package api

import (
	"errors"
	"fmt"
	"math/big"
	"net/http"

	ethCommon "github.com/ethereum/go-ethereum/common"
	"github.com/gin-gonic/gin"
	"github.com/hermeznetwork/hermez-node/api/apitypes"
	"github.com/hermeznetwork/hermez-node/common"
	"github.com/hermeznetwork/hermez-node/db/l2db"
	"github.com/hermeznetwork/tracerr"
	"github.com/iden3/go-iden3-crypto/babyjub"
)

func (a *API) postPoolTx(c *gin.Context) {
	// Parse body
	var receivedTx receivedPoolTx
	if err := c.ShouldBindJSON(&receivedTx); err != nil {
		retBadReq(err, c)
		return
	}
	// Transform from received to insert format and validate
	writeTx := receivedTx.toPoolL2TxWrite()
	if err := a.verifyPoolL2TxWrite(writeTx); err != nil {
		retBadReq(err, c)
		return
	}
	writeTx.ClientIP = c.ClientIP()
	// Insert to DB
	if err := a.l2.AddTxAPI(writeTx); err != nil {
		retSQLErr(err, c)
		return
	}
	// Return TxID
	c.JSON(http.StatusOK, writeTx.TxID.String())
}

func (a *API) getPoolTx(c *gin.Context) {
	// Get TxID
	txID, err := parseParamTxID(c)
	if err != nil {
		retBadReq(err, c)
		return
	}
	// Fetch tx from l2DB
	tx, err := a.l2.GetTxAPI(txID)
	if err != nil {
		retSQLErr(err, c)
		return
	}
	// Build successful response
	c.JSON(http.StatusOK, tx)
}

func (a *API) getPoolTxs(c *gin.Context) {
	// Get idx
	idx, err := parseIdx(c)
	if err != nil {
		retBadReq(err, c)
		return
	}
	// Get state
	state, err := parseQueryPoolL2TxState(c)
	if err != nil {
		retBadReq(err, c)
		return
	}
	// Fetch txs from l2DB
	txs, err := a.l2.GetPoolTxs(idx, state)
	if err != nil {
		retSQLErr(err, c)
		return
	}

	// Build successful response
	type txsResponse struct {
		Txs []*l2db.PoolTxAPI `json:"transactions"`
	}
	c.JSON(http.StatusOK, &txsResponse{
		Txs: txs,
	})
}

type receivedPoolTx struct {
	TxID        common.TxID             `json:"id" binding:"required"`
	Type        common.TxType           `json:"type" binding:"required"`
	TokenID     common.TokenID          `json:"tokenId"`
	FromIdx     apitypes.StrHezIdx      `json:"fromAccountIndex" binding:"required"`
	ToIdx       *apitypes.StrHezIdx     `json:"toAccountIndex"`
	ToEthAddr   *apitypes.StrHezEthAddr `json:"toHezEthereumAddress"`
	ToBJJ       *apitypes.StrHezBJJ     `json:"toBjj"`
	Amount      apitypes.StrBigInt      `json:"amount" binding:"required"`
	Fee         common.FeeSelector      `json:"fee"`
	Nonce       common.Nonce            `json:"nonce"`
	Signature   babyjub.SignatureComp   `json:"signature" binding:"required"`
	RqFromIdx   *apitypes.StrHezIdx     `json:"requestFromAccountIndex"`
	RqToIdx     *apitypes.StrHezIdx     `json:"requestToAccountIndex"`
	RqToEthAddr *apitypes.StrHezEthAddr `json:"requestToHezEthereumAddress"`
	RqToBJJ     *apitypes.StrHezBJJ     `json:"requestToBjj"`
	RqTokenID   *common.TokenID         `json:"requestTokenId"`
	RqAmount    *apitypes.StrBigInt     `json:"requestAmount"`
	RqFee       *common.FeeSelector     `json:"requestFee"`
	RqNonce     *common.Nonce           `json:"requestNonce"`
}

func (tx *receivedPoolTx) toPoolL2TxWrite() *l2db.PoolL2TxWrite {
	f := new(big.Float).SetInt((*big.Int)(&tx.Amount))
	amountF, _ := f.Float64()
	return &l2db.PoolL2TxWrite{
		TxID:        tx.TxID,
		FromIdx:     common.Idx(tx.FromIdx),
		ToIdx:       (*common.Idx)(tx.ToIdx),
		ToEthAddr:   (*ethCommon.Address)(tx.ToEthAddr),
		ToBJJ:       (*babyjub.PublicKeyComp)(tx.ToBJJ),
		TokenID:     tx.TokenID,
		Amount:      (*big.Int)(&tx.Amount),
		AmountFloat: amountF,
		Fee:         tx.Fee,
		Nonce:       tx.Nonce,
		State:       common.PoolL2TxStatePending,
		Signature:   tx.Signature,
		RqFromIdx:   (*common.Idx)(tx.RqFromIdx),
		RqToIdx:     (*common.Idx)(tx.RqToIdx),
		RqToEthAddr: (*ethCommon.Address)(tx.RqToEthAddr),
		RqToBJJ:     (*babyjub.PublicKeyComp)(tx.RqToBJJ),
		RqTokenID:   tx.RqTokenID,
		RqAmount:    (*big.Int)(tx.RqAmount),
		RqFee:       tx.RqFee,
		RqNonce:     tx.RqNonce,
		Type:        tx.Type,
	}
}

func (a *API) verifyPoolL2TxWrite(txw *l2db.PoolL2TxWrite) error {
	poolTx := common.PoolL2Tx{
		TxID:    txw.TxID,
		FromIdx: txw.FromIdx,
		TokenID: txw.TokenID,
		Amount:  txw.Amount,
		Fee:     txw.Fee,
		Nonce:   txw.Nonce,
		// State:     txw.State,
		Signature: txw.Signature,
		RqAmount:  txw.RqAmount,
		Type:      txw.Type,
	}
	// ToIdx
	if txw.ToIdx != nil {
		poolTx.ToIdx = *txw.ToIdx
	}
	// ToEthAddr
	if txw.ToEthAddr == nil {
		poolTx.ToEthAddr = common.EmptyAddr
	} else {
		poolTx.ToEthAddr = *txw.ToEthAddr
	}
	// ToBJJ
	if txw.ToBJJ == nil {
		poolTx.ToBJJ = common.EmptyBJJComp
	} else {
		poolTx.ToBJJ = *txw.ToBJJ
	}
	// RqFromIdx
	if txw.RqFromIdx != nil {
		poolTx.RqFromIdx = *txw.RqFromIdx
	}
	// RqToIdx
	if txw.RqToIdx != nil {
		poolTx.RqToIdx = *txw.RqToIdx
	}
	// RqToEthAddr
	if txw.RqToEthAddr == nil {
		poolTx.RqToEthAddr = common.EmptyAddr
	} else {
		poolTx.RqToEthAddr = *txw.RqToEthAddr
	}
	// RqToBJJ
	if txw.RqToBJJ == nil {
		poolTx.RqToBJJ = common.EmptyBJJComp
	} else {
		poolTx.RqToBJJ = *txw.RqToBJJ
	}
	// RqTokenID
	if txw.RqTokenID != nil {
		poolTx.RqTokenID = *txw.RqTokenID
	}
	// RqFee
	if txw.RqFee != nil {
		poolTx.RqFee = *txw.RqFee
	}
	// RqNonce
	if txw.RqNonce != nil {
		poolTx.RqNonce = *txw.RqNonce
	}
	// Check type and id
	_, err := common.NewPoolL2Tx(&poolTx)
	if err != nil {
		return tracerr.Wrap(err)
	}
	// Validate feeAmount
	_, err = common.CalcFeeAmount(poolTx.Amount, poolTx.Fee)
	if err != nil {
		return tracerr.Wrap(err)
	}
	// Get public key
	account, err := a.h.GetCommonAccountAPI(poolTx.FromIdx)
	if err != nil {
		return tracerr.Wrap(fmt.Errorf("Error getting from account: %w", err))
	}
	// Validate TokenID
	if poolTx.TokenID != account.TokenID {
		return tracerr.Wrap(fmt.Errorf("tx.TokenID (%v) != account.TokenID (%v)",
			poolTx.TokenID, account.TokenID))
	}
	// Check signature
	if !poolTx.VerifySignature(a.chainID, account.BJJ) {
		return tracerr.Wrap(errors.New("wrong signature"))
	}
	return nil
}