Hello world 👋

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

internal/instance/tmux.go

@@ -0,0 +1,123 @@
+package instance
+
+import (
+	"os"
+	"os/exec"
+	"slices"
+	"strconv"
+	"strings"
+
+	"git.kebcloud.no/keb/lazysecrets/internal/linkhandler"
+)
+
+// Where an instance shows depends on its terminal app (on macOS): for an
+// instance in tmux, the app of a tmux client showing its session, or one
+// that could be switched to it. front is the app the link was clicked in;
+// clients in it are preferred, so a link clicked in a terminal opens
+// there.
+
+// tmux runs tmux on the server this instance runs in.
+func tmux(args ...string) (string, error) {
+	out, err := exec.Command("tmux", args...).Output()
+	return strings.TrimSpace(string(out)), err
+}
+
+func inTmux() bool { return os.Getenv("TMUX") != "" && os.Getenv("TMUX_PANE") != "" }
+
+type client struct {
+	name, session, activity string // activity: Unix seconds
+	pid                     int
+	app                     string
+}
+
+// clients lists the tmux server's clients, the one last typed in first.
+func clients() []client {
+	out, err := tmux("list-clients", "-F", "#{client_activity} #{client_pid} #{client_name} #{session_name}")
+	if err != nil {
+		return nil
+	}
+	var cs []client
+	for _, l := range strings.Split(out, "\n") {
+		f := strings.SplitN(l, " ", 4)
+		if len(f) < 4 {
+			continue
+		}
+		pid, err := strconv.Atoi(f[1])
+		if err != nil {
+			continue
+		}
+		cs = append(cs, client{name: f[2], session: f[3], activity: f[0], pid: pid, app: linkhandler.HostApp(pid)})
+	}
+	// Activity has the same width for centuries: strings compare like
+	// numbers.
+	slices.SortStableFunc(cs, func(a, b client) int { return strings.Compare(b.activity, a.activity) })
+	return cs
+}
+
+// place is where this instance would show: the tmux client (zero outside
+// tmux), the app, and reach: 2 already on screen there (outside tmux, or
+// a client on its session), 1 after switching a client, 0 nowhere.
+func place(front string) (client, string, int) {
+	if !inTmux() {
+		return client{}, linkhandler.HostApp(os.Getpid()), 2
+	}
+	session, err := tmux("display-message", "-p", "-t", os.Getenv("TMUX_PANE"), "#{session_name}")
+	if err != nil {
+		return client{}, "", 0
+	}
+	cs := clients()
+	// Best first: in the front app on its session, in the front app,
+	// on its session, any.
+	rank := func(c client) int {
+		r := 0
+		if front != "" && c.app == front {
+			r += 2
+		}
+		if c.session == session {
+			r++
+		}
+		return r
+	}
+	var best client
+	found := false
+	for _, c := range cs {
+		if !found || rank(c) > rank(best) {
+			best, found = c, true
+		}
+	}
+	if !found {
+		return client{}, "", 0
+	}
+	if best.session == session {
+		return best, best.app, 2
+	}
+	return best, best.app, 1
+}
+
+// Raise brings this instance into view for a link clicked in front: in
+// tmux its window and pane, switching a client to its session if needed;
+// then its app to the front, showing a hidden dropdown terminal.
+func Raise(front string) {
+	c, app, reach := place(front)
+	if reach == 0 {
+		return
+	}
+	if inTmux() {
+		pane := os.Getenv("TMUX_PANE")
+		_, _ = tmux("select-window", "-t", pane)
+		_, _ = tmux("select-pane", "-t", pane)
+		if reach == 1 {
+			_, _ = tmux("switch-client", "-c", c.name, "-t", pane)
+		}
+	}
+	switch {
+	case app == "" || app == front:
+		// already in front (or unknown)
+	case linkhandler.IsDropdown(app):
+		linkhandler.ShowDropdown(app) // it isn't front, so hidden: this shows it
+	default:
+		// The bundle, not the name: "kitty" may pick an instance without
+		// windows, which then opens a new one.
+		linkhandler.Activate(app)
+	}
+}