commit f816d601383a2230eb8501c0e5cda27d84387aea
Author: Magnus Åhall <magnus.ahall@gibon.se>
Date:   Tue Dec 21 19:43:46 2021 +0100

    Initial commit

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..e8e1c68
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,2 @@
+i3-session-manager
+test/
diff --git a/go.mod b/go.mod
new file mode 100644
index 0000000..b1ccc67
--- /dev/null
+++ b/go.mod
@@ -0,0 +1,3 @@
+module i3-session-manager
+
+go 1.16
diff --git a/main.go b/main.go
new file mode 100644
index 0000000..ead1997
--- /dev/null
+++ b/main.go
@@ -0,0 +1,109 @@
+package main
+
+import (
+	// Standard
+	"fmt"
+	"net"
+	"os"
+	"regexp"
+	"strings"
+)
+
+var (
+	session I3Session
+	sessionSubscription I3Session
+	workspaces []I3Workspace
+	outputIndices map[string]int
+)
+
+func init() {
+	outputIndices = make(map[string]int)
+	workspaces = []I3Workspace{
+		{ Num: 0, Name: "Development" },
+		{ Num: 1, Name: "Terminal" },
+		{ Num: 2, Name: "Browser" },
+		{ Num: 3, Name: "Communication" },
+		{ Num: 4, Name: "Multimedia" },
+		{ Num: 5, Name: "Graphics" },
+		{ Num: 6, Name: "SQL" },
+		{ Num: 7, Name: "Debug" },
+		{ Num: 8, Name: "Email" },
+		{ Num: 9, Name: "Virtualization" },
+	}
+}
+
+func main() {
+	var err error
+
+	// session is used for interactively communicating with i3,
+	// like getting workspace and output data.
+	if session, err = NewI3Session(); err != nil {
+		fmt.Printf("%s\n", err)
+		os.Exit(1)
+	}
+	defer session.Close()
+
+	// sessionSubscription is used for listening to subscribed events
+	// from i3.
+	if sessionSubscription, err = NewI3Session(); err != nil {
+		fmt.Printf("%s\n", err)
+		os.Exit(1)
+	}
+	sessionSubscription.Subscribe([]string{"binding", "output"})
+	defer sessionSubscription.Close()
+	go sessionSubscription.Loop()
+
+	// Socket server reading commands and acting upon them
+	var listener net.Listener
+	listener, err = net.Listen("unix", "/tmp/i3-session.sock")
+	if err != nil {
+		fmt.Printf("Socket listener: %s\n", err)
+		os.Exit(1)
+	}
+
+	// Find outputs and assign an index to them
+	outputs, err := session.Outputs()
+	if err != nil {
+		fmt.Printf("Output error: %s\n", err)
+		os.Exit(1)
+	}
+	idx := 0
+	for _, output := range outputs {
+		if output.Active {
+			outputIndices[output.Name] = idx
+			idx++
+		}
+	}
+
+	// XXX: still needed? Find the configured workspaces
+	if false {
+	var configData string
+	var configLines []string
+	configData, err = session.Config()
+	configLines = strings.Split(configData, "\n")
+	r := regexp.MustCompile(`(?i)^\s*workspace\s+["']?([^"']+?)["']?\s+output\s+["']?([^"']+?)["']?\s*$`)
+	for _, line := range configLines {
+		matches := r.FindAllStringSubmatch(line, -1)
+		if len(matches) > 0 && len(matches[0]) == 3 {
+			fmt.Printf("%#v\n", matches[0][1:])
+		}
+	}
+	}
+
+	// Listen for external commands
+	var conn net.Conn
+	for {
+		conn, err = listener.Accept()
+		if err != nil {
+			fmt.Printf("Connection accept: %s\n", err)
+		}
+		buf := make([]byte, 1024)
+		_, err = conn.Read(buf)
+		if err != nil {
+			fmt.Printf("Connection read: %s\n", err)
+		} else {
+			fmt.Printf("%s\n", buf)
+		}
+		conn.Close()
+	}
+}
diff --git a/session.go b/session.go
new file mode 100644
index 0000000..08fc85d
--- /dev/null
+++ b/session.go
@@ -0,0 +1,371 @@
+package main
+
+import (
+	// Standard
+	"encoding/json"
+	"fmt"
+	"os"
+	"os/exec"
+	"regexp"
+	"strconv"
+	"strings"
+)
+
+// NewI3Session finds the i3 socket path and connects to it.
+func NewI3Session() (session I3Session, err error) {
+	// Find path to i3 socket
+	i3SocketPathCmd := exec.Command("i3", "--get-socketpath")
+	i3SocketPathBytes, _ := i3SocketPathCmd.CombinedOutput()
+	i3SocketPath := strings.TrimSpace(string(i3SocketPathBytes))
+	session.Socket, err = NewI3Socket(i3SocketPath)
+	return
+}
+
+// Close closes the socket.
+func (sess I3Session) Close() error {
+	return sess.Socket.Close()
+}
+
+// Outputs query I3 for output data.
+func (sess I3Session) Outputs() (outputs []I3Output, err error) {
+	var outputJson []byte
+
+	outputJson, err = sess.Socket.Request(GET_OUTPUTS, "")
+	if err != nil {
+		return
+	}
+
+	err = json.Unmarshal(outputJson, &outputs)
+	return
+}
+
+// Marks query I3 for mark data.
+func (sess I3Session) Marks() (marks []string, err error) {
+	var outputJson []byte
+
+	outputJson, err = sess.Socket.Request(GET_MARKS, "")
+	if err != nil {
+		return
+	}
+
+	err = json.Unmarshal(outputJson, &marks)
+	return
+}
+
+// Workspaces query I3 for workspace data.
+func (sess I3Session) Workspaces() (workspaces []I3Workspace, err error) {
+	var workspacesJson []byte
+	workspacesJson, err = sess.Socket.Request(GET_WORKSPACES, "")
+	if err != nil {
+		return
+	}
+
+	err = json.Unmarshal(workspacesJson, &workspaces)
+	return
+}
+
+// Subscribe subscribes to events.
+func (sess I3Session) Subscribe(events []string) error {
+	eventsJSON, _ := json.Marshal(events)
+	res, err := sess.Socket.Request(SUBSCRIBE, string(eventsJSON))
+	if err != nil {
+		return err
+	}
+	fmt.Printf("Subscribe: %s\n", res)
+	return nil
+}
+
+// Config returns the currently running configuration data, as
+// written in the configuration file.
+func (sess I3Session) Config() (config string, err error) {
+	var configJSON []byte
+	var configStruct I3Config
+	configJSON, err = sess.Socket.Request(GET_CONFIG, "")
+	err = json.Unmarshal(configJSON, &configStruct)
+	if err != nil {
+		return
+	}
+
+	config = configStruct.Config
+	return
+}
+
+func (sess I3Session) Loop() {
+	var msg []byte
+	var err error
+	var cmdBinding I3EventBinding
+
+	cmdOutput := regexp.MustCompile(`(?i)^\s*nop\s*output\s*(.*?)\s*$`)
+	cmdWS := regexp.MustCompile(`(?i)^\s*nop\s*workspace\s*(\d+)\s*$`)
+	cmdSession := regexp.MustCompile(`(?i)^\s*nop\s*manage\s+session`)
+	cmdMarkTag := regexp.MustCompile(`(?i)^\s*nop\s*mark\s+tag`)
+	cmdMarkMove := regexp.MustCompile(`(?i)^\s*nop\s*mark\s+move`)
+	cmdMarkClear := regexp.MustCompile(`(?i)^\s*nop\s*mark\s+clear`)
+
+	for {
+		msg, err = I3ReadMessage(sess.Socket)
+		if err != nil {
+			fmt.Printf("Loop error: %s\n", err)
+			os.Exit(1)
+		}
+
+		cmdBinding = I3EventBinding{}
+		err = json.Unmarshal(msg, &cmdBinding)
+		if err != nil {
+			fmt.Printf(
+				"Loop JSON parse: %s\n\nMessage:\n(%s)\n",
+				err,
+				msg,
+			)
+		}
+		binding := cmdBinding.Binding
+
+		// Switch output
+		m := cmdOutput.FindAllStringSubmatch(binding.Command, 1)
+		if len(m) == 1 && len(m[0]) == 2 {
+			err = sess.SwitchOutput(m[0][1])
+			if err != nil {
+				fmt.Printf("%s\n", err)
+			}
+			continue
+		}
+
+		// Switch output
+		m = cmdWS.FindAllStringSubmatch(binding.Command, 1)
+		if len(m) == 1 && len(m[0]) == 2 {
+			i, _ := strconv.Atoi(m[0][1])
+			err = sess.SwitchWorkspace(i)
+			if err != nil {
+				fmt.Printf("%s\n", err)
+			}
+			continue
+		}
+
+		// Manage session
+		if cmdSession.Match([]byte(binding.Command)) {
+			err = sess.ManageSession()
+			if err != nil {
+				fmt.Printf("Manage session: %s\n", err)
+			}
+			continue
+		}
+
+		// Mark current window with move tag
+		if cmdMarkTag.Match([]byte(binding.Command)) {
+			err = sess.MarkTag()
+			if err != nil {
+				fmt.Printf("Mark tag: %s\n", err)
+			}
+			continue
+		}
+
+		// Remove all move tags
+		if cmdMarkClear.Match([]byte(binding.Command)) {
+			err = sess.MarkClear()
+			if err != nil {
+				fmt.Printf("Mark clear: %s\n", err)
+			}
+			continue
+		}
+
+		// Move all windows with move tag
+		if cmdMarkMove.Match([]byte(binding.Command)) {
+			err = sess.MarkMove()
+			if err != nil {
+				fmt.Printf("Mark move: %s\n", err)
+			}
+			continue
+		}
+
+		fmt.Printf("%s\n", msg)
+
+	}
+}
+
+// SwitchWorkspace switches to the given workspace index on the same output
+// that has the workspace that is currently focused.
+func (sess I3Session) SwitchWorkspace(workspaceIndex int) error {
+	var output string
+	i3Workspaces, err := sess.Workspaces()
+	if err != nil {
+		return err
+	}
+
+	for _, ws := range i3Workspaces {
+		if ws.Focused {
+			output = ws.Output
+			break
+		}
+	}
+
+	if output == "" {
+		return fmt.Errorf("Focused workspace not found")
+	}
+
+	outputIdx := outputIndices[output]
+	workspaceName := fmt.Sprintf(
+		"%d:%s",
+		outputIdx*10+workspaceIndex,
+		workspaces[workspaceIndex].Name,
+	)
+	fmt.Printf("Switch to workspace: %s\n", workspaceName)
+	sess.Socket.Request(
+		RUN_COMMAND,
+		fmt.Sprintf("workspace \"%s\"", workspaceName),
+	)
+
+	return nil
+}
+
+// SwitchOutput looks up the visible workspace on the given monitor,
+// and switches to that.
+func (sess I3Session) SwitchOutput(output string) error {
+	workspaces, err := sess.Workspaces()
+	if err != nil {
+		return err
+	}
+
+	var nextWorkspace string
+	for _, workspace := range workspaces {
+		if workspace.Output == output && workspace.Visible {
+			nextWorkspace = workspace.Name
+			break
+		}
+	}
+
+	if nextWorkspace == "" {
+		return fmt.Errorf(
+			"Switch to output (%s) failed, "+
+			"no visible workspace found",
+			output,
+		)
+	}
+
+	fmt.Printf("Switching to output: %s\n", output)
+	sess.Socket.Request(RUN_COMMAND, "workspace "+nextWorkspace)
+
+	return nil
+}
+
+// ManageSession runs dmenu and asks for reload, restart or exit.
+func (sess I3Session) ManageSession() error {
+	cmd := exec.Command(
+		"sh", "-c",
+		"echo \"reload\nrestart\nexit\" | dmenu -l 3 -i",
+	)
+	out, err := cmd.CombinedOutput()
+	if err != nil {
+		return err
+	}
+	choice := strings.TrimSpace(string(out))
+
+	switch(choice) {
+	case "reload", "restart", "exit":
+		res, err := sess.Socket.Request(RUN_COMMAND, choice)
+		if err != nil {
+			return err
+		}
+		fmt.Printf("Management %s: %s\n", choice, res)
+	default:
+		return fmt.Errorf("Unknown management command")
+	}
+
+	return nil
+}
+
+// MarkTag marks a window with a tag for moving
+func (sess I3Session) MarkTag() error {
+	var max int
+	var cur int
+	var match []string
+	r := regexp.MustCompile(`^move (\d+)$`)
+
+	marks, err := sess.Marks()
+	if err != nil {
+		return err
+	}
+
+	for _, mark := range marks {
+		match = r.FindStringSubmatch(mark)
+		if len(match) == 2 {
+			cur, _ = strconv.Atoi(match[1])
+			if cur > max {
+				max = cur
+			}
+		}
+	}
+
+	res, err := sess.Socket.Request(
+		RUN_COMMAND,
+		fmt.Sprintf("mark \"move %d\"", max+1),
+	)
+	if err != nil {
+		return err
+	}
+	fmt.Printf("Mark tag: %s\n", res)
+
+	return nil
+}
+
+// MarkTag marks a window with a tag for moving
+func (sess I3Session) MarkClear() error {
+	marks, err := sess.Marks()
+	if err != nil {
+		return err
+	}
+
+	r := regexp.MustCompile(`^move \d+$`)
+	for _, mark := range marks {
+		if r.Match([]byte(mark)) {
+			_, err := sess.Socket.Request(
+				RUN_COMMAND,
+				fmt.Sprintf("unmark \"%s\"", mark),
+			)
+			if err != nil {
+				return err
+			}
+		}
+	}
+
+	return nil
+}
+
+// MarkMove moves tagged windows to current workspace
+func (sess I3Session) MarkMove() error {
+	i3Workspaces, err := sess.Workspaces()
+	if err != nil {
+		return err
+	}
+
+	var focusedWorkspace *I3Workspace
+	for _, ws := range i3Workspaces {
+		if ws.Focused {
+			focusedWorkspace = &ws
+			break
+		}
+	}
+
+	if focusedWorkspace == nil {
+		return fmt.Errorf("No focused workspace")
+	}
+
+	cmd := fmt.Sprintf(
+		"[con_mark=\"^move [0-9]\"] move workspace \"%s\"",
+		focusedWorkspace.Name,
+	)
+	res, err := sess.Socket.Request(RUN_COMMAND, cmd)
+	if err != nil {
+		return err
+	}
+
+	fmt.Printf("Mark move: %s\n", res)
+
+	err = sess.MarkClear()
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+// vim: foldmethod=marker
diff --git a/socket.go b/socket.go
new file mode 100644
index 0000000..cd4c969
--- /dev/null
+++ b/socket.go
@@ -0,0 +1,91 @@
+package main
+
+import (
+	// Standard
+	"encoding/binary"
+	"fmt"
+	"net"
+)
+
+const (
+	RUN_COMMAND       = 0
+	GET_WORKSPACES    = 1
+	SUBSCRIBE         = 2
+	GET_OUTPUTS       = 3
+	GET_TREE          = 4
+	GET_MARKS         = 5
+	GET_BAR_CONFIG    = 6
+	GET_VERSION       = 7
+	GET_BINDING_MODES = 8
+	GET_CONFIG        = 9
+	SEND_TICK         = 10
+	SYNC              = 11
+)
+
+func NewI3Socket(filename string) (I3Socket, error) {
+	var i3Socket I3Socket
+	var err error
+
+	i3Socket.conn, err = net.Dial("unix", filename)
+	if err != nil {
+		return i3Socket, err
+	}
+
+	return i3Socket, nil
+}
+
+func (sock I3Socket) Close() error {
+	return sock.conn.Close()
+}
+
+func I3ReadMessage(sock I3Socket) (msg []byte, err error) {
+	buf := make([]byte, 6)
+	if _, err = sock.conn.Read(buf); err != nil {
+		return nil, err
+	}
+	if string(buf) != "i3-ipc" {
+		return nil, fmt.Errorf("Invalid i3 IPC answer")
+	}
+
+	// LE encoded length
+	buf = make([]byte, 4)
+	if _, err = sock.conn.Read(buf); err != nil {
+		return nil, err
+	}
+	msgLength := binary.LittleEndian.Uint32(buf)
+
+	// LE encoded msg type
+	buf = make([]byte, 4)
+	if _, err = sock.conn.Read(buf); err != nil {
+		return nil, err
+	}
+
+	// Requested data
+	buf = make([]byte, msgLength)
+	if _, err = sock.conn.Read(buf); err != nil {
+		return nil, err
+	}
+	msg = buf
+
+	return
+}
+
+func (sock I3Socket) Request(typ int, message string) ([]byte, error) {
+	header := []byte("i3-ipc")
+	buf := make([]byte, 8)
+	binary.LittleEndian.PutUint32(buf, uint32(len(message)))
+	binary.LittleEndian.PutUint32(buf[4:], uint32(typ))
+	msg := append(header, buf...)
+	msg = append(msg, ([]byte(message))...)
+
+	_, err := sock.conn.Write(msg)
+	if err != nil {
+		return nil, err
+	}
+
+	buf, err = I3ReadMessage(sock)
+	if err != nil {
+		return nil, err
+	}
+	return buf, nil
+}
diff --git a/types.go b/types.go
new file mode 100644
index 0000000..2beeafc
--- /dev/null
+++ b/types.go
@@ -0,0 +1,46 @@
+package main
+
+import (
+	// Standard
+	"net"
+)
+
+type I3Session struct {
+	Socket I3Socket
+}
+
+type I3Socket struct {
+	filename string
+	socket   string
+	conn     net.Conn
+}
+
+type I3Output struct {
+	Name   string
+	Active bool
+	CurrentWorkspace string `json:"current_workspace"`
+}
+
+type I3Workspace struct {
+	Id         int
+	Num        int
+	Name       string
+	Visible    bool
+	Focused    bool
+	Output     string
+}
+
+type I3Config struct {
+	Config string
+}
+
+type I3EventBinding struct {
+	Change  string
+	Binding struct {
+		InputCode      int `json:"input_code"`
+		Symbol         string
+		Command        string
+		Mods           []string
+		EventStateMask []string `json:"event_state_mask"`
+	}
+}