From 6023806f7b9ccea6af3570c36e78c67569cd4b07 Mon Sep 17 00:00:00 2001
From: Elara Musayelyan <elara@elara.ws>
Date: Mon, 12 Dec 2022 17:35:41 -0800
Subject: [PATCH] Add support for websocket api

---
 go.mod         | 11 +++++++-
 go.sum         |  8 ++++++
 types/types.go |  5 ++++
 websocket.go   | 76 ++++++++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 99 insertions(+), 1 deletion(-)
 create mode 100644 websocket.go

diff --git a/go.mod b/go.mod
index 0e8c126..016190c 100644
--- a/go.mod
+++ b/go.mod
@@ -2,4 +2,13 @@ module go.arsenm.dev/go-lemmy
 
 go 1.19
 
-require github.com/google/go-querystring v1.1.0
+require (
+	github.com/google/go-querystring v1.1.0
+	github.com/mitchellh/mapstructure v1.5.0
+	github.com/recws-org/recws v1.4.0
+)
+
+require (
+	github.com/gorilla/websocket v1.4.2 // indirect
+	github.com/jpillora/backoff v1.0.0 // indirect
+)
diff --git a/go.sum b/go.sum
index f99081b..c4801d4 100644
--- a/go.sum
+++ b/go.sum
@@ -2,4 +2,12 @@ github.com/google/go-cmp v0.5.2 h1:X2ev0eStA3AbceY54o37/0PQ/UWqKEiiO2dKL5OPaFM=
 github.com/google/go-cmp v0.5.2/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
 github.com/google/go-querystring v1.1.0 h1:AnCroh3fv4ZBgVIf1Iwtovgjaw/GiKJo8M8yD/fhyJ8=
 github.com/google/go-querystring v1.1.0/go.mod h1:Kcdr2DB4koayq7X8pmAG4sNG59So17icRSOU623lUBU=
+github.com/gorilla/websocket v1.4.2 h1:+/TMaTYc4QFitKJxsQ7Yye35DkWvkdLcvGKqM+x0Ufc=
+github.com/gorilla/websocket v1.4.2/go.mod h1:YR8l580nyteQvAITg2hZ9XVh4b55+EU/adAjf1fMHhE=
+github.com/jpillora/backoff v1.0.0 h1:uvFg412JmmHBHw7iwprIxkPMI+sGQ4kzOWsMeHnm2EA=
+github.com/jpillora/backoff v1.0.0/go.mod h1:J/6gKK9jxlEcS3zixgDgUAsiuZ7yrSoa/FX5e0EB2j4=
+github.com/mitchellh/mapstructure v1.5.0 h1:jeMsZIYE/09sWLaz43PL7Gy6RuMjD2eJVyuac5Z2hdY=
+github.com/mitchellh/mapstructure v1.5.0/go.mod h1:bFUtVrKA4DC2yAKiSyO/QUcy7e+RRV2QTWOzhPopBRo=
+github.com/recws-org/recws v1.4.0 h1:y9LLddtAicjejikNZXiaY9DQjIwcAQ82acd1XU6n0lU=
+github.com/recws-org/recws v1.4.0/go.mod h1:7+NQkTmBdU98VSzkzq9/P7+X0xExioUVBx9OeRKQIkk=
 golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
diff --git a/types/types.go b/types/types.go
index 2a86577..126e549 100644
--- a/types/types.go
+++ b/types/types.go
@@ -25,3 +25,8 @@ type LemmyError struct {
 func (le LemmyError) Error() string {
 	return fmt.Sprintf("%d %s: %s", le.Code, http.StatusText(le.Code), le.ErrStr)
 }
+
+type LemmyWebSocketMsg struct {
+	Op   UserOperation `json:"op"`
+	Data any           `json:"data"`
+}
diff --git a/websocket.go b/websocket.go
new file mode 100644
index 0000000..d45660b
--- /dev/null
+++ b/websocket.go
@@ -0,0 +1,76 @@
+package lemmy
+
+import (
+	"net/url"
+	"time"
+
+	"github.com/mitchellh/mapstructure"
+	"github.com/recws-org/recws"
+	"go.arsenm.dev/go-lemmy/types"
+)
+
+type WSClient struct {
+	conn   *recws.RecConn
+	respCh chan types.LemmyWebSocketMsg
+	errCh  chan error
+}
+
+func NewWebSocket(baseURL string) (*WSClient, error) {
+	ws := &recws.RecConn{
+		KeepAliveTimeout: 10 * time.Second,
+	}
+
+	u, err := url.Parse(baseURL)
+	if err != nil {
+		return nil, err
+	}
+	u = u.JoinPath("/api/v3")
+
+	ws.Dial(u.String(), nil)
+
+	out := &WSClient{
+		conn:   ws,
+		respCh: make(chan types.LemmyWebSocketMsg, 10),
+		errCh:  make(chan error, 10),
+	}
+
+	go func() {
+		for {
+			var msg types.LemmyWebSocketMsg
+			err = ws.ReadJSON(&msg)
+			if err != nil {
+				out.errCh <- err
+				continue
+			}
+			out.respCh <- msg
+		}
+	}()
+
+	return out, nil
+}
+
+func (c *WSClient) Request(op types.UserOperation, data any) error {
+	return c.conn.WriteJSON(types.LemmyWebSocketMsg{
+		Op:   op,
+		Data: data,
+	})
+}
+
+func (c *WSClient) Responses() <-chan types.LemmyWebSocketMsg {
+	return c.respCh
+}
+
+func (c *WSClient) Errors() <-chan error {
+	return c.errCh
+}
+
+func DecodeResponse(data, out any) error {
+	dec, err := mapstructure.NewDecoder(&mapstructure.DecoderConfig{
+		TagName: "json",
+		Result:  out,
+	})
+	if err != nil {
+		return err
+	}
+	return dec.Decode(data)
+}