// This file is part of Substrate.

// Copyright (C) Parity Technologies (UK) Ltd.
// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0

// This program 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.

// This program 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 this program. If not, see <https://www.gnu.org/licenses/>.

use sp_blockchain::Error;

/// Subscription management error.
#[derive(Debug, thiserror::Error)]
pub enum SubscriptionManagementError {
	/// The subscription has exceeded the internal limits
	/// regarding the number of pinned blocks in memory or
	/// the number of ongoing operations.
	#[error("Exceeded pinning or operation limits")]
	ExceededLimits,
	/// Error originated from the blockchain (client or backend).
	#[error("Blockchain error {0}")]
	Blockchain(Error),
	/// The database does not contain a block hash.
	#[error("Block hash is absent")]
	BlockHashAbsent,
	/// The database does not contain a block header.
	#[error("Block header is absent")]
	BlockHeaderAbsent,
	/// The specified subscription ID is not present.
	#[error("Subscription is absent")]
	SubscriptionAbsent,
	/// The unpin method was called with duplicate hashes.
	#[error("Duplicate hashes")]
	DuplicateHashes,
	/// The distance between the leaves and the current finalized block is too large.
	#[error("Distance too large")]
	BlockDistanceTooLarge,
	/// Custom error.
	#[error("Subscription error {0}")]
	Custom(String),
}

// Blockchain error does not implement `PartialEq` needed for testing.
impl PartialEq for SubscriptionManagementError {
	fn eq(&self, other: &SubscriptionManagementError) -> bool {
		match (self, other) {
			(Self::ExceededLimits, Self::ExceededLimits) |
			// Not needed for testing.
			(Self::Blockchain(_), Self::Blockchain(_)) |
			(Self::BlockHashAbsent, Self::BlockHashAbsent) |
			(Self::BlockHeaderAbsent, Self::BlockHeaderAbsent) |
			(Self::SubscriptionAbsent, Self::SubscriptionAbsent) |
			(Self::DuplicateHashes, Self::DuplicateHashes) => true,
			(Self::BlockDistanceTooLarge, Self::BlockDistanceTooLarge) => true,
			(Self::Custom(lhs), Self::Custom(rhs)) => lhs == rhs,
			_ => false,
		}
	}
}

impl From<Error> for SubscriptionManagementError {
	fn from(err: Error) -> Self {
		SubscriptionManagementError::Blockchain(err)
	}
}
