package backendwrapper

import (
	"context"
	"encoding/json"
	"fmt"
	"math/big"
	"reflect"
	"sync"

	"github.com/ethereum/go-ethereum"
	"github.com/ethereum/go-ethereum/common"
	gcore "github.com/ethereum/go-ethereum/core"
	"github.com/ethereum/go-ethereum/core/state"
	"github.com/ethereum/go-ethereum/core/types"
	"github.com/ethereum/go-ethereum/event"
	gparams "github.com/ethereum/go-ethereum/params"
	"github.com/ethereum/go-ethereum/internal/ethapi"
	"github.com/ethereum/go-ethereum/log"
	"github.com/ethereum/go-ethereum/rlp"
	"github.com/ethereum/go-ethereum/rpc"

	"github.com/openrelayxyz/plugeth-utils/core"
	"github.com/openrelayxyz/plugeth-utils/restricted"
	"github.com/openrelayxyz/plugeth-utils/restricted/params"
)

type Backend struct {
	b               ethapi.Backend
	db              state.Database
	newTxsFeed      event.Feed
	newTxsOnce      sync.Once
	chainFeed       event.Feed
	chainOnce       sync.Once
	chainHeadFeed   event.Feed
	chainHeadOnce   sync.Once
	chainSideFeed   event.Feed
	chainSideOnce   sync.Once
	logsFeed        event.Feed
	logsOnce        sync.Once
	pendingLogsFeed event.Feed
	pendingLogsOnce sync.Once
	removedLogsFeed event.Feed
	removedLogsOnce sync.Once
	chainConfig     *params.ChainConfig
}

func NewBackend(b ethapi.Backend) *Backend {
	state, _, err := b.StateAndHeaderByNumber(context.Background(), 0)
	if err != nil {
		panic(err.Error())
	}
	return &Backend{
		b: b,
		db: state.Database(),
	}
}

func (b *Backend) SuggestGasTipCap(ctx context.Context) (*big.Int, error) {
	return b.b.SuggestGasTipCap(ctx)
}
func (b *Backend) ChainDb() restricted.Database {
	return &dbWrapper{b.b.ChainDb()}
}
func (b *Backend) ExtRPCEnabled() bool {
	return b.b.ExtRPCEnabled()
}
func (b *Backend) RPCGasCap() uint64 {
	return b.b.RPCGasCap()
}
func (b *Backend) RPCTxFeeCap() float64 {
	return b.b.RPCTxFeeCap()
}
func (b *Backend) UnprotectedAllowed() bool {
	return b.b.UnprotectedAllowed()
}
func (b *Backend) SetHead(number uint64) {
	b.b.SetHead(number)
}
func (b *Backend) HeaderByNumber(ctx context.Context, number int64) ([]byte, error) {
	header, err := b.b.HeaderByNumber(ctx, rpc.BlockNumber(number))
	if err != nil {
		return nil, err
	}
	return rlp.EncodeToBytes(header)
}
func (b *Backend) HeaderByHash(ctx context.Context, hash core.Hash) ([]byte, error) {
	header, err := b.b.HeaderByHash(ctx, common.Hash(hash))
	if err != nil {
		return nil, err
	}
	return rlp.EncodeToBytes(header)
}
func (b *Backend) CurrentHeader() []byte {
	ret, _ := rlp.EncodeToBytes(b.b.CurrentHeader())
	return ret
}
func (b *Backend) CurrentBlock() []byte {
	ret, _ := rlp.EncodeToBytes(b.b.CurrentBlock())
	return ret
}
func (b *Backend) BlockByNumber(ctx context.Context, number int64) ([]byte, error) {
	block, err := b.b.BlockByNumber(ctx, rpc.BlockNumber(number))
	if err != nil {
		return nil, err
	}
	return rlp.EncodeToBytes(block)
}
func (b *Backend) BlockByHash(ctx context.Context, hash core.Hash) ([]byte, error) {
	block, err := b.b.BlockByHash(ctx, common.Hash(hash))
	if err != nil {
		return nil, err
	}
	return rlp.EncodeToBytes(block)
}
func (b *Backend) GetReceipts(ctx context.Context, hash core.Hash) ([]byte, error) {
	receipts, err := b.b.GetReceipts(ctx, common.Hash(hash))
	if err != nil {
		return nil, err
	}
	return json.Marshal(receipts)
}
func (b *Backend) GetTd(ctx context.Context, hash core.Hash) *big.Int {
	return b.b.GetTd(ctx, common.Hash(hash))
}
func (b *Backend) SendTx(ctx context.Context, signedTx []byte) error {
	tx := new(types.Transaction)
	if err := tx.UnmarshalBinary(signedTx); err != nil {
		return err
	}
	return b.b.SendTx(ctx, tx)
}
func (b *Backend) GetTransaction(ctx context.Context, txHash core.Hash) ([]byte, core.Hash, uint64, uint64, error) { // RLP Encoded transaction {
	_, tx, blockHash, blockNumber, index, err := b.b.GetTransaction(ctx, common.Hash(txHash))
	if err != nil {
		return nil, core.Hash(blockHash), blockNumber, index, err
	}
	enc, err := tx.MarshalBinary()
	return enc, core.Hash(blockHash), blockNumber, index, err
}
func (b *Backend) GetPoolTransactions() ([][]byte, error) {
	txs, err := b.b.GetPoolTransactions()
	if err != nil {
		return nil, err
	}
	results := make([][]byte, len(txs))
	for i, tx := range txs {
		results[i], _ = rlp.EncodeToBytes(tx)
	}
	return results, nil
}
func (b *Backend) GetPoolTransaction(txHash core.Hash) []byte {
	tx := b.b.GetPoolTransaction(common.Hash(txHash))
	if tx == nil {
		return []byte{}
	}
	enc, _ := rlp.EncodeToBytes(tx)
	return enc
}
func (b *Backend) GetPoolNonce(ctx context.Context, addr core.Address) (uint64, error) {
	return b.b.GetPoolNonce(ctx, common.Address(addr))
}
func (b *Backend) Stats() (pending int, queued int) {
	return b.b.Stats()
}
func (b *Backend) TxPoolContent() (map[core.Address][][]byte, map[core.Address][][]byte) {
	pending, queued := b.b.TxPoolContent()
	trpending, trqueued := make(map[core.Address][][]byte), make(map[core.Address][][]byte)
	for k, v := range pending {
		trpending[core.Address(k)] = make([][]byte, len(v))
		for i, tx := range v {
			trpending[core.Address(k)][i], _ = tx.MarshalBinary()
		}
	}
	for k, v := range queued {
		trqueued[core.Address(k)] = make([][]byte, len(v))
		for i, tx := range v {
			trpending[core.Address(k)][i], _ = tx.MarshalBinary()
		}
	}
	return trpending, trqueued
} // RLP encoded transactions
func (b *Backend) BloomStatus() (uint64, uint64) {
	return b.b.BloomStatus()
}
func (b *Backend) GetLogs(ctx context.Context, blockHash core.Hash) ([][]byte, error) {
	header, _ := b.b.HeaderByHash(ctx, common.Hash(blockHash))
	logs, err := b.b.GetLogs(ctx, common.Hash(blockHash), uint64(header.Number.Uint64()))
	if err != nil {
		return nil, err
	}
	encLogs := make([][]byte, len(logs))
	for i, log := range logs {
		encLogs[i], _ = rlp.EncodeToBytes(log)
	}
	return encLogs, nil
} // []RLP encoded logs

type dli interface {
	SyncProgress() ethereum.SyncProgress
}

type dl struct {
	dl dli
}

type progress struct {
	p ethereum.SyncProgress
}

func (p *progress) StartingBlock() uint64 {
	return p.p.StartingBlock
}
func (p *progress) CurrentBlock() uint64 {
	return p.p.CurrentBlock
}
func (p *progress) HighestBlock() uint64 {
	return p.p.HighestBlock
}

func (p *progress) PulledStates() uint64 {
	log.Warn("PulledStates is no longer supported by Geth")
	return 0
}
func (p *progress) KnownStates() uint64 {
	log.Warn("KnownStates is no longer supported by Geth")
	return 0
}
func (p *progress) SyncedAccounts() uint64 {
	return p.p.SyncedAccounts
}
func (p *progress) SyncedAccountBytes() uint64 {
	return p.p.SyncedAccountBytes
}
func (p *progress) SyncedBytecodes() uint64 {
	return p.p.SyncedBytecodes
}
func (p *progress) SyncedBytecodeBytes() uint64 {
	return p.p.SyncedBytecodeBytes
}
func (p *progress) SyncedStorage() uint64 {
	return p.p.SyncedStorage
}
func (p *progress) SyncedStorageBytes() uint64 {
	return p.p.SyncedStorageBytes
}
func (p *progress) HealedTrienodes() uint64 {
	return p.p.HealedTrienodes
}
func (p *progress) HealedTrienodeBytes() uint64 {
	return p.p.HealedTrienodeBytes
}
func (p *progress) HealedBytecodes() uint64 {
	return p.p.HealedBytecodes
}
func (p *progress) HealedBytecodeBytes() uint64 {
	return p.p.HealedBytecodeBytes
}
func (p *progress) HealingTrienodes() uint64 {
	return p.p.HealingTrienodes
}
func (p *progress) HealingBytecode() uint64 {
	return p.p.HealingBytecode
}

func (d *dl) Progress() core.Progress {
	return &progress{d.dl.SyncProgress()}
}

func (b *Backend) Downloader() core.Downloader {
	return &dl{b.b}
}

func (b *Backend) SubscribeNewTxsEvent(ch chan<- core.NewTxsEvent) core.Subscription {
	var sub event.Subscription
	b.newTxsOnce.Do(func() {
		bch := make(chan gcore.NewTxsEvent, 100)
		sub = b.b.SubscribeNewTxsEvent(bch)
		go func() {
			for {
				select {
				case item := <-bch:
					txe := core.NewTxsEvent{
						Txs: make([][]byte, len(item.Txs)),
					}
					for i, tx := range item.Txs {
						txe.Txs[i], _ = tx.MarshalBinary()
					}
					b.newTxsFeed.Send(txe)
				case err := <-sub.Err():
					log.Warn("Subscription error for NewTxs", "err", err)
					return
				}
			}
		}()
	})
	return b.newTxsFeed.Subscribe(ch)
}
func (b *Backend) SubscribeChainEvent(ch chan<- core.ChainEvent) core.Subscription {
	var sub event.Subscription
	b.chainOnce.Do(func() {
		bch := make(chan gcore.ChainEvent, 100)
		sub = b.b.SubscribeChainEvent(bch)
		go func() {
			for {
				select {
				case item := <-bch:
					ce := core.ChainEvent{
						Hash: core.Hash(item.Hash),
					}
					ce.Block, _ = rlp.EncodeToBytes(item.Block)
					ce.Logs, _ = rlp.EncodeToBytes(item.Logs)
					b.chainFeed.Send(ce)
				case err := <-sub.Err():
					log.Warn("Subscription error for Chain", "err", err)
					return
				}
			}
		}()
	})
	return b.chainFeed.Subscribe(ch)
}
func (b *Backend) SubscribeChainHeadEvent(ch chan<- core.ChainHeadEvent) core.Subscription {
	var sub event.Subscription
	b.chainHeadOnce.Do(func() {
		bch := make(chan gcore.ChainHeadEvent, 100)
		sub = b.b.SubscribeChainHeadEvent(bch)
		go func() {
			for {
				select {
				case item := <-bch:
					che := core.ChainHeadEvent{}
					che.Block, _ = rlp.EncodeToBytes(item.Block)
					b.chainHeadFeed.Send(che)
				case err := <-sub.Err():
					log.Warn("Subscription error for ChainHead", "err", err)
					return
				}
			}
		}()
	})
	return b.chainHeadFeed.Subscribe(ch)
}
func (b *Backend) SubscribeChainSideEvent(ch chan<- core.ChainSideEvent) core.Subscription {
	var sub event.Subscription
	b.chainSideOnce.Do(func() {
		bch := make(chan gcore.ChainSideEvent, 100)
		sub = b.b.SubscribeChainSideEvent(bch)
		go func() {
			for {
				select {
				case item := <-bch:
					cse := core.ChainSideEvent{}
					cse.Block, _ = rlp.EncodeToBytes(item.Block)
					b.chainSideFeed.Send(cse)
				case err := <-sub.Err():
					log.Warn("Subscription error for ChainSide", "err", err)
					return
				}
			}
		}()
	})
	return b.chainSideFeed.Subscribe(ch)
}
func (b *Backend) SubscribeLogsEvent(ch chan<- [][]byte) core.Subscription {
	var sub event.Subscription
	b.logsOnce.Do(func() {
		bch := make(chan []*types.Log, 100)
		sub = b.b.SubscribeLogsEvent(bch)
		go func() {
			for {
				select {
				case item := <-bch:
					logs := make([][]byte, len(item))
					for i, log := range item {
						logs[i], _ = rlp.EncodeToBytes(log)
					}
					b.logsFeed.Send(logs)
				case err := <-sub.Err():
					log.Warn("Subscription error for Logs", "err", err)
					return
				}
			}
		}()
	})
	return b.logsFeed.Subscribe(ch)
} // []RLP encoded logs
func (b *Backend) SubscribePendingLogsEvent(ch chan<- [][]byte) core.Subscription {
	var sub event.Subscription
	b.pendingLogsOnce.Do(func() {
		bch := make(chan []*types.Log, 100)
		sub = b.b.SubscribePendingLogsEvent(bch)
		go func() {
			for {
				select {
				case item := <-bch:
					logs := make([][]byte, len(item))
					for i, log := range item {
						logs[i], _ = rlp.EncodeToBytes(log)
					}
					b.pendingLogsFeed.Send(logs)
				case err := <-sub.Err():
					log.Warn("Subscription error for PendingLogs", "err", err)
					return
				}
			}
		}()
	})
	return b.pendingLogsFeed.Subscribe(ch)
} // RLP Encoded logs
func (b *Backend) SubscribeRemovedLogsEvent(ch chan<- []byte) core.Subscription {
	var sub event.Subscription
	b.removedLogsOnce.Do(func() {
		bch := make(chan gcore.RemovedLogsEvent, 100)
		sub = b.b.SubscribeRemovedLogsEvent(bch)
		go func() {
			for {
				select {
				case item := <-bch:
					logs := make([][]byte, len(item.Logs))
					for i, log := range item.Logs {
						logs[i], _ = rlp.EncodeToBytes(log)
					}
					b.removedLogsFeed.Send(item)
				case err := <-sub.Err():
					log.Warn("Subscription error for RemovedLogs", "err", err)
					return
				}
			}
		}()
	})
	return b.removedLogsFeed.Subscribe(ch)
} // RLP encoded logs

func convertAndSet(a, b reflect.Value) (err error) {
	defer func() {
		if recover() != nil {
			fmt.Errorf("error converting: %v", err.Error())
		}
	}()
	a.Set(b.Convert(a.Type()))
	return nil
}

func (b *Backend) ChainConfig() *params.ChainConfig {
	// We're using the reflect library to copy data from params.ChainConfig to
	// pparams.ChainConfig, so this function shouldn't need to be touched for
	// simple changes to ChainConfig (though pparams.ChainConfig may need to be
	// updated). Note that this probably won't carry over consensus engine data.
	if b.chainConfig != nil {
		return b.chainConfig
	}
	b.chainConfig = &params.ChainConfig{}
	nval := reflect.ValueOf(b.b.ChainConfig())
	ntype := nval.Elem().Type()
	lval := reflect.ValueOf(b.chainConfig)
	for i := 0; i < nval.Elem().NumField(); i++ {
		field := ntype.Field(i)
		v := nval.Elem().FieldByName(field.Name)
		lv := lval.Elem().FieldByName(field.Name)
		log.Info("Checking value for", "field", field.Name)
		if lv.Kind() != reflect.Invalid {
			// If core.ChainConfig doesn't have this field, skip it.
			if v.Type() == lv.Type() && lv.CanSet() {
				lv.Set(v)
			} else {
				convertAndSet(lv, v)
			}
		}
	}
	return b.chainConfig
}

func CloneChainConfig(cf *gparams.ChainConfig) *params.ChainConfig {
	result := &params.ChainConfig{}
	nval := reflect.ValueOf(result)
	ntype := nval.Elem().Type()
	lval := reflect.ValueOf(cf)
	for i := 0; i < nval.Elem().NumField(); i++ {
		field := ntype.Field(i)
		v := nval.Elem().FieldByName(field.Name)
		lv := lval.Elem().FieldByName(field.Name)
		log.Info("Checking value for", "field", field.Name)
		if lv.Kind() != reflect.Invalid {
			// If core.ChainConfig doesn't have this field, skip it.
			if v.Type() == lv.Type() && lv.CanSet() {
				v.Set(lv)
			} else {
				convertAndSet(v, lv)
			}
		}
	}
	return result
}

func (b *Backend) GetTrie(h core.Hash) (core.Trie, error) {
	tr, err := b.db.OpenTrie(common.Hash(h))
	if err != nil {
		return nil, err
	}
	return NewWrappedTrie(tr), nil
}

func (b *Backend) GetAccountTrie(stateRoot core.Hash, account core.Address) (core.Trie, error) {
	tr, err := b.db.OpenTrie(common.Hash(stateRoot))
	if err != nil {
		return nil, err
	}
	act, err := tr.GetAccount(common.Address(account))
	if err != nil {
		return nil, err
	}
	acTr, err := b.db.OpenStorageTrie(common.Hash(stateRoot), common.Address(account), common.Hash(act.Root), tr)
	if err != nil {
		return nil, err
	}
	return NewWrappedTrie(acTr), nil
}

func (b *Backend) GetContractCode(h core.Hash) ([]byte, error) {
	return state.NewDatabase(b.b.ChainDb()).ContractCode(common.Address{}, common.Hash(h))
}