// Copyright 2015-2020 Parity Technologies (UK) Ltd.
// This file is part of OpenEthereum.

// OpenEthereum 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.

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

//! Import route.

use crate::block_info::{BlockInfo, BlockLocation};
use ethereum_types::H256;

/// Import route for newly inserted block.
#[derive(Debug, PartialEq, Clone)]
pub struct ImportRoute {
    /// Blocks that were invalidated by new block.
    pub retracted: Vec<H256>,
    /// Blocks that were validated by new block.
    pub enacted: Vec<H256>,
    /// Blocks which are neither retracted nor enacted.
    pub omitted: Vec<H256>,
}

impl ImportRoute {
    /// Empty import route.
    pub fn none() -> Self {
        ImportRoute {
            retracted: vec![],
            enacted: vec![],
            omitted: vec![],
        }
    }
}

impl From<BlockInfo> for ImportRoute {
    fn from(info: BlockInfo) -> ImportRoute {
        match info.location {
            BlockLocation::CanonChain => ImportRoute {
                retracted: vec![],
                enacted: vec![info.hash],
                omitted: vec![],
            },
            BlockLocation::Branch => ImportRoute {
                retracted: vec![],
                enacted: vec![],
                omitted: vec![info.hash],
            },
            BlockLocation::BranchBecomingCanonChain(mut data) => {
                data.enacted.push(info.hash);
                ImportRoute {
                    retracted: data.retracted,
                    enacted: data.enacted,
                    omitted: vec![],
                }
            }
        }
    }
}

#[cfg(test)]
mod tests {
    use super::ImportRoute;
    use crate::block_info::{BlockInfo, BlockLocation, BranchBecomingCanonChainData};
    use ethereum_types::{BigEndianHash, U256};

    #[test]
    fn import_route_none() {
        assert_eq!(
            ImportRoute::none(),
            ImportRoute {
                enacted: vec![],
                retracted: vec![],
                omitted: vec![],
            }
        );
    }

    #[test]
    fn import_route_branch() {
        let info = BlockInfo {
            hash: BigEndianHash::from_uint(&U256::from(1)),
            number: 0,
            total_difficulty: U256::from(0),
            location: BlockLocation::Branch,
        };

        assert_eq!(
            ImportRoute::from(info),
            ImportRoute {
                retracted: vec![],
                enacted: vec![],
                omitted: vec![BigEndianHash::from_uint(&U256::from(1))],
            }
        );
    }

    #[test]
    fn import_route_canon_chain() {
        let info = BlockInfo {
            hash: BigEndianHash::from_uint(&U256::from(1)),
            number: 0,
            total_difficulty: U256::from(0),
            location: BlockLocation::CanonChain,
        };

        assert_eq!(
            ImportRoute::from(info),
            ImportRoute {
                retracted: vec![],
                enacted: vec![BigEndianHash::from_uint(&U256::from(1))],
                omitted: vec![],
            }
        );
    }

    #[test]
    fn import_route_branch_becoming_canon_chain() {
        let info = BlockInfo {
            hash: BigEndianHash::from_uint(&U256::from(2)),
            number: 0,
            total_difficulty: U256::from(0),
            location: BlockLocation::BranchBecomingCanonChain(BranchBecomingCanonChainData {
                ancestor: BigEndianHash::from_uint(&U256::from(0)),
                enacted: vec![BigEndianHash::from_uint(&U256::from(1))],
                retracted: vec![
                    BigEndianHash::from_uint(&U256::from(3)),
                    BigEndianHash::from_uint(&U256::from(4)),
                ],
            }),
        };

        assert_eq!(
            ImportRoute::from(info),
            ImportRoute {
                retracted: vec![
                    BigEndianHash::from_uint(&U256::from(3)),
                    BigEndianHash::from_uint(&U256::from(4))
                ],
                enacted: vec![
                    BigEndianHash::from_uint(&U256::from(1)),
                    BigEndianHash::from_uint(&U256::from(2))
                ],
                omitted: vec![],
            }
        );
    }
}
