export interface ParsedMessage {
    operationCode: string;
    metaInfo?: { [key: string]: any };
    fileContent?: Buffer;
}

export class MessageHandler {
    // Format the message with operationCode, guid, metaInfo, and fileContent (Base64 for fileContent)
    static formatMessage(
        operationCode: string,
        metaInfo?: { [key: string]: any },
        fileContent?: Buffer
    ): string {
        let message = `${operationCode}\n`;  // First part: operationCode and guid

        if (metaInfo && Object.keys(metaInfo).length > 0) {
            message += `${JSON.stringify(metaInfo)}\n`;  // Add metaInfo
        }

        if (fileContent && fileContent.length > 0) {
            message += fileContent.toString('base64'); // Convert buffer to Base64 for fileContent
        }

        return message;
    }

    // Parse the incoming message (convert Base64 back to Buffer if fileContent is present)
    static parseMessage(msg: string): ParsedMessage {
        const parts = msg.split('\n');  // Split by \n (operationCode, metaInfo, and fileContent are on separate lines)

        // First part should always be the operation code
        const operationCode = parts[0]?.trim();
        if (!operationCode) {
            throw new Error('Missing operation code in the message');
        }

        let metaInfo: { [key: string]: any } | undefined = undefined;
        let fileContent: Buffer | undefined = undefined;

        // Parse the metaInfo (JSON object) if present
        if (parts[1]) {
            try {
                metaInfo = JSON.parse(parts[1].trim());
            } catch (err) {
                console.error('Invalid metaInfo JSON format:', err);
            }
        }

        // Convert Base64 string back to Buffer for fileContent if present
        if (parts[2]) {
            fileContent = Buffer.from(parts[2].trim(), 'base64');
        }

        return {
            operationCode,
            metaInfo,
            fileContent,
        };
    }

    // Validate if the parsed message contains an operation code
    static validateMessage(parsedMessage: ParsedMessage | null): boolean {
        return !!parsedMessage?.operationCode;
    }
}