Don't remove attendees used in suggestions

attendees.go

@@ -60,6 +60,12 @@ func (aeu AttendeeExistsError) Error() string {
 	return "Attendee exists"
 }
 
+type AttendeeInUseError struct{}
+
+func (aeu AttendeeInUseError) Error() string {
+	return "Attendee in use (by suggestion)"
+}
+
 func GetAttendees(userid int64, date time.Time) (*[]*Attendee, error) {
 	var attendees []*Attendee
 
@@ -140,7 +146,16 @@ func DeleteAttendee(a *Attendee) error {
 		return err
 	}
 
-	// TODO ensure attendee isn't used in any suggestions
+	// Ensure attendee isn't used in any suggestions
+	suggestions, err := GetAttendeesSuggestions(transaction, a.UserId, a.Date, a.AttendeeId)
+	if err != nil {
+		transaction.Rollback()
+		return err
+	}
+	if len(*suggestions) > 0 {
+		transaction.Rollback()
+		return AttendeeInUseError{}
+	}
 
 	count, err := transaction.Delete(a)
 	if err != nil {
@@ -237,8 +252,12 @@ func AttendeeHandler(w http.ResponseWriter, r *http.Request) {
 
 		err = DeleteAttendee(attendee)
 		if err != nil {
+			if _, ok := err.(AttendeeInUseError); ok {
+				WriteError(w, 7 /*Attendee In Use*/)
+			} else {
 				WriteError(w, 999 /*Internal Error*/)
 				log.Print(err)
+			}
 			return
 		}
 

errors.go

@@ -18,6 +18,7 @@ var error_codes = map[int]string{
 	4: "User Exists",
 	5: "Attendee Exists",
 	6: "Suggestion Exists",
+	7: "Attendee In Use",
 	//  5:   "Connection Failed", //client-side error
 	999: "Internal Error",
 }

suggestions.go

@@ -2,6 +2,7 @@ package main
 
 import (
 	"encoding/json"
+	"gopkg.in/gorp.v1"
 	"log"
 	"net/http"
 	"strings"
@@ -61,6 +62,16 @@ func (sl *PopularSuggestionList) Write(w http.ResponseWriter) error {
 	return enc.Encode(sl)
 }
 
+func GetAttendeesSuggestions(transaction *gorp.Transaction, userid int64, date time.Time, attendeeid int64) (*[]*Suggestion, error) {
+	var suggestions []*Suggestion
+
+	_, err := transaction.Select(&suggestions, "SELECT * from suggestions WHERE UserId=? AND Date=? AND AttendeeID=?", userid, date, attendeeid)
+	if err != nil {
+		return nil, err
+	}
+	return &suggestions, nil
+}
+
 func GetSuggestions(userid int64, date time.Time) (*[]*Suggestion, error) {
 	var suggestions []*Suggestion