package zb

import (
	"errors"
	"fmt"
	"net/http"
	"net/url"
	"time"

	"github.com/gorilla/websocket"
	"github.com/thrasher-/gocryptotrader/common"
	"github.com/thrasher-/gocryptotrader/currency/pair"
	"github.com/thrasher-/gocryptotrader/exchanges"
	"github.com/thrasher-/gocryptotrader/exchanges/orderbook"
)

const (
	zbWebsocketAPI = "wss://api.zb.cn:9999/websocket"
)

// WsConnect initiates a websocket connection
func (z *ZB) WsConnect() error {
	if !z.Websocket.IsEnabled() || !z.IsEnabled() {
		return errors.New(exchange.WebsocketNotEnabled)
	}

	var dialer websocket.Dialer
	if z.Websocket.GetProxyAddress() != "" {
		proxy, err := url.Parse(z.Websocket.GetProxyAddress())
		if err != nil {
			return err
		}

		dialer.Proxy = http.ProxyURL(proxy)
	}

	var err error
	z.WebsocketConn, _, err = dialer.Dial(z.Websocket.GetWebsocketURL(),
		http.Header{})
	if err != nil {
		return err
	}

	go z.WsHandleData()

	return z.WsSubscribe()
}

// WsSubscribe subscribes to the full websocket suite on ZB exchange
func (z *ZB) WsSubscribe() error {
	markets := Subscription{
		Event:   "addChannel",
		Channel: "markets",
	}

	reqMarkets, err := common.JSONEncode(markets)
	if err != nil {
		return err
	}

	err = z.WebsocketConn.WriteMessage(websocket.TextMessage, reqMarkets)
	if err != nil {
		return err
	}

	for _, c := range z.GetEnabledCurrencies() {
		cPair := c.FirstCurrency.Lower() + c.SecondCurrency.Lower()

		ticker := Subscription{
			Event:   "addChannel",
			Channel: fmt.Sprintf("%s_ticker", cPair),
		}

		reqTicker, err := common.JSONEncode(ticker)
		if err != nil {
			return err
		}

		err = z.WebsocketConn.WriteMessage(websocket.TextMessage, reqTicker)
		if err != nil {
			return err
		}

		depth := Subscription{
			Event:   "addChannel",
			Channel: fmt.Sprintf("%s_depth", cPair),
		}

		reqDepth, err := common.JSONEncode(depth)
		if err != nil {
			return err
		}

		err = z.WebsocketConn.WriteMessage(websocket.TextMessage, reqDepth)
		if err != nil {
			return err
		}

		trades := Subscription{
			Event:   "addChannel",
			Channel: fmt.Sprintf("%s_trades", cPair),
		}

		reqTrades, err := common.JSONEncode(trades)
		if err != nil {
			return err
		}

		err = z.WebsocketConn.WriteMessage(websocket.TextMessage, reqTrades)
		if err != nil {
			return err
		}
	}

	return nil
}

// WsReadData reads from the websocket connection and returns the websocket
// response
func (z *ZB) WsReadData() (exchange.WebsocketResponse, error) {
	_, resp, err := z.WebsocketConn.ReadMessage()
	if err != nil {
		return exchange.WebsocketResponse{}, err
	}

	z.Websocket.TrafficAlert <- struct{}{}
	return exchange.WebsocketResponse{Raw: resp}, nil
}

// WsHandleData handles all the websocket data coming from the websocket
// connection
func (z *ZB) WsHandleData() {
	z.Websocket.Wg.Add(1)

	defer func() {
		err := z.WebsocketConn.Close()
		if err != nil {
			z.Websocket.DataHandler <- fmt.Errorf("zb_websocket.go - Unable to to close Websocket connection. Error: %s",
				err)
		}
		z.Websocket.Wg.Done()
	}()

	for {
		select {
		case <-z.Websocket.ShutdownC:

		default:
			resp, err := z.WsReadData()
			if err != nil {
				z.Websocket.DataHandler <- err
				continue
			}

			var result Generic
			err = common.JSONDecode(resp.Raw, &result)
			if err != nil {
				z.Websocket.DataHandler <- err
				continue
			}

			switch {
			case common.StringContains(result.Channel, "markets"):
				if !result.Success {
					z.Websocket.DataHandler <- fmt.Errorf("zb_websocket.go error - unsuccessful market response %s", wsErrCodes[result.Code])
					continue
				}

				var markets Markets
				err := common.JSONDecode(result.Data, &markets)
				if err != nil {
					z.Websocket.DataHandler <- err
					continue
				}

			case common.StringContains(result.Channel, "ticker"):
				cPair := common.SplitStrings(result.Channel, "_")

				var ticker WsTicker

				err := common.JSONDecode(resp.Raw, &ticker)
				if err != nil {
					z.Websocket.DataHandler <- err
					continue
				}

				z.Websocket.DataHandler <- exchange.TickerData{
					Timestamp:  time.Unix(0, ticker.Date),
					Pair:       pair.NewCurrencyPairFromString(cPair[0]),
					AssetType:  "SPOT",
					Exchange:   z.GetName(),
					ClosePrice: ticker.Data.Last,
					HighPrice:  ticker.Data.High,
					LowPrice:   ticker.Data.Low,
				}

			case common.StringContains(result.Channel, "depth"):
				var depth WsDepth
				err := common.JSONDecode(resp.Raw, &depth)
				if err != nil {
					z.Websocket.DataHandler <- err
					continue
				}

				var asks []orderbook.Item
				for _, askDepth := range depth.Asks {
					ask := askDepth.([]interface{})
					asks = append(asks, orderbook.Item{
						Amount: ask[1].(float64),
						Price:  ask[0].(float64),
					})
				}

				var bids []orderbook.Item
				for _, bidDepth := range depth.Bids {
					bid := bidDepth.([]interface{})
					bids = append(bids, orderbook.Item{
						Amount: bid[1].(float64),
						Price:  bid[0].(float64),
					})
				}

				channelInfo := common.SplitStrings(result.Channel, "_")
				cPair := pair.NewCurrencyPairFromString(channelInfo[0])

				var newOrderbook orderbook.Base
				newOrderbook.Asks = asks
				newOrderbook.Bids = bids
				newOrderbook.AssetType = "SPOT"
				newOrderbook.Pair = cPair
				newOrderbook.CurrencyPair = channelInfo[0]
				newOrderbook.LastUpdated = time.Now()

				err = z.Websocket.Orderbook.LoadSnapshot(newOrderbook, z.GetName(), true)
				if err != nil {
					z.Websocket.DataHandler <- err
					continue
				}

				z.Websocket.DataHandler <- exchange.WebsocketOrderbookUpdate{
					Pair:     cPair,
					Asset:    "SPOT",
					Exchange: z.GetName(),
				}

			case common.StringContains(result.Channel, "trades"):
				var trades WsTrades
				err := common.JSONDecode(resp.Raw, &trades)
				if err != nil {
					z.Websocket.DataHandler <- err
					continue
				}

				// Most up to date trade
				t := trades.Data[len(trades.Data)-1]

				channelInfo := common.SplitStrings(result.Channel, "_")
				cPair := pair.NewCurrencyPairFromString(channelInfo[0])

				z.Websocket.DataHandler <- exchange.TradeData{
					Timestamp:    time.Unix(0, t.Date),
					CurrencyPair: cPair,
					AssetType:    "SPOT",
					Exchange:     z.GetName(),
					EventTime:    t.Date,
					Price:        t.Price,
					Amount:       t.Amount,
					Side:         t.TradeType,
				}

			default:
				z.Websocket.DataHandler <- errors.New("zb_websocket.go error - unhandled websocket response")
				continue
			}
		}
	}
}

var wsErrCodes = map[int64]string{
	1000: "Successful call",
	1001: "General error message",
	1002: "internal error",
	1003: "Verification failed",
	1004: "Financial security password lock",
	1005: "The fund security password is incorrect. Please confirm and re-enter.",
	1006: "Real-name certification is awaiting review or review",
	1007: "Channel is empty",
	1008: "Event is empty",
	1009: "This interface is being maintained",
	1011: "Not open yet",
	1012: "Insufficient permissions",
	1013: "Can not trade, if you have any questions, please contact online customer service",
	1014: "Cannot be sold during the pre-sale period",
	2002: "Insufficient balance in Bitcoin account",
	2003: "Insufficient balance of Litecoin account",
	2005: "Insufficient balance in Ethereum account",
	2006: "Insufficient balance in ETC currency account",
	2007: "Insufficient balance of BTS currency account",
	2008: "Insufficient balance in EOS currency account",
	2009: "Insufficient account balance",
	3001: "Pending order not found",
	3002: "Invalid amount",
	3003: "Invalid quantity",
	3004: "User does not exist",
	3005: "Invalid parameter",
	3006: "Invalid IP or inconsistent with the bound IP",
	3007: "Request time has expired",
	3008: "Transaction history not found",
	4001: "API interface is locked",
	4002: "Request too frequently",
}