package op_e2e

import (
	"context"
	"crypto/ecdsa"
	"errors"
	"fmt"
	"math/big"
	"time"

	"github.com/ethereum/go-ethereum/cmd/utils"

	rollupEth "github.com/ethereum-optimism/optimism/op-node/eth"
	"github.com/ethereum/go-ethereum"
	"github.com/ethereum/go-ethereum/accounts/keystore"
	"github.com/ethereum/go-ethereum/common"
	"github.com/ethereum/go-ethereum/core"
	"github.com/ethereum/go-ethereum/core/types"
	"github.com/ethereum/go-ethereum/eth"
	"github.com/ethereum/go-ethereum/eth/catalyst"
	"github.com/ethereum/go-ethereum/eth/ethconfig"
	"github.com/ethereum/go-ethereum/eth/tracers"
	"github.com/ethereum/go-ethereum/ethclient"
	"github.com/ethereum/go-ethereum/event"
	"github.com/ethereum/go-ethereum/node"

	hdwallet "github.com/miguelmota/go-ethereum-hdwallet"
)

func waitForTransaction(hash common.Hash, client *ethclient.Client, timeout time.Duration) (*types.Receipt, error) {
	timeoutCh := time.After(timeout)
	ticker := time.NewTicker(100 * time.Millisecond)
	defer ticker.Stop()
	ctx, cancel := context.WithTimeout(context.Background(), timeout)
	defer cancel()
	for {
		receipt, err := client.TransactionReceipt(ctx, hash)
		if receipt != nil && err == nil {
			return receipt, nil
		} else if err != nil && !errors.Is(err, ethereum.NotFound) {
			return nil, err
		}

		select {
		case <-timeoutCh:
			return nil, errors.New("timeout")
		case <-ticker.C:
		}
	}
}

func waitForBlock(number *big.Int, client *ethclient.Client, timeout time.Duration) (*types.Block, error) {
	timeoutCh := time.After(timeout)
	ctx, cancel := context.WithTimeout(context.Background(), timeout)
	defer cancel()

	headChan := make(chan *types.Header, 100)
	headSub, err := client.SubscribeNewHead(ctx, headChan)
	if err != nil {
		return nil, err
	}
	defer headSub.Unsubscribe()

	for {
		select {
		case head := <-headChan:
			if head.Number.Cmp(number) >= 0 {
				return client.BlockByNumber(ctx, number)
			}
		case err := <-headSub.Err():
			return nil, fmt.Errorf("Error in head subscription: %w", err)
		case <-timeoutCh:
			return nil, errors.New("timeout")
		}
	}
}

func getGenesisInfo(client *ethclient.Client) (id rollupEth.BlockID, timestamp uint64) {
	ctx, cancel := context.WithTimeout(context.Background(), 1*time.Second)
	defer cancel()
	block, err := client.BlockByNumber(ctx, common.Big0)
	if err != nil {
		panic(err)
	}
	return rollupEth.BlockID{Hash: block.Hash(), Number: block.NumberU64()}, block.Time()
}

func initL1Geth(cfg *SystemConfig, wallet *hdwallet.Wallet, genesis *core.Genesis) (*node.Node, *eth.Ethereum, error) {
	signer := deriveAccount(wallet, cfg.CliqueSignerDerivationPath)
	pk, err := wallet.PrivateKey(signer)
	if err != nil {
		return nil, nil, fmt.Errorf("failed to locate private key in wallet: %w", err)
	}

	ethConfig := &ethconfig.Config{
		NetworkId: cfg.L1ChainID.Uint64(),
		Genesis:   genesis,
	}
	nodeConfig := &node.Config{
		Name:        "l1-geth",
		WSHost:      "127.0.0.1",
		WSPort:      0,
		WSModules:   []string{"debug", "admin", "eth", "txpool", "net", "rpc", "web3", "personal", "engine"},
		HTTPModules: []string{"debug", "admin", "eth", "txpool", "net", "rpc", "web3", "personal", "engine"},
	}

	l1Node, l1Eth, err := createGethNode(false, nodeConfig, ethConfig, []*ecdsa.PrivateKey{pk})
	if err != nil {
		return nil, nil, err
	}

	// Clique does not have safe/finalized block info. But we do want to test the usage of that,
	// since post-merge L1 has it (incl. Goerli testnet which is already upgraded). So we mock it on top of clique.
	l1Node.RegisterLifecycle(&fakeSafeFinalizedL1{
		eth: l1Eth,
		// for testing purposes we make it really fast, otherwise we don't see it finalize in short tests
		finalizedDistance: 8,
		safeDistance:      4,
	})

	return l1Node, l1Eth, nil
}

type fakeSafeFinalizedL1 struct {
	eth               *eth.Ethereum
	finalizedDistance uint64
	safeDistance      uint64
	sub               ethereum.Subscription
}

var _ node.Lifecycle = (*fakeSafeFinalizedL1)(nil)

func (f *fakeSafeFinalizedL1) Start() error {
	headChanges := make(chan core.ChainHeadEvent, 10)
	headsSub := f.eth.BlockChain().SubscribeChainHeadEvent(headChanges)
	f.sub = event.NewSubscription(func(quit <-chan struct{}) error {
		defer headsSub.Unsubscribe()
		for {
			select {
			case head := <-headChanges:
				num := head.Block.NumberU64()
				if num > f.finalizedDistance {
					toFinalize := f.eth.BlockChain().GetBlockByNumber(num - f.finalizedDistance)
					f.eth.BlockChain().SetFinalized(toFinalize)
				}
				if num > f.safeDistance {
					toSafe := f.eth.BlockChain().GetBlockByNumber(num - f.safeDistance)
					f.eth.BlockChain().SetSafe(toSafe)
				}
			case <-quit:
				return nil
			}
		}
	})
	return nil
}

func (f *fakeSafeFinalizedL1) Stop() error {
	f.sub.Unsubscribe()
	return nil
}

// init a geth node.
func initL2Geth(name string, l2ChainID *big.Int, genesis *core.Genesis, jwtPath string) (*node.Node, *eth.Ethereum, error) {
	ethConfig := &ethconfig.Config{
		NetworkId: l2ChainID.Uint64(),
		Genesis:   genesis,
	}
	nodeConfig := &node.Config{
		Name:        fmt.Sprintf("l2-geth-%v", name),
		WSHost:      "127.0.0.1",
		WSPort:      0,
		AuthAddr:    "127.0.0.1",
		AuthPort:    0,
		WSModules:   []string{"debug", "admin", "eth", "txpool", "net", "rpc", "web3", "personal", "engine"},
		HTTPModules: []string{"debug", "admin", "eth", "txpool", "net", "rpc", "web3", "personal", "engine"},
		JWTSecret:   jwtPath,
	}
	return createGethNode(true, nodeConfig, ethConfig, nil)
}

// createGethNode creates an in-memory geth node based on the configuration.
// The private keys are added to the keystore and are unlocked.
// If the node is l2, catalyst is enabled.
// The node should be started and then closed when done.
func createGethNode(l2 bool, nodeCfg *node.Config, ethCfg *ethconfig.Config, privateKeys []*ecdsa.PrivateKey) (*node.Node, *eth.Ethereum, error) {
	ethCfg.NoPruning = true // force everything to be an archive node
	n, err := node.New(nodeCfg)
	if err != nil {
		n.Close()
		return nil, nil, err
	}

	keydir := n.KeyStoreDir()
	scryptN := 2
	scryptP := 1
	n.AccountManager().AddBackend(keystore.NewKeyStore(keydir, scryptN, scryptP))
	ks := n.AccountManager().Backends(keystore.KeyStoreType)[0].(*keystore.KeyStore)

	password := "foobar"
	for _, pk := range privateKeys {
		act, err := ks.ImportECDSA(pk, password)
		if err != nil {
			n.Close()
			return nil, nil, err
		}
		err = ks.Unlock(act, password)
		if err != nil {
			n.Close()
			return nil, nil, err
		}
	}

	backend, err := eth.New(n, ethCfg)
	if err != nil {
		n.Close()
		return nil, nil, err

	}

	// PR 25459 changed this to only default in CLI, but not in default programmatic RPC selection.
	// PR 25642 fixed it for the mobile version only...
	utils.RegisterFilterAPI(n, backend.APIBackend, ethCfg)

	n.RegisterAPIs(tracers.APIs(backend.APIBackend))

	// Enable catalyst if l2
	if l2 {
		if err := catalyst.Register(n, backend); err != nil {
			n.Close()
			return nil, nil, err
		}
	}
	return n, backend, nil

}
