import { CallHandler, ExecutionContext, Injectable, NestInterceptor } from '@nestjs/common';
import { Observable } from 'rxjs';
import { GqlExecutionContext } from '@nestjs/graphql';
import { default as slugify } from 'slugify';

@Injectable()
export class SlugInterceptor implements NestInterceptor {
  intercept(context: ExecutionContext, next: CallHandler): Observable<any> {
    const ctx = GqlExecutionContext.create(context);
    const input = ctx.getArgs().input;
    if (input.title || input.slug) {
      if (!input.slug || input.slug === '') {
        input.slug = slugify(input.title, {
          lower: true,
        });
      } else {
        input.slug = slugify(input.slug, {
          replacement: '-',
          lower: true,
        });
      }
    }
    return next.handle();
  }
}