package api

import (
	"bytes"
	"crypto/ecdsa"
	"encoding/binary"
	"encoding/hex"
	"encoding/json"
	"math/big"
	"testing"
	"time"

	ethCrypto "github.com/ethereum/go-ethereum/crypto"
	"github.com/hermeznetwork/hermez-node/common"
	"github.com/hermeznetwork/hermez-node/db/historydb"
	"github.com/iden3/go-iden3-crypto/babyjub"
	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
)

// testPoolTxReceive is a struct to be used to assert the response
// of GET /transactions-pool/:id
type testPoolTxReceive struct {
	TxID        common.TxID            `json:"id"`
	Type        common.TxType          `json:"type"`
	FromIdx     string                 `json:"fromAccountIndex"`
	FromEthAddr *string                `json:"fromHezEthereumAddress"`
	FromBJJ     *string                `json:"fromBJJ"`
	ToIdx       *string                `json:"toAccountIndex"`
	ToEthAddr   *string                `json:"toHezEthereumAddress"`
	ToBJJ       *string                `json:"toBjj"`
	Amount      string                 `json:"amount"`
	Fee         common.FeeSelector     `json:"fee"`
	Nonce       common.Nonce           `json:"nonce"`
	State       common.PoolL2TxState   `json:"state"`
	Signature   babyjub.SignatureComp  `json:"signature"`
	RqFromIdx   *string                `json:"requestFromAccountIndex"`
	RqToIdx     *string                `json:"requestToAccountIndex"`
	RqToEthAddr *string                `json:"requestToHezEthereumAddress"`
	RqToBJJ     *string                `json:"requestToBJJ"`
	RqTokenID   *common.TokenID        `json:"requestTokenId"`
	RqAmount    *string                `json:"requestAmount"`
	RqFee       *common.FeeSelector    `json:"requestFee"`
	RqNonce     *common.Nonce          `json:"requestNonce"`
	BatchNum    *common.BatchNum       `json:"batchNum"`
	Timestamp   time.Time              `json:"timestamp"`
	Token       historydb.TokenWithUSD `json:"token"`
}

// testPoolTxSend is a struct to be used as a JSON body
// when testing POST /transactions-pool
type testPoolTxSend struct {
	TxID        common.TxID           `json:"id" binding:"required"`
	Type        common.TxType         `json:"type" binding:"required"`
	TokenID     common.TokenID        `json:"tokenId"`
	FromIdx     string                `json:"fromAccountIndex" binding:"required"`
	ToIdx       *string               `json:"toAccountIndex"`
	ToEthAddr   *string               `json:"toHezEthereumAddress"`
	ToBJJ       *string               `json:"toBjj"`
	Amount      string                `json:"amount" binding:"required"`
	Fee         common.FeeSelector    `json:"fee"`
	Nonce       common.Nonce          `json:"nonce"`
	Signature   babyjub.SignatureComp `json:"signature" binding:"required"`
	RqFromIdx   *string               `json:"requestFromAccountIndex"`
	RqToIdx     *string               `json:"requestToAccountIndex"`
	RqToEthAddr *string               `json:"requestToHezEthereumAddress"`
	RqToBJJ     *string               `json:"requestToBjj"`
	RqTokenID   *common.TokenID       `json:"requestTokenId"`
	RqAmount    *string               `json:"requestAmount"`
	RqFee       *common.FeeSelector   `json:"requestFee"`
	RqNonce     *common.Nonce         `json:"requestNonce"`
}

func genTestPoolTxs(
	poolTxs []common.PoolL2Tx,
	tokens []historydb.TokenWithUSD,
	accs []common.Account,
) (poolTxsToSend []testPoolTxSend, poolTxsToReceive []testPoolTxReceive) {
	poolTxsToSend = []testPoolTxSend{}
	poolTxsToReceive = []testPoolTxReceive{}
	for _, poolTx := range poolTxs {
		// common.PoolL2Tx ==> testPoolTxSend
		token := getTokenByID(poolTx.TokenID, tokens)
		genSendTx := testPoolTxSend{
			TxID:      poolTx.TxID,
			Type:      poolTx.Type,
			TokenID:   poolTx.TokenID,
			FromIdx:   idxToHez(poolTx.FromIdx, token.Symbol),
			Amount:    poolTx.Amount.String(),
			Fee:       poolTx.Fee,
			Nonce:     poolTx.Nonce,
			Signature: poolTx.Signature,
			RqFee:     &poolTx.RqFee,
			RqNonce:   &poolTx.RqNonce,
		}
		// common.PoolL2Tx ==> testPoolTxReceive
		genReceiveTx := testPoolTxReceive{
			TxID:      poolTx.TxID,
			Type:      poolTx.Type,
			FromIdx:   idxToHez(poolTx.FromIdx, token.Symbol),
			Amount:    poolTx.Amount.String(),
			Fee:       poolTx.Fee,
			Nonce:     poolTx.Nonce,
			State:     poolTx.State,
			Signature: poolTx.Signature,
			Timestamp: poolTx.Timestamp,
			// BatchNum:    poolTx.BatchNum,
			RqFee:   &poolTx.RqFee,
			RqNonce: &poolTx.RqNonce,
			Token:   token,
		}
		fromAcc := getAccountByIdx(poolTx.FromIdx, accs)
		fromAddr := ethAddrToHez(fromAcc.EthAddr)
		genReceiveTx.FromEthAddr = &fromAddr
		fromBjj := bjjToString(fromAcc.BJJ)
		genReceiveTx.FromBJJ = &fromBjj
		if poolTx.ToIdx != 0 {
			toIdx := idxToHez(poolTx.ToIdx, token.Symbol)
			genSendTx.ToIdx = &toIdx
			genReceiveTx.ToIdx = &toIdx
		}
		if poolTx.ToEthAddr != common.EmptyAddr {
			toEth := ethAddrToHez(poolTx.ToEthAddr)
			genSendTx.ToEthAddr = &toEth
			genReceiveTx.ToEthAddr = &toEth
		} else if poolTx.ToIdx > 255 {
			acc := getAccountByIdx(poolTx.ToIdx, accs)
			addr := ethAddrToHez(acc.EthAddr)
			genReceiveTx.ToEthAddr = &addr
		}
		if poolTx.ToBJJ != common.EmptyBJJComp {
			toBJJ := bjjToString(poolTx.ToBJJ)
			genSendTx.ToBJJ = &toBJJ
			genReceiveTx.ToBJJ = &toBJJ
		} else if poolTx.ToIdx > 255 {
			acc := getAccountByIdx(poolTx.ToIdx, accs)
			bjj := bjjToString(acc.BJJ)
			genReceiveTx.ToBJJ = &bjj
		}
		if poolTx.RqFromIdx != 0 {
			rqFromIdx := idxToHez(poolTx.RqFromIdx, token.Symbol)
			genSendTx.RqFromIdx = &rqFromIdx
			genReceiveTx.RqFromIdx = &rqFromIdx
			genSendTx.RqTokenID = &token.TokenID
			genReceiveTx.RqTokenID = &token.TokenID
			rqAmount := poolTx.RqAmount.String()
			genSendTx.RqAmount = &rqAmount
			genReceiveTx.RqAmount = &rqAmount

			if poolTx.RqToIdx != 0 {
				rqToIdx := idxToHez(poolTx.RqToIdx, token.Symbol)
				genSendTx.RqToIdx = &rqToIdx
				genReceiveTx.RqToIdx = &rqToIdx
			}
			if poolTx.RqToEthAddr != common.EmptyAddr {
				rqToEth := ethAddrToHez(poolTx.RqToEthAddr)
				genSendTx.RqToEthAddr = &rqToEth
				genReceiveTx.RqToEthAddr = &rqToEth
			}
			if poolTx.RqToBJJ != common.EmptyBJJComp {
				rqToBJJ := bjjToString(poolTx.RqToBJJ)
				genSendTx.RqToBJJ = &rqToBJJ
				genReceiveTx.RqToBJJ = &rqToBJJ
			}
		}

		poolTxsToSend = append(poolTxsToSend, genSendTx)
		poolTxsToReceive = append(poolTxsToReceive, genReceiveTx)
	}
	return poolTxsToSend, poolTxsToReceive
}

func TestPoolTxs(t *testing.T) {
	// POST
	endpoint := apiURL + "transactions-pool"
	fetchedTxID := common.TxID{}
	for _, tx := range tc.poolTxsToSend {
		jsonTxBytes, err := json.Marshal(tx)
		require.NoError(t, err)
		jsonTxReader := bytes.NewReader(jsonTxBytes)
		require.NoError(
			t, doGoodReq(
				"POST",
				endpoint,
				jsonTxReader, &fetchedTxID,
			),
		)
		assert.Equal(t, tx.TxID, fetchedTxID)
	}
	// 400
	// Wrong fee
	badTx := tc.poolTxsToSend[0]
	badTx.Amount = "99950000000000000"
	badTx.Fee = 255
	jsonTxBytes, err := json.Marshal(badTx)
	require.NoError(t, err)
	jsonTxReader := bytes.NewReader(jsonTxBytes)
	err = doBadReq("POST", endpoint, jsonTxReader, 400)
	require.NoError(t, err)
	// Wrong signature
	badTx = tc.poolTxsToSend[0]
	badTx.FromIdx = "hez:foo:1000"
	jsonTxBytes, err = json.Marshal(badTx)
	require.NoError(t, err)
	jsonTxReader = bytes.NewReader(jsonTxBytes)
	err = doBadReq("POST", endpoint, jsonTxReader, 400)
	require.NoError(t, err)
	// Wrong to
	badTx = tc.poolTxsToSend[0]
	ethAddr := "hez:0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF"
	badTx.ToEthAddr = &ethAddr
	badTx.ToIdx = nil
	jsonTxBytes, err = json.Marshal(badTx)
	require.NoError(t, err)
	jsonTxReader = bytes.NewReader(jsonTxBytes)
	err = doBadReq("POST", endpoint, jsonTxReader, 400)
	require.NoError(t, err)
	// Wrong rq
	badTx = tc.poolTxsToSend[0]
	rqFromIdx := "hez:foo:30"
	badTx.RqFromIdx = &rqFromIdx
	jsonTxBytes, err = json.Marshal(badTx)
	require.NoError(t, err)
	jsonTxReader = bytes.NewReader(jsonTxBytes)
	err = doBadReq("POST", endpoint, jsonTxReader, 400)
	require.NoError(t, err)
	// GET
	endpoint += "/"
	for _, tx := range tc.poolTxsToReceive {
		fetchedTx := testPoolTxReceive{}
		require.NoError(
			t, doGoodReq(
				"GET",
				endpoint+tx.TxID.String(),
				nil, &fetchedTx,
			),
		)
		assertPoolTx(t, tx, fetchedTx)
	}
	// 400, due invalid TxID
	err = doBadReq("GET", endpoint+"0xG2241b6f2b1dd772dba391f4a1a3407c7c21f598d86e2585a14e616fb4a255f823", nil, 400)
	require.NoError(t, err)
	// 404, due nonexistent TxID in DB
	err = doBadReq("GET", endpoint+"0x02241b6f2b1dd772dba391f4a1a3407c7c21f598d86e2585a14e616fb4a255f823", nil, 404)
	require.NoError(t, err)
}

func assertPoolTx(t *testing.T, expected, actual testPoolTxReceive) {
	// state should be pending
	assert.Equal(t, common.PoolL2TxStatePending, actual.State)
	expected.State = actual.State
	actual.Token.ItemID = 0
	// timestamp should be very close to now
	assert.Less(t, time.Now().UTC().Unix()-3, actual.Timestamp.Unix())
	expected.Timestamp = actual.Timestamp
	// token timestamp
	if expected.Token.USDUpdate == nil {
		assert.Equal(t, expected.Token.USDUpdate, actual.Token.USDUpdate)
	} else {
		assert.Equal(t, expected.Token.USDUpdate.Unix(), actual.Token.USDUpdate.Unix())
		expected.Token.USDUpdate = actual.Token.USDUpdate
	}
	assert.Equal(t, expected, actual)
}

// TestAllTosNull test that the API doesn't accept txs with all the TOs set to null (to eth, to bjj, to idx)
func TestAllTosNull(t *testing.T) {
	// Generate account:
	// Ethereum private key
	var key ecdsa.PrivateKey
	key.D = big.NewInt(int64(4444)) // only for testing
	key.PublicKey.X, key.PublicKey.Y = ethCrypto.S256().ScalarBaseMult(key.D.Bytes())
	key.Curve = ethCrypto.S256()
	addr := ethCrypto.PubkeyToAddress(key.PublicKey)
	// BJJ private key
	var sk babyjub.PrivateKey
	var iBytes [8]byte
	binary.LittleEndian.PutUint64(iBytes[:], 4444)
	copy(sk[:], iBytes[:]) // only for testing
	account := common.Account{
		Idx:      4444,
		TokenID:  0,
		BatchNum: 1,
		BJJ:      sk.Public().Compress(),
		EthAddr:  addr,
		Nonce:    0,
		Balance:  big.NewInt(1000000),
	}
	// Add account to history DB (required to verify signature)
	err := api.h.AddAccounts([]common.Account{account})
	assert.NoError(t, err)
	// Genrate tx with all tos set to nil (to eth, to bjj, to idx)
	tx := common.PoolL2Tx{
		FromIdx: account.Idx,
		TokenID: account.TokenID,
		Amount:  big.NewInt(1000),
		Fee:     200,
		Nonce:   0,
	}
	// Set idx and type manually, and check that the function doesn't allow it
	_, err = common.NewPoolL2Tx(&tx)
	assert.Error(t, err)
	tx.Type = common.TxTypeTransfer
	var txID common.TxID
	txIDRaw, err := hex.DecodeString("02e66e24f7f25272906647c8fd1d7fe8acf3cf3e9b38ffc9f94bbb5090dc275073")
	assert.NoError(t, err)
	copy(txID[:], txIDRaw)
	tx.TxID = txID
	// Sign tx
	toSign, err := tx.HashToSign(0)
	assert.NoError(t, err)
	sig := sk.SignPoseidon(toSign)
	tx.Signature = sig.Compress()
	// Transform common.PoolL2Tx ==> testPoolTxSend
	txToSend := testPoolTxSend{
		TxID:      tx.TxID,
		Type:      tx.Type,
		TokenID:   tx.TokenID,
		FromIdx:   idxToHez(tx.FromIdx, "ETH"),
		Amount:    tx.Amount.String(),
		Fee:       tx.Fee,
		Nonce:     tx.Nonce,
		Signature: tx.Signature,
	}
	// Send tx to the API
	jsonTxBytes, err := json.Marshal(txToSend)
	require.NoError(t, err)
	jsonTxReader := bytes.NewReader(jsonTxBytes)
	err = doBadReq("POST", apiURL+"transactions-pool", jsonTxReader, 400)
	require.NoError(t, err)
	// Clean historyDB: the added account shouldn't be there for other tests
	_, err = api.h.DB().DB.Exec("delete from account where idx = 4444")
	assert.NoError(t, err)
}