// Copyright 2015-2019 Parity Technologies (UK) Ltd.
// This file is part of Parity Ethereum.

// Parity Ethereum 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.

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

use bytes::Bytes;
use call_contract::RegistryInfo;
use common_types::transaction::{Action, SignedTransaction, Transaction};
use ethcore::{
    client::{BlockChainClient, BlockId, ChainInfo, Client, Nonce},
    miner::{Miner, MinerService},
};
use ethereum_types::Address;
use helpers::{get_confirmed_block_hash, REQUEST_CONFIRMATIONS_REQUIRED};
use std::sync::{Arc, Weak};
use sync::SyncProvider;
use ContractAddress;
use Error;
use NodeKeyPair;

#[derive(Clone)]
/// 'Trusted' client weak reference.
pub struct TrustedClient {
    /// This key server node key pair.
    self_key_pair: Arc<NodeKeyPair>,
    /// Blockchain client.
    client: Weak<Client>,
    /// Sync provider.
    sync: Weak<SyncProvider>,
    /// Miner service.
    miner: Weak<Miner>,
}

impl TrustedClient {
    /// Create new trusted client.
    pub fn new(
        self_key_pair: Arc<NodeKeyPair>,
        client: Arc<Client>,
        sync: Arc<SyncProvider>,
        miner: Arc<Miner>,
    ) -> Self {
        TrustedClient {
            self_key_pair: self_key_pair,
            client: Arc::downgrade(&client),
            sync: Arc::downgrade(&sync),
            miner: Arc::downgrade(&miner),
        }
    }

    /// Get 'trusted' `Client` reference only if it is synchronized && trusted.
    pub fn get(&self) -> Option<Arc<Client>> {
        self.client
            .upgrade()
            .and_then(|client| self.sync.upgrade().map(|sync| (client, sync)))
            .and_then(|(client, sync)| {
                let is_synced = !sync.status().is_syncing(client.queue_info());
                let is_trusted = client.chain_info().security_level().is_full();
                match is_synced && is_trusted {
                    true => Some(client),
                    false => None,
                }
            })
    }

    /// Get untrusted `Client` reference.
    pub fn get_untrusted(&self) -> Option<Arc<Client>> {
        self.client.upgrade()
    }

    /// Transact contract.
    pub fn transact_contract(&self, contract: Address, tx_data: Bytes) -> Result<(), Error> {
        let client = self
            .client
            .upgrade()
            .ok_or_else(|| Error::Internal("cannot submit tx when client is offline".into()))?;
        let miner = self
            .miner
            .upgrade()
            .ok_or_else(|| Error::Internal("cannot submit tx when miner is offline".into()))?;
        let engine = client.engine();
        let transaction = Transaction {
            nonce: client.latest_nonce(&self.self_key_pair.address()),
            action: Action::Call(contract),
            gas: miner.authoring_params().gas_range_target.0,
            gas_price: miner.sensible_gas_price(),
            value: Default::default(),
            data: tx_data,
        };
        let chain_id = engine.signing_chain_id(&client.latest_env_info());
        let signature = self.self_key_pair.sign(&transaction.hash(chain_id))?;
        let signed = SignedTransaction::new(transaction.with_signature(signature, chain_id))?;
        miner
            .import_own_transaction(&*client, signed.into())
            .map_err(|e| Error::Internal(format!("failed to import tx: {}", e)))
    }

    /// Read contract address. If address source is registry, address only returned if current client state is
    /// trusted. Address from registry is read from registry from block latest block with
    /// REQUEST_CONFIRMATIONS_REQUIRED confirmations.
    pub fn read_contract_address(
        &self,
        registry_name: String,
        address: &ContractAddress,
    ) -> Option<Address> {
        match *address {
            ContractAddress::Address(ref address) => Some(address.clone()),
            ContractAddress::Registry => self.get().and_then(|client| {
                get_confirmed_block_hash(&*client, REQUEST_CONFIRMATIONS_REQUIRED)
                    .and_then(|block| client.registry_address(registry_name, BlockId::Hash(block)))
            }),
        }
    }
}