module-fee

use support::{decl_module, dispatch::Result,
	traits::{Currency, ExistenceRequirement, WithdrawReason}};
use system::ensure_signed;

// v1.0 branch
// use runtime_primitives::traits::As;

pub trait Trait: balances::Trait {}

decl_module! {
	pub struct Module<T: Trait> for enum Call where origin: T::Origin {
		pub fn do_something(origin) -> Result
		{
			let who = ensure_signed(origin)?;

			let fee = 1337.into();
			// v1.0 branch
			// let fee = T::Balance::sa(1337);

			Self::pay_fee(who, fee)?;

			// Do stuff after fee is paid successfully...

			Ok(())
		}
		
	}
}

impl<T: Trait> Module<T> {
	fn pay_fee(who: T::AccountId, amount: T::Balance) -> Result {
		let _ = <balances::Module<T> as Currency<_>>::withdraw(
			&who,
			amount,
			WithdrawReason::Fee,
			ExistenceRequirement::KeepAlive
		)?;

		Ok(())
	}
}