From 2c247bf9c3c186f725e0d36b99744132548f10b0 Mon Sep 17 00:00:00 2001
From: arnau <17317030+arnaucube@users.noreply.github.com>
Date: Fri, 31 Jul 2020 10:23:52 +0200
Subject: [PATCH] Priceupdater-v0 (#23)
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* First price-updater implementation

* Lint corrections

* Structs revision

* Read Write Mutex

* Review price updater and apply small changes

Co-authored-by: Toni Ramírez <toni@iden3.com>
Co-authored-by: Eduard S <eduard@iden3.io>
---
 priceupdater/priceupdater.go      | 136 ++++++++++++++++++++++++++++++
 priceupdater/priceupdater_test.go |  40 +++++++++
 2 files changed, 176 insertions(+)
 create mode 100644 priceupdater/priceupdater.go
 create mode 100644 priceupdater/priceupdater_test.go

diff --git a/priceupdater/priceupdater.go b/priceupdater/priceupdater.go
new file mode 100644
index 0000000..0775a50
--- /dev/null
+++ b/priceupdater/priceupdater.go
@@ -0,0 +1,136 @@
+package priceupdater
+
+import (
+	"errors"
+	"fmt"
+	"net/http"
+	"sync"
+	"time"
+
+	"github.com/dghubble/sling"
+)
+
+var (
+	// ErrSymbolDoesNotExistInDatabase is used when trying to get a token that is not in the DB
+	ErrSymbolDoesNotExistInDatabase = errors.New("symbol does not exist in database")
+)
+
+// ConfigPriceUpdater contains the configuration set by the coordinator
+type ConfigPriceUpdater struct {
+	RecommendedFee              uint64 // in dollars
+	RecommendedCreateAccountFee uint64 // in dollars
+	TokensList                  []string
+	APIURL                      string
+}
+
+// TokenInfo contains the updated value for the token
+type TokenInfo struct {
+	Symbol      string
+	Value       float64
+	LastUpdated time.Time
+}
+
+// PriceUpdater definition
+type PriceUpdater struct {
+	db     map[string]TokenInfo
+	config ConfigPriceUpdater
+	mu     sync.RWMutex
+}
+
+// NewPriceUpdater is the constructor for the updater
+func NewPriceUpdater(config ConfigPriceUpdater) PriceUpdater {
+
+	return PriceUpdater{
+		db:     make(map[string]TokenInfo),
+		config: config,
+	}
+
+}
+
+// UpdatePrices is triggered by the Coordinator, and internally will update the token prices in the db
+func (p *PriceUpdater) UpdatePrices() error {
+
+	tr := &http.Transport{
+		MaxIdleConns:       10,
+		IdleConnTimeout:    10 * time.Second,
+		DisableCompression: true,
+	}
+	httpClient := &http.Client{Transport: tr}
+	client := sling.New().Base(p.config.APIURL).Client(httpClient)
+
+	state := [10]float64{}
+
+	for _, tokenSymbol := range p.config.TokensList {
+
+		resp, err := client.New().Get("ticker/t" + tokenSymbol + "USD").ReceiveSuccess(&state)
+		if err != nil {
+			return err
+		}
+		if resp.StatusCode != 200 {
+			return fmt.Errorf("Unexpected response status code: %v", resp.StatusCode)
+		}
+
+		tinfo := TokenInfo{
+			Symbol:      tokenSymbol,
+			Value:       state[6],
+			LastUpdated: time.Now(),
+		}
+
+		p.UpdateTokenInfo(tinfo)
+
+	}
+
+	return nil
+}
+
+// UpdateConfig allows to update the price-updater configuration
+func (p *PriceUpdater) UpdateConfig(config ConfigPriceUpdater) {
+
+	p.mu.Lock()
+	defer p.mu.Unlock()
+
+	p.config = config
+
+}
+
+// Get one token information
+func (p *PriceUpdater) Get(tokenSymbol string) (TokenInfo, error) {
+
+	var info TokenInfo
+
+	// Check if symbol exists in database
+	p.mu.RLock()
+	defer p.mu.RUnlock()
+
+	if info, ok := p.db[tokenSymbol]; ok {
+		return info, nil
+	}
+
+	return info, ErrSymbolDoesNotExistInDatabase
+
+}
+
+// GetPrices gets all the prices contained in the db
+func (p *PriceUpdater) GetPrices() map[string]TokenInfo {
+
+	var info = make(map[string]TokenInfo)
+
+	p.mu.RLock()
+	defer p.mu.RUnlock()
+
+	for key, value := range p.db {
+		info[key] = value
+	}
+
+	return info
+}
+
+// UpdateTokenInfo updates one token info
+func (p *PriceUpdater) UpdateTokenInfo(tokenInfo TokenInfo) {
+
+	p.mu.Lock()
+	defer p.mu.Unlock()
+
+	p.db[tokenInfo.Symbol] = tokenInfo
+
+}
diff --git a/priceupdater/priceupdater_test.go b/priceupdater/priceupdater_test.go
new file mode 100644
index 0000000..354d62e
--- /dev/null
+++ b/priceupdater/priceupdater_test.go
@@ -0,0 +1,40 @@
+package priceupdater
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestCon(t *testing.T) {
+
+	config := ConfigPriceUpdater{
+
+		RecommendedFee:              1,
+		RecommendedCreateAccountFee: 1,
+		TokensList:                  []string{"ETH", "NEC"},
+		APIURL:                      "https://api-pub.bitfinex.com/v2/",
+	}
+
+	pud := NewPriceUpdater(config)
+
+	err := pud.UpdatePrices()
+	assert.Equal(t, err, nil)
+
+	info, _ := pud.Get("ETH")
+	assert.NotZero(t, info.Value)
+
+	info2, _ := pud.Get("NEC")
+	assert.NotZero(t, info2.Value)
+
+	info3, err := pud.Get("INVENTED")
+	if assert.Error(t, err) {
+		assert.Equal(t, ErrSymbolDoesNotExistInDatabase, err)
+	}
+	assert.Equal(t, info3.Value, float64(0))
+
+	prices := pud.GetPrices()
+	assert.Equal(t, prices["ETH"], info)
+	assert.Equal(t, prices["NEC"], info2)
+
+}