// 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/>.

//! Client-side stratum job dispatcher and mining notifier handler

use std::{
    fmt,
    net::{AddrParseError, SocketAddr},
    sync::{Arc, Weak},
};

use client::{Client, ImportSealedBlock};
use ethash::{self, SeedHashCompute};
#[cfg(feature = "work-notify")]
use ethcore_miner::work_notify::NotifyWork;
#[cfg(feature = "work-notify")]
use ethcore_stratum::PushWorkHandler;
use ethcore_stratum::{Error as StratumServiceError, JobDispatcher, Stratum as StratumService};
use ethereum_types::{clean_0x, H256, H64, U256};
use miner::{Miner, MinerService};
use parking_lot::Mutex;
use rlp::encode;

/// Configures stratum server options.
#[derive(Debug, PartialEq, Clone)]
pub struct Options {
    /// Working directory
    pub io_path: String,
    /// Network address
    pub listen_addr: String,
    /// Port
    pub port: u16,
    /// Secret for peers
    pub secret: Option<H256>,
}

struct SubmitPayload {
    nonce: H64,
    pow_hash: H256,
    mix_hash: H256,
}

impl SubmitPayload {
    fn from_args(payload: Vec<String>) -> Result<Self, PayloadError> {
        if payload.len() != 3 {
            return Err(PayloadError::ArgumentsAmountUnexpected(payload.len()));
        }

        let nonce = match clean_0x(&payload[0]).parse::<H64>() {
            Ok(nonce) => nonce,
            Err(e) => {
                warn!(target: "stratum", "submit_work ({}): invalid nonce ({:?})", &payload[0], e);
                return Err(PayloadError::InvalidNonce(payload[0].clone()));
            }
        };

        let pow_hash = match clean_0x(&payload[1]).parse::<H256>() {
            Ok(pow_hash) => pow_hash,
            Err(e) => {
                warn!(target: "stratum", "submit_work ({}): invalid hash ({:?})", &payload[1], e);
                return Err(PayloadError::InvalidPowHash(payload[1].clone()));
            }
        };

        let mix_hash = match clean_0x(&payload[2]).parse::<H256>() {
            Ok(mix_hash) => mix_hash,
            Err(e) => {
                warn!(target: "stratum", "submit_work ({}): invalid mix-hash ({:?})",  &payload[2], e);
                return Err(PayloadError::InvalidMixHash(payload[2].clone()));
            }
        };

        Ok(SubmitPayload {
            nonce: nonce,
            pow_hash: pow_hash,
            mix_hash: mix_hash,
        })
    }
}

#[derive(Debug)]
enum PayloadError {
    ArgumentsAmountUnexpected(usize),
    InvalidNonce(String),
    InvalidPowHash(String),
    InvalidMixHash(String),
}

impl fmt::Display for PayloadError {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        fmt::Debug::fmt(&self, f)
    }
}

/// Job dispatcher for stratum service
pub struct StratumJobDispatcher {
    seed_compute: Mutex<SeedHashCompute>,
    client: Weak<Client>,
    miner: Weak<Miner>,
}

impl JobDispatcher for StratumJobDispatcher {
    fn initial(&self) -> Option<String> {
        // initial payload may contain additional data, not in this case
        self.job()
    }

    fn job(&self) -> Option<String> {
        self.with_core(|client, miner| {
            miner
                .work_package(&*client)
                .map(|(pow_hash, number, _timestamp, difficulty)| {
                    self.payload(pow_hash, difficulty, number)
                })
        })
    }

    fn submit(&self, payload: Vec<String>) -> Result<(), StratumServiceError> {
        let payload = SubmitPayload::from_args(payload)
            .map_err(|e| StratumServiceError::Dispatch(e.to_string()))?;

        trace!(
            target: "stratum",
            "submit_work: Decoded: nonce={}, pow_hash={}, mix_hash={}",
            payload.nonce,
            payload.pow_hash,
            payload.mix_hash,
        );

        self.with_core_result(|client, miner| {
            let seal = vec![encode(&payload.mix_hash), encode(&payload.nonce)];

            let import = miner
                .submit_seal(payload.pow_hash, seal)
                .and_then(|block| client.import_sealed_block(block));
            match import {
                Ok(_) => Ok(()),
                Err(e) => {
                    warn!(target: "stratum", "submit_seal error: {:?}", e);
                    Err(StratumServiceError::Dispatch(e.to_string()))
                }
            }
        })
    }
}

impl StratumJobDispatcher {
    /// New stratum job dispatcher given the miner and client
    fn new(miner: Weak<Miner>, client: Weak<Client>) -> StratumJobDispatcher {
        StratumJobDispatcher {
            seed_compute: Mutex::new(SeedHashCompute::default()),
            client: client,
            miner: miner,
        }
    }

    /// Serializes payload for stratum service
    fn payload(&self, pow_hash: H256, difficulty: U256, number: u64) -> String {
        // TODO: move this to engine
        let target = ethash::difficulty_to_boundary(&difficulty);
        let seed_hash = &self.seed_compute.lock().hash_block_number(number);
        let seed_hash = H256::from_slice(&seed_hash[..]);
        format!(
            r#"["0x", "0x{:x}","0x{:x}","0x{:x}","0x{:x}"]"#,
            pow_hash, seed_hash, target, number
        )
    }

    fn with_core<F, R>(&self, f: F) -> Option<R>
    where
        F: Fn(Arc<Client>, Arc<Miner>) -> Option<R>,
    {
        self.client
            .upgrade()
            .and_then(|client| self.miner.upgrade().and_then(|miner| (f)(client, miner)))
    }

    fn with_core_result<F>(&self, f: F) -> Result<(), StratumServiceError>
    where
        F: Fn(Arc<Client>, Arc<Miner>) -> Result<(), StratumServiceError>,
    {
        match (self.client.upgrade(), self.miner.upgrade()) {
            (Some(client), Some(miner)) => f(client, miner),
            _ => Ok(()),
        }
    }
}

/// Wrapper for dedicated stratum service
pub struct Stratum {
    dispatcher: Arc<StratumJobDispatcher>,
    service: Arc<StratumService>,
}

#[derive(Debug)]
/// Stratum error
pub enum Error {
    /// IPC sockets error
    Service(StratumServiceError),
    /// Invalid network address
    Address(AddrParseError),
}

impl From<StratumServiceError> for Error {
    fn from(service_err: StratumServiceError) -> Error {
        Error::Service(service_err)
    }
}

impl From<AddrParseError> for Error {
    fn from(err: AddrParseError) -> Error {
        Error::Address(err)
    }
}

#[cfg(feature = "work-notify")]
impl NotifyWork for Stratum {
    fn notify(&self, pow_hash: H256, difficulty: U256, number: u64) {
        trace!(target: "stratum", "Notify work");

        self.service
            .push_work_all(self.dispatcher.payload(pow_hash, difficulty, number));
    }
}

impl Stratum {
    /// New stratum job dispatcher, given the miner, client and dedicated stratum service
    pub fn start(
        options: &Options,
        miner: Weak<Miner>,
        client: Weak<Client>,
    ) -> Result<Stratum, Error> {
        use std::net::IpAddr;

        let dispatcher = Arc::new(StratumJobDispatcher::new(miner, client));

        let service = StratumService::start(
            &SocketAddr::new(options.listen_addr.parse::<IpAddr>()?, options.port),
            dispatcher.clone(),
            options.secret.clone(),
        )?;

        Ok(Stratum {
            dispatcher,
            service,
        })
    }

    /// Start STRATUM job dispatcher and register it in the miner
    #[cfg(feature = "work-notify")]
    pub fn register(cfg: &Options, miner: Arc<Miner>, client: Weak<Client>) -> Result<(), Error> {
        let stratum = Stratum::start(cfg, Arc::downgrade(&miner.clone()), client)?;
        miner.add_work_listener(Box::new(stratum) as Box<dyn NotifyWork>);
        Ok(())
    }
}