From 33bb853438cc2abb40db54a41cd1c1555f7ac93b Mon Sep 17 00:00:00 2001
From: nxshock <nxshock@gmail.com>
Date: Thu, 25 Jul 2019 20:14:37 +0500
Subject: [PATCH] Add capabilities method

---
 README.md                                    |  1 +
 internal/handlers.go                         | 25 ++++++++++++++++++
 internal/models/capabilities/capabilities.go | 27 ++++++++++++++++++++
 internal/server.go                           |  7 ++++-
 4 files changed, 59 insertions(+), 1 deletion(-)
 create mode 100644 internal/models/capabilities/capabilities.go

diff --git a/README.md b/README.md
index 0a82b24..84a90c7 100644
--- a/README.md
+++ b/README.md
@@ -15,4 +15,5 @@ Implemented from [Client-Server API](https://matrix.org/docs/spec/client_server/
 - [x] [5.4.3 POST /_matrix/client/r0/logout](https://matrix.org/docs/spec/client_server/latest#post-matrix-client-r0-logout)
 - [x] [5.4.4 POST /_matrix/client/r0/logout/all](https://matrix.org/docs/spec/client_server/latest#post-matrix-client-r0-logout-all)
 - [x] [5.7.1 GET /_matrix/client/r0/account/whoami](https://matrix.org/docs/spec/client_server/latest#get-matrix-client-r0-account-whoami)
+- [x] [6.1 GET /_matrix/client/r0/capabilities](https://matrix.org/docs/spec/client_server/latest#get-matrix-client-r0-capabilities)
 - [x] [10.4.1 GET /_matrix/client/r0/joined_rooms](https://matrix.org/docs/spec/client_server/latest#get-matrix-client-r0-joined-rooms)
diff --git a/internal/handlers.go b/internal/handlers.go
index c6807df..d0a487f 100644
--- a/internal/handlers.go
+++ b/internal/handlers.go
@@ -11,6 +11,7 @@ import (
 	"github.com/nxshock/signaller/internal/models/common"
 
 	"github.com/nxshock/signaller/internal/models"
+	"github.com/nxshock/signaller/internal/models/capabilities"
 	"github.com/nxshock/signaller/internal/models/joinedrooms"
 	login "github.com/nxshock/signaller/internal/models/login"
 	register "github.com/nxshock/signaller/internal/models/register"
@@ -224,6 +225,30 @@ func SyncHandler(w http.ResponseWriter, r *http.Request) {
 	sendJsonResponse(w, http.StatusOK, response)
 }
 
+// https://matrix.org/docs/spec/client_server/latest#get-matrix-client-r0-capabilities
+func CapabilitiesHandler(w http.ResponseWriter, r *http.Request) {
+	if r.Method != http.MethodGet {
+		errorResponse(w, models.M_UNKNOWN, http.StatusBadRequest, "wrong method: "+r.Method)
+		return
+	}
+
+	token := getTokenFromResponse(r)
+	if token == "" {
+		errorResponse(w, models.M_FORBIDDEN, http.StatusForbidden, "")
+	}
+
+	user := currServer.Backend.GetUserByToken(token)
+	if user == nil {
+		errorResponse(w, models.M_UNKNOWN_TOKEN, http.StatusBadRequest, "")
+		return
+	}
+
+	var response capabilities.Response
+	response.Capabilities = currServer.Capabilities
+
+	sendJsonResponse(w, http.StatusOK, response)
+}
+
 func sendJsonResponse(w http.ResponseWriter, httpStatus int, data interface{}) error {
 	b, err := json.Marshal(data)
 	if err != nil {
diff --git a/internal/models/capabilities/capabilities.go b/internal/models/capabilities/capabilities.go
new file mode 100644
index 0000000..a337355
--- /dev/null
+++ b/internal/models/capabilities/capabilities.go
@@ -0,0 +1,27 @@
+package capabilities
+
+// https://matrix.org/docs/spec/client_server/latest#get-matrix-client-r0-capabilities
+type Response struct {
+	Capabilities Capabilities `json:"capabilities"` // Required. The custom capabilities the server supports, using the Java package naming convention.
+}
+
+type Capabilities struct {
+	ChangePassword ChangePasswordCapability `json:"m.change_password"` // Capability to indicate if the user can change their password.
+	RoomVersions   RoomVersionsCapability   `json:"m.room_versions"`   // The room versions the server supports.
+}
+
+type ChangePasswordCapability struct {
+	Enabled bool `json:"enabled"` // Required. True if the user can change their password, false otherwise.
+}
+
+type RoomVersionsCapability struct {
+	Default   string               `json:"default"`   // Required. The default room version the server is using for new rooms.
+	Available map[string]Stability `json:"available"` // Required. A detailed description of the room versions the server supports.
+}
+
+type Stability string
+
+const (
+	Stable   Stability = "stable"
+	Unstable Stability = "unstable"
+)
diff --git a/internal/server.go b/internal/server.go
index bc10e6d..a5d2379 100644
--- a/internal/server.go
+++ b/internal/server.go
@@ -4,6 +4,8 @@ import (
 	"net/http"
 
 	"github.com/gorilla/mux"
+
+	"github.com/nxshock/signaller/internal/models/capabilities"
 )
 
 var currServer *Server
@@ -13,7 +15,9 @@ type Server struct {
 	router     *mux.Router
 
 	Address string
-	Backend Backend
+
+	Capabilities capabilities.Capabilities
+	Backend      Backend
 }
 
 func New() *Server {
@@ -26,6 +30,7 @@ func New() *Server {
 	router.HandleFunc("/_matrix/client/r0/account/whoami", WhoAmIHandler)
 	router.HandleFunc("/_matrix/client/r0/joined_rooms", JoinedRoomsHandler)
 	router.HandleFunc("/_matrix/client/r0/sync", SyncHandler)
+	router.HandleFunc("/_matrix/client/r0/capabilities", CapabilitiesHandler)
 	router.HandleFunc("/", RootHandler)
 
 	httpServer := new(http.Server)