false, error: 'File extension does not match file type. Please ensure the file has the correct extension.' };
	}

	// Validate file size (max 50MB)
	const maxSize = 50 * 1024 * 1024;
	if (file.size > maxSize) {
		return { success: false, error: 'File size must be less than 50MB' };
	}

	// Generate unique storage path
	const timestamp = Date.now();
	const randomStr = Math.random().toString(36).substring(2, 8);
	const safeName = sanitizeFilename(file.name).substring(0, 50);
	const path = options?.folder ? `${options.folder}/${timestamp}-${randomStr}-${safeName}` : `${timestamp}-${randomStr}-${safeName}`;

	// Convert to ArrayBuffer
	const arrayBuffer = await file.arrayBuffer();

	// Validate magic bytes match declared MIME type
	if (!validateFileMagicBytes(arrayBuffer, file.type)) {
		return { success: false, error: 'File content does not match declared type. The file may be corrupted or mislabeled.' };
	}

	// Check if S3 is enabled
	const s3Enabled = await isS3Enabled();

	// Result object
	const result: UploadResult = {
		success: false,
		path
	};

	// Upload to S3 if enabled
	if (s3Enabled) {
		const s3Result = await uploadToS3('documents', path, arrayBuffer, {
			contentType: file.type
		});

		if (!s3Result.success) {
			return s3Result;
		}

		result.s3Url = s3Result.publicUrl;
		result.publicUrl = s3Result.publicUrl;
		result.success = true;
	}

	// Always upload to Supabase Storage as well (for fallback)
	try {
		const { data, error } = await supabaseAdmin.storage.from('documents').upload(path, arrayBuffer, {
			contentType: file.type,
			cacheControl: '3600',
			upsert: false
		});

		if (error) {
			// If S3 succeeded, this is okay - just log
			if (result.success) {
				console.warn('Local storage upload failed (S3 succeeded):', error);
			} else {
				console.error('Document upload error:', error);
				return { success: false, error: error.message };
			}
		} else {
			// Generate browser-accessible public URL (not the internal Docker URL)
			result.localUrl = getBrowserAccessibleUrl('documents', path);

			// If S3 is not enabled, use local URL as the public URL
			if (!s3Enabled) {
				result.publicUrl = result.localUrl;
				result.success = true;
			}
		}
	} catch (error) {
		// If S3 succeeded, this is okay
		if (!result.success) {
			const errorMessage = error instanceof Error ? error.message : 'Unknown error';
			console.error('Document upload exception:', error);
			return { success: false, error: errorMessage };
		}
	}

	return result;
}

/**
 * Delete a document from ALL storage backends
 * Always attempts to delete from both S3 and Supabase Storage
 */
export async function deleteDocument(
	storagePath: string
): Promise<{ success: boolean; error?: string }> {
	const errors: string[] = [];

	// Always try to delete from S3 (in case it was uploaded when S3 was enabled)
	try {
		const s3Config = await getS3Config();
		if (s3Config) {
			const result = await deleteFromS3('documents', storagePath);
			if (!result.success && result.error) {
				console.warn('S3 document delete warning:', result.error);
			}
		}
	} catch (error) {
		console.warn('S3 document delete error (non-critical):', error);
	}

	// Always try to delete from Supabase Storage
	try {
		await supabaseAdmin.storage.from('documents').remove([storagePath]);
	} catch (error) {
		console.warn('Local storage document delete error (non-critical):', error);
	}

	return { success: true };
}

/**
 * Get the appropriate document URL based on current storage settings
 * Useful for getting the right URL when storage setting is toggled
 */
export async function getActiveDocumentUrl(document: {
	file_url_s3?: string | null;
	file_url_local?: string | null;
	file_path?: string | null;
}): Promise<string | null> {
	// Check if S3 is enabled
	if (await isS3Enabled()) {
		return document.file_url_s3 || document.file_path || null;
	}
	return document.file_url_local || document.file_path || null;
}

/**
 * Upload an event cover image
 */
export async function uploadEventImage(eventId: string, file: File): Promise<UploadResult> {
	// Validate file type
	const allowedTypes = ['image/jpeg', 'image/png', 'image/webp'];
	if (!allowedTypes.includes(file.type)) {
		return { success: false, error: 'Invalid image type. Allowed: JPEG, PNG, WebP' };
	}

	// Validate file size (max 10MB)
	const maxSize = 10 * 1024 * 1024;
	if (file.size > maxSize) {
		return { success: false, error: 'Image size must be less than 10MB' };
	}

	// Generate path
	const ext = file.name.split('.').pop() || 'jpg';
	const path = `${eventId}/cover.${ext}`;

	// Convert to ArrayBuffer
	const arrayBuffer = await file.arrayBuffer();

	// Upload with upsert to replace existing cover
	return uploadFile('event-images', path, arrayBuffer, {
		contentType: file.type,
		cacheControl: '3600',
		upsert: true
	});
}