// Copyright 2015 The go-ethereum Authors
// This file is part of go-ethereum.
//
// go-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.
//
// go-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 go-ethereum. If not, see <http://www.gnu.org/licenses/>.

package miner

import (
	"fmt"

	"github.com/ethereum/go-ethereum/common"
	"github.com/ethereum/go-ethereum/logger/glog"
	rpc "github.com/ethereum/go-ethereum/rpc/v2"
)

// PublicMinerAPI provides an API to control the miner.
// It offers only methods that operate on data that pose no security risk when it is publicly accessible.
type PublicMinerAPI struct {
	miner *Miner
	agent *RemoteAgent
}

// NewPublicMinerAPI create a new PublicMinerAPI instance.
func NewPublicMinerAPI(miner *Miner) *PublicMinerAPI {
	return &PublicMinerAPI{miner, NewRemoteAgent()}
}

// Mining returns an indication if this node is currently mining.
func (s *PublicMinerAPI) Mining() bool {
	return s.miner.Mining()
}

// SubmitWork can be used by external miner to submit their POW solution. It returns an indication if the work was
// accepted. Note, this is not an indication if the provided work was valid!
func (s *PublicMinerAPI) SubmitWork(nonce rpc.HexNumber, solution, digest common.Hash) bool {
	return s.agent.SubmitWork(nonce.Uint64(), digest, solution)
}

// GetWork returns a work package for external miner. The work package consists of 3 strings
// result[0], 32 bytes hex encoded current block header pow-hash
// result[1], 32 bytes hex encoded seed hash used for DAG
// result[2], 32 bytes hex encoded boundary condition ("target"), 2^256/difficulty
func (s *PublicMinerAPI) GetWork() ([]string, error) {
	if !s.Mining() {
		s.miner.Start(s.miner.coinbase, 0)
	}
	if work, err := s.agent.GetWork(); err == nil {
		return work[:], nil
	} else {
		glog.Infof("%v\n", err)
	}
	return nil, fmt.Errorf("mining not ready")
}

// SubmitHashrate can be used for remote miners to submit their hash rate. This enables the node to report the combined
// hash rate of all miners which submit work through this node. It accepts the miner hash rate and an identifier which
// must be unique between nodes.
func (s *PublicMinerAPI) SubmitHashrate(hashrate rpc.HexNumber, id common.Hash) bool {
	s.agent.SubmitHashrate(id, hashrate.Uint64())
	return true
}