Strip markdown while keeping URLs

I want to remove markdown while still enable user to follow links. 

I.e. I want 
```markdown
**bold text**  [link](https://example.com)
```
to be rendered into something that keeps "example.com"

```txt
bold text  link (https://example.com)
```

Use case: sending some user-generated content like "comment" in plain text email

How I can achieve this? I'm ready to develop extension.