// The zfs module's Go bundle: the mesh's view of ZFS on a machine — its pools' health, layout, space,
// scrubs, I/O, cache and events, every dataset with its space and snapshots — and one act, taking a named
// snapshot of one dataset.
//
// One binary, four ways to run. With no argument it is the bundle the node's tool runner launches and
// speaks MCP to over stdio (novox/hq ADR 0188, ADR 0193), as the operator account. With `watch` and
// `events` it is one of the module's two long-running processes, run by the node-engine: the watch, which
// the health check zfs_health stands on (watch.go), and the event follower, as root, judged by its unit
// (follow.go). With `run` it is the scheduled run, as root by the node-engine's timer (run.go), and with `apply` the
// apply that converges the node to its config file (apply.go).
package main

import (
	"context"
	"fmt"
	"os"
	"os/signal"
	"syscall"

	stdio "git.novox.be/novox/mesh-sdk/go"
)

func main() {
	if len(os.Args) > 1 {
		ctx, stop := signal.NotifyContext(context.Background(), syscall.SIGTERM, os.Interrupt)
		defer stop()
		switch os.Args[1] {
		case "watch":
			(&Watch{M: Here(), Out: os.Stdout}).Loop(ctx)
		case "run":
			m := Here()
			closeBus := m.JoinBus()
			said, err := m.RunScheduled(ctx, ServedFile)
			closeBus()
			for _, w := range m.Warnings {
				fmt.Fprintln(os.Stderr, "warning:", w)
			}
			if err != nil {
				fmt.Fprintln(os.Stderr, err)
				os.Exit(1)
			}
			fmt.Println(said)
		case "apply":
			m := Here()
			closeBus := m.JoinBus()
			said, err := m.Apply(ctx)
			closeBus()
			for _, w := range m.Warnings {
				fmt.Fprintln(os.Stderr, "warning:", w)
			}
			if err != nil {
				fmt.Fprintln(os.Stderr, err)
				os.Exit(1)
			}
			fmt.Println(said)
		case "keeper":
			if err := RunKeeper(ctx); err != nil {
				fmt.Fprintln(os.Stderr, err)
				os.Exit(1)
			}
		case "events":
			if err := Follower(ctx, os.Stdout); err != nil {
				fmt.Fprintln(os.Stderr, err)
				os.Exit(1)
			}
		default:
			fmt.Fprintf(os.Stderr, "zfs-tools: %q is not a way to run; with no argument it serves its tools, with watch it "+
				"watches the pools, with events it follows ZFS's events, with run it runs the scheduled scrub, trim and snapshots, with apply it converges the node to its config file\n", os.Args[1])
			os.Exit(2)
		}
		return
	}
	m := Here()
	m.Emit = toolEmit(stdio.BusState)
	m.States, m.Call, m.Ledger, m.Log = toolStates{}, stdio.Ask, busLedger{}, busStream{}
	// An empty name serves as the module the runtime names (MESH_SERVED_MODULE): zfs.
	if err := stdio.Serve("", Tools(m)); err != nil {
		fmt.Fprintln(os.Stderr, err)
		os.Exit(1)
	}
}