// 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/>.

use super::helpers::*;
use bytes::Bytes;
use ethcore::{
    client::EachBlockWith,
    snapshot::{CreationStatus, ManifestData, RestorationStatus, SnapshotService},
};
use ethereum_types::H256;
use hash::keccak;
use parking_lot::Mutex;
use std::{collections::HashMap, sync::Arc};
use types::BlockNumber;
use SyncConfig;
use WarpSync;

pub struct TestSnapshotService {
    manifest: Option<ManifestData>,
    chunks: HashMap<H256, Bytes>,

    restoration_manifest: Mutex<Option<ManifestData>>,
    state_restoration_chunks: Mutex<HashMap<H256, Bytes>>,
    block_restoration_chunks: Mutex<HashMap<H256, Bytes>>,
}

impl TestSnapshotService {
    pub fn new() -> TestSnapshotService {
        TestSnapshotService {
            manifest: None,
            chunks: HashMap::new(),
            restoration_manifest: Mutex::new(None),
            state_restoration_chunks: Mutex::new(HashMap::new()),
            block_restoration_chunks: Mutex::new(HashMap::new()),
        }
    }

    pub fn new_with_snapshot(
        num_chunks: usize,
        block_hash: H256,
        block_number: BlockNumber,
    ) -> TestSnapshotService {
        let num_state_chunks = num_chunks / 2;
        let num_block_chunks = num_chunks - num_state_chunks;
        let state_chunks: Vec<Bytes> = (0..num_state_chunks)
            .map(|_| H256::random().as_bytes().to_vec())
            .collect();
        let block_chunks: Vec<Bytes> = (0..num_block_chunks)
            .map(|_| H256::random().as_bytes().to_vec())
            .collect();
        let manifest = ManifestData {
            version: 2,
            state_hashes: state_chunks.iter().map(|data| keccak(data)).collect(),
            block_hashes: block_chunks.iter().map(|data| keccak(data)).collect(),
            state_root: H256::default(),
            block_number: block_number,
            block_hash: block_hash,
        };
        let mut chunks: HashMap<H256, Bytes> = state_chunks
            .into_iter()
            .map(|data| (keccak(&data), data))
            .collect();
        chunks.extend(block_chunks.into_iter().map(|data| (keccak(&data), data)));
        TestSnapshotService {
            manifest: Some(manifest),
            chunks: chunks,
            restoration_manifest: Mutex::new(None),
            state_restoration_chunks: Mutex::new(HashMap::new()),
            block_restoration_chunks: Mutex::new(HashMap::new()),
        }
    }
}

impl SnapshotService for TestSnapshotService {
    fn manifest(&self) -> Option<ManifestData> {
        self.manifest.as_ref().cloned()
    }

    fn manifest_block(&self) -> Option<(u64, H256)> {
        self.manifest
            .as_ref()
            .map(|manifest| (manifest.block_number, manifest.block_hash))
    }

    fn supported_versions(&self) -> Option<(u64, u64)> {
        Some((1, 2))
    }

    fn completed_chunks(&self) -> Option<Vec<H256>> {
        Some(vec![])
    }

    fn chunk(&self, hash: H256) -> Option<Bytes> {
        self.chunks.get(&hash).cloned()
    }

    fn creation_status(&self) -> CreationStatus {
        CreationStatus::Inactive
    }

    fn restoration_status(&self) -> RestorationStatus {
        match *self.restoration_manifest.lock() {
            Some(ref manifest)
                if self.state_restoration_chunks.lock().len() == manifest.state_hashes.len()
                    && self.block_restoration_chunks.lock().len()
                        == manifest.block_hashes.len() =>
            {
                RestorationStatus::Inactive
            }
            Some(ref manifest) => RestorationStatus::Ongoing {
                block_number: 0,
                state_chunks: manifest.state_hashes.len() as u32,
                block_chunks: manifest.block_hashes.len() as u32,
                state_chunks_done: self.state_restoration_chunks.lock().len() as u32,
                block_chunks_done: self.block_restoration_chunks.lock().len() as u32,
            },
            None => RestorationStatus::Inactive,
        }
    }

    fn begin_restore(&self, manifest: ManifestData) {
        let mut restoration_manifest = self.restoration_manifest.lock();

        if let Some(ref c_manifest) = *restoration_manifest {
            if c_manifest.state_root == manifest.state_root {
                return;
            }
        }

        *restoration_manifest = Some(manifest);
        self.state_restoration_chunks.lock().clear();
        self.block_restoration_chunks.lock().clear();
    }

    fn abort_restore(&self) {
        *self.restoration_manifest.lock() = None;
        self.state_restoration_chunks.lock().clear();
        self.block_restoration_chunks.lock().clear();
    }

    fn abort_snapshot(&self) {}

    fn restore_state_chunk(&self, hash: H256, chunk: Bytes) {
        if self
            .restoration_manifest
            .lock()
            .as_ref()
            .map_or(false, |m| m.state_hashes.iter().any(|h| h == &hash))
        {
            self.state_restoration_chunks.lock().insert(hash, chunk);
        }
    }

    fn restore_block_chunk(&self, hash: H256, chunk: Bytes) {
        if self
            .restoration_manifest
            .lock()
            .as_ref()
            .map_or(false, |m| m.block_hashes.iter().any(|h| h == &hash))
        {
            self.block_restoration_chunks.lock().insert(hash, chunk);
        }
    }

    fn shutdown(&self) {
        self.abort_restore();
    }
}

#[test]
fn snapshot_sync() {
    ::env_logger::try_init().ok();
    let mut config = SyncConfig::default();
    config.warp_sync = WarpSync::Enabled;
    let mut net = TestNet::new_with_config(5, config);
    let snapshot_service = Arc::new(TestSnapshotService::new_with_snapshot(
        16,
        H256::default(),
        500000,
    ));
    for i in 0..4 {
        net.peer_mut(i).snapshot_service = snapshot_service.clone();
        net.peer(i).chain.add_blocks(1, EachBlockWith::Nothing);
    }
    net.sync_steps(50);
    assert_eq!(
        net.peer(4)
            .snapshot_service
            .state_restoration_chunks
            .lock()
            .len(),
        net.peer(0)
            .snapshot_service
            .manifest
            .as_ref()
            .unwrap()
            .state_hashes
            .len()
    );
    assert_eq!(
        net.peer(4)
            .snapshot_service
            .block_restoration_chunks
            .lock()
            .len(),
        net.peer(0)
            .snapshot_service
            .manifest
            .as_ref()
            .unwrap()
            .block_hashes
            .len()
    );
}
