// 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/>.

//! Transaction execution format module.

use bytes::Bytes;
use ethereum_types::{Address, U256, U512};
use ethtrie;
use trace::{FlatTrace, VMTrace};
use types::{log_entry::LogEntry, state_diff::StateDiff};
use vm;

use std::{error, fmt};

/// Transaction execution receipt.
#[derive(Debug, PartialEq, Clone)]
pub struct Executed<T = FlatTrace, V = VMTrace> {
    /// True if the outer call/create resulted in an exceptional exit.
    pub exception: Option<vm::Error>,

    /// Gas paid up front for execution of transaction.
    pub gas: U256,

    /// Gas used during execution of transaction.
    pub gas_used: U256,

    /// Gas refunded after the execution of transaction.
    /// To get gas that was required up front, add `refunded` and `gas_used`.
    pub refunded: U256,

    /// Cumulative gas used in current block so far.
    ///
    /// `cumulative_gas_used = gas_used(t0) + gas_used(t1) + ... gas_used(tn)`
    ///
    /// where `tn` is current transaction.
    pub cumulative_gas_used: U256,

    /// Vector of logs generated by transaction.
    pub logs: Vec<LogEntry>,

    /// Addresses of contracts created during execution of transaction.
    /// Ordered from earliest creation.
    ///
    /// eg. sender creates contract A and A in constructor creates contract B
    ///
    /// B creation ends first, and it will be the first element of the vector.
    pub contracts_created: Vec<Address>,
    /// Transaction output.
    pub output: Bytes,
    /// The trace of this transaction.
    pub trace: Vec<T>,
    /// The VM trace of this transaction.
    pub vm_trace: Option<V>,
    /// The state diff, if we traced it.
    pub state_diff: Option<StateDiff>,
}

/// Result of executing the transaction.
#[derive(PartialEq, Debug, Clone)]
pub enum ExecutionError {
    /// Returned when there gas paid for transaction execution is
    /// lower than base gas required.
    NotEnoughBaseGas {
        /// Absolute minimum gas required.
        required: U256,
        /// Gas provided.
        got: U256,
    },
    /// Returned when block (gas_used + gas) > gas_limit.
    ///
    /// If gas =< gas_limit, upstream may try to execute the transaction
    /// in next block.
    BlockGasLimitReached {
        /// Gas limit of block for transaction.
        gas_limit: U256,
        /// Gas used in block prior to transaction.
        gas_used: U256,
        /// Amount of gas in block.
        gas: U256,
    },
    /// Returned when transaction nonce does not match state nonce.
    InvalidNonce {
        /// Nonce expected.
        expected: U256,
        /// Nonce found.
        got: U256,
    },
    /// Returned when cost of transaction (value + gas_price * gas) exceeds
    /// current sender balance.
    NotEnoughCash {
        /// Minimum required balance.
        required: U512,
        /// Actual balance.
        got: U512,
    },
    /// When execution tries to modify the state in static context
    MutableCallInStaticContext,
    /// Returned when transacting from a non-existing account with dust protection enabled.
    SenderMustExist,
    /// Returned when internal evm error occurs.
    Internal(String),
    /// Returned when generic transaction occurs
    TransactionMalformed(String),
}

impl From<Box<ethtrie::TrieError>> for ExecutionError {
    fn from(err: Box<ethtrie::TrieError>) -> Self {
        ExecutionError::Internal(format!("{:?}", err))
    }
}
impl From<ethtrie::TrieError> for ExecutionError {
    fn from(err: ethtrie::TrieError) -> Self {
        ExecutionError::Internal(format!("{:?}", err))
    }
}

impl fmt::Display for ExecutionError {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        use self::ExecutionError::*;

        let msg = match *self {
            NotEnoughBaseGas {
                ref required,
                ref got,
            } => format!(
                "Not enough base gas. {} is required, but only {} paid",
                required, got
            ),
            BlockGasLimitReached {
                ref gas_limit,
                ref gas_used,
                ref gas,
            } => format!(
                "Block gas limit reached. The limit is {}, {} has \
					already been used, and {} more is required",
                gas_limit, gas_used, gas
            ),
            InvalidNonce {
                ref expected,
                ref got,
            } => format!(
                "Invalid transaction nonce: expected {}, found {}",
                expected, got
            ),
            NotEnoughCash {
                ref required,
                ref got,
            } => format!(
                "Cost of transaction exceeds sender balance. {} is required \
					but the sender only has {}",
                required, got
            ),
            MutableCallInStaticContext => "Mutable Call in static context".to_owned(),
            SenderMustExist => "Transacting from an empty account".to_owned(),
            Internal(ref msg) => msg.clone(),
            TransactionMalformed(ref err) => format!("Malformed transaction: {}", err),
        };

        f.write_fmt(format_args!("Transaction execution error ({}).", msg))
    }
}

impl error::Error for ExecutionError {
    fn description(&self) -> &str {
        "Transaction execution error"
    }
}

/// Result of executing the transaction.
#[derive(PartialEq, Debug, Clone)]
pub enum CallError {
    /// Couldn't find the transaction in the chain.
    TransactionNotFound,
    /// Couldn't find requested block's state in the chain.
    StatePruned,
    /// Couldn't find an amount of gas that didn't result in an exception.
    Exceptional(vm::Error),
    /// Corrupt state.
    StateCorrupt,
    /// Error executing.
    Execution(ExecutionError),
}

impl From<ExecutionError> for CallError {
    fn from(error: ExecutionError) -> Self {
        CallError::Execution(error)
    }
}

impl fmt::Display for CallError {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        use self::CallError::*;

        let msg = match *self {
            TransactionNotFound => "Transaction couldn't be found in the chain".into(),
            StatePruned => "Couldn't find the transaction block's state in the chain".into(),
            Exceptional(ref e) => format!("An exception ({}) happened in the execution", e),
            StateCorrupt => "Stored state found to be corrupted.".into(),
            Execution(ref e) => format!("{}", e),
        };

        f.write_fmt(format_args!("Transaction execution error ({}).", msg))
    }
}

/// Transaction execution result.
pub type ExecutionResult = Result<Box<Executed>, ExecutionError>;