Extend 'order_placed' endpoint to handle different item categories

internal/pretix/client.go

@@ -0,0 +1,24 @@
+package pretix
+
+import (
+	"fmt"
+	"net/http"
+	"strings"
+)
+
+func (s Server) buildURL(endpoint string, args ...any) string {
+	baseURL := strings.TrimSuffix(s.config.BaseURL, "/")
+	return fmt.Sprintf(endpoint, append([]any{baseURL}, args...)...)
+}
+
+func (s Server) doGetRequest(url string) (*http.Response, error) {
+	req, err := http.NewRequest(http.MethodGet, url, nil)
+	if err != nil {
+		return nil, err
+	}
+
+	req.Header.Set("Accept", "application/json")
+	req.Header.Set("Authorization", fmt.Sprint("Token ", s.config.APIToken))
+
+	return s.client.Do(req)
+}

internal/pretix/order_placed.go

@@ -3,6 +3,7 @@ package pretix
 import (
 	"encoding/json"
 	"fmt"
+	"math/rand"
 	"net/http"
 	"strconv"
 	"strings"
@@ -15,8 +16,17 @@ const (
 	eventOrderPlaced	= "pretix.event.order.placed"
 
 	urlIndividualOrder	= "%s/api/v1/organizers/%s/events/%s/orders/%s/"
+	urlItem			= "%s/api/v1/organizers/%s/events/%s/items/%d/"
+	urlItemCategory		= "%s/api/v1/organizers/%s/events/%s/categories/%d/"
 )
 
+var adverbs = []string{" Außerdem ", " Zusätzlich ", " Weiterhin ", " Des Weiteren "}
+
+type categoryBin struct {
+	NumFree	uint
+	NumPaid	uint
+}
+
 func (s Server) orderPlaced(w http.ResponseWriter, r *http.Request) {
 	if r.Header.Get("Content-Type") != "application/json" {
 		writeStatus(w, http.StatusBadRequest)
@@ -42,16 +52,7 @@ func (s Server) orderPlaced(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	req, err := http.NewRequest(http.MethodGet, s.buildURL(urlIndividualOrder, data.Organizer, data.Event, data.Code), nil)
-	if err != nil {
-		writeStatus(w, http.StatusInternalServerError)
-		return
-	}
-
-	req.Header.Set("Accept", "application/json")
-	req.Header.Set("Authorization", fmt.Sprint("Token ", s.config.APIToken))
-
-	resp, err := s.client.Do(req)
+	resp, err := s.doGetRequest(s.buildURL(urlIndividualOrder, data.Organizer, data.Event, data.Code))
 	if err != nil {
 		writeStatus(w, http.StatusInternalServerError)
 		return
@@ -73,6 +74,7 @@ func (s Server) orderPlaced(w http.ResponseWriter, r *http.Request) {
 		Code		string
 		Datetime	time.Time
 		Positions	[]struct{
+			Item	uint
 			Price	string
 		}
 		Total		string
@@ -97,59 +99,80 @@ func (s Server) orderPlaced(w http.ResponseWriter, r *http.Request) {
 	}
 
 	if rowsAffected > 0 && order.Datetime.Add(72 * time.Hour).After(time.Now()) { // pretix retries failed webhooks for up to three days
-		numFree := 0
-		numPaid := 0
+		categories := map[string]categoryBin{}
+
 		for _, position := range order.Positions {
 			euros, cents, err := parsePrice(position.Price)
 			if err != nil {
 				continue
 			}
 
+			name := s.fetchCategory(data.Organizer, data.Event, position.Item)
+
+			category := categories[name]
 			if euros > 0 || cents > 0 {
-				numPaid++
+				category.NumPaid++
 			} else {
-				numFree++
+				category.NumFree++
 			}
+
+			categories[name] = category
 		}
 
-		var verb, free, conjunction, paid, noun, total string
-		if numFree+numPaid == 1 {
-			verb = "wurde "
-		} else {
-			verb = "wurden "
-		}
-		if numFree == 1 {
-			free = "ein kostenloses "
-		} else if numFree > 1 {
-			free = fmt.Sprint(numFree, " kostenlose ")
-		}
-		if numPaid == 1 {
-			paid = "ein bezahltes "
-		} else if numPaid > 1 {
-			paid = fmt.Sprint(numPaid, " bezahlte ")
-		}
-		if numFree > 0 && numPaid > 0 {
-			conjunction = "und "
-		}
-		if numPaid == 1 || numPaid == 0 && numFree == 1 { // match number of adjective immediately before noun
-			noun = "Ticket "
-		} else {
-			noun = "Tickets "
-		}
-		if totalEuros, totalCents, err := parsePrice(order.Total); err == nil && (totalEuros > 0 || totalCents > 0) {
-			var adverb, fraction string
-			if numPaid > 1 {
-				adverb = "insgesamt "
+		var body strings.Builder
+		body.WriteString("\U0001f389")
+
+		rng := rand.New(rand.NewSource(time.Now().Unix()))
+
+		adverb := " Es "
+		for category, bin := range categories {
+			var verb, free, conjunction, paid, noun, preposition, quote, total string
+			if bin.NumFree+bin.NumPaid == 1 {
+				verb = "wurde "
+			} else {
+				verb = "wurden "
 			}
-			if totalCents > 0 {
-				fraction = fmt.Sprintf(",%02d", totalCents)
+			if bin.NumFree == 1 {
+				free = "ein kostenloses "
+			} else if bin.NumFree > 1 {
+				free = fmt.Sprint(bin.NumFree, " kostenlose ")
 			}
-			total = fmt.Sprint("für ", adverb, totalEuros, fraction, " Euro ")
+			if bin.NumPaid == 1 {
+				paid = "ein bezahltes "
+			} else if bin.NumPaid > 1 {
+				paid = fmt.Sprint(bin.NumPaid, " bezahlte ")
+			}
+			if bin.NumFree > 0 && bin.NumPaid > 0 {
+				conjunction = "und "
+			}
+			if bin.NumPaid == 1 || bin.NumPaid == 0 && bin.NumFree == 1 { // match number of adjective immediately before noun
+				noun = "Produkt "
+			} else {
+				noun = "Produkte "
+			}
+			if category != "" {
+				preposition = `aus der Kategorie "`
+				quote = `" `
+			}
+			if totalEuros, totalCents, err := parsePrice(order.Total); err == nil && (totalEuros > 0 || totalCents > 0) {
+				var adverb, fraction string
+				if bin.NumPaid > 1 {
+					adverb = "insgesamt "
+				}
+				if totalCents > 0 {
+					fraction = fmt.Sprintf(",%02d", totalCents)
+				}
+				total = fmt.Sprint("für ", adverb, totalEuros, fraction, " Euro ")
+			}
+
+			body.WriteString(fmt.Sprint(adverb, verb, free, conjunction, paid, noun, preposition, category, quote, total, "bestellt."))
+
+			adverb = adverbs[rng.Intn(len(adverbs))]
 		}
 
 		message := event.MessageEventContent{
 			MsgType:	event.MsgText,
-			Body:		fmt.Sprint("\U0001f389 Es ", verb, free, conjunction, paid, noun, total, "bestellt."),
+			Body:		body.String(),
 		}
 
 		success := s.matrix.Broadcast(&message)
@@ -159,6 +182,50 @@ func (s Server) orderPlaced(w http.ResponseWriter, r *http.Request) {
 	}
 }
 
+func (s Server) fetchCategory(organizer, event string, item uint) string {
+	resp, err := s.doGetRequest(s.buildURL(urlItem, organizer, event, item))
+	if err != nil {
+		return ""
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != 200 || resp.Header.Get("Content-Type") != "application/json" {
+		return ""
+	}
+
+	decoder := json.NewDecoder(resp.Body)
+	itemData := struct{
+		Category	uint
+	}{}
+
+	err = decoder.Decode(&itemData)
+	if err != nil || itemData.Category == 0 {
+		return ""
+	}
+
+	resp, err = s.doGetRequest(s.buildURL(urlItemCategory, organizer, event, itemData.Category))
+	if err != nil {
+		return ""
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != 200 || resp.Header.Get("Content-Type") != "application/json" {
+		return ""
+	}
+
+	decoder = json.NewDecoder(resp.Body)
+	itemCategory := struct{
+		Name		string
+	}{}
+
+	err = decoder.Decode(&itemCategory)
+	if err != nil {
+		return ""
+	}
+
+	return itemCategory.Name
+}
+
 func parsePrice(price string) (euros uint64, cents uint64, err error) {
 	parts := strings.Split(price, ".")
 

internal/pretix/server.go

@@ -3,11 +3,9 @@ package pretix
 import (
 	"context"
 	"database/sql"
-	"fmt"
 	"io"
 	"log"
 	"net/http"
-	"strings"
 	"sync"
 
 	"git.luj0ga.de/franconian/matrix"
@@ -96,11 +94,6 @@ func (s Server) createTables() error {
 	return nil
 }
 
-func (s Server) buildURL(endpoint string, args ...any) string {
-	baseURL := strings.TrimSuffix(s.config.BaseURL, "/")
-	return fmt.Sprintf(endpoint, append([]any{baseURL}, args...)...)
-}
-
 func writeStatus(w http.ResponseWriter, code int) {
 	w.WriteHeader(code)
 	io.WriteString(w, http.StatusText(code))