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// Copyright 2021-2022 Semantic Network Ltd.
// This file is part of Tidechain.

// Tidechain 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.

// Tidechain 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 Tidechain.  If not, see <http://www.gnu.org/licenses/>.

// This file is part of Substrate.

// Copyright (C) 2017-2021 Parity Technologies (UK) Ltd.
// SPDX-License-Identifier: Apache-2.0

// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// 	http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

//! Assets pallet's `StoredMap` implementation.

use super::*;

impl<T: Config<I>, I: 'static> StoredMap<(T::AssetId, T::AccountId), T::Extra> for Pallet<T, I> {
  fn get(id_who: &(T::AssetId, T::AccountId)) -> T::Extra {
    let &(id, ref who) = id_who;
    Account::<T, I>::get(who, id)
      .map(|a| a.extra)
      .unwrap_or_default()
  }

  fn try_mutate_exists<R, E: From<DispatchError>>(
    id_who: &(T::AssetId, T::AccountId),
    f: impl FnOnce(&mut Option<T::Extra>) -> Result<R, E>,
  ) -> Result<R, E> {
    let &(id, ref who) = id_who;
    let mut maybe_extra = Account::<T, I>::get(who, id).map(|a| a.extra);
    let r = f(&mut maybe_extra)?;
    // They want to write some value or delete it.
    // If the account existed and they want to write a value, then we write.
    // If the account didn't exist and they want to delete it, then we let it pass.
    // Otherwise, we fail.
    Account::<T, I>::try_mutate(who, id, |maybe_account| {
      if let Some(extra) = maybe_extra {
        // They want to write a value. Let this happen only if the account actually exists.
        if let Some(ref mut account) = maybe_account {
          account.extra = extra;
        } else {
          return Err(DispatchError::NoProviders.into());
        }
      } else {
        // They want to delete it. Let this pass if the item never existed anyway.
        ensure!(maybe_account.is_none(), DispatchError::ConsumerRemaining);
      }
      Ok(r)
    })
  }
}