From 25d67194826cddbd69d3beb1e4569455f93e42f8 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?M=C3=A1ximo=20Cuadros?= <mcuadros@gmail.com>
Date: Mon, 24 Oct 2016 01:47:11 +0200
Subject: [PATCH] rpc: draft of a RPC service

---
 rpc/client.go | 79 +++++++++++++++++++++++++++++++++++++++++++++++++++
 rpc/server.go | 54 +++++++++++++++++++++++++++++++++++
 2 files changed, 133 insertions(+)
 create mode 100644 rpc/client.go
 create mode 100644 rpc/server.go

diff --git a/rpc/client.go b/rpc/client.go
new file mode 100644
index 0000000..de167b7
--- /dev/null
+++ b/rpc/client.go
@@ -0,0 +1,79 @@
+package rpc
+
+import (
+	"encoding/gob"
+	"image/color"
+	"net/rpc"
+
+	"github.com/mcuadros/go-rpi-rgb-led-matrix"
+)
+
+func init() {
+	gob.Register(color.RGBA{})
+}
+
+// RGBLedMatrix matrix representation for ws281x
+type Client struct {
+	network string
+	addr    string
+	client  *rpc.Client
+	leds    []color.Color
+}
+
+// NewRGBLedMatrix returns a new matrix using the given size and config
+func NewClient(network, addr string) (rgbmatrix.Matrix, error) {
+	client, err := rpc.DialHTTP(network, addr)
+	if err != nil {
+		return nil, err
+	}
+
+	return &Client{
+		network: network,
+		addr:    addr,
+		client:  client,
+		leds:    make([]color.Color, 2048),
+	}, nil
+}
+
+// Geometry returns the width and the height of the matrix
+func (c *Client) Geometry() (width, height int) {
+	var reply *GeometryReply
+	err := c.client.Call("RPCMatrix.Geometry", &GeometryArgs{}, &reply)
+	if err != nil {
+		panic(err)
+	}
+
+	return reply.Width, reply.Height
+}
+
+func (c *Client) Apply(leds []color.Color) error {
+	defer func() { c.leds = make([]color.Color, 2048) }()
+
+	var reply *ApplyReply
+	return c.client.Call("RPCMatrix.Apply", &ApplyArgs{Colors: leds}, &reply)
+}
+
+// Render update the display with the data from the LED buffer
+func (c *Client) Render() error {
+	return c.Apply(c.leds)
+}
+
+// At return an Color which allows access to the LED display data as
+// if it were a sequence of 24-bit RGB values.
+func (c *Client) At(position int) color.Color {
+	if c.leds[position] == nil {
+		return color.Black
+	}
+
+	return c.leds[position]
+}
+
+// Set set LED at position x,y to the provided 24-bit color value.
+func (m *Client) Set(position int, c color.Color) {
+	m.leds[position] = color.RGBAModel.Convert(c)
+}
+
+// Close finalizes the ws281x interface
+func (c *Client) Close() error {
+	return c.Apply(make([]color.Color, 2048))
+}
diff --git a/rpc/server.go b/rpc/server.go
new file mode 100644
index 0000000..9840bd2
--- /dev/null
+++ b/rpc/server.go
@@ -0,0 +1,54 @@
+package rpc
+
+import (
+	"fmt"
+	"image/color"
+	"log"
+	"net"
+	"net/http"
+	"net/rpc"
+
+	"github.com/mcuadros/go-rpi-rgb-led-matrix"
+)
+
+type RPCMatrix struct {
+	m rgbmatrix.Matrix
+}
+
+type GeometryArgs struct{}
+type GeometryReply struct{ Width, Height int }
+
+func (m *RPCMatrix) Geometry(_ *GeometryArgs, reply *GeometryReply) error {
+	w, h := m.m.Geometry()
+	reply.Width = w
+	reply.Height = h
+
+	return nil
+}
+
+type ApplyArgs struct{ Colors []color.Color }
+type ApplyReply struct{}
+
+func (m *RPCMatrix) Apply(args *ApplyArgs, reply *ApplyReply) error {
+	return m.m.Apply(args.Colors)
+}
+
+type CloseArgs struct{}
+type CloseReply struct{}
+
+func (m *RPCMatrix) Close(_ *CloseArgs, _ *CloseReply) error {
+	return m.m.Close()
+}
+
+func Serve(m rgbmatrix.Matrix) {
+	rpc.Register(&RPCMatrix{m})
+
+	rpc.HandleHTTP()
+	l, e := net.Listen("tcp", ":1234")
+	if e != nil {
+		log.Fatal("listen error:", e)
+	}
+
+	fmt.Println(l)
+	http.Serve(l, nil)
+}