import {
    BadRequestException,
    InternalServerErrorException,
    Logger,
} from '@nestjs/common';
import * as oracledb from 'oracledb';

const logger = new Logger('Helper');

export const handleError = (error: any, context: string = 'UnknownService'): never => {
    if (error instanceof BadRequestException) {
        logger.warn(`[${context}] ${error.message}`);
        throw error;
    }

    if (error.message?.includes('NJS-107')) {
        logger.warn(`[${context}] Invalid cursor encountered: ${error.message}`);
        throw new BadRequestException('Invalid database response.');
    }

    if (error.message?.includes('ORA-')) {
        logger.error(`[${context}] Oracle error occurred: ${error.message}`);
        throw new InternalServerErrorException(error.message);
    }

    logger.error(`[${context}] Unexpected error:`, error.stack || error);
    throw new InternalServerErrorException(error.message || 'Internal error');
};

export const closeOracleDbConnection = async (connection: any, context: string = 'UnknownService'): Promise<void> => {
    if (connection) {
        try {
            await connection.close();
        } catch (closeErr) {
            logger.error(`[${context}] Failed to close DB connection`, closeErr.stack || closeErr);
        }
    }
};

export const fetchCursor = async <T>(cursor: oracledb.ResultSet<T>, context: string = 'UnknownService'): Promise<T[]> => {
    try {
        const rows = await cursor.getRows();
        await cursor.close();
        return rows;
    } catch (err) {
        logger.error(`[${context}] Failed to fetch from cursor`, err.stack || err);
        throw new InternalServerErrorException('Error reading data from database.');
    }
};

export const setEmptyStringsToNull = (obj: any): void => {
    Object.keys(obj).forEach((key) => {
        if (typeof obj[key] === 'object' && obj[key] !== null) {
            setEmptyStringsToNull(obj[key]);
        } else if (obj[key] === '') {
            obj[key] = null;
        }
    });
}