Extract statement data creation to a file

Author: twoGiants

refactoring/theatre/createStatementData.go

@@ -0,0 +1,107 @@
+package theatre
+
+import (
+	"fmt"
+	"math"
+)
+
+type StatementData struct {
+	Customer           string
+	Performances       []EnrichedPerformance
+	TotalAmount        int
+	TotalVolumeCredits int
+}
+
+type EnrichedPerformance struct {
+	PlayID        string
+	Audience      int
+	play          Play
+	amount        int
+	volumeCredits int
+}
+
+type Plays map[string]Play
+
+func (p Plays) playFor(aPerformance Performance) Play {
+	return p[aPerformance.PlayID]
+}
+
+func createStatementData(invoice Invoice, plays map[string]Play) (StatementData, error) {
+	result := StatementData{}
+	result.Customer = invoice.Customer
+
+	var enrichedPerformances []EnrichedPerformance
+	for _, performance := range invoice.Performances {
+		enrichedPerformance, err := enrichPerformance(performance, Plays(plays))
+		if err != nil {
+			return StatementData{}, err
+		}
+		enrichedPerformances = append(enrichedPerformances, enrichedPerformance)
+	}
+	result.Performances = enrichedPerformances
+
+	result.TotalAmount = totalAmount(result)
+	result.TotalVolumeCredits = totalVolumeCredits(result)
+
+	return result, nil
+}
+
+func enrichPerformance(performance Performance, plays Plays) (EnrichedPerformance, error) {
+	result := EnrichedPerformance{}
+	result.PlayID = performance.PlayID
+	result.Audience = performance.Audience
+	result.play = plays.playFor(performance)
+	amount, err := amountFor(result)
+	if err != nil {
+		return EnrichedPerformance{}, err
+	}
+	result.amount = amount
+	result.volumeCredits = volumeCreditsFor(result)
+
+	return result, nil
+}
+
+func totalVolumeCredits(data StatementData) int {
+	result := 0
+	for _, perf := range data.Performances {
+		result += perf.volumeCredits
+	}
+	return result
+}
+
+func totalAmount(data StatementData) int {
+	result := 0
+	for _, perf := range data.Performances {
+		result += perf.amount
+	}
+	return result
+}
+
+func volumeCreditsFor(aPerformance EnrichedPerformance) int {
+	result := int(math.Max(float64(aPerformance.Audience)-30, 0))
+	// add extra credit for every ten comedy attendees
+	if aPerformance.play.Type == "comedy" {
+		result += int(math.Floor(float64(aPerformance.Audience) / 5))
+	}
+	return result
+}
+
+func amountFor(aPerformance EnrichedPerformance) (int, error) {
+	result := 0
+	switch aPerformance.play.Type {
+	case "tragedy":
+		result = 40000
+		if aPerformance.Audience > 30 {
+			result += 1000 * (aPerformance.Audience - 30)
+		}
+	case "comedy":
+		result = 30000
+		if aPerformance.Audience > 20 {
+			result += 10000 + 500*(aPerformance.Audience-20)
+		}
+		result += 300 * aPerformance.Audience
+	default:
+		return 0, fmt.Errorf("unknown type: %s", aPerformance.play.Type)
+	}
+	return result, nil
+}

refactoring/theatre/statement.go

@@ -2,7 +2,6 @@ package theatre
 
 import (
 	"fmt"
-	"math"
 
 	"github.com/leekchan/accounting"
 )
@@ -22,110 +21,15 @@ type Performance struct {
 	Audience int
 }
 
-type EnrichedPerformance struct {
-	PlayID        string
-	Audience      int
-	play          Play
-	amount        int
-	volumeCredits int
-}
-
-type StatementPrinter struct {
-	invoice Invoice
-	plays   map[string]Play
-}
+type StatementPrinter struct{}
 
 func (s StatementPrinter) Print(invoice Invoice, plays map[string]Play) (string, error) {
-	s.invoice = invoice
-	s.plays = plays
-	statementData := StatementData{}
-	statementData.Customer = s.invoice.Customer
-
-	var enrichedPerformances []EnrichedPerformance
-	for _, performance := range s.invoice.Performances {
-		enrichedPerformance, err := s.enrichPerformance(performance)
-		if err != nil {
-			return "", err
-		}
-		enrichedPerformances = append(enrichedPerformances, enrichedPerformance)
-	}
-	statementData.Performances = enrichedPerformances
-
-	statementData.totalAmount = s.totalAmount(statementData)
-	statementData.totalVolumeCredits = s.totalVolumeCredits(statementData)
-
-	return renderPlainText(statementData), nil
-}
-
-func (StatementPrinter) totalVolumeCredits(data StatementData) int {
-	result := 0
-	for _, perf := range data.Performances {
-		result += perf.volumeCredits
-	}
-	return result
-}
-
-func (StatementPrinter) totalAmount(data StatementData) int {
-	result := 0
-	for _, perf := range data.Performances {
-		result += perf.amount
-	}
-	return result
-}
-
-func (s StatementPrinter) enrichPerformance(performance Performance) (EnrichedPerformance, error) {
-	result := EnrichedPerformance{}
-	result.PlayID = performance.PlayID
-	result.Audience = performance.Audience
-	result.play = s.playFor(performance)
-	amount, err := s.amountFor(result)
+	statementData, err := createStatementData(invoice, plays)
 	if err != nil {
-		return EnrichedPerformance{}, err
-	}
-	result.amount = amount
-	result.volumeCredits = s.volumeCreditsFor(result)
-
-	return result, nil
-}
-
-func (StatementPrinter) volumeCreditsFor(aPerformance EnrichedPerformance) int {
-	result := int(math.Max(float64(aPerformance.Audience)-30, 0))
-	// add extra credit for every ten comedy attendees
-	if aPerformance.play.Type == "comedy" {
-		result += int(math.Floor(float64(aPerformance.Audience) / 5))
+		return "", err
 	}
-	return result
-}
-
-func (s StatementPrinter) playFor(aPerformance Performance) Play {
-	return s.plays[aPerformance.PlayID]
-}
 
-func (StatementPrinter) amountFor(aPerformance EnrichedPerformance) (int, error) {
-	result := 0
-	switch aPerformance.play.Type {
-	case "tragedy":
-		result = 40000
-		if aPerformance.Audience > 30 {
-			result += 1000 * (aPerformance.Audience - 30)
-		}
-	case "comedy":
-		result = 30000
-		if aPerformance.Audience > 20 {
-			result += 10000 + 500*(aPerformance.Audience-20)
-		}
-		result += 300 * aPerformance.Audience
-	default:
-		return 0, fmt.Errorf("unknown type: %s", aPerformance.play.Type)
-	}
-	return result, nil
-}
-
-type StatementData struct {
-	Customer           string
-	Performances       []EnrichedPerformance
-	totalAmount        int
-	totalVolumeCredits int
+	return renderPlainText(statementData), nil
 }
 
 func renderPlainText(data StatementData) string {
@@ -140,8 +44,8 @@ func renderPlainText(data StatementData) string {
 		)
 	}
 
-	result += fmt.Sprintf("Amount owed is %s\n", usd(data.totalAmount))
-	result += fmt.Sprintf("You earned %d credits\n", data.totalVolumeCredits)
+	result += fmt.Sprintf("Amount owed is %s\n", usd(data.TotalAmount))
+	result += fmt.Sprintf("You earned %d credits\n", data.TotalVolumeCredits)
 	return result
 }