// Command mavupdate deploys a new build of Maven to the box she runs on, with
// an automatic rollback when the new build does not come up (Vikunja #249).
//
// It is a CLI on purpose, and it is the ONLY trigger for the update path.
//
// The obvious design — an IPC method plus a button on the web UI behind the
// step-up passkey gate, the way /tools works — was considered and refused. A
// step-up gate protects against the wrong person clicking; it does not change
// the fact that anything reachable over the network becomes, in the event of a
// mavweb bug, a remote arbitrary-code path with a build system attached. An
// update needs shell access on the host, which is a strictly higher bar than
// the gate that guards the tool allowlist. That is deliberate and it is the
// reason there is no MethodApplyUpdate anywhere in internal/ipc.
//
// Consequently: mavend does not import internal/update, nothing runs on a timer,
// nothing checks a release server, and no act, intent, tool or LLM output can
// reach any of this. She cannot update herself. She can be updated, by him.
//
//	mavupdate -config deploy/mavend.json list          # snapshots available to roll back to
//	mavupdate -config deploy/mavend.json verify        # make build + make test, deploys nothing
//	mavupdate -config deploy/mavend.json apply -yes    # the whole thing
//	mavupdate -config deploy/mavend.json rollback [id] # restore + restart (default: newest)
package main

import (
	"context"
	"errors"
	"flag"
	"fmt"
	"os"
	"os/signal"
	"syscall"
	"time"

	"github.com/kami/maven/internal/config"
	"github.com/kami/maven/internal/update"
)

func main() {
	cfgPath := flag.String("config", "deploy/mavend.json", "path to mavend.json (the update block is read from it)")
	yes := flag.Bool("yes", false, "required by `apply` and `rollback`: yes, restart the daemon")
	flag.Usage = usage
	flag.Parse()

	// The stdlib flag package stops parsing at the first non-flag argument, so a
	// `-yes` written after the subcommand (which is how anyone would type it, and
	// how the usage text shows it) lands in Args instead of the flag. Pick it out
	// by hand rather than silently treating "apply -yes" as an unconfirmed apply.
	var args []string
	for _, a := range flag.Args() {
		if a == "-yes" || a == "--yes" {
			*yes = true
			continue
		}
		args = append(args, a)
	}
	if len(args) == 0 {
		usage()
		os.Exit(2)
	}

	cfg, err := config.Load(*cfgPath)
	if err != nil {
		die("config: %v", err)
	}
	if cfg.Update == nil {
		die("no `update` block in %s — the update capability is off unless configured.\nSee the package comment in internal/update for what it does and does not do.", *cfgPath)
	}

	logf := func(format string, a ...any) {
		fmt.Fprintf(os.Stderr, "%s  %s\n", time.Now().Format("15:04:05"), fmt.Sprintf(format, a...))
	}
	u, err := update.New(*cfg.Update, update.WithLogger(logf))
	if err != nil {
		die("%v", err)
	}

	// Ctrl-C cancels the build or the health wait. It cannot cancel a rollback
	// midway into leaving the box in an unknown state, because the rollback runs
	// on its own context — see cmdApply.
	ctx, stop := signal.NotifyContext(context.Background(), syscall.SIGINT, syscall.SIGTERM)
	defer stop()

	switch args[0] {
	case "list":
		cmdList(u)
	case "verify":
		cmdVerify(ctx, u)
	case "apply":
		if !*yes {
			die("apply restarts mavend and can roll her back. Re-run with -yes if that is what you want.")
		}
		cmdApply(ctx, u)
	case "rollback":
		if !*yes {
			die("rollback restores the previous artifacts and restarts mavend. Re-run with -yes.")
		}
		id := ""
		if len(args) > 1 {
			id = args[1]
		}
		cmdRollback(ctx, u, id)
	default:
		usage()
		os.Exit(2)
	}
}

func cmdList(u *update.Updater) {
	snaps, err := u.Snapshots()
	if err != nil {
		die("snapshots: %v", err)
	}
	if len(snaps) == 0 {
		fmt.Println("no snapshots yet — the first `apply` takes one before it builds anything")
		return
	}
	fmt.Printf("%-18s  %-12s  %s\n", "SNAPSHOT", "COMMIT", "FILES")
	for _, s := range snaps {
		commit := s.Commit
		if len(commit) > 12 {
			commit = commit[:12]
		}
		if commit == "" {
			commit = "-"
		}
		fmt.Printf("%-18s  %-12s  %d\n", s.ID, commit, len(s.Files))
	}
	fmt.Printf("\nrollback to the newest with:  mavupdate rollback -yes\n")
}

func cmdVerify(ctx context.Context, u *update.Updater) {
	steps, err := u.Verify(ctx)
	report(steps)
	if err != nil {
		die("%v", err)
	}
	fmt.Println("verified: the tree builds and passes its own tests. Nothing was deployed — run `apply -yes` for that.")
}

func cmdApply(ctx context.Context, u *update.Updater) {
	res, err := u.Apply(ctx)
	report(res.Steps)
	summarize(res)
	switch {
	case err == nil:
		fmt.Println("\nupdate committed: she answers on the new build.")
	case errors.Is(err, update.ErrRollbackFailed):
		die("\n%v\n\nSHE IS PROBABLY DOWN. The previous artifacts are in the snapshot dir; copy them\nover the install dir and restart by hand.", err)
	case errors.Is(err, update.ErrRolledBack):
		die("\n%v\n\nShe is answering again on the previous build. Nothing was lost; fix the change and retry.", err)
	default:
		die("\n%v", err)
	}
}

func cmdRollback(ctx context.Context, u *update.Updater, id string) {
	res, err := u.Rollback(ctx, id)
	report(res.Steps)
	summarize(res)
	if err != nil && !errors.Is(err, update.ErrRolledBack) {
		die("\n%v", err)
	}
	fmt.Printf("\nrolled back to %s; she answers on it.\n", res.SnapshotID)
}

func report(steps []update.Step) {
	for _, s := range steps {
		status := "ok"
		if s.Err != nil {
			status = "FAILED: " + s.Err.Error()
		}
		fmt.Printf("  %-8s %-8s %s\n", s.Name, s.Took.Round(time.Second), status)
		if s.Output != "" {
			fmt.Printf("---- %s output ----\n%s\n-------------------\n", s.Name, s.Output)
		}
	}
}

func summarize(res update.Result) {
	fmt.Printf("\nverified=%v snapshot=%s installed=%d restarted=%v healthy=%v rolled_back=%v rollback_healthy=%v took=%s\n",
		res.Verified, res.SnapshotID, len(res.Installed), res.Restarted, res.Healthy, res.RolledBack, res.RollbackHealthy, res.Took.Round(time.Second))
}

func usage() {
	fmt.Fprint(os.Stderr, `mavupdate — deploy a new build of Maven, with rollback.

  mavupdate [-config path] list
  mavupdate [-config path] verify
  mavupdate [-config path] apply -yes
  mavupdate [-config path] rollback [snapshot-id] -yes

apply is: health-check the running daemon, snapshot the deployed artifacts,
make build, make test, install, restart, health-check — and restore the
snapshot if any of that fails. It never fetches code and never runs by itself.

`)
	flag.PrintDefaults()
}

func die(format string, a ...any) {
	fmt.Fprintf(os.Stderr, format+"\n", a...)
	os.Exit(1)
}