// Copyright 2014 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library 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 Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.

package core

import (
	"bytes"
	"encoding/hex"
	"encoding/json"
	"errors"
	"fmt"
	"math/big"
	"strings"

	"github.com/ethereum/go-ethereum/common"
	"github.com/ethereum/go-ethereum/common/hexutil"
	"github.com/ethereum/go-ethereum/common/math"
	"github.com/ethereum/go-ethereum/core/rawdb"
	"github.com/ethereum/go-ethereum/core/state"
	"github.com/ethereum/go-ethereum/core/types"
	"github.com/ethereum/go-ethereum/crypto"
	"github.com/ethereum/go-ethereum/ethdb"
	"github.com/ethereum/go-ethereum/log"
	"github.com/ethereum/go-ethereum/params"
	"github.com/ethereum/go-ethereum/rlp"
	"github.com/ethereum/go-ethereum/trie"
)

//go:generate gencodec -type Genesis -field-override genesisSpecMarshaling -out gen_genesis.go
//go:generate gencodec -type GenesisAccount -field-override genesisAccountMarshaling -out gen_genesis_account.go

var errGenesisNoConfig = errors.New("genesis has no chain configuration")

// Genesis specifies the header fields, state of a genesis block. It also defines hard
// fork switch-over blocks through the chain configuration.
type Genesis struct {
	Config     *params.ChainConfig `json:"config"`
	Nonce      uint64              `json:"nonce"`
	Timestamp  uint64              `json:"timestamp"`
	ExtraData  []byte              `json:"extraData"`
	GasLimit   uint64              `json:"gasLimit"   gencodec:"required"`
	Difficulty *big.Int            `json:"difficulty" gencodec:"required"`
	Mixhash    common.Hash         `json:"mixHash"`
	Coinbase   common.Address      `json:"coinbase"`
	Alloc      GenesisAlloc        `json:"alloc"      gencodec:"required"`

	// These fields are used for consensus tests. Please don't use them
	// in actual genesis blocks.
	Number     uint64      `json:"number"`
	GasUsed    uint64      `json:"gasUsed"`
	ParentHash common.Hash `json:"parentHash"`
}

// GenesisAlloc specifies the initial state that is part of the genesis block.
type GenesisAlloc map[common.Address]GenesisAccount

func (ga *GenesisAlloc) UnmarshalJSON(data []byte) error {
	m := make(map[common.UnprefixedAddress]GenesisAccount)
	if err := json.Unmarshal(data, &m); err != nil {
		return err
	}
	*ga = make(GenesisAlloc)
	for addr, a := range m {
		(*ga)[common.Address(addr)] = a
	}
	return nil
}

// GenesisAccount is an account in the state of the genesis block.
type GenesisAccount struct {
	Code       []byte                      `json:"code,omitempty"`
	Storage    map[common.Hash]common.Hash `json:"storage,omitempty"`
	Balance    *big.Int                    `json:"balance" gencodec:"required"`
	Nonce      uint64                      `json:"nonce,omitempty"`
	PrivateKey []byte                      `json:"secretKey,omitempty"` // for tests
}

// field type overrides for gencodec
type genesisSpecMarshaling struct {
	Nonce      math.HexOrDecimal64
	Timestamp  math.HexOrDecimal64
	ExtraData  hexutil.Bytes
	GasLimit   math.HexOrDecimal64
	GasUsed    math.HexOrDecimal64
	Number     math.HexOrDecimal64
	Difficulty *math.HexOrDecimal256
	Alloc      map[common.UnprefixedAddress]GenesisAccount
}

type genesisAccountMarshaling struct {
	Code       hexutil.Bytes
	Balance    *math.HexOrDecimal256
	Nonce      math.HexOrDecimal64
	Storage    map[storageJSON]storageJSON
	PrivateKey hexutil.Bytes
}

// storageJSON represents a 256 bit byte array, but allows less than 256 bits when
// unmarshaling from hex.
type storageJSON common.Hash

func (h *storageJSON) UnmarshalText(text []byte) error {
	text = bytes.TrimPrefix(text, []byte("0x"))
	if len(text) > 64 {
		return fmt.Errorf("too many hex characters in storage key/value %q", text)
	}
	offset := len(h) - len(text)/2 // pad on the left
	if _, err := hex.Decode(h[offset:], text); err != nil {
		fmt.Println(err)
		return fmt.Errorf("invalid hex storage key/value %q", text)
	}
	return nil
}

func (h storageJSON) MarshalText() ([]byte, error) {
	return hexutil.Bytes(h[:]).MarshalText()
}

// GenesisMismatchError is raised when trying to overwrite an existing
// genesis block with an incompatible one.
type GenesisMismatchError struct {
	Stored, New common.Hash
}

func (e *GenesisMismatchError) Error() string {
	return fmt.Sprintf("database contains incompatible genesis (have %x, new %x)", e.Stored, e.New)
}

// SetupGenesisBlock writes or updates the genesis block in db.
// The block that will be used is:
//
//                          genesis == nil       genesis != nil
//                       +------------------------------------------
//     db has no genesis |  main-net default  |  genesis
//     db has genesis    |  from DB           |  genesis (if compatible)
//
// The stored chain configuration will be updated if it is compatible (i.e. does not
// specify a fork block below the local head block). In case of a conflict, the
// error is a *params.ConfigCompatError and the new, unwritten config is returned.
//
// The returned chain configuration is never nil.
func SetupGenesisBlock(db ethdb.Database, genesis *Genesis) (*params.ChainConfig, common.Hash, error) {
	return SetupGenesisBlockWithOverride(db, genesis, nil)
}

func SetupGenesisBlockWithOverride(db ethdb.Database, genesis *Genesis, overrideBerlin *big.Int) (*params.ChainConfig, common.Hash, error) {
	if genesis != nil && genesis.Config == nil {
		return params.AllEthashProtocolChanges, common.Hash{}, errGenesisNoConfig
	}
	// Just commit the new block if there is no stored genesis block.
	stored := rawdb.ReadCanonicalHash(db, 0)
	if (stored == common.Hash{}) {
		if genesis == nil {
			log.Info("Writing default main-net genesis block")
			genesis = DefaultGenesisBlock()
		} else {
			log.Info("Writing custom genesis block")
		}

		// Quorum: Set default transaction size limit if not set in genesis
		if genesis.Config.TransactionSizeLimit == 0 {
			genesis.Config.TransactionSizeLimit = 64
		}

		// Check transaction size limit and max contract code size
		err := genesis.Config.IsValid()
		if err != nil {
			return genesis.Config, common.Hash{}, err
		}

		// /Quorum

		block, err := genesis.Commit(db)
		if err != nil {
			return genesis.Config, common.Hash{}, err
		}
		checkAndPrintPrivacyEnhancementsWarning(genesis.Config)
		return genesis.Config, block.Hash(), nil
	}
	// We have the genesis block in database(perhaps in ancient database)
	// but the corresponding state is missing.
	header := rawdb.ReadHeader(db, stored, 0)
	if _, err := state.New(header.Root, state.NewDatabaseWithConfig(db, nil), nil); err != nil {
		if genesis == nil {
			genesis = DefaultGenesisBlock()
		}
		// Ensure the stored genesis matches with the given one.
		hash := genesis.ToBlock(nil).Hash()
		if hash != stored {
			return genesis.Config, hash, &GenesisMismatchError{stored, hash}
		}
		block, err := genesis.Commit(db)
		if err != nil {
			return genesis.Config, hash, err
		}
		return genesis.Config, block.Hash(), nil
	}
	// Check whether the genesis block is already written.
	if genesis != nil {
		hash := genesis.ToBlock(nil).Hash()
		if hash != stored {
			return genesis.Config, hash, &GenesisMismatchError{stored, hash}
		}
	}
	// Get the existing chain configuration.
	newcfg := genesis.configOrDefault(stored)
	if overrideBerlin != nil {
		newcfg.BerlinBlock = overrideBerlin
	}
	if err := newcfg.CheckConfigForkOrder(); err != nil {
		return newcfg, common.Hash{}, err
	}
	storedcfg := rawdb.ReadChainConfig(db, stored)
	if storedcfg == nil {
		log.Warn("Found genesis block without chain config")
		rawdb.WriteChainConfig(db, stored, newcfg)
		checkAndPrintPrivacyEnhancementsWarning(newcfg)
		return newcfg, stored, nil
	}
	// Special case: don't change the existing config of a non-mainnet chain if no new
	// config is supplied. These chains would get AllProtocolChanges (and a compat error)
	// if we just continued here.
	if genesis == nil && stored != params.MainnetGenesisHash {
		return storedcfg, stored, nil
	}
	// Check config compatibility and write the config. Compatibility errors
	// are returned to the caller unless we're already at block zero.
	height := rawdb.ReadHeaderNumber(db, rawdb.ReadHeadHeaderHash(db))
	if height == nil {
		return newcfg, stored, fmt.Errorf("missing block number for head header hash")
	}
	if storedcfg.IsMPS != newcfg.IsMPS && *height > 0 {
		// TODO once we implement the MPS upgrade logic the error message should be updated (to reflect the other ways of setting the IsMPS flag value)
		return newcfg, stored, fmt.Errorf("the IsMPS (multiple private states support) flag once configured at block height 0 cannot be changed")
	}
	compatErr := storedcfg.CheckCompatible(newcfg, *height, rawdb.GetIsQuorumEIP155Activated(db))
	if compatErr != nil && *height != 0 && compatErr.RewindTo != 0 {
		return newcfg, stored, compatErr
	}
	rawdb.WriteChainConfig(db, stored, newcfg)

	// Quorum
	if storedcfg.PrivacyEnhancementsBlock == nil {
		checkAndPrintPrivacyEnhancementsWarning(newcfg)
	}
	// End Quorum

	return newcfg, stored, nil
}

func checkAndPrintPrivacyEnhancementsWarning(config *params.ChainConfig) {
	if config.PrivacyEnhancementsBlock != nil {
		log.Warn("Privacy enhancements have been enabled from block height " + config.PrivacyEnhancementsBlock.String() +
			". Please ensure your privacy manager is upgraded and supports privacy enhancements (tessera version 1.*) " +
			"otherwise your quorum node will fail to start.")
	}
}

func (g *Genesis) configOrDefault(ghash common.Hash) *params.ChainConfig {
	switch {
	case g != nil:
		return g.Config
	case ghash == params.MainnetGenesisHash:
		return params.MainnetChainConfig
	case ghash == params.RopstenGenesisHash:
		return params.RopstenChainConfig
	case ghash == params.RinkebyGenesisHash:
		return params.RinkebyChainConfig
	case ghash == params.GoerliGenesisHash:
		return params.GoerliChainConfig
	case ghash == params.YoloV3GenesisHash:
		return params.YoloV3ChainConfig
	default:
		return params.AllEthashProtocolChanges
	}
}

// ToBlock creates the genesis block and writes state of a genesis specification
// to the given database (or discards it if nil).
func (g *Genesis) ToBlock(db ethdb.Database) *types.Block {
	if db == nil {
		db = rawdb.NewMemoryDatabase()
	}
	statedb, _ := state.New(common.Hash{}, state.NewDatabase(db), nil)
	for addr, account := range g.Alloc {
		statedb.AddBalance(addr, account.Balance)
		statedb.SetCode(addr, account.Code)
		statedb.SetNonce(addr, account.Nonce)
		for key, value := range account.Storage {
			statedb.SetState(addr, key, value)
		}
	}
	root := statedb.IntermediateRoot(false)
	head := &types.Header{
		Number:     new(big.Int).SetUint64(g.Number),
		Nonce:      types.EncodeNonce(g.Nonce),
		Time:       g.Timestamp,
		ParentHash: g.ParentHash,
		Extra:      g.ExtraData,
		GasLimit:   g.GasLimit,
		GasUsed:    g.GasUsed,
		Difficulty: g.Difficulty,
		MixDigest:  g.Mixhash,
		Coinbase:   g.Coinbase,
		Root:       root,
	}
	if g.GasLimit == 0 {
		head.GasLimit = params.GenesisGasLimit
	}
	if g.Difficulty == nil {
		head.Difficulty = params.GenesisDifficulty
	}
	statedb.Commit(false)
	statedb.Database().TrieDB().Commit(root, true, nil)

	return types.NewBlock(head, nil, nil, nil, trie.NewStackTrie(nil))
}

// Commit writes the block and state of a genesis specification to the database.
// The block is committed as the canonical head block.
func (g *Genesis) Commit(db ethdb.Database) (*types.Block, error) {
	block := g.ToBlock(db)
	if block.Number().Sign() != 0 {
		return nil, fmt.Errorf("can't commit genesis block with number > 0")
	}
	config := g.Config
	if config == nil {
		config = params.AllEthashProtocolChanges
	}
	if err := config.CheckConfigForkOrder(); err != nil {
		return nil, err
	}
	rawdb.WriteTd(db, block.Hash(), block.NumberU64(), g.Difficulty)
	rawdb.WriteBlock(db, block)
	rawdb.WriteReceipts(db, block.Hash(), block.NumberU64(), nil)
	rawdb.WriteCanonicalHash(db, block.Hash(), block.NumberU64())
	rawdb.WriteHeadBlockHash(db, block.Hash())
	rawdb.WriteHeadFastBlockHash(db, block.Hash())
	rawdb.WriteHeadHeaderHash(db, block.Hash())
	rawdb.WriteChainConfig(db, block.Hash(), config)
	return block, nil
}

// MustCommit writes the genesis block and state to db, panicking on error.
// The block is committed as the canonical head block.
func (g *Genesis) MustCommit(db ethdb.Database) *types.Block {
	block, err := g.Commit(db)
	if err != nil {
		panic(err)
	}
	return block
}

// GenesisBlockForTesting creates and writes a block in which addr has the given wei balance.
func GenesisBlockForTesting(db ethdb.Database, addr common.Address, balance *big.Int) *types.Block {
	g := Genesis{Alloc: GenesisAlloc{addr: {Balance: balance}}}
	return g.MustCommit(db)
}

// DefaultGenesisBlock returns the Ethereum main net genesis block.
func DefaultGenesisBlock() *Genesis {
	return &Genesis{
		Config:     params.MainnetChainConfig,
		Nonce:      66,
		ExtraData:  hexutil.MustDecode("0x11bbe8db4e347b4e8c937c1c8370e4b5ed33adb3db69cbdb7a38e1e50b1b82fa"),
		GasLimit:   5000,
		Difficulty: big.NewInt(17179869184),
		Alloc:      decodePrealloc(mainnetAllocData),
	}
}

// DefaultRopstenGenesisBlock returns the Ropsten network genesis block.
func DefaultRopstenGenesisBlock() *Genesis {
	return &Genesis{
		Config:     params.RopstenChainConfig,
		Nonce:      66,
		ExtraData:  hexutil.MustDecode("0x3535353535353535353535353535353535353535353535353535353535353535"),
		GasLimit:   16777216,
		Difficulty: big.NewInt(1048576),
		Alloc:      decodePrealloc(ropstenAllocData),
	}
}

// DefaultRinkebyGenesisBlock returns the Rinkeby network genesis block.
func DefaultRinkebyGenesisBlock() *Genesis {
	return &Genesis{
		Config:     params.RinkebyChainConfig,
		Timestamp:  1492009146,
		ExtraData:  hexutil.MustDecode("0x52657370656374206d7920617574686f7269746168207e452e436172746d616e42eb768f2244c8811c63729a21a3569731535f067ffc57839b00206d1ad20c69a1981b489f772031b279182d99e65703f0076e4812653aab85fca0f00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000"),
		GasLimit:   4700000,
		Difficulty: big.NewInt(1),
		Alloc:      decodePrealloc(rinkebyAllocData),
	}
}

// DefaultGoerliGenesisBlock returns the Görli network genesis block.
func DefaultGoerliGenesisBlock() *Genesis {
	return &Genesis{
		Config:     params.GoerliChainConfig,
		Timestamp:  1548854791,
		ExtraData:  hexutil.MustDecode("0x22466c6578692069732061207468696e6722202d204166726900000000000000e0a2bd4258d2768837baa26a28fe71dc079f84c70000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000"),
		GasLimit:   10485760,
		Difficulty: big.NewInt(1),
		Alloc:      decodePrealloc(goerliAllocData),
	}
}

func DefaultYoloV3GenesisBlock() *Genesis {
	// Full genesis: https://gist.github.com/holiman/c6ed9269dce28304ad176314caa75e97
	return &Genesis{
		Config:     params.YoloV3ChainConfig,
		Timestamp:  0x6027dd2e,
		ExtraData:  hexutil.MustDecode("0x00000000000000000000000000000000000000000000000000000000000000001041afbcb359d5a8dc58c15b2ff51354ff8a217d0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000"),
		GasLimit:   0x47b760,
		Difficulty: big.NewInt(1),
		Alloc:      decodePrealloc(yoloV3AllocData),
	}
}

// DeveloperGenesisBlock returns the 'geth --dev' genesis block.
func DeveloperGenesisBlock(period uint64, faucet common.Address) *Genesis {
	// Override the default period to the user requested one
	config := *params.AllCliqueProtocolChanges
	config.Clique.Period = period

	// Assemble and return the genesis with the precompiles and faucet pre-funded
	return &Genesis{
		Config:     &config,
		ExtraData:  append(append(make([]byte, 32), faucet[:]...), make([]byte, crypto.SignatureLength)...),
		GasLimit:   11500000,
		Difficulty: big.NewInt(1),
		Alloc: map[common.Address]GenesisAccount{
			common.BytesToAddress([]byte{1}): {Balance: big.NewInt(1)}, // ECRecover
			common.BytesToAddress([]byte{2}): {Balance: big.NewInt(1)}, // SHA256
			common.BytesToAddress([]byte{3}): {Balance: big.NewInt(1)}, // RIPEMD
			common.BytesToAddress([]byte{4}): {Balance: big.NewInt(1)}, // Identity
			common.BytesToAddress([]byte{5}): {Balance: big.NewInt(1)}, // ModExp
			common.BytesToAddress([]byte{6}): {Balance: big.NewInt(1)}, // ECAdd
			common.BytesToAddress([]byte{7}): {Balance: big.NewInt(1)}, // ECScalarMul
			common.BytesToAddress([]byte{8}): {Balance: big.NewInt(1)}, // ECPairing
			common.BytesToAddress([]byte{9}): {Balance: big.NewInt(1)}, // BLAKE2b
			faucet:                           {Balance: new(big.Int).Sub(new(big.Int).Lsh(big.NewInt(1), 256), big.NewInt(9))},
		},
	}
}

func decodePrealloc(data string) GenesisAlloc {
	var p []struct{ Addr, Balance *big.Int }
	if err := rlp.NewStream(strings.NewReader(data), 0).Decode(&p); err != nil {
		panic(err)
	}
	ga := make(GenesisAlloc, len(p))
	for _, account := range p {
		ga[common.BigToAddress(account.Addr)] = GenesisAccount{Balance: account.Balance}
	}
	return ga
}