import {
  ArgumentsHost,
  Catch,
  ExceptionFilter,
  HttpException,
  HttpStatus,
} from '@nestjs/common';
import type { Request, Response } from 'express';

@Catch()
export class GlobalExceptionFilter implements ExceptionFilter {
  catch(exception: unknown, host: ArgumentsHost) {
    const ctx = host.switchToHttp();
    const response = ctx.getResponse<Response>();
    const request = ctx.getRequest<Request>();

    const isHttpException = exception instanceof HttpException;
    const status = isHttpException
      ? exception.getStatus()
      : HttpStatus.INTERNAL_SERVER_ERROR;
    const payload = isHttpException ? exception.getResponse() : null;

    response.status(status).json({
      success: false,
      statusCode: status,
      message: this.resolveMessage(payload, exception),
      error:
        typeof payload === 'object' && payload !== null ? payload : undefined,
      timestamp: new Date().toISOString(),
      path: request.url,
    });
  }

  private resolveMessage(payload: unknown, exception: unknown): string {
    if (typeof payload === 'string') {
      return payload;
    }

    if (typeof payload === 'object' && payload !== null && 'message' in payload) {
      const message = (payload as { message?: string | string[] }).message;
      if (Array.isArray(message)) {
        return message.join(', ');
      }
      if (typeof message === 'string') {
        return message;
      }
    }

    if (exception instanceof Error) {
      return exception.message;
    }

    return 'Internal server error';
  }
}