X-Git-Url: https://code.octet-stream.net/broadcaster/blobdiff_plain/8320951221d45c5f5f3d387c5cb4b97d9fa2094c..33a19d553807d171f6ba9f4dafe30f43bc4bab5e:/internal/protocol/protocol.go

diff --git a/internal/protocol/protocol.go b/internal/protocol/protocol.go
new file mode 100644
index 0000000..e23da3a
--- /dev/null
+++ b/internal/protocol/protocol.go
@@ -0,0 +1,167 @@
+package protocol
+
+import (
+	"encoding/json"
+	"errors"
+	"fmt"
+)
+
+const (
+	StartTimeFormat = "2006-01-02T15:04"
+	LocalTimeFormat = "Mon _2 Jan 2006 15:04:05"
+
+	// Radio to server
+
+	AuthenticateType = "authenticate"
+	StatusType       = "status"
+
+	// Server to radio
+
+	FilesType     = "files"
+	PlaylistsType = "playlists"
+	StopType      = "stop"
+
+	// Status values
+
+	StatusIdle         = "idle"
+	StatusDelay        = "delay"
+	StatusChannelInUse = "channel_in_use"
+	StatusPlaying      = "playing"
+)
+
+// Base message type to determine what type of payload is expected.
+type Message struct {
+	T string
+}
+
+// Initial message from Radio to authenticate itself with a token string.
+type AuthenticateMessage struct {
+	T     string
+	Token string
+}
+
+// Server updates the radio with the list of files that currently exist.
+// This will be provided on connect and when there are any changes.
+// The radio is expected to obtain all these files and cache them locally.
+type FilesMessage struct {
+	T     string
+	Files []FileSpec
+}
+
+type PlaylistsMessage struct {
+	T         string
+	Playlists []PlaylistSpec
+}
+
+// Any playlist currently being played should be stopped and PTT disengaged.
+type StopMessage struct {
+	T string
+}
+
+type StatusMessage struct {
+	T string
+
+	// Status w.r.t. playing a playlist
+	Status string
+
+	// File being played or about to be played - empty string in idle status
+	Filename string
+
+	// Name of playlist being played - empty string in idle status
+	Playlist string
+
+	// Seconds until playback begins - never mind latency
+	DelaySecondsRemaining int
+
+	// Number of seconds file has been actually playing
+	PlaybackSecondsElapsed int
+
+	// Number of seconds waiting for channel to clear
+	WaitingForChannelSeconds int
+
+	PTT         bool
+	COS         bool
+	FilesInSync bool
+
+	// Timestamp of the current time on this radio, using LocalTimeFormat
+	LocalTime string
+
+	// Time zone in use, e.g. "Australia/Hobart"
+	TimeZone string
+}
+
+// Description of an individual file available in the broadcasting system.
+type FileSpec struct {
+	// Filename, e.g. "broadcast.wav"
+	Name string
+	// SHA-256 hash of the file's contents
+	Hash string
+}
+
+type PlaylistSpec struct {
+	Id        int
+	Name      string
+	StartTime string
+	Entries   []EntrySpec
+}
+
+type EntrySpec struct {
+	Filename     string
+	DelaySeconds int
+	IsRelative   bool
+}
+
+func ParseMessage(data []byte) (string, interface{}, error) {
+	var t Message
+	err := json.Unmarshal(data, &t)
+	if err != nil {
+		return "", nil, err
+	}
+
+	if t.T == AuthenticateType {
+		var auth AuthenticateMessage
+		err = json.Unmarshal(data, &auth)
+		if err != nil {
+			return "", nil, err
+		}
+		return t.T, auth, nil
+	}
+
+	if t.T == FilesType {
+		var files FilesMessage
+		err = json.Unmarshal(data, &files)
+		if err != nil {
+			return "", nil, err
+		}
+		return t.T, files, nil
+	}
+
+	if t.T == PlaylistsType {
+		var playlists PlaylistsMessage
+		err = json.Unmarshal(data, &playlists)
+		if err != nil {
+			return "", nil, err
+		}
+		return t.T, playlists, nil
+	}
+
+	if t.T == StatusType {
+		var status StatusMessage
+		err = json.Unmarshal(data, &status)
+		if err != nil {
+			return "", nil, err
+		}
+		return t.T, status, nil
+	}
+
+	if t.T == StopType {
+		var stop StopMessage
+		err = json.Unmarshal(data, &stop)
+		if err != nil {
+			return "", nil, err
+		}
+		return t.T, stop, nil
+	}
+
+	return "", nil, errors.New(fmt.Sprintf("unknown message type %v", t.T))
+}