Hello,
I have extensive experience in .Net (C#), working in the software development industry for more than five years i have worked on developing complex applications in almost all areas e.g. Desktop apps, web apps, web services, WPF, WCF, Web API etc.
i already have a bot that posts comments on youtube urls, i can modify it and implement your required functionality, the tool is written in C#. i can modify the app to any kind of project like a consol app, or just a code snippit, but it will be in C#.net. PM if you are interested in taking this as a .Net solution instead of PHP.
Thank You