package core

import (
	"context"
	"math/big"
	"time"

	"github.com/holiman/uint256"
)

type Backend interface {
	// General Ethereum API
	Downloader() Downloader
	SuggestGasTipCap(ctx context.Context) (*big.Int, error)
	// ChainDb() Database
	// AccountManager() *accounts.Manager
	ExtRPCEnabled() bool
	RPCGasCap() uint64        // global gas cap for eth_call over rpc: DoS protection
	RPCTxFeeCap() float64     // global tx fee cap for all transaction related APIs
	UnprotectedAllowed() bool // allows only for EIP155 transactions.

	// Blockchain API
	SetHead(number uint64)
	HeaderByNumber(ctx context.Context, number int64) ([]byte, error) // RLP encoded header
	HeaderByHash(ctx context.Context, hash Hash) ([]byte, error)
	// HeaderByNumberOrHash(ctx context.Context, blockNrOrHash rpc.BlockNumberOrHash) (*types.Header, error)
	CurrentHeader() []byte                                           // RLP encoded header
	CurrentBlock() []byte                                            // RLP encoded block
	BlockByNumber(ctx context.Context, number int64) ([]byte, error) // RLP encoded block
	BlockByHash(ctx context.Context, hash Hash) ([]byte, error)      // RLP encoded block
	// BlockByNumberOrHash(ctx context.Context, blockNrOrHash rpc.BlockNumberOrHash) (*types.Block, error)
	// StateAndHeaderByNumber(ctx context.Context, number rpc.BlockNumber) (*state.StateDB, *types.Header, error)
	// StateAndHeaderByNumberOrHash(ctx context.Context, blockNrOrHash rpc.BlockNumberOrHash) (*state.StateDB, *types.Header, error)
	GetReceipts(ctx context.Context, hash Hash) ([]byte, error) // JSON encoded receipt (YES, JSON)
	GetTd(ctx context.Context, hash Hash) *big.Int

	SubscribeChainEvent(ch chan<- ChainEvent) Subscription
	SubscribeChainHeadEvent(ch chan<- ChainHeadEvent) Subscription
	SubscribeChainSideEvent(ch chan<- ChainSideEvent) Subscription

	// Transaction pool API
	SendTx(ctx context.Context, signedTx []byte) error                                     // RLP Encoded Transaction
	GetTransaction(ctx context.Context, txHash Hash) ([]byte, Hash, uint64, uint64, error) // RLP Encoded transaction
	GetPoolTransactions() ([][]byte, error)                                                // []RLP ecnoded transactions
	GetPoolTransaction(txHash Hash) []byte                                                 // RLP encoded transaction
	GetPoolNonce(ctx context.Context, addr Address) (uint64, error)
	Stats() (pending int, queued int)
	TxPoolContent() (map[Address][][]byte, map[Address][][]byte) // RLP encoded transactions
	SubscribeNewTxsEvent(chan<- NewTxsEvent) Subscription

	// Filter API
	BloomStatus() (uint64, uint64)
	GetLogs(ctx context.Context, blockHash Hash) ([][]byte, error) // []RLP encoded logs
	SubscribeLogsEvent(ch chan<- [][]byte) Subscription            // []RLP encoded logs
	SubscribePendingLogsEvent(ch chan<- [][]byte) Subscription     // RLP Encoded logs
	SubscribeRemovedLogsEvent(ch chan<- []byte) Subscription       // RLP encoded logs

	// ChainConfig() *params.ChainConfig
	// Engine() consensus.Engine
}

type OpCode byte

type TracerResult interface {
	CaptureStart(from Address, to Address, create bool, input []byte, gas uint64, value *big.Int)
	CaptureState(pc uint64, op OpCode, gas, cost uint64, scope ScopeContext, rData []byte, depth int, err error)
	CaptureFault(pc uint64, op OpCode, gas, cost uint64, scope ScopeContext, depth int, err error)
	CaptureEnd(output []byte, gasUsed uint64, t time.Duration, err error)
	Result() (interface{}, error)
}

type StateDB interface {
	GetBalance(Address) *big.Int

	GetNonce(Address) uint64

	GetCodeHash(Address) Hash
	GetCode(Address) []byte
	GetCodeSize(Address) int

	GetRefund() uint64

	GetCommittedState(Address, Hash) Hash
	GetState(Address, Hash) Hash

	HasSuicided(Address) bool

	// Exist reports whether the given account exists in state.
	// Notably this should also return true for suicided accounts.
	Exist(Address) bool
	// Empty returns whether the given account is empty. Empty
	// is defined according to EIP161 (balance = nonce = code = 0).
	Empty(Address) bool

	AddressInAccessList(addr Address) bool
	SlotInAccessList(addr Address, slot Hash) (addressOk bool, slotOk bool)
}

type ScopeContext interface {
	Memory() Memory
	Stack() Stack
	Contract() Contract
}

type Memory interface {
	GetCopy(int64, int64) []byte
	Len() int
}

type Stack interface {
	Back(n int) *uint256.Int
	Len() int
}

type Contract interface {
	AsDelegate() Contract
	GetOp(n uint64) OpCode
	GetByte(n uint64) byte
	Caller() Address
	Address() Address
	Value() *big.Int
}

type Downloader interface {
	Progress() Progress
}

type Progress interface {
	StartingBlock() uint64
	CurrentBlock() uint64
	HighestBlock() uint64
	PulledStates() uint64
	KnownStates() uint64
}

type Node interface {
	Server() Server
	DataDir() string
	InstanceDir() string
	IPCEndpoint() string
	HTTPEndpoint() string
	WSEndpoint() string
	ResolvePath(x string) string
}

type Server interface {
	PeerCount() int
}

type Logger interface {
	Trace(string, ...interface{})
	Debug(string, ...interface{})
	Info(string, ...interface{})
	Warn(string, ...interface{})
	Crit(string, ...interface{})
	Error(string, ...interface{})
}

type PluginLoader interface {
	Lookup(name string, validate func(interface{}) bool) []interface{}
	GetFeed() Feed
}


type Subscription interface {
	Err() <-chan error // returns the error channel
	Unsubscribe()      // cancels sending of events, closing the error channel
}

type Feed interface {
	Send(interface{}) int
	Subscribe(channel interface{}) Subscription
}