From cf0df07adcfa4345a65d481fcc38262b309c1a22 Mon Sep 17 00:00:00 2001
From: Mylloon <kennel.anri@tutanota.com>
Date: Mon, 11 Dec 2023 08:58:29 +0100
Subject: [PATCH] email the modifications

---
 go.mod  |  1 +
 go.sum  |  2 ++
 wecr.go | 48 ++++++++++++++++++++++++++----------------------
 3 files changed, 29 insertions(+), 22 deletions(-)

diff --git a/go.mod b/go.mod
index 669b17d..23ccfc4 100644
--- a/go.mod
+++ b/go.mod
@@ -5,6 +5,7 @@ go 1.21.1
 require github.com/joho/godotenv v1.5.1
 
 require (
+	github.com/hexops/gotextdiff v1.0.3
 	gopkg.in/alexcesaro/quotedprintable.v3 v3.0.0-20150716171945-2caba252f4dc // indirect
 	gopkg.in/gomail.v2 v2.0.0-20160411212932-81ebce5c23df
 )
diff --git a/go.sum b/go.sum
index 2c85102..5609a32 100644
--- a/go.sum
+++ b/go.sum
@@ -1,3 +1,5 @@
+github.com/hexops/gotextdiff v1.0.3 h1:gitA9+qJrrTCsiCl7+kh75nPqQt1cx4ZkudSTLoUqJM=
+github.com/hexops/gotextdiff v1.0.3/go.mod h1:pSWU5MAI3yDq+fZBTazCSJysOMbxWL1BSow5/V2vxeg=
 github.com/joho/godotenv v1.5.1 h1:7eLL/+HRGLY0ldzfGMeQkb7vMd0as4CfYvUVzLqw0N0=
 github.com/joho/godotenv v1.5.1/go.mod h1:f4LDr5Voq0i2e/R5DDNOoa2zzDfwtkZa6DnEwAbqwq4=
 gopkg.in/alexcesaro/quotedprintable.v3 v3.0.0-20150716171945-2caba252f4dc h1:2gGKlE2+asNV9m7xrywl36YYNnBG5ZQ0r/BOOxqPpmk=
diff --git a/wecr.go b/wecr.go
index 8e62f88..2a6060e 100644
--- a/wecr.go
+++ b/wecr.go
@@ -1,7 +1,7 @@
 package main
 
 import (
-	"crypto/sha256"
+	"fmt"
 	"io"
 	"log"
 	"net/http"
@@ -10,6 +10,9 @@ import (
 	"strings"
 	"time"
 
+	"github.com/hexops/gotextdiff"
+	"github.com/hexops/gotextdiff/myers"
+	"github.com/hexops/gotextdiff/span"
 	"github.com/joho/godotenv"
 	"gopkg.in/gomail.v2"
 )
@@ -30,19 +33,13 @@ func getWebsite(url string) []byte {
 	return body
 }
 
-/* Convert data to sha256 hash. */
-func stringToHash(data []byte) string {
-	hash := sha256.Sum256(data)
-	return string(hash[:])
-}
-
 /* Send an email. */
-func sendEmail(identity string, username string, password string, host string, recipient []string, port int) {
+func sendEmail(identity string, username string, password string, host string, recipient []string, port int, body string) {
 	message := gomail.NewMessage()
 	message.SetHeader("From", identity)
 	message.SetHeader("To", strings.Join(recipient, ", "))
 	message.SetHeader("Subject", "Changes on website")
-	message.SetBody("text/plain", "A changed has been found on the website.")
+	message.SetBody("text/plain", body)
 
 	dialer := gomail.NewDialer(host, port, username, password)
 
@@ -97,24 +94,31 @@ func main() {
 		log.Fatal("SMTP port is invalid.")
 	}
 
-	last_hash := ""
+	last_bodypage := ""
+	last_name := ""
 	sleepDuration := 24
 	log.Default().Print("Checking: ", url)
 	log.Default().Print("Running each ", sleepDuration, "h, starting now.")
 	for {
-		body := getWebsite(url)
-		hash := stringToHash(body)
-		if last_hash != hash && len(last_hash) > 0 {
-			sendEmail(
-				smtp_from,
-				smtp_user,
-				smtp_pass,
-				smtp_host,
-				strings.Split(recipient_adress, ","),
-				smtp_port,
-			)
+		bodypage := string(getWebsite(url))
+		fname := time.Now().Format(time.DateTime)
+		if last_bodypage != "" {
+			edits := myers.ComputeEdits(span.URIFromPath(last_name), last_bodypage, bodypage)
+			diff := fmt.Sprint(gotextdiff.ToUnified(last_name, fname, last_bodypage, edits))
+			if diff != "" {
+				sendEmail(
+					smtp_from,
+					smtp_user,
+					smtp_pass,
+					smtp_host,
+					strings.Split(recipient_adress, ","),
+					smtp_port,
+					"A changed has been found on the website:\n"+diff,
+				)
+			}
 		}
-		last_hash = hash
+		last_bodypage = bodypage
+		last_name = fname
 
 		/* log.Default().Print("Next loop in ", sleepDuration, "h.") */
 		time.Sleep(time.Duration(sleepDuration) * time.Hour)