// 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/json"
	"errors"
	"fmt"
	"math/big"

	"github.com/XinFinOrg/XDPoSChain/common"
	"github.com/XinFinOrg/XDPoSChain/common/hexutil"
	"github.com/XinFinOrg/XDPoSChain/common/math"
	"github.com/XinFinOrg/XDPoSChain/core/rawdb"
	"github.com/XinFinOrg/XDPoSChain/core/state"
	"github.com/XinFinOrg/XDPoSChain/core/tracing"
	"github.com/XinFinOrg/XDPoSChain/core/types"
	"github.com/XinFinOrg/XDPoSChain/crypto"
	"github.com/XinFinOrg/XDPoSChain/ethdb"
	"github.com/XinFinOrg/XDPoSChain/log"
	"github.com/XinFinOrg/XDPoSChain/params"
	"github.com/XinFinOrg/XDPoSChain/trie"
)

//go:generate go run github.com/fjl/gencodec -type Genesis -field-override genesisSpecMarshaling -out gen_genesis.go

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

// Deprecated: use types.Account instead.
type GenesisAccount = types.Account

// Deprecated: use types.GenesisAlloc instead.
type GenesisAlloc = types.GenesisAlloc

// 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      types.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"`
	BaseFee    *big.Int    `json:"baseFeePerGas"`
}

func getGenesisState(db ethdb.Database, blockhash common.Hash) (alloc types.GenesisAlloc, err error) {
	blob := rawdb.ReadGenesisStateSpec(db, blockhash)
	if len(blob) != 0 {
		if err := alloc.UnmarshalJSON(blob); err != nil {
			return nil, err
		}

		return alloc, nil
	}

	// Genesis allocation is missing and there are several possibilities:
	// the node is legacy which doesn't persist the genesis allocation or
	// the persisted allocation is just lost.
	// - supported networks(mainnet, testnets), recover with defined allocations
	// - private network, can't recover
	var genesis *Genesis
	switch blockhash {
	case params.MainnetGenesisHash:
		genesis = DefaultGenesisBlock()
	case params.TestnetGenesisHash:
		genesis = DefaultTestnetGenesisBlock()
	case params.DevnetGenesisHash:
		genesis = DefaultDevnetGenesisBlock()
	}
	if genesis != nil {
		return genesis.Alloc, nil
	}

	return nil, nil
}

// hashAlloc computes the state root according to the genesis specification.
func hashAlloc(ga *types.GenesisAlloc) (common.Hash, error) {
	// Create an ephemeral in-memory database for computing hash,
	// all the derived states will be discarded to not pollute disk.
	db := state.NewDatabaseWithConfig(rawdb.NewMemoryDatabase(), nil)
	statedb, err := state.New(types.EmptyRootHash, db)
	if err != nil {
		return common.Hash{}, err
	}
	for addr, account := range *ga {
		if account.Balance != nil {
			statedb.AddBalance(addr, account.Balance, tracing.BalanceIncreaseGenesisBalance)
		}
		statedb.SetCode(addr, account.Code)
		statedb.SetNonce(addr, account.Nonce)
		for key, value := range account.Storage {
			statedb.SetState(addr, key, value)
		}
	}
	return statedb.Commit(0, false)
}

// flushAlloc is very similar to hashAlloc, but the main difference is
// all the generated states will be persisted into the given database.
// Also, the genesis state specification will be flushed as well.
func flushAlloc(ga *types.GenesisAlloc, db ethdb.Database, blockhash common.Hash) error {
	statedb, err := state.New(types.EmptyRootHash, state.NewDatabase(db))
	if err != nil {
		return err
	}
	for addr, account := range *ga {
		if account.Balance != nil {
			statedb.AddBalance(addr, account.Balance, tracing.BalanceIncreaseGenesisBalance)
		}
		statedb.SetCode(addr, account.Code)
		statedb.SetNonce(addr, account.Nonce)
		for key, value := range account.Storage {
			statedb.SetState(addr, key, value)
		}
	}
	root, err := statedb.Commit(0, false)
	if err != nil {
		return err
	}
	err = statedb.Database().TrieDB().Commit(root, true)
	if err != nil {
		return err
	}
	// Marshal the genesis state specification and persist.
	blob, err := json.Marshal(ga)
	if err != nil {
		return err
	}
	rawdb.WriteGenesisStateSpec(db, blockhash, blob)
	return nil
}

// 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
	BaseFee    *math.HexOrDecimal256
	Alloc      map[common.UnprefixedAddress]types.Account
}

// 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) {
	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")
		}
		block, err := genesis.Commit(db)
		if err != nil {
			return genesis.Config, common.Hash{}, err
		}
		return genesis.Config, block.Hash(), err
	}

	// We have the genesis block in database (perhaps in ancient database)
	// but the corresponding state is missing.
	header := rawdb.ReadHeader(db, stored, 0)
	if header == nil {
		cfg := genesis.configOrDefault(stored)
		return cfg, stored, fmt.Errorf("missing genesis header for hash: %s", stored.Hex())
	}
	if _, err := state.New(header.Root, state.NewDatabaseWithConfig(db, nil)); err != nil {
		if genesis == nil {
			genesis = DefaultGenesisBlock()
		}
		// Ensure the stored genesis matches with the given one.
		hash := genesis.ToBlock().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().Hash()
		if hash != stored {
			return genesis.Config, hash, &GenesisMismatchError{stored, hash}
		}
	}

	// Get the existing chain configuration.
	newcfg := genesis.configOrDefault(stored)
	storedcfg, err := rawdb.ReadChainConfig(db, stored)
	if err != nil {
		return nil, common.Hash{}, err
	}
	if storedcfg == nil {
		log.Warn("Found genesis block without chain config")
		rawdb.WriteChainConfig(db, stored, newcfg)
		return newcfg, stored, nil
	}

	// Special case: don't change the existing config of a non-xinfin chain if no new
	// config is supplied. These chains would get AllProtocolChanges (and a compat error)
	// if we just continued here.
	if genesis == nil && newcfg == params.AllEthashProtocolChanges {
		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, errors.New("missing block number for head header hash")
	}
	compatErr := storedcfg.CheckCompatible(newcfg, *height)
	if compatErr != nil && *height != 0 && compatErr.RewindTo != 0 {
		return newcfg, stored, compatErr
	}
	// Don't overwrite if the old is identical to the new
	storedData, err := json.Marshal(storedcfg)
	if err != nil {
		return newcfg, stored, fmt.Errorf("failed to marshal stored chain config: %w", err)
	}
	newData, err := json.Marshal(newcfg)
	if err != nil {
		return newcfg, stored, fmt.Errorf("failed to marshal new chain config: %w", err)
	}
	if !bytes.Equal(storedData, newData) {
		rawdb.WriteChainConfig(db, stored, newcfg)
	}
	return newcfg, stored, nil
}

// LoadChainConfig loads the stored chain config if it is already present in
// database, otherwise, return the config in the provided genesis specification.
func LoadChainConfig(db ethdb.Database, genesis *Genesis) (cfg *params.ChainConfig, ghash common.Hash, err error) {
	// Load the stored chain config from the database. It can be nil
	// in case the database is empty. Notably, we only care about the
	// chain config corresponds to the canonical chain.
	stored := rawdb.ReadCanonicalHash(db, 0)
	if stored != (common.Hash{}) {
		storedcfg, err := rawdb.ReadChainConfig(db, stored)
		if err != nil {
			return nil, common.Hash{}, err
		}
		if storedcfg != nil {
			return storedcfg, stored, nil
		}
	}
	// Load the config from the provided genesis specification
	if genesis != nil {
		// Reject invalid genesis spec without valid chain config
		if genesis.Config == nil {
			return nil, common.Hash{}, errGenesisNoConfig
		}
		// If the canonical genesis header is present, but the chain
		// config is missing(initialize the empty leveldb with an
		// external ancient chain segment), ensure the provided genesis
		// is matched.
		ghash := genesis.ToBlock().Hash()
		if stored != (common.Hash{}) && ghash != stored {
			return nil, ghash, &GenesisMismatchError{stored, ghash}
		}
		return genesis.Config, ghash, nil
	}
	// There is no stored chain config and no new config provided,
	// In this case the default chain config(mainnet) will be used
	return params.XDCMainnetChainConfig, params.MainnetGenesisHash, nil
}

func (g *Genesis) configOrDefault(ghash common.Hash) *params.ChainConfig {
	switch {
	case g != nil:
		log.Info("[configOrDefault] load orignal config", "hash", ghash)
		return g.Config
	case ghash == params.MainnetGenesisHash:
		log.Info("[configOrDefault] load mainnetconfig")
		return params.XDCMainnetChainConfig
	case ghash == params.TestnetGenesisHash:
		log.Info("[configOrDefault] load TestnetChainConfig")
		return params.TestnetChainConfig
	case ghash == params.DevnetGenesisHash:
		log.Info("[configOrDefault] load DevnetChainConfig")
		return params.DevnetChainConfig
	default:
		log.Info("[configOrDefault] load AllEthashProtocolChanges", "hash", ghash)
		return params.AllEthashProtocolChanges
	}
}

// ToBlock returns the genesis block according to genesis specification.
func (g *Genesis) ToBlock() *types.Block {
	root, err := hashAlloc(&g.Alloc)
	if err != nil {
		panic(err)
	}
	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,
		BaseFee:    g.BaseFee,
		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
	}
	// Notice: Eip1559Block affects the block hash, we must set:
	//   1. g.Config.Eip1559Block
	//   2. or common.Eip1559Block
	if g.Config != nil && g.Config.IsEIP1559(common.Big0) {
		if g.BaseFee != nil {
			head.BaseFee = g.BaseFee
		} else {
			head.BaseFee = new(big.Int).SetUint64(params.InitialBaseFee)
		}
	}
	return types.NewBlock(head, 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()
	if block.Number().Sign() != 0 {
		return nil, errors.New("can't commit genesis block with number > 0")
	}
	config := g.Config
	if config == nil {
		return nil, errors.New("invalid genesis without chain config")
	}
	if config.XDPoS != nil && len(g.ExtraData) < 32+crypto.SignatureLength {
		return nil, errors.New("can't start XDPoS chain without signers")
	}
	// All the checks have passed, flushAlloc the states derived from the genesis
	// specification as well as the specification itself into the provided
	// database.
	if err := flushAlloc(&g.Alloc, db, block.Hash()); err != nil {
		return nil, err
	}
	batch := db.NewBatch()
	rawdb.WriteTd(batch, block.Hash(), block.NumberU64(), g.Difficulty)
	rawdb.WriteBlock(batch, block)
	rawdb.WriteReceipts(batch, block.Hash(), block.NumberU64(), nil)
	rawdb.WriteCanonicalHash(batch, block.Hash(), block.NumberU64())
	rawdb.WriteHeadBlockHash(batch, block.Hash())
	rawdb.WriteHeadFastBlockHash(batch, block.Hash())
	rawdb.WriteHeadHeaderHash(batch, block.Hash())
	rawdb.WriteChainConfig(batch, block.Hash(), config)
	return block, batch.Write()
}

// 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
}

// DefaultGenesisBlock returns the XDC mainnet genesis block.
func DefaultGenesisBlock() *Genesis {
	return &Genesis{
		Config:     params.XDCMainnetChainConfig,
		Nonce:      0,
		ExtraData:  hexutil.MustDecode("0x000000000000000000000000000000000000000000000000000000000000000025c65b4b379ac37cf78357c4915f73677022eaffc7d49d0a2cf198deebd6ce581af465944ec8b2bbcfccdea1006a5cfa7d9484b5b293b46964c265c00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000"),
		GasLimit:   4700000,
		Difficulty: big.NewInt(1),
		Alloc:      DecodeAllocJson(MainnetAllocData),
		Timestamp:  1559211559,
	}
}

// DefaultTestnetGenesisBlock returns the XDC testnet genesis block.
func DefaultTestnetGenesisBlock() *Genesis {
	return &Genesis{
		Config:     params.TestnetChainConfig,
		Nonce:      0,
		ExtraData:  hexutil.MustDecode("0x00000000000000000000000000000000000000000000000000000000000000003ea0a3555f9b1de983572bff6444aeb1899ec58c4f7900282f3d371d585ab1361205b0940ab1789c942a5885a8844ee5587c8ac5e371fc39ffe618960000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000"),
		GasLimit:   4700000,
		Difficulty: big.NewInt(1),
		Alloc:      DecodeAllocJson(TestnetAllocData),
		Timestamp:  1560417871,
	}
}

// DefaultDevnetGenesisBlock returns the XDC devnet genesis block.
func DefaultDevnetGenesisBlock() *Genesis {
	return &Genesis{
		Config:     params.DevnetChainConfig,
		Nonce:      0,
		ExtraData:  hexutil.MustDecode("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"),
		GasLimit:   4700000,
		Difficulty: big.NewInt(1),
		Alloc:      DecodeAllocJson(DevnetAllocData),
		Timestamp:  1735513074,
	}
}

// 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.AllXDPoSProtocolChanges
	config.XDPoS.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:   6283185,
		BaseFee:    big.NewInt(params.InitialBaseFee),
		Difficulty: big.NewInt(1),
		Alloc: map[common.Address]types.Account{
			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
			faucet:                           {Balance: new(big.Int).Sub(new(big.Int).Lsh(big.NewInt(1), 256), big.NewInt(9))},
			// Pre-deploy system contracts
			params.HistoryStorageAddress: {Nonce: 1, Code: params.HistoryStorageCode, Balance: common.Big0},
		},
	}
}

func DecodeAllocJson(s string) types.GenesisAlloc {
	alloc := types.GenesisAlloc{}
	json.Unmarshal([]byte(s), &alloc)
	return alloc
}