claim.rs

use frame_support::{decl_module, decl_storage, decl_event, decl_error, ensure};
use sp_std::vec::Vec;
use system::ensure_signed;

pub trait Trait: system::Trait {
    type Event: From<Event<Self>> + Into<<Self as system::Trait>::Event>;
}

decl_event! {
    pub enum Event<T> where AccountId = <T as system::Trait>::AccountId {
        // Events 
        ClaimCreated(AccountId, Vec<u8>),
        ClaimRevoked(AccountId, Vec<u8>), // This is a temporary event to make things compile :)
    }
}

decl_storage! {
    trait Store for Module<T: Trait> as TemplateModule {
        // Storage
        Proofs: map Vec<u8> => (T::AccountId, T::BlockNumber);
    }
}

decl_module! {
    pub struct Module<T: Trait> for enum Call where origin: T::Origin {
        // Functions
        fn deposit_event() = default;

        fn create_claim(origin, proof: Vec<u8>) {
            let sender = ensure_signed(origin)?;
            ensure!(!Proofs::<T>::exists(&proof), Error::<T>::AlreadyClaimed);
            
            let current_block = <system::Module<T>>::block_number();
            Proofs::<T>::insert(&proof, (&sender, current_block));
            Self::deposit_event(RawEvent::ClaimCreated(sender, proof));
        }
    }
}

decl_error! {
    pub enum Error for Module<T: Trait> {
        /// This proof is already claimed.
        AlreadyClaimed,
    }
}