// Copyright (C) Moondance Labs Ltd.

// This file is part of Tanssi.

// Tanssi is free software: you can redistribute it and/or modify

// it under the terms of the GNU General Public License as published by

// the Free Software Foundation, either version 3 of the License, or

// (at your option) any later version.

// Tanssi is distributed in the hope that it will be useful,

// but WITHOUT ANY WARRANTY; without even the implied warranty of

// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License

// along with Tanssi.  If not, see <http://www.gnu.org/licenses/>

//! # Authority Mapping Pallet

//!

//! This pallet stores the AuthorityId -> AccountID mapping for two sessions

//! In particular it holds the mapping for the current and the past session

//! Both are necessary to verify block-authorship with respect to current

//! block proposals or blocks that have been proposed in the past-session

#![cfg_attr(not(feature = "std"), no_std)]

extern crate alloc;

pub use pallet::*;

use {

    alloc::{collections::btree_map::BTreeMap, vec},

    frame_support::pallet_prelude::*,

    sp_runtime::{

        traits::{AtLeast32BitUnsigned, CheckedSub},

        RuntimeAppPublic,

    },

};

#[cfg(test)]

mod mock;

#[cfg(test)]

mod tests;

#[frame_support::pallet]

pub mod pallet {

    use super::*;

    #[pallet::pallet]

    pub struct Pallet<T>(_);

    /// Configure the pallet by specifying the parameters and types on which it depends.

    #[pallet::config]

    pub trait Config: frame_system::Config {

        type SessionIndex: parity_scale_codec::FullCodec

            + TypeInfo

            + Copy

            + AtLeast32BitUnsigned

            + MaxEncodedLen;

        // Sessions after which keys should be removed

        #[pallet::constant]

        type SessionRemovalBoundary: Get<Self::SessionIndex>;

        type AuthorityId: Member

            + Parameter

            + Ord

            + RuntimeAppPublic

            + MaybeSerializeDeserialize

            + MaxEncodedLen;

    }

    #[pallet::storage]

    #[pallet::unbounded]

    pub type AuthorityIdMapping<T: Config> = StorageMap<

        _,

        Twox64Concat,

        T::SessionIndex,

        BTreeMap<T::AuthorityId, T::AccountId>,

        OptionQuery,

    >;

    impl<T: Config> Pallet<T> {

            // Remove only if the checked sub does not saturate

            {

    }

}