// Copyright 2019 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/>.

// Contains a batch of utility type declarations used by the tests. As the node
// operates on unique types, a lot of them are needed to check various features.

package statediff

import (
	"encoding/json"
	"math/big"

	"github.com/ethereum/go-ethereum/core/state"

	"github.com/ethereum/go-ethereum/common"
)

// Subscription struct holds our subscription channels
type Subscription struct {
	PayloadChan chan<- Payload
	QuitChan    chan<- bool
}

// Payload packages the data to send to StateDiffingService subscriptions
type Payload struct {
	BlockRlp     []byte `json:"blockRlp"`
	ReceiptsRlp  []byte `json:"receiptsRlp"`
	StateDiffRlp []byte `json:"stateDiff"    gencodec:"required"`
	Err          error  `json:"error"`
}

// StateDiff is the final output structure from the builder
type StateDiff struct {
	BlockNumber     *big.Int      `json:"blockNumber"	  gencodec:"required"`
	BlockHash       common.Hash   `json:"blockHash" 	  gencodec:"required"`
	CreatedAccounts []AccountDiff `json:"createdAccounts" gencodec:"required"`
	DeletedAccounts []AccountDiff `json:"deletedAccounts" gencodec:"required"`
	UpdatedAccounts []AccountDiff `json:"updatedAccounts" gencodec:"required"`

	encoded []byte
	err     error
}

func (sd *StateDiff) ensureEncoded() {
	if sd.encoded == nil && sd.err == nil {
		sd.encoded, sd.err = json.Marshal(sd)
	}
}

// Length to implement Encoder interface for StateDiff
func (sd *StateDiff) Length() int {
	sd.ensureEncoded()
	return len(sd.encoded)
}

// Encode to implement Encoder interface for StateDiff
func (sd *StateDiff) Encode() ([]byte, error) {
	sd.ensureEncoded()
	return sd.encoded, sd.err
}

// AccountDiff holds the data for a single state diff node
type AccountDiff struct {
	Leaf    bool          `json:"leaf"	      gencodec:"required"`
	Key     []byte        `json:"key"         gencodec:"required"`
	Value   []byte        `json:"value"       gencodec:"required"`
	Proof   [][]byte      `json:"proof"       gencodec:"required"`
	Path    []byte        `json:"path"        gencodec:"required"`
	Storage []StorageDiff `json:"storage"     gencodec:"required"`
}

// StorageDiff holds the data for a single storage diff node
type StorageDiff struct {
	Leaf  bool     `json:"leaf"	       gencodec:"required"`
	Key   []byte   `json:"key"         gencodec:"required"`
	Value []byte   `json:"value"       gencodec:"required"`
	Proof [][]byte `json:"proof"       gencodec:"required"`
	Path  []byte   `json:"path"        gencodec:"required"`
}

// AccountsMap is a mapping of keccak256(address) => accountWrapper
type AccountsMap map[common.Hash]accountWrapper

// AccountWrapper is used to temporary associate the unpacked account with its raw values
type accountWrapper struct {
	Account  *state.Account
	Leaf     bool
	RawKey   []byte
	RawValue []byte
	Proof    [][]byte
	Path     []byte
}