package api

import (
	"encoding/base64"
	"strconv"
	"time"

	ethCommon "github.com/ethereum/go-ethereum/common"
	"github.com/hermeznetwork/hermez-node/common"
	"github.com/hermeznetwork/hermez-node/db/historydb"
	"github.com/iden3/go-iden3-crypto/babyjub"
)

// Commons of the API

type pagination struct {
	TotalItems       int `json:"totalItems"`
	LastReturnedItem int `json:"lastReturnedItem"`
}

type paginationer interface {
	GetPagination() pagination
	Len() int
}

type errorMsg struct {
	Message string
}

// History Tx related

type historyTxsAPI struct {
	Txs        []historyTxAPI `json:"transactions"`
	Pagination pagination     `json:"pagination"`
}

func (htx *historyTxsAPI) GetPagination() pagination { return htx.Pagination }
func (htx *historyTxsAPI) Len() int                  { return len(htx.Txs) }

type l1Info struct {
	ToForgeL1TxsNum       *int64   `json:"toForgeL1TransactionsNum"`
	UserOrigin            bool     `json:"userOrigin"`
	FromEthAddr           string   `json:"fromHezEthereumAddress"`
	FromBJJ               string   `json:"fromBJJ"`
	LoadAmount            string   `json:"loadAmount"`
	HistoricLoadAmountUSD *float64 `json:"historicLoadAmountUSD"`
	EthBlockNum           int64    `json:"ethereumBlockNum"`
}

type l2Info struct {
	Fee            common.FeeSelector `json:"fee"`
	HistoricFeeUSD *float64           `json:"historicFeeUSD"`
	Nonce          common.Nonce       `json:"nonce"`
}

type historyTxAPI struct {
	IsL1        string           `json:"L1orL2"`
	TxID        string           `json:"id"`
	Type        common.TxType    `json:"type"`
	Position    int              `json:"position"`
	FromIdx     *string          `json:"fromAccountIndex"`
	ToIdx       string           `json:"toAccountIndex"`
	Amount      string           `json:"amount"`
	BatchNum    *common.BatchNum `json:"batchNum"`
	HistoricUSD *float64         `json:"historicUSD"`
	Timestamp   time.Time        `json:"timestamp"`
	L1Info      *l1Info          `json:"L1Info"`
	L2Info      *l2Info          `json:"L2Info"`
	Token       common.Token     `json:"token"`
}

func historyTxsToAPI(dbTxs []historydb.HistoryTx) []historyTxAPI {
	apiTxs := []historyTxAPI{}
	for i := 0; i < len(dbTxs); i++ {
		apiTx := historyTxAPI{
			TxID:        dbTxs[i].TxID.String(),
			Type:        dbTxs[i].Type,
			Position:    dbTxs[i].Position,
			ToIdx:       idxToHez(dbTxs[i].ToIdx, dbTxs[i].TokenSymbol),
			Amount:      dbTxs[i].Amount.String(),
			HistoricUSD: dbTxs[i].HistoricUSD,
			BatchNum:    dbTxs[i].BatchNum,
			Timestamp:   dbTxs[i].Timestamp,
			Token: common.Token{
				TokenID:     dbTxs[i].TokenID,
				EthBlockNum: dbTxs[i].TokenEthBlockNum,
				EthAddr:     dbTxs[i].TokenEthAddr,
				Name:        dbTxs[i].TokenName,
				Symbol:      dbTxs[i].TokenSymbol,
				Decimals:    dbTxs[i].TokenDecimals,
				USD:         dbTxs[i].TokenUSD,
				USDUpdate:   dbTxs[i].TokenUSDUpdate,
			},
			L1Info: nil,
			L2Info: nil,
		}
		if dbTxs[i].FromIdx != nil {
			fromIdx := new(string)
			*fromIdx = idxToHez(*dbTxs[i].FromIdx, dbTxs[i].TokenSymbol)
			apiTx.FromIdx = fromIdx
		}
		if dbTxs[i].IsL1 {
			apiTx.IsL1 = "L1"
			apiTx.L1Info = &l1Info{
				ToForgeL1TxsNum:       dbTxs[i].ToForgeL1TxsNum,
				UserOrigin:            *dbTxs[i].UserOrigin,
				FromEthAddr:           ethAddrToHez(*dbTxs[i].FromEthAddr),
				FromBJJ:               bjjToString(dbTxs[i].FromBJJ),
				LoadAmount:            dbTxs[i].LoadAmount.String(),
				HistoricLoadAmountUSD: dbTxs[i].HistoricLoadAmountUSD,
				EthBlockNum:           dbTxs[i].EthBlockNum,
			}
		} else {
			apiTx.IsL1 = "L2"
			apiTx.L2Info = &l2Info{
				Fee:            *dbTxs[i].Fee,
				HistoricFeeUSD: dbTxs[i].HistoricFeeUSD,
				Nonce:          *dbTxs[i].Nonce,
			}
		}
		apiTxs = append(apiTxs, apiTx)
	}
	return apiTxs
}

func bjjToString(bjj *babyjub.PublicKey) string {
	pkComp := [32]byte(bjj.Compress())
	sum := pkComp[0]
	for i := 1; i < len(pkComp); i++ {
		sum += pkComp[i]
	}
	bjjSum := append(pkComp[:], sum)
	return "hez:" + base64.RawURLEncoding.EncodeToString(bjjSum)
}

func ethAddrToHez(addr ethCommon.Address) string {
	return "hez:" + addr.String()
}

func idxToHez(idx common.Idx, tokenSymbol string) string {
	return "hez:" + tokenSymbol + ":" + strconv.Itoa(int(idx))
}