From b2d01e7dd7a23baf369d95bdf4c166630fdf9078 Mon Sep 17 00:00:00 2001
From: David Haukeness <david@code.hauken.us>
Date: Thu, 14 Jan 2021 14:40:35 -0700
Subject: [PATCH] added currency conversions

---
 cmd/convert.go | 94 ++++++++++++++++++++++++++++++++++++++++++++++++++
 cmd/types.go   | 24 +++++++++++++
 main.go        |  5 +++
 3 files changed, 123 insertions(+)
 create mode 100644 cmd/convert.go
 create mode 100644 cmd/types.go

diff --git a/cmd/convert.go b/cmd/convert.go
new file mode 100644
index 0000000..ac708a2
--- /dev/null
+++ b/cmd/convert.go
@@ -0,0 +1,94 @@
+package cmd
+
+import (
+	"encoding/json"
+	"fmt"
+	"io/ioutil"
+	"net/http"
+	"strconv"
+	"strings"
+	"unicode"
+
+	"github.com/kf5grd/keybasebot"
+	"github.com/teris-io/shortid"
+	"samhofi.us/x/keybase/v2/types/chat1"
+)
+
+var ConvertAd = chat1.UserBotCommandInput{
+	Name:        "convert",
+	Usage:       "<currency> to <currency>",
+	Description: "Converts between many crypto and fiat currencies.  Try !convert 50 USD to XLM",
+}
+
+func Convert(m chat1.MsgSummary, b *keybasebot.Bot) (bool, error) {
+	fields := strings.Fields(strings.TrimSpace(strings.Replace(m.Content.Text.Body, "!convert", "", 1)))
+
+	// first pass filters
+	if fields == nil || len(fields) != 4 || fields[2] != "to" {
+		return true, fmt.Errorf("@%s - Invalid Request.", m.Sender.Username)
+	}
+
+	// get the arguments
+	lhq := fields[0]
+	lhc := strings.ToUpper(fields[1])
+	rhc := strings.ToUpper(fields[3])
+
+	// validate the args
+	leftQuantity, err := strconv.ParseFloat(lhq, 64)
+	if err != nil {
+		return true, fmt.Errorf("@%s - Unable to parse %s into a number", m.Sender.Username, lhq)
+	}
+	if !isAlpha(lhc) || !isAlpha(rhc) {
+		return true, fmt.Errorf("@%s - Only letters are allowed in currency symbols", m.Sender.Username)
+	}
+	rate, err := getConversion(lhc, rhc)
+	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
+	}
+	rhq := leftQuantity * rate
+	b.KB.ReactByConvID(m.ConvID, m.Id, fmt.Sprintf("%.4f %s", rhq, rhc))
+	return true, nil
+}
+
+func getConversion(lhc string, rhc string) (float64, error) {
+	client := &http.Client{}
+	target := fmt.Sprintf("https://api.cryptonator.com/api/ticker/%s-%s", lhc, rhc)
+	req, err := http.NewRequest("GET", target, nil)
+	if err != nil {
+		return 0.0, err
+	}
+	req.Header.Set("User-Agent", "GoLang Currency Bot ssh0le/0.99")
+	resp, err := client.Do(req)
+	if err != nil {
+		return 0.0, err
+	}
+	defer resp.Body.Close()
+	body, err := ioutil.ReadAll(resp.Body)
+	if err != nil {
+		return 0.0, err
+	}
+	var apiResponse CryptApiResponse
+	if err := json.Unmarshal(body, &apiResponse); err != nil {
+		return 0.0, err
+	}
+	if !apiResponse.Success {
+		return 0.0, fmt.Errorf(apiResponse.Error)
+	}
+	result, err := strconv.ParseFloat(apiResponse.Ticker.Price, 64)
+	if err != nil {
+		return 0.0, err
+	}
+	return result, nil
+}
+
+func isAlpha(s string) bool {
+	for _, letter := range s {
+		if !unicode.IsLetter(letter) {
+			return false
+		}
+	}
+	return true
+}
diff --git a/cmd/types.go b/cmd/types.go
new file mode 100644
index 0000000..504726a
--- /dev/null
+++ b/cmd/types.go
@@ -0,0 +1,24 @@
+package cmd
+
+// CryptApiResponse hold a response for currency conversions, used in !convert
+type CryptApiResponse struct {
+	Ticker    CryptonatorRate `json:"ticker"`
+	Timestamp int             `json:"timestamp"`
+	Success   bool            `json:"success"`
+	Error     string          `json:"error"`
+}
+
+type CryptonatorRate struct {
+	Base    string              `json:"base"`
+	Target  string              `json:"target"`
+	Price   string              `json:"price"`
+	Volume  string              `json:"volume"`
+	Change  string              `json:"change"`
+	Markets []CryptonatorMarket `json:"markets,omitempty"`
+}
+
+type CryptonatorMarket struct {
+	Market string  `json:"market"`
+	Price  string  `json:"price"`
+	Volume float64 `json:"volume"`
+}
diff --git a/main.go b/main.go
index 0aa837d..3e2945e 100644
--- a/main.go
+++ b/main.go
@@ -55,6 +55,11 @@ func main() {
 			Ad:   &cmd.AgeAd,
 			Run:  keybasebot.Adapt(cmd.Age, keybasebot.MessageType("text"), keybasebot.CommandPrefix("!age")),
 		},
+		keybasebot.BotCommand{
+			Name: "convert",
+			Ad:   &cmd.ConvertAd,
+			Run:  keybasebot.Adapt(cmd.Convert, keybasebot.MessageType("text"), keybasebot.CommandPrefix("!convert")),
+		},
 	)
 	// catch ctrl-c so we can clean up
 	c := make(chan os.Signal)