mesh-sdk/go/catalogue/graphical_session.go

package catalogue

import (
	"fmt"
	"strings"
)

// The graphical session's seats (novox/hq ADR 0208): one module per piece of software, each piece's
// role a node seat in the mesh's own set, so i3 and sway, xterm and foot, rofi and dmenu compete for
// a role rather than each inventing one — and a machine running two of one role is refused at
// assignment instead of found by two bars on one screen.
const (
	LoginManagerSeat     = "node-login-manager"
	DisplayServerSeat    = "node-display-server"
	DisplaySessionSeat   = "node-display-session"
	TerminalEmulatorSeat = "node-terminal-emulator"
	LauncherSeat         = "node-launcher"
	NotifierSeat         = "node-notifier"
	LockScreenSeat       = "node-lock-screen"
	ClipboardSeat        = "node-clipboard"
	BarSeat              = "node-bar"
	CompositorSeat       = "node-compositor"
	SecretServiceSeat    = "node-secret-service"
)

// BarKindBlock is the bar's one received kind: a block (novox/hq ADR 0255).
const BarKindBlock = "block"

// barShows is what a contributed block may show, and the options each takes — the bar-neutral
// vocabulary every holder of node-bar renders. A new entry is a decision, and every holder's template
// renders it (the shape's examples) before it is accepted.
var barShows = map[string]map[string]barOption{
	// The machine's battery: its charge, and how long it lasts or takes to fill.
	"battery": {"device": {kind: "text"}},
	// One line a command prints, run every interval seconds: what the bar cannot know itself.
	"command": {"command": {kind: "text", required: true}, "interval": {kind: "seconds", required: true}},
	// A value the contributor keeps on the bus (novox/hq ADR 0255): its state `<module>.<name>` and the
	// key, this machine's name when absent. The value is an object whose `text` is what is shown. The
	// holder is granted to read it and shows it however its bar shows a changing value; no file and
	// no command passes between the two modules.
	"state": {"state": {kind: "text", required: true}, "key": {kind: "text"}},
}

// barBlockReads is the state and key a block shows, if any; an empty key is the machine's own.
func barBlockReads(data map[string]any) []StateRead {
	if data["shows"] != "state" {
		return nil
	}
	options, _ := data["options"].(map[string]any)
	s, ok := options["state"].(string)
	if !ok || s == "" {
		return nil
	}
	key, _ := options["key"].(string)
	return []StateRead{{Read: s, Key: key}}
}

type barOption struct {
	kind     string // text, or seconds (a whole number from 1 to 86400)
	required bool
}

func barBlockProblems(data map[string]any) []string {
	var problems []string
	for field := range data {
		if !oneOf([]string{"bar", "place", "order", "shows", "options"}, field) {
			problems = append(problems, fmt.Sprintf("a block has no field %q; it has bar, place, order, shows and options", field))
		}
	}
	shows, _ := data["shows"].(string)
	takes, known := barShows[shows]
	if !known {
		return append(problems, fmt.Sprintf("a block shows %v; it shows one of %s", data["shows"],
			strings.Join(sortedKeys(barShows), ", ")))
	}
	options := map[string]any{}
	if raw, has := data["options"]; has {
		o, ok := raw.(map[string]any)
		if !ok {
			return append(problems, "a block's options are an object")
		}
		options = o
	}
	for name, v := range options {
		opt, ok := takes[name]
		if !ok {
			problems = append(problems, fmt.Sprintf("a %s block has no option %q; it takes %s", shows, name,
				orNothing(sortedKeys(takes))))
			continue
		}
		switch opt.kind {
		case "text":
			if t, isText := v.(string); !isText || strings.TrimSpace(t) == "" {
				problems = append(problems, fmt.Sprintf("a %s block's %s is text", shows, name))
			}
		case "seconds":
			if _, whole := wholeIn(v, 1, 86400); !whole {
				problems = append(problems, fmt.Sprintf("a %s block's %s is a whole number of seconds from 1 to 86400", shows, name))
			}
		}
	}
	for _, name := range sortedKeys(takes) {
		if _, has := options[name]; takes[name].required && !has {
			problems = append(problems, fmt.Sprintf("a %s block needs the option %s", shows, name))
		}
	}
	return problems
}

// withShapeCode gives a data-shaped kind of the generated seat list the checks its definition cannot carry, being code:
// the bar's block (novox/hq ADR 0255, ADR 0260).
func withShapeCode(seat, kind string, sh *Shape) {
	if seat == BarSeat && kind == BarKindBlock {
		sh.Check, sh.Reads = barBlockProblems, barBlockReads
	}
}