Refactor and cleanup (#9)

* Refactor some more

cmd/root.go

@@ -16,7 +16,7 @@ import (
 	"gopkg.in/gomail.v2"
 )
 
-var version string = "0.1.0"
+var version string = "0.2.0"
 
 type Data struct {
 	Name     string   `json:"name"`
@@ -50,7 +50,7 @@ func generateSecretSantaMatches(data []Data) []MatchPair {
 }
 
 func circlularMatchingAlgorithm(data []Data) []MatchPair {
-	var matches []MatchPair
+	var matches = make([]MatchPair, 0, len(data))
 	for i := 0; i < len(data); i++ {
 		from := data[i]
 		to := data[(i+1)%len(data)]
@@ -59,7 +59,54 @@ func circlularMatchingAlgorithm(data []Data) []MatchPair {
 	return matches
 }
 
-func sendEmail(to, subject, body string) error {
+func createEmailMessage(to, body string) *gomail.Message {
+	subject := "Your Secret Santa Match!"
+
+	message := gomail.NewMessage()
+
+	message.SetHeader("From", os.Getenv("EMAIL_FROM"))
+	message.SetHeader("To", to)
+	message.SetHeader("Subject", subject)
+	message.SetBody("text/html", body)
+
+	return message
+
+}
+
+func populateEmailBody(match MatchPair, tmpl *template.Template) (string, error) {
+	var emailBodyBuffer = &strings.Builder{}
+	err := tmpl.Execute(emailBodyBuffer, match)
+	if err != nil {
+		return "", errors.Wrap(err, "failed to execute template for email body")
+	}
+	emailBody := emailBodyBuffer.String()
+
+	return emailBody, nil
+}
+
+func loadEmailTemplate(filePath string) (*template.Template, error) {
+	tmpl, err := template.ParseFiles(filePath)
+	if err != nil {
+		return nil, errors.Wrap(err, "failed to parse email template")
+	}
+	return tmpl, nil
+}
+
+func generateEmailMessages(matches []MatchPair, tmpl *template.Template) ([]*gomail.Message, error) {
+
+	emailMessages := make([]*gomail.Message, 0, len(matches))
+	for _, match := range matches {
+		emailBody, err := populateEmailBody(match, tmpl)
+		if err != nil {
+			return nil, errors.Wrap(err, "failed to generate email body")
+		}
+		emailMessages = append(emailMessages, createEmailMessage(match.From.Email, emailBody))
+	}
+
+	return emailMessages, nil
+}
+
+func sendEmails(emailMessages ...*gomail.Message) error {
 	host := os.Getenv("EMAIL_HOST")
 	strPort := os.Getenv("EMAIL_PORT")
 	user := os.Getenv("EMAIL_USER")
@@ -75,45 +122,14 @@ func sendEmail(to, subject, body string) error {
 	if err != nil {
 		return errors.Wrap(err, "error dialing email server")
 	}
+	defer s.Close()
 
-	m := gomail.NewMessage()
-	m.SetHeader("From", os.Getenv("EMAIL_FROM"))
-	m.SetHeader("To", to)
-	m.SetHeader("Subject", subject)
-	m.SetBody("text/html", body)
-
-	return gomail.Send(s, m)
-}
-
-func sendEmails(matches []MatchPair) ([]string, error) {
-	// TODO: add retry logic for failed emails (maybe use a queue)
-	// instead of sending each email individually,
-	// generate all the emails and send them in bulk to avoid individual errors
-	// or prompt the user to retry
-	emailIssues := make([]string, 0, len(matches))
-	subject := "Your Secret Santa Match!"
-
-	templateFile := "./templates/email_template.html"
-	tmpl, err := template.ParseFiles(templateFile)
+	err = gomail.Send(s, emailMessages...)
 	if err != nil {
-		return emailIssues, errors.Wrap(err, "failed to parse email template")
+		return err
 	}
+	return nil
 
-	for _, match := range matches {
-		var emailBodyBuffer = &strings.Builder{}
-		err := tmpl.Execute(emailBodyBuffer, match)
-		if err != nil {
-			emailIssues = append(emailIssues, fmt.Sprintf("failed to execute template for %s: %v", match.From.Email, err))
-			continue
-
-		}
-		emailBody := emailBodyBuffer.String()
-
-		if err := sendEmail(match.From.Email, subject, emailBody); err != nil {
-			emailIssues = append(emailIssues, fmt.Sprintf("failed to send email to %s: %v", match.From.Email, err))
-		}
-	}
-	return emailIssues, nil
 }
 
 var rootCmd = &cobra.Command{
@@ -123,14 +139,22 @@ var rootCmd = &cobra.Command{
 	Version:      version,
 	SilenceUsage: true,
 	RunE: func(cmd *cobra.Command, args []string) error {
+		defaultValues := struct {
+			FilePath     string
+			TemplatePath string
+		}{
+			FilePath:     "data.json",
+			TemplatePath: "./templates/email_template.html",
+		}
+
 		var filePath string
 		if len(args) == 0 {
-			filePath = "data.json"
+			filePath = defaultValues.FilePath
 		} else {
 			filePath = args[0]
 		}
 		if filePath == "" {
-			filePath = "data.json"
+			filePath = defaultValues.FilePath
 		}
 
 		if !checkFileExists(filePath) {
@@ -158,15 +182,21 @@ var rootCmd = &cobra.Command{
 		}
 
 		matches := generateSecretSantaMatches(payload)
-		emailIssues, err := sendEmails(matches)
+		// TODO: Give users the option to use their own template
+		templateFilePath := defaultValues.TemplatePath
+		tmpl, err := loadEmailTemplate(templateFilePath)
 		if err != nil {
-			return errors.Wrap(err, "error sending emails")
+			return errors.Wrap(err, "error loading email template")
 		}
-		if len(emailIssues) > 0 {
-			for _, issue := range emailIssues {
-				fmt.Println(issue)
-			}
-			fmt.Println("Some emails failed to send, please check the logs for more details")
+
+		emailMessages, err := generateEmailMessages(matches, tmpl)
+		if err != nil {
+			return errors.Wrap(err, "error generating email messages")
+		}
+
+		err = sendEmails(emailMessages...)
+		if err != nil {
+			return errors.Wrap(err, "error sending emails")
 		}
 
 		return nil

cmd/root_test.go

@@ -1,8 +1,11 @@
 package cmd
 
 import (
+	"html/template"
 	"reflect"
 	"testing"
+
+	"github.com/stretchr/testify/assert"
 )
 
 func TestCheckFileExistsReturnsTrueWhenFileExists(t *testing.T) {
@@ -31,7 +34,7 @@ func TestCheckIsJsonReturnsFalseWhenFileIsNotJson(t *testing.T) {
 }
 
 func TestGenerateSecretSantaMachesReturnsAppropriateLenghtOfMatchPairs(t *testing.T) {
-	var payload []Data
+	payload := make([]Data, 0, 3)
 	payload = append(payload, Data{Name: "A", Email: "[email protected]"})
 	payload = append(payload, Data{Name: "B", Email: "[email protected]"})
 	payload = append(payload, Data{Name: "C", Email: "[email protected]"})
@@ -44,12 +47,12 @@ func TestGenerateSecretSantaMachesReturnsAppropriateLenghtOfMatchPairs(t *testin
 }
 
 func TestCircularMatchingAlgorithmReturnsExpectedMatchPairs(t *testing.T) {
-	var payload []Data
+	payload := make([]Data, 0, 3)
 	payload = append(payload, Data{Name: "A", Email: "[email protected]"})
 	payload = append(payload, Data{Name: "B", Email: "[email protected]"})
 	payload = append(payload, Data{Name: "C", Email: "[email protected]"})
 
-	var expected []MatchPair
+	expected := make([]MatchPair, 0, 3)
 
 	expected = append(expected, MatchPair{From: payload[0], To: payload[1]})
 	expected = append(expected, MatchPair{From: payload[1], To: payload[2]})
@@ -62,3 +65,69 @@ func TestCircularMatchingAlgorithmReturnsExpectedMatchPairs(t *testing.T) {
 	}
 
 }
+
+func TestPopulateEmailBodyReturnsExpectedString(t *testing.T) {
+	p1 := Data{Name: "A", Email: "[email protected]"}
+	p2 := Data{Name: "B", Email: "[email protected]"}
+
+	matchPair := MatchPair{From: p1, To: p2}
+
+	tmpl, err := template.New("test").Parse("Hi {{.From.Name}} your Secret Santa match is {{.To.Name}}!")
+	if err != nil {
+		t.Error("Expected template to be parsed without error")
+	}
+
+	emailBody, err := populateEmailBody(matchPair, tmpl)
+
+	if err != nil {
+		t.Error("Expected populateEmailBody to not return an error")
+	}
+
+	assert.Equal(t, "Hi A your Secret Santa match is B!", emailBody)
+
+}
+
+func TestPopulateEmailBodyReturnsErrorWhenInvalidTemplateProvided(t *testing.T) {
+	p1 := Data{Name: "A", Email: "[email protected]"}
+	p2 := Data{Name: "B", Email: "[email protected]"}
+
+	matchPair := MatchPair{From: p1, To: p2}
+
+	tmpl, err := template.New("test").Parse("Hi {{.Something.Unexpected}}!")
+	if err != nil {
+		t.Error("Expected template to be parsed without error")
+	}
+
+	emailBody, err := populateEmailBody(matchPair, tmpl)
+
+	assert.Equal(t, "", emailBody)
+	if err == nil {
+		t.Error("Expected populateEmailBody to return an error when invalid template is provided")
+	}
+
+}
+
+func TestGenerateEmailMessagesReturnsExpectedNumberOfMessages(t *testing.T) {
+	payload := make([]Data, 0, 3)
+	payload = append(payload, Data{Name: "A", Email: "[email protected]"})
+	payload = append(payload, Data{Name: "B", Email: "[email protected]"})
+	payload = append(payload, Data{Name: "C", Email: "[email protected]"})
+
+	matchPairs := make([]MatchPair, 0, 3)
+
+	matchPairs = append(matchPairs, MatchPair{From: payload[0], To: payload[1]})
+	matchPairs = append(matchPairs, MatchPair{From: payload[1], To: payload[2]})
+	matchPairs = append(matchPairs, MatchPair{From: payload[2], To: payload[0]})
+
+	tmpl, err := template.New("test").Parse("Hi {{.From.Name}} your Secret Santa match is {{.To.Name}}!")
+	if err != nil {
+		t.Error("Expected template to be parsed without error")
+	}
+	messages, err := generateEmailMessages(matchPairs, tmpl)
+
+	if err != nil {
+		t.Error("Expected generateEmailMessages to not return an error")
+	}
+
+	assert.Equal(t, len(matchPairs), len(messages))
+}

go.mod

@@ -4,7 +4,13 @@ go 1.21.4
 
 require github.com/spf13/cobra v1.8.0
 
-require github.com/pkg/errors v0.9.1 // indirect
+require (
+	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/pkg/errors v0.9.1 // indirect
+	github.com/pmezard/go-difflib v1.0.0 // indirect
+	github.com/stretchr/testify v1.8.4 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
+)
 
 require (
 	github.com/inconshreveable/mousetrap v1.1.0 // indirect

go.sum

@@ -1,16 +1,23 @@
 github.com/cpuguy83/go-md2man/v2 v2.0.3/go.mod h1:tgQtvFlXSQOSOSIRvRPT7W67SCa46tRHOmNcaadrF8o=
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/inconshreveable/mousetrap v1.1.0 h1:wN+x4NVGpMsO7ErUn/mUI3vEoE6Jt13X2s0bqwp9tc8=
 github.com/inconshreveable/mousetrap v1.1.0/go.mod h1:vpF70FUmC8bwa3OWnCshd2FqLfsEA9PFc4w1p2J65bw=
 github.com/pkg/errors v0.9.1 h1:FEBLx1zS214owpjy7qsBeixbURkuhQAwrK5UwLGTwt4=
 github.com/pkg/errors v0.9.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/russross/blackfriday/v2 v2.1.0/go.mod h1:+Rmxgy9KzJVeS9/2gXHxylqXiyQDYRxCVz55jmeOWTM=
 github.com/spf13/cobra v1.8.0 h1:7aJaZx1B85qltLMc546zn58BxxfZdR/W22ej9CFoEf0=
 github.com/spf13/cobra v1.8.0/go.mod h1:WXLWApfZ71AjXPya3WOlMsY9yMs7YeiHhFVlvLyhcho=
 github.com/spf13/pflag v1.0.5 h1:iy+VFUOCP1a+8yFto/drg2CJ5u0yRoB7fZw3DKv/JXA=
 github.com/spf13/pflag v1.0.5/go.mod h1:McXfInJRrz4CZXVZOBLb0bTZqETkiAhM9Iw0y3An2Bg=
+github.com/stretchr/testify v1.8.4 h1:CcVxjf3Q8PM0mHUKJCdn+eZZtm5yQwehR5yeSVQQcUk=
+github.com/stretchr/testify v1.8.4/go.mod h1:sz/lmYIOXD/1dqDmKjjqLyZ2RngseejIcXlSw2iwfAo=
 gopkg.in/alexcesaro/quotedprintable.v3 v3.0.0-20150716171945-2caba252f4dc h1:2gGKlE2+asNV9m7xrywl36YYNnBG5ZQ0r/BOOxqPpmk=
 gopkg.in/alexcesaro/quotedprintable.v3 v3.0.0-20150716171945-2caba252f4dc/go.mod h1:m7x9LTH6d71AHyAX77c9yqWCCa3UKHcVEj9y7hAtKDk=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/gomail.v2 v2.0.0-20160411212932-81ebce5c23df h1:n7WqCuqOuCbNr617RXOY0AWRXxgwEyPp2z+p0+hgMuE=
 gopkg.in/gomail.v2 v2.0.0-20160411212932-81ebce5c23df/go.mod h1:LRQQ+SO6ZHR7tOkpBDuZnXENFzX8qRjMDMyPD6BRkCw=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
 gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=