ssh0le/cmd/price.go

package cmd

import (
	"bytes"
	"encoding/json"
	"fmt"
	"io/ioutil"
	"net/http"
	"sort"
	"strings"
	"text/tabwriter"

	"github.com/kf5grd/keybasebot"
	"github.com/teris-io/shortid"
	"samhofi.us/x/keybase/v2/types/chat1"
)

var PriceAd = chat1.UserBotCommandInput{
	Name:        "price",
	Usage:       "<cryptocurrency>",
	Description: "Gets lowest crypto prices",
}

func SendPrice(m chat1.MsgSummary, b *keybasebot.Bot) (bool, error) {
	fields := strings.Fields(strings.TrimSpace(strings.Replace(m.Content.Text.Body, "!price", "", 1)))

	// first pass filtering
	if fields == nil || len(fields) > 2 {
		return true, fmt.Errorf("Invalid Request")
	}
	// get the args
	currency := strings.ToUpper(fields[0])
	var target string
	if len(fields) == 2 {
		target = strings.ToUpper(fields[1])
	} else {
		target = "USD"
	}
	// validate the args
	if !isAlpha(currency) || !isAlpha(target) {
		return true, fmt.Errorf("@%s - only letters are allowed in currency symbols", m.Sender.Username)
	}
	// get all the market prices
	prices, err := getPrices(currency, target)
	if err != nil {
		eid := shortid.MustGenerate()
		b.Logger.Error("%s: %+v", eid, err)
		b.KB.ReactByConvID(m.ConvID, m.Id, "Error: %s", eid)
		return true, nil
	}
	// sort them by price
	sort.Slice(prices, func(i, j int) bool { return prices[i].Price < prices[j].Price })
	// get the top 5 best prices
	var numPrices int
	if len(prices) > 5 {
		numPrices = 5
	} else if len(prices) > 0 {
		numPrices = len(prices)
	} else {
		return true, fmt.Errorf("@%s - no exchanges list %s", m.Sender.Username, currency)
	}
	// then use a tabwriter to format the output
	var buf bytes.Buffer
	w := tabwriter.NewWriter(&buf, 0, 0, 1, ' ', tabwriter.AlignRight)
	fmt.Fprintf(w, "@%s - Lowest %s Prices:```\n", m.Sender.Username, currency)
	for _, price := range prices[:numPrices] {
		fmt.Fprintf(w, "%s:\t%s\t%s\t\n", price.Market, price.Price, target)
	}
	fmt.Fprintln(w, "```")
	w.Flush()
	b.KB.SendMessageByConvID(m.ConvID, buf.String())
	return true, nil
}

func getPrices(currency string, target string) ([]CryptonatorMarket, error) {
	client := &http.Client{}
	apiTargetURL := fmt.Sprintf("https://api.cryptonator.com/api/full/%s-%s", currency, target)
	req, err := http.NewRequest("GET", apiTargetURL, nil)
	if err != nil {
		return nil, err
	}
	req.Header.Set("User-Agent", "GoLang Currency Bot ssh0le/0.99")
	resp, err := client.Do(req)
	if err != nil {
		return nil, err
	}
	defer resp.Body.Close()
	body, err := ioutil.ReadAll(resp.Body)
	if err != nil {
		return nil, err
	}
	var apiResponse CryptApiResponse
	if err := json.Unmarshal(body, &apiResponse); err != nil {
		return nil, err
	}
	if !apiResponse.Success {
		return nil, fmt.Errorf(apiResponse.Error)
	}
	return apiResponse.Ticker.Markets, nil
}