// 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 std::sync::{atomic, Arc};

use ethereum_types::{Address, H256, U256};
use rlp::Rlp;
use types::transaction::{
    self, SignedTransaction, Transaction, TypedTransaction, UnverifiedTransaction,
};

use pool::{self, client::AccountDetails};

const MAX_TRANSACTION_SIZE: usize = 15 * 1024;

#[derive(Debug, Clone)]
pub struct TestClient {
    verification_invoked: Arc<atomic::AtomicBool>,
    account_details: AccountDetails,
    gas_required: U256,
    is_service_transaction: bool,
    local_address: Address,
    max_transaction_size: usize,
}

impl Default for TestClient {
    fn default() -> Self {
        TestClient {
            verification_invoked: Default::default(),
            account_details: AccountDetails {
                nonce: 123.into(),
                balance: 63_100.into(),
                code_hash: None,
                is_local: false,
            },
            gas_required: 21_000.into(),
            is_service_transaction: false,
            local_address: Default::default(),
            max_transaction_size: MAX_TRANSACTION_SIZE,
        }
    }
}

impl TestClient {
    pub fn new() -> Self {
        TestClient::default()
    }

    pub fn with_balance<T: Into<U256>>(mut self, balance: T) -> Self {
        self.account_details.balance = balance.into();
        self
    }

    pub fn with_nonce<T: Into<U256>>(mut self, nonce: T) -> Self {
        self.account_details.nonce = nonce.into();
        self
    }

    pub fn with_code_hash<T: Into<H256>>(mut self, code_hash: T) -> Self {
        self.account_details.code_hash = Some(code_hash.into());
        self
    }

    pub fn with_gas_required<T: Into<U256>>(mut self, gas_required: T) -> Self {
        self.gas_required = gas_required.into();
        self
    }

    pub fn with_local(mut self, address: &Address) -> Self {
        self.local_address = *address;
        self
    }

    pub fn with_service_transaction(mut self) -> Self {
        self.is_service_transaction = true;
        self
    }

    pub fn verify<T: Into<transaction::PendingTransaction>>(
        &self,
        tx: T,
    ) -> pool::VerifiedTransaction {
        let tx = tx.into();
        pool::VerifiedTransaction {
            hash: tx.hash(),
            sender: tx.sender(),
            priority: pool::Priority::Regular,
            transaction: tx,
            insertion_id: 1,
        }
    }

    pub fn was_verification_triggered(&self) -> bool {
        self.verification_invoked.load(atomic::Ordering::SeqCst)
    }
}

impl pool::client::Client for TestClient {
    fn transaction_already_included(&self, _hash: &H256) -> bool {
        false
    }

    fn verify_transaction_basic(
        &self,
        _tx: &UnverifiedTransaction,
    ) -> Result<(), transaction::Error> {
        Ok(())
    }

    fn verify_transaction(
        &self,
        tx: UnverifiedTransaction,
    ) -> Result<SignedTransaction, transaction::Error> {
        self.verification_invoked
            .store(true, atomic::Ordering::SeqCst);
        Ok(SignedTransaction::new(tx)?)
    }

    fn account_details(&self, address: &Address) -> AccountDetails {
        let mut details = self.account_details.clone();
        if address == &self.local_address {
            details.is_local = true;
        }

        details
    }

    fn required_gas(&self, _tx: &Transaction) -> U256 {
        self.gas_required
    }

    fn transaction_type(&self, _tx: &SignedTransaction) -> pool::client::TransactionType {
        if self.is_service_transaction {
            pool::client::TransactionType::Service
        } else {
            pool::client::TransactionType::Regular
        }
    }

    fn decode_transaction(
        &self,
        transaction: &[u8],
    ) -> Result<UnverifiedTransaction, transaction::Error> {
        let rlp = Rlp::new(&transaction);
        if rlp.as_raw().len() > self.max_transaction_size {
            return Err(transaction::Error::TooBig);
        }
        TypedTransaction::decode(transaction)
            .map_err(|e| transaction::Error::InvalidRlp(e.to_string()))
    }
}

impl pool::client::NonceClient for TestClient {
    fn account_nonce(&self, _address: &Address) -> U256 {
        self.account_details.nonce
    }
}