// Copyright 2017 Monax Industries Limited
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//    http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package rpc

import (
	"context"
	"fmt"

	acm "github.com/hyperledger/burrow/account"
	"github.com/hyperledger/burrow/account/state"
	"github.com/hyperledger/burrow/binary"
	bcm "github.com/hyperledger/burrow/blockchain"
	"github.com/hyperledger/burrow/consensus/tendermint/query"
	"github.com/hyperledger/burrow/event"
	"github.com/hyperledger/burrow/execution"
	"github.com/hyperledger/burrow/keys"
	"github.com/hyperledger/burrow/logging"
	"github.com/hyperledger/burrow/logging/structure"
	"github.com/hyperledger/burrow/permission"
	"github.com/hyperledger/burrow/project"
	"github.com/hyperledger/burrow/txs"
	tm_types "github.com/tendermint/tendermint/types"
	"github.com/tmthrgd/go-hex"
)

// Magic! Should probably be configurable, but not shouldn't be so huge we
// end up DoSing ourselves.
const MaxBlockLookback = 100

// Base service that provides implementation for all underlying RPC methods
type Service struct {
	ctx          context.Context
	committed    *execution.Accounts
	mempool      *execution.Accounts
	subscribable event.Subscribable
	nameReg      execution.NameRegIterable
	blockchain   bcm.Blockchain
	transactor   *execution.Transactor
	nodeView     query.NodeView
	logger       *logging.Logger
}

func NewService(ctx context.Context, committedState state.Iterable, mempoolState state.Iterable,
	nameReg execution.NameRegIterable, subscribable event.Subscribable, blockchain bcm.Blockchain,
	keyClient keys.KeyClient, transactor *execution.Transactor, nodeView query.NodeView,
	logger *logging.Logger) *Service {

	return &Service{
		ctx:          ctx,
		committed:    execution.NewAccounts(committedState, keyClient),
		mempool:      execution.NewAccounts(mempoolState, keyClient),
		nameReg:      nameReg,
		subscribable: subscribable,
		blockchain:   blockchain,
		transactor:   transactor,
		nodeView:     nodeView,
		logger:       logger.With(structure.ComponentKey, "Service"),
	}
}

// Provides a sub-service with only the subscriptions methods
func NewSubscribableService(subscribable event.Subscribable, logger *logging.Logger) *Service {
	return &Service{
		ctx:          context.Background(),
		subscribable: subscribable,
		logger:       logger.With(structure.ComponentKey, "Service"),
	}
}

// Transacting...

func (s *Service) Transactor() *execution.Transactor {
	return s.transactor
}

func (s *Service) Committed() *execution.Accounts {
	return s.committed
}

func (s *Service) Mempool() *execution.Accounts {
	return s.mempool
}

func (s *Service) ListUnconfirmedTxs(maxTxs int) (*ResultListUnconfirmedTxs, error) {
	// Get all transactions for now
	transactions, err := s.nodeView.MempoolTransactions(maxTxs)
	if err != nil {
		return nil, err
	}
	wrappedTxs := make([]txs.Wrapper, len(transactions))
	for i, tx := range transactions {
		wrappedTxs[i] = txs.Wrap(tx)
	}
	return &ResultListUnconfirmedTxs{
		NumTxs: len(transactions),
		Txs:    wrappedTxs,
	}, nil
}

func (s *Service) Subscribe(ctx context.Context, subscriptionID string, eventID string,
	callback func(resultEvent *ResultEvent) bool) error {

	queryBuilder := event.QueryForEventID(eventID)
	s.logger.InfoMsg("Subscribing to events",
		"query", queryBuilder.String(),
		"subscription_id", subscriptionID,
		"event_id", eventID)
	return event.SubscribeCallback(ctx, s.subscribable, subscriptionID, queryBuilder,
		func(message interface{}) bool {
			resultEvent, err := NewResultEvent(eventID, message)
			if err != nil {
				s.logger.InfoMsg("Received event that could not be mapped to ResultEvent",
					structure.ErrorKey, err,
					"subscription_id", subscriptionID,
					"event_id", eventID)
				return true
			}
			return callback(resultEvent)
		})
}

func (s *Service) Unsubscribe(ctx context.Context, subscriptionID string) error {
	s.logger.InfoMsg("Unsubscribing from events",
		"subscription_id", subscriptionID)
	err := s.subscribable.UnsubscribeAll(ctx, subscriptionID)
	if err != nil {
		return fmt.Errorf("error unsubscribing from event with subscriptionID '%s': %v", subscriptionID, err)
	}
	return nil
}

func (s *Service) Status() (*ResultStatus, error) {
	tip := s.blockchain.Tip()
	latestHeight := tip.LastBlockHeight()
	var (
		latestBlockMeta *tm_types.BlockMeta
		latestBlockHash []byte
		latestBlockTime int64
	)
	if latestHeight != 0 {
		latestBlockMeta = s.nodeView.BlockStore().LoadBlockMeta(int64(latestHeight))
		latestBlockHash = latestBlockMeta.Header.Hash()
		latestBlockTime = latestBlockMeta.Header.Time.UnixNano()
	}
	publicKey, err := s.nodeView.PrivValidatorPublicKey()
	if err != nil {
		return nil, err
	}
	return &ResultStatus{
		NodeInfo:          s.nodeView.NodeInfo(),
		GenesisHash:       s.blockchain.GenesisHash(),
		PubKey:            publicKey,
		LatestBlockHash:   latestBlockHash,
		LatestBlockHeight: latestHeight,
		LatestBlockTime:   latestBlockTime,
		NodeVersion:       project.History.CurrentVersion().String(),
	}, nil
}

func (s *Service) ChainId() (*ResultChainId, error) {
	return &ResultChainId{
		ChainName:   s.blockchain.GenesisDoc().ChainName,
		ChainId:     s.blockchain.ChainID(),
		GenesisHash: s.blockchain.GenesisHash(),
	}, nil
}

func (s *Service) Peers() (*ResultPeers, error) {
	peers := make([]*Peer, s.nodeView.Peers().Size())
	for i, peer := range s.nodeView.Peers().List() {
		peers[i] = &Peer{
			NodeInfo:   peer.NodeInfo(),
			IsOutbound: peer.IsOutbound(),
		}
	}
	return &ResultPeers{
		Peers: peers,
	}, nil
}

func (s *Service) NetInfo() (*ResultNetInfo, error) {
	listening := s.nodeView.IsListening()
	var listeners []string
	for _, listener := range s.nodeView.Listeners() {
		listeners = append(listeners, listener.String())
	}
	peers, err := s.Peers()
	if err != nil {
		return nil, err
	}
	return &ResultNetInfo{
		Listening: listening,
		Listeners: listeners,
		Peers:     peers.Peers,
	}, nil
}

func (s *Service) Genesis() (*ResultGenesis, error) {
	return &ResultGenesis{
		Genesis: s.blockchain.GenesisDoc(),
	}, nil
}

// Accounts
func (s *Service) GetAccount(address acm.Address) (*ResultGetAccount, error) {
	acc, err := s.committed.GetAccount(address)
	if err != nil {
		return nil, err
	}
	s.logger.Trace.Log("method", "GetAccount",
		"address", address,
		"sequence", acc.Sequence())
	return &ResultGetAccount{Account: acm.AsConcreteAccount(acc)}, nil
}

func (s *Service) ListAccounts(predicate func(acm.Account) bool) (*ResultListAccounts, error) {
	accounts := make([]*acm.ConcreteAccount, 0)
	s.committed.IterateAccounts(func(account acm.Account) (stop bool) {
		if predicate(account) {
			accounts = append(accounts, acm.AsConcreteAccount(account))
		}
		return
	})

	return &ResultListAccounts{
		BlockHeight: s.blockchain.Tip().LastBlockHeight(),
		Accounts:    accounts,
	}, nil
}

func (s *Service) GetStorage(address acm.Address, key []byte) (*ResultGetStorage, error) {
	account, err := s.committed.GetAccount(address)
	if err != nil {
		return nil, err
	}
	if account == nil {
		return nil, fmt.Errorf("UnknownAddress: %s", address)
	}

	value, err := s.committed.GetStorage(address, binary.LeftPadWord256(key))
	if err != nil {
		return nil, err
	}
	if value == binary.Zero256 {
		return &ResultGetStorage{Key: key, Value: nil}, nil
	}
	return &ResultGetStorage{Key: key, Value: value.UnpadLeft()}, nil
}

func (s *Service) DumpStorage(address acm.Address) (*ResultDumpStorage, error) {
	account, err := s.committed.GetAccount(address)
	if err != nil {
		return nil, err
	}
	if account == nil {
		return nil, fmt.Errorf("UnknownAddress: %X", address)
	}
	var storageItems []StorageItem
	s.committed.IterateStorage(address, func(key, value binary.Word256) (stop bool) {
		storageItems = append(storageItems, StorageItem{Key: key.UnpadLeft(), Value: value.UnpadLeft()})
		return
	})
	return &ResultDumpStorage{
		StorageRoot:  account.StorageRoot(),
		StorageItems: storageItems,
	}, nil
}

func (s *Service) GetAccountHumanReadable(address acm.Address) (*ResultGetAccountHumanReadable, error) {
	acc, err := s.committed.GetAccount(address)
	if err != nil {
		return nil, err
	}
	if acc == nil {
		return &ResultGetAccountHumanReadable{}, nil
	}
	tokens, err := acc.Code().Tokens()
	if acc == nil {
		return &ResultGetAccountHumanReadable{}, nil
	}
	perms, err := permission.BasePermissionsToStringList(acc.Permissions().Base)
	if acc == nil {
		return &ResultGetAccountHumanReadable{}, nil
	}
	return &ResultGetAccountHumanReadable{
		Account: &AccountHumanReadable{
			Address:     acc.Address(),
			PublicKey:   acc.PublicKey(),
			Sequence:    acc.Sequence(),
			Balance:     acc.Balance(),
			Code:        tokens,
			StorageRoot: hex.EncodeUpperToString(acc.StorageRoot()),
			Permissions: perms,
			Roles:       acc.Permissions().Roles,
		},
	}, nil
}

// Name registry
func (s *Service) GetName(name string) (*ResultGetName, error) {
	entry, err := s.nameReg.GetNameRegEntry(name)
	if err != nil {
		return nil, err
	}
	if entry == nil {
		return nil, fmt.Errorf("name %s not found", name)
	}
	return &ResultGetName{Entry: entry}, nil
}

func (s *Service) ListNames(predicate func(*execution.NameRegEntry) bool) (*ResultListNames, error) {
	var names []*execution.NameRegEntry
	s.nameReg.IterateNameRegEntries(func(entry *execution.NameRegEntry) (stop bool) {
		if predicate(entry) {
			names = append(names, entry)
		}
		return
	})
	return &ResultListNames{
		BlockHeight: s.blockchain.Tip().LastBlockHeight(),
		Names:       names,
	}, nil
}

func (s *Service) GetBlock(height uint64) (*ResultGetBlock, error) {
	return &ResultGetBlock{
		Block:     s.nodeView.BlockStore().LoadBlock(int64(height)),
		BlockMeta: s.nodeView.BlockStore().LoadBlockMeta(int64(height)),
	}, nil
}

// Returns the current blockchain height and metadata for a range of blocks
// between minHeight and maxHeight. Only returns maxBlockLookback block metadata
// from the top of the range of blocks.
// Passing 0 for maxHeight sets the upper height of the range to the current
// blockchain height.
func (s *Service) ListBlocks(minHeight, maxHeight uint64) (*ResultListBlocks, error) {
	latestHeight := s.blockchain.Tip().LastBlockHeight()

	if minHeight == 0 {
		minHeight = 1
	}
	if maxHeight == 0 || latestHeight < maxHeight {
		maxHeight = latestHeight
	}
	if maxHeight > minHeight && maxHeight-minHeight > MaxBlockLookback {
		minHeight = maxHeight - MaxBlockLookback
	}

	var blockMetas []*tm_types.BlockMeta
	for height := maxHeight; height >= minHeight; height-- {
		blockMeta := s.nodeView.BlockStore().LoadBlockMeta(int64(height))
		blockMetas = append(blockMetas, blockMeta)
	}

	return &ResultListBlocks{
		LastHeight: latestHeight,
		BlockMetas: blockMetas,
	}, nil
}

func (s *Service) ListValidators() (*ResultListValidators, error) {
	// TODO: when we reintroduce support for bonding and unbonding update this
	// to reflect the mutable bonding state
	validators := s.blockchain.Validators()
	concreteValidators := make([]*acm.ConcreteValidator, len(validators))
	for i, validator := range validators {
		concreteValidators[i] = acm.AsConcreteValidator(validator)
	}
	return &ResultListValidators{
		BlockHeight:         s.blockchain.Tip().LastBlockHeight(),
		BondedValidators:    concreteValidators,
		UnbondingValidators: nil,
	}, nil
}

func (s *Service) DumpConsensusState() (*ResultDumpConsensusState, error) {
	peerRoundState, err := s.nodeView.PeerRoundStates()
	if err != nil {
		return nil, err
	}
	return &ResultDumpConsensusState{
		RoundState:      s.nodeView.RoundState(),
		PeerRoundStates: peerRoundState,
	}, nil
}

func (s *Service) GeneratePrivateAccount() (*ResultGeneratePrivateAccount, error) {
	privateAccount, err := acm.GeneratePrivateAccount()
	if err != nil {
		return nil, err
	}
	return &ResultGeneratePrivateAccount{
		PrivateAccount: acm.AsConcretePrivateAccount(privateAccount),
	}, nil
}