1 files changed, 205 insertions, 0 deletions
diff --git a/monitor/notifier.go b/monitor/notifier.go
new file mode 100644
index 0000000..a89d330
--- /dev/null
+++ b/monitor/notifier.go
@@ -0,0 +1,205 @@
+package monitor
+
+import (
+	"crypto/tls"
+	"fmt"
+	"log"
+	"net"
+	"net/mail"
+	"net/smtp"
+	"strings"
+
+	"github.com/ethereum/go-ethereum/common"
+)
+
+const (
+	// FINED notes the node is fined
+	FINED uint = iota
+	// INSUFFICIENT_TAN notes the node key with balance < 100 TAN
+	INSUFFICIENT_TAN
+	// INSUFFICIENT_ETH notes the node key with balance < threshold
+	INSUFFICIENT_ETH
+)
+
+// Notifier is the interface for notifier interfaces.
+type Notifier interface {
+	notify(node, string, uint, string)
+}
+
+// Email is the email notifier object.
+type Email struct {
+	sender     string
+	password   string
+	smtpServer string
+	ccList     string
+}
+
+// NewEmail is the Email constructor.
+func NewEmail(sender, password, server, ccList string) Notifier {
+	e := Email{
+		sender:     sender,
+		password:   password,
+		smtpServer: server,
+		ccList:     ccList,
+	}
+	return &e
+}
+
+func (e *Email) notify(n node, network string, notifyType uint, threshold string) {
+	var subj string
+	var body string
+	switch notifyType {
+	case FINED:
+		subj = "[Notification] Your Tangerine " + network + " Network Full Node is Fined"
+		body = e.finedBody(n.name)
+		go e.send(n.email, network, subj, body)
+	case INSUFFICIENT_TAN:
+		subj = "[Notification] Tangerine " + network + " Insufficient Balance in Node Key"
+		body = e.insufficientBalanceBody(n.name, n.nodeKeyAddress)
+		go e.send(n.email, network, subj, body)
+	case INSUFFICIENT_ETH:
+		subj = "[Notification] Tangerine " + network + " Insufficient ETH in Node Key"
+		body = e.insufficientETHBalanceBody(n.name,
+			n.nodeKeyAddress, threshold, network)
+		go e.send(n.email, network, subj, body)
+	}
+}
+
+func (e *Email) finedBody(name string) string {
+	body := `
+Dear Node Operator:
+
+	Your full node "` + name + `" is fined.
+	Please pay the fine, and check your node status.
+	Also, please check https://byzantine-lab.gitlab.io/wiki/#/Rules-for-the-node-set?id=penalty for the penalty condition.
+
+	Thanks for your cooperation.
+
+-- Tangerine Network
+`
+	return body
+}
+
+func (e *Email) insufficientBalanceBody(name string, address common.Address) string {
+	body := `
+Dear Node Operator:
+
+	There is no sufficient balacne in your full node "` + name + `" key address "` + address.Hex() + `".
+	Please transfer some tokens to the node key address and keep the balance at least 200 TAN.
+
+	Thanks for your cooperation.
+
+-- Tangerine Network
+`
+	return body
+}
+
+func (e *Email) insufficientETHBalanceBody(
+	name string,
+	address common.Address,
+	threshold string,
+	network string) string {
+	ethNet := "Rinkeby"
+	if network == "Mainnet" {
+		ethNet = "Mainnet"
+	}
+	body := `
+Dear Node Operator:
+
+	There is no sufficient ETH in your full node "` + name + `" key address "` + address.Hex() + `".
+	Please transfer some ETH (` + ethNet + `) to the node key address and keep the balance at least ` + threshold + ` ETH.
+
+	Thanks for your cooperation.
+
+-- Tangerine Network
+`
+	return body
+}
+
+func (e *Email) send(toAddress, network, subj, body string) {
+	from := mail.Address{Name: "Tangerine Notifier", Address: e.sender}
+	to := mail.Address{Address: toAddress}
+	// Setup headers
+	headers := make(map[string]string)
+	headers["From"] = from.String()
+	headers["To"] = to.String()
+	headers["Subject"] = subj
+	if e.ccList != "" {
+		headers["Cc"] = strings.TrimSuffix(e.ccList, "\n")
+	}
+
+	// Setup message
+	message := ""
+	for k, v := range headers {
+		message += fmt.Sprintf("%s: %s\r\n", k, v)
+	}
+	message += "\r\n" + body
+
+	// Connect to the SMTP Server
+	servername := e.smtpServer + ":465"
+
+	host, _, _ := net.SplitHostPort(servername)
+
+	auth := smtp.PlainAuth("", e.sender, e.password, host)
+
+	// TLS config
+	tlsconfig := &tls.Config{
+		InsecureSkipVerify: false,
+		ServerName:         host,
+	}
+
+	// Here is the key, you need to call tls.Dial instead of smtp.Dial
+	// for smtp servers running on 465 that require an ssl connection
+	// from the very beginning (no starttls)
+	conn, err := tls.Dial("tcp", servername, tlsconfig)
+	if err != nil {
+		log.Panic(err)
+	}
+
+	c, err := smtp.NewClient(conn, host)
+	if err != nil {
+		log.Panic(err)
+	}
+
+	// Auth
+	if err = c.Auth(auth); err != nil {
+		log.Panic(err)
+	}
+
+	// To && From
+	if err = c.Mail(from.Address); err != nil {
+		log.Panic(err)
+	}
+
+	if err = c.Rcpt(to.Address); err != nil {
+		log.Panic(err)
+	}
+
+	if e.ccList != "" {
+		cc := strings.Split(e.ccList, ",")
+		for _, address := range cc {
+			address = strings.TrimSuffix(address, "\n")
+			if err = c.Rcpt(address); err != nil {
+				log.Println("add cc fail", address, err)
+			}
+		}
+	}
+
+	// Data
+	w, err := c.Data()
+	if err != nil {
+		log.Panic(err)
+	}
+
+	_, err = w.Write([]byte(message))
+	if err != nil {
+		log.Panic(err)
+	}
+
+	err = w.Close()
+	if err != nil {
+		log.Panic(err)
+	}
+
+	c.Quit()
+}