fix: correct destination initialization and response handling

This commit makes corrections to the initialization of the dests array to 
ensure it properly allocates space for each destination. It also fixes the 
response handling by correctly extending the response structure after 
the loop, improving overall stability and accuracy of the distance 
matrix request handling.

go.sum

@@ -1,6 +1,5 @@
 cloud.google.com/go v0.26.0/go.mod h1:aQUYkXzVsufM+DwF1aE+0xfcU+56JwCaLick0ClmMTw=
-cloud.google.com/go/auth v0.14.0 h1:A5C4dKV/Spdvxcl0ggWwWEzzP7AZMJSEIgrkngwhGYM=
+cloud.google.com/go/auth v0.14.1 h1:AwoJbzUdxA/whv1qj3TLKwh3XX5sikny2fc40wUl+h0=
-cloud.google.com/go/auth v0.14.0/go.mod h1:CYsoRL1PdiDuqeQpZE0bP2pnPrGqFcOkI0nldEQis+A=
 cloud.google.com/go/auth v0.14.1/go.mod h1:4JHUxlGXisL0AW8kXPtUF6ztuOksyfUQNFjfsOCXkPM=
 cloud.google.com/go/auth/oauth2adapt v0.2.7 h1:/Lc7xODdqcEw8IrZ9SvwnlLX6j9FHQM74z6cBk9Rw6M=
 cloud.google.com/go/auth/oauth2adapt v0.2.7/go.mod h1:NTbTTzfvPl1Y3V1nPpOgl2w6d/FjO7NNUQaWSox6ZMc=
@@ -105,8 +104,7 @@ go.opentelemetry.io/otel/trace v1.34.0 h1:+ouXS2V8Rd4hp4580a8q23bg0azF2nI8cqLYnC
 go.opentelemetry.io/otel/trace v1.34.0/go.mod h1:Svm7lSjQD7kG7KJ/MUHPVXSDGz2OX4h0M2jHBhmSfRE=
 golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
 golang.org/x/crypto v0.0.0-20200622213623-75b288015ac9/go.mod h1:LzIPMQfyMNhhGPhUkYOs5KpL4U8rLKemX1yGLhDgUto=
-golang.org/x/crypto v0.32.0 h1:euUpcYgM8WcP71gNpTqQCn6rC2t6ULUPiOzfWaXVVfc=
+golang.org/x/crypto v0.33.0 h1:IOBPskki6Lysi0lo9qQvbxiQ+FvsCC/YWOecCHAixus=
-golang.org/x/crypto v0.32.0/go.mod h1:ZnnJkOaASj8g0AjIduWNlq2NRxL0PlBrbKVyZ6V/Ugc=
 golang.org/x/crypto v0.33.0/go.mod h1:bVdXmD7IV/4GdElGPozy6U7lWdRXA4qyRVGJV57uQ5M=
 golang.org/x/exp v0.0.0-20190121172915-509febef88a4/go.mod h1:CJ0aWSM057203Lf6IL+f9T1iT9GByDxfZKAQTCR3kQA=
 golang.org/x/lint v0.0.0-20181026193005-c67002cb31c3/go.mod h1:UVdnD1Gm6xHRNCYTkRU2/jEulfH38KcIWyp/GAMgvoE=
@@ -119,37 +117,30 @@ golang.org/x/net v0.0.0-20190311183353-d8887717615a/go.mod h1:t9HGtf8HONx5eT2rtn
 golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
 golang.org/x/net v0.0.0-20190620200207-3b0461eec859/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
 golang.org/x/net v0.0.0-20201110031124-69a78807bb2b/go.mod h1:sp8m0HH+o8qH0wwXwYZr8TS3Oi6o0r6Gce1SSxlDquU=
-golang.org/x/net v0.34.0 h1:Mb7Mrk043xzHgnRM88suvJFwzVrRfHEHJEl5/71CKw0=
+golang.org/x/net v0.35.0 h1:T5GQRQb2y08kTAByq9L4/bz8cipCdA8FbRTXewonqY8=
-golang.org/x/net v0.34.0/go.mod h1:di0qlW3YNM5oh6GqDGQr92MyTozJPmybPK4Ev/Gm31k=
 golang.org/x/net v0.35.0/go.mod h1:EglIi67kWsHKlRzzVMUD93VMSWGFOMSZgxFjparz1Qk=
 golang.org/x/oauth2 v0.0.0-20180821212333-d2e6202438be/go.mod h1:N/0e6XlmueqKjAGxoOufVs8QHGRruUQn6yWY3a++T0U=
-golang.org/x/oauth2 v0.25.0 h1:CY4y7XT9v0cRI9oupztF8AgiIu99L/ksR/Xp/6jrZ70=
+golang.org/x/oauth2 v0.26.0 h1:afQXWNNaeC4nvZ0Ed9XvCCzXM6UHJG7iCg0W4fPqSBE=
-golang.org/x/oauth2 v0.25.0/go.mod h1:XYTD2NtWslqkgxebSiOHnXEap4TF09sJSc7H1sXbhtI=
 golang.org/x/oauth2 v0.26.0/go.mod h1:XYTD2NtWslqkgxebSiOHnXEap4TF09sJSc7H1sXbhtI=
 golang.org/x/sync v0.0.0-20180314180146-1d60e4601c6f/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.0.0-20181108010431-42b317875d0f/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.0.0-20190227155943-e225da77a7e6/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
-golang.org/x/sync v0.10.0 h1:3NQrjDixjgGwUOCaF8w2+VYHv0Ve/vGYSbdkTa98gmQ=
+golang.org/x/sync v0.11.0 h1:GGz8+XQP4FvTTrjZPzNKTMFtSXH80RAzG+5ghFPgK9w=
-golang.org/x/sync v0.10.0/go.mod h1:Czt+wKu1gCyEFDUtn0jG5QVvpJ6rzVqr5aXyt9drQfk=
 golang.org/x/sync v0.11.0/go.mod h1:Czt+wKu1gCyEFDUtn0jG5QVvpJ6rzVqr5aXyt9drQfk=
 golang.org/x/sys v0.0.0-20180830151530-49385e6e1522/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20190502145724-3ef323f4f1fd/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20200930185726-fdedc70b468f/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
-golang.org/x/sys v0.29.0 h1:TPYlXGxvx1MGTn2GiZDhnjPA9wZzZeGKHHmKhHYvgaU=
+golang.org/x/sys v0.30.0 h1:QjkSwP/36a20jFYWkSue1YwXzLmsV5Gfq7Eiy72C1uc=
-golang.org/x/sys v0.29.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
 golang.org/x/sys v0.30.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 golang.org/x/text v0.3.2/go.mod h1:bEr9sfX3Q8Zfm5fL9x+3itogRgK3+ptLWKqgva+5dAk=
 golang.org/x/text v0.3.3/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
-golang.org/x/text v0.21.0 h1:zyQAAkrwaneQ066sspRyJaG9VNi/YJ1NfzcGB3hZ/qo=
+golang.org/x/text v0.22.0 h1:bofq7m3/HAFvbF51jz3Q9wLg3jkvSPuiZu/pD1XwgtM=
-golang.org/x/text v0.21.0/go.mod h1:4IBbMaMmOPCJ8SecivzSH54+73PCFmPWxNTLm+vZkEQ=
 golang.org/x/text v0.22.0/go.mod h1:YRoo4H8PVmsu+E3Ou7cqLVH8oXWIHVoX0jqUWALQhfY=
 golang.org/x/time v0.0.0-20200416051211-89c76fbcd5d1/go.mod h1:tRJNPiyCQ0inRvYxbN9jk5I+vvW/OXSQhTDSoE431IQ=
-golang.org/x/time v0.9.0 h1:EsRrnYcQiGH+5FfbgvV4AP7qEZstoyrHB0DzarOQ4ZY=
-golang.org/x/time v0.9.0/go.mod h1:3BpzKBy/shNhVucY/MWOyx10tF3SFh9QdLuxbVysPQM=
 golang.org/x/time v0.10.0 h1:3usCWA8tQn0L8+hFJQNgzpWbd89begxN66o1Ojdn5L4=
 golang.org/x/time v0.10.0/go.mod h1:3BpzKBy/shNhVucY/MWOyx10tF3SFh9QdLuxbVysPQM=
 golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
@@ -158,8 +149,6 @@ golang.org/x/tools v0.0.0-20190226205152-f727befe758c/go.mod h1:9Yl7xja0Znq3iFh3
 golang.org/x/tools v0.0.0-20190311212946-11955173bddd/go.mod h1:LCzVGOaR6xXOjkQ3onu1FJEFr0SW1gC7cKk1uF8kGRs=
 golang.org/x/tools v0.0.0-20190524140312-2c0ae7006135/go.mod h1:RgjU9mgBXZiqYHBnxXauZ1Gv1EHHAz9KjViQ78xBX0Q=
 golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
-google.golang.org/api v0.218.0 h1:x6JCjEWeZ9PFCRe9z0FBrNwj7pB7DOAqT35N+IPnAUA=
-google.golang.org/api v0.218.0/go.mod h1:5VGHBAkxrA/8EFjLVEYmMUJ8/8+gWWQ3s4cFH0FxG2M=
 google.golang.org/api v0.221.0 h1:qzaJfLhDsbMeFee8zBRdt/Nc+xmOuafD/dbdgGfutOU=
 google.golang.org/api v0.221.0/go.mod h1:7sOU2+TL4TxUTdbi0gWgAIg7tH5qBXxoyhtL+9x3biQ=
 google.golang.org/appengine v1.1.0/go.mod h1:EbEs0AVv82hx2wNQdGPgUI5lhzA/G0D9YwlJXL52JkM=
@@ -172,8 +161,6 @@ google.golang.org/genproto v0.0.0-20250212204824-5a70512c5d8b h1:TdBaFxGAABTI8sz
 google.golang.org/genproto v0.0.0-20250212204824-5a70512c5d8b/go.mod h1:0TrvLFkilZy+XULmuoWfiTbTRXLWXJ1S44jQTW3lWwE=
 google.golang.org/genproto/googleapis/api v0.0.0-20250124145028-65684f501c47 h1:5iw9XJTD4thFidQmFVvx0wi4g5yOHk76rNRUxz1ZG5g=
 google.golang.org/genproto/googleapis/api v0.0.0-20250124145028-65684f501c47/go.mod h1:AfA77qWLcidQWywD0YgqfpJzf50w2VjzBml3TybHeJU=
-google.golang.org/genproto/googleapis/rpc v0.0.0-20250124145028-65684f501c47 h1:91mG8dNTpkC0uChJUQ9zCiRqx3GEEFOWaRZ0mI6Oj2I=
-google.golang.org/genproto/googleapis/rpc v0.0.0-20250124145028-65684f501c47/go.mod h1:+2Yz8+CLJbIfL9z73EW45avw8Lmge3xVElCP9zEKi50=
 google.golang.org/genproto/googleapis/rpc v0.0.0-20250207221924-e9438ea467c6 h1:2duwAxN2+k0xLNpjnHTXoMUgnv6VPSp5fiqTuwSxjmI=
 google.golang.org/genproto/googleapis/rpc v0.0.0-20250207221924-e9438ea467c6/go.mod h1:8BS3B93F/U1juMFq9+EDk+qOT5CO1R9IzXxG3PTqiRk=
 google.golang.org/grpc v1.19.0/go.mod h1:mqu4LbDTu4XGKhr4mRzUsmM4RtVoemTSY81AxZiDr8c=
@@ -193,8 +180,6 @@ google.golang.org/protobuf v1.22.0/go.mod h1:EGpADcykh3NcUnDUJcl1+ZksZNG86OlYog2
 google.golang.org/protobuf v1.23.0/go.mod h1:EGpADcykh3NcUnDUJcl1+ZksZNG86OlYog2l/sGQquU=
 google.golang.org/protobuf v1.23.1-0.20200526195155-81db48ad09cc/go.mod h1:EGpADcykh3NcUnDUJcl1+ZksZNG86OlYog2l/sGQquU=
 google.golang.org/protobuf v1.25.0/go.mod h1:9JNX74DMeImyA3h4bdi1ymwjUzf21/xIlbajtzgsN7c=
-google.golang.org/protobuf v1.36.4 h1:6A3ZDJHn/eNqc1i+IdefRzy/9PokBTPvcqMySR7NNIM=
-google.golang.org/protobuf v1.36.4/go.mod h1:9fA7Ob0pmnwhb644+1+CVWFRbNajQ6iRojtC/QF5bRE=
 google.golang.org/protobuf v1.36.5 h1:tPhr+woSbjfYvY6/GPufUoYizxw1cF/yFoxJ2fmpwlM=
 google.golang.org/protobuf v1.36.5/go.mod h1:9fA7Ob0pmnwhb644+1+CVWFRbNajQ6iRojtC/QF5bRE=
 googlemaps.github.io/maps v1.7.0 h1:9yAEgaAyg6bWn+TpY8PmNJ0C+YfUBtN9KjJypjCOioo=

main.go

@@ -151,7 +151,9 @@ func handleDistanceMatrixRequest(w http.ResponseWriter, r *http.Request, client
 
 	res := distanceResponse{}
 	dests := make([][]destination, len(origins))
-
+	for i := range dests {
+		dests[i] = make([]destination, len(destinations))
+	}
 	for {
 		elem, err := response.Recv()
 		if err != nil {
@@ -164,7 +166,7 @@ func handleDistanceMatrixRequest(w http.ResponseWriter, r *http.Request, client
 		}
 		ll := destinations[*elem.DestinationIndex].Waypoint.GetLocation().LatLng
 
-		dests[*elem.OriginIndex] = append(dests[*elem.OriginIndex], destination{
+		dests[*elem.OriginIndex][*elem.DestinationIndex] = destination{
 			Destination: fmt.Sprintf("%f,%f", ll.Latitude, ll.Longitude),
 			Distance: distance{
 				Text:  string(elem.DistanceMeters),
@@ -174,7 +176,7 @@ func handleDistanceMatrixRequest(w http.ResponseWriter, r *http.Request, client
 				elem.Duration.AsDuration().String(),
 				elem.Duration.AsDuration().Minutes(),
 			},
-		})
+		}
 	}
 	for i, dest := range dests {
 		res.Origins = append(res.Origins, origin{origins[i].Waypoint.GetAddress(), dest})