package main

import (
	"context"
	"errors"
	"fmt"
	"io"
	"os"
	"os/exec"
	"path/filepath"
	"sort"
	"strconv"
	"strings"
	"text/tabwriter"
	"time"

	tea "charm.land/bubbletea/v2"
	"github.com/spf13/cobra"

	"git.zb-server.de/Sebi/ssh-netbox-wrapper/internal/cache"
	"git.zb-server.de/Sebi/ssh-netbox-wrapper/internal/config"
	"git.zb-server.de/Sebi/ssh-netbox-wrapper/internal/hook"
	"git.zb-server.de/Sebi/ssh-netbox-wrapper/internal/netbox"
	"git.zb-server.de/Sebi/ssh-netbox-wrapper/internal/notes"
	"git.zb-server.de/Sebi/ssh-netbox-wrapper/internal/resolver"
	"git.zb-server.de/Sebi/ssh-netbox-wrapper/internal/setup"
	internalssh "git.zb-server.de/Sebi/ssh-netbox-wrapper/internal/ssh"
	"git.zb-server.de/Sebi/ssh-netbox-wrapper/internal/tui"
)

// managedSubcommands are dispatched to cobra; everything else is treated as SSH wrapper mode.
var managedSubcommands = map[string]bool{
	"configure":  true,
	"notes":      true,
	"search":     true,
	"cache":      true,
	"alias":      true,
	"hook":       true,
	"shell-init": true,
	"completion": true,
	"__complete": true,
	"help":       true,
	"version":    true,
	"uninstall":  true,
	"sftp":       true,
	"scp":        true,
	"tunnel":     true,
	"hosts":      true,
	"multi":      true,
	"sync":       true,
}

func main() {
	args := os.Args[1:]

	if len(args) == 0 {
		runTUI()
		return
	}
	if args[0] == "--version" {
		fmt.Printf("netssh %s\n", buildVersion())
		return
	}

	if managedSubcommands[args[0]] {
		if err := rootCmd().Execute(); err != nil {
			os.Exit(1)
		}
		return
	}

	runSSHWrapper(args)
}

// loadConfigOrSetup loads the config and runs the setup wizard if NetBox is not configured.
func loadConfigOrSetup() *config.Config {
	cfg, err := config.Load()
	if err != nil {
		fatalf("config: %v", err)
	}
	if !cfg.HasHosts() {
		fmt.Fprintln(os.Stderr, "No configuration found. Starting setup…")
		if err := setup.RunWizard(cfg); err != nil {
			fatalf("setup: %v", err)
		}
		cfg, err = config.Load()
		if err != nil {
			fatalf("config: %v", err)
		}
	}
	return cfg
}

// runSSHWrapper resolves the target hostname via NetBox and execs the native ssh binary.
func runSSHWrapper(args []string) {
	flags, args, err := internalssh.ExtractWrapperFlags(args)
	if err != nil {
		fatalf("%v", err)
	}
	runClient(internalssh.SSH, flags, args)
}

// destination is the NetBox host named in the arguments of a client.
type destination struct {
	host  string
	user  string
	dests []int // argument indices naming the host; several only for scp
}

func findDestination(client internalssh.Client, args []string) (*destination, error) {
	if client.Name == internalssh.SCP.Name {
		operands, err := client.Operands(args)
		if err != nil || len(operands) == 0 {
			return nil, err
		}
		dest := &destination{host: operands[0].Host}
		for _, operand := range operands {
			dest.dests = append(dest.dests, operand.Idx)
			if operand.User != "" {
				dest.user = operand.User
			}
		}
		return dest, nil
	}
	parsed := client.Parse(args)
	if parsed == nil {
		return nil, nil
	}
	return &destination{host: parsed.Host, user: parsed.User, dests: []int{parsed.DestIdx}}, nil
}

// runClient resolves the NetBox host in args and execs ssh, sftp, or scp.
func runClient(client internalssh.Client, flags internalssh.WrapperFlags, args []string) {
	cfg := loadConfigOrSetup()
	client = client.WithInstances(instanceNames(cfg))

	dest, err := findDestination(client, args)
	if err != nil {
		fatalf("%v", err)
	}
	if dest == nil {
		if len(flags.Forwards) > 0 {
			fatalf("--forward needs a destination host")
		}
		// No destination found — pass arguments straight through.
		execClient(client, internalssh.Result{Args: args}, flags)
		return
	}

	host := resolveTarget(cfg, dest.host)
	user, port := hostDefaults(cfg, host)
	// Inject the default user if none was given on the command line.
	if user != "" && dest.user == "" && !client.HasUserFlag(args) {
		args = prependArgs(client.UserArgs(user), args, dest.dests)
	}
	// Inject the default port if none was given on the command line.
	if port > 0 && !client.HasPortFlag(args) {
		args = prependArgs(client.PortArgs(strconv.Itoa(port)), args, dest.dests)
	}

	connectHost(cfg, client, flags, host, dest.dests, args)
}

// hostDefaults returns the login user and port for host: those of a static
// host if set, else ssh.default_user and ssh.default_port.
func hostDefaults(cfg *config.Config, host resolvedHost) (string, int) {
	user, port := cfg.SSH.DefaultUser, cfg.SSH.DefaultPort
	if host.Kind == config.StaticKind {
		if static := cfg.StaticHost(host.Name); static != nil {
			if static.User != "" {
				user = static.User
			}
			if static.Port > 0 {
				port = static.Port
			}
		}
	}
	return user, port
}

// instanceNames lists the named NetBox instances, which may prefix hostnames.
func instanceNames(cfg *config.Config) []string {
	names := make([]string, 0, len(cfg.NetBoxes))
	for _, source := range cfg.NetBoxes {
		names = append(names, source.Name)
	}
	return names
}

// prependArgs puts extra before args and shifts the destination indices.
func prependArgs(extra, args []string, dests []int) []string {
	for i := range dests {
		dests[i] += len(extra)
	}
	return append(append([]string(nil), extra...), args...)
}

// resolvedHost is a NetBox host with the address to connect to.
type resolvedHost struct {
	Name string // cache/selector name, may carry an instance prefix
	Kind string
	IP   string
	Tags []string
}

// resolveTarget finds host in the cache (also by shortcut) or NetBox and
// resolves its address. It exits on failure.
func resolveTarget(cfg *config.Config, host string) resolvedHost {
	c := newCache(cfg)
	_ = c.Load()
	maybeBackgroundRefresh(cfg, c)

	source, _ := netbox.SplitTarget(host)
	useCache := len(cfg.NetBoxes) == 0 || source != ""
	used := func(entry cache.Entry) resolvedHost {
		c.MarkUsed(entry.Name)
		_ = c.Save()
		return resolvedHost{Name: entry.Name, Kind: entry.Kind, IP: entry.IP, Tags: entry.Tags}
	}

	// Static hosts from the config win and need no NetBox.
	if source == "" {
		var normalize func(string) string
		if cfg.Shortcuts.Enabled() {
			normalize = normalizeTarget(cfg.Shortcuts, false)
		}
		entry, found, err := c.GetStatic(host, normalize)
		if err != nil {
			fatalf("%v", err)
		}
		if found {
			return used(entry)
		}
	}

	// Cache hit with a fresh TTL — connect directly without querying NetBox.
	if entry, fresh := c.Get(host); fresh && useCache {
		return used(entry)
	}

	// Shortcut cache lookup: scan entries whose normalized name matches the input.
	// If a stale match is found, use the canonical name for the NetBox re-fetch below.
	lookupHost := host
	shortcutsEnabled := cfg.Shortcuts.Enabled()
	if cached, _ := c.Get(lookupHost); shortcutsEnabled && cached.Name == "" && useCache {
		normalize := normalizeTarget(cfg.Shortcuts, source != "")
		entry, found, fresh, err := c.GetByShortcut(lookupHost, normalize)
		if err != nil {
			fatalf("%v", err)
		}
		if found {
			if fresh {
				return used(entry)
			}
			// Stale shortcut match — use canonical name for NetBox re-fetch.
			lookupHost = entry.Name
		}
	}

	if !cfg.HasNetBox() {
		fatalf("host %q is not in hosts: and no NetBox is configured (netssh configure)", host)
	}
	nbClient := newNetBoxClient(cfg)

	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
	defer cancel()

	target, err := findSSHHost(ctx, nbClient, lookupHost, cfg.Shortcuts.Domains)
	if errors.Is(err, netbox.ErrHostNotFound) && !useCache && shortcutsEnabled {
		entry, found, _, cacheErr := c.GetByShortcut(host, normalizeTarget(cfg.Shortcuts, false))
		if cacheErr != nil {
			fatalf("%v", cacheErr)
		}
		if found {
			target, err = findSSHHost(ctx, nbClient, entry.Name, cfg.Shortcuts.Domains)
		}
	}
	if err != nil {
		fatalf("NetBox: %v", err)
	}

	if cached, fresh := c.Get(target.Target()); fresh && cached.Kind == target.Kind {
		return used(cached)
	}

	chain, err := resolver.New(cfg.Resolver)
	if err != nil {
		fatalf("resolver: %v", err)
	}

	ip, err := chain.Resolve(ctx, &target, nbClient)
	if err != nil {
		fatalf("IP resolution for %q: %v", host, err)
	}

	entry := cache.Entry{Name: target.Target(), IP: ip, Kind: target.Kind, Tags: target.Tags, Cluster: target.Cluster}
	c.Upsert(entry)
	return used(entry)
}

// findSSHHost uses the paginated, ambiguity-checking lookup for connection
// targets. Only a genuine missing host permits trying configured suffixes.
func findSSHHost(ctx context.Context, client *netbox.Client, name string, domains []string) (netbox.HostEntry, error) {
	target, err := client.FindHost(ctx, name, "")
	if !errors.Is(err, netbox.ErrHostNotFound) || strings.Contains(name, ".") {
		return target, err
	}
	for _, domain := range domains {
		domain = strings.TrimPrefix(strings.TrimSpace(domain), ".")
		if domain == "" {
			continue
		}
		target, err = client.FindHost(ctx, name+"."+domain, "")
		if !errors.Is(err, netbox.ErrHostNotFound) {
			return target, err
		}
	}
	return netbox.HostEntry{}, fmt.Errorf("%w: %q", netbox.ErrHostNotFound, name)
}

// connectHost applies the SSH options configured for the host and execs the client.
func connectHost(cfg *config.Config, client internalssh.Client, flags internalssh.WrapperFlags, host resolvedHost, dests []int, args []string) {
	opts := hostOptions(cfg, host)
	if len(flags.Forwards) > 0 {
		forwardArgs, err := internalssh.ForwardArgs(flags.Forwards, opts.Forwards)
		if err != nil {
			fatalf("%v", err)
		}
		flags.ForwardArgs = forwardArgs
	}
	if flags.Tunnel && len(flags.ForwardArgs) == 0 && !client.HasForwardFlag(args) {
		available := "none configured (ssh.forwards)"
		if names := forwardNames(opts); len(names) > 0 {
			available = strings.Join(names, ", ")
		}
		fatalf("name a forward or a spec such as 8080:localhost:80; forwards for %s: %s", host.Name, available)
	}
	_, name := netbox.SplitTarget(host.Name)
	execClient(client, client.Apply(args, dests, internalssh.Host{Name: name, IP: host.IP}, opts, flags), flags)
}

// hostOptions merges the global, instance, and rule SSH options for host.
func hostOptions(cfg *config.Config, host resolvedHost) config.SSHOptions {
	instance, name := netbox.SplitTarget(host.Name)
	return cfg.SSHOptionsFor(config.SSHHost{Instance: instance, Name: name, Kind: host.Kind, Tags: host.Tags})
}

// execClient replaces the process with the client, or prints the command for --dry-run.
func execClient(client internalssh.Client, result internalssh.Result, flags internalssh.WrapperFlags) {
	if flags.DryRun {
		fmt.Println(internalssh.Quote(append([]string{client.Name}, result.Args...)))
		return
	}
	if result.Notice != "" {
		fmt.Fprintf(os.Stderr, "netssh: %s\n", result.Notice)
	}
	if err := client.Exec(result.Args); err != nil {
		fatalf("%v", err)
	}
}

// runTUI starts the interactive host search.
func runTUI() {
	cfg := loadConfigOrSetup()

	c := newCache(cfg)
	_ = c.Load()
	maybeBackgroundRefresh(cfg, c)

	var nbClient *netbox.Client
	if cfg.HasNetBox() {
		nbClient = newNetBoxClient(cfg)
	}

	m := tui.New(nbClient, c, cfg.SSH.DefaultUser, cfg.SSH.DefaultPort)
	m.SetNotes(notes.New(cfg.NetBox.URL, nbClient))
	m.SetForwards(func(name, kind string, tags []string) []string {
		return forwardNames(hostOptions(cfg, resolvedHost{Name: name, Kind: kind, Tags: tags}))
	})
	p := tea.NewProgram(m)
	final, err := p.Run()
	if err != nil {
		fatalf("TUI: %v", err)
	}

	tuiModel, ok := final.(*tui.Model)
	if !ok {
		return
	}
	host := tuiModel.Selected()
	if host == nil {
		return
	}
	if host.Action == tui.ActionMulti {
		if err := runMulti(cfg, host.Targets, multiFlags{}); err != nil {
			fatalf("%v", err)
		}
		return
	}

	// Revalidate stale or live TUI results through the configured resolver chain.
	var tags []string
	if cached, fresh := c.Get(host.Name); fresh && cached.Kind == host.Kind {
		host.IP = cached.IP
		tags = cached.Tags
	} else {
		if nbClient == nil {
			fatalf("cannot resolve %q: NetBox is not configured", host.Name)
		}
		ctx, cancel := context.WithTimeout(context.Background(), 15*time.Second)
		defer cancel()
		target, err := nbClient.FindHost(ctx, host.Name, host.Kind)
		if err != nil {
			fatalf("NetBox: %v", err)
		}
		chain, err := resolver.New(cfg.Resolver)
		if err != nil {
			fatalf("resolver: %v", err)
		}
		host.IP, err = chain.Resolve(ctx, &target, nbClient)
		if err != nil {
			fatalf("IP resolution: %v", err)
		}
		c.Upsert(cache.Entry{Name: target.Target(), IP: host.IP, Kind: target.Kind, Tags: target.Tags, Cluster: target.Cluster})
		tags = target.Tags
	}
	fmt.Fprintf(os.Stderr, "Connecting to %s (%s)…\n", host.Name, host.IP)

	c.MarkUsed(host.Name)
	_ = c.Save()

	client, flags, args := tuiCommand(cfg, host)
	connectHost(cfg, client, flags, resolvedHost{Name: host.Name, Kind: host.Kind, IP: host.IP, Tags: tags}, []int{len(args) - 1}, args)
}

// tuiCommand builds the client and arguments for the action chosen in the TUI.
func tuiCommand(cfg *config.Config, host *tui.SelectedHost) (internalssh.Client, internalssh.WrapperFlags, []string) {
	client := internalssh.SSH
	var flags internalssh.WrapperFlags
	switch host.Action {
	case tui.ActionSFTP:
		client = internalssh.SFTP
	case tui.ActionTunnel:
		flags = internalssh.WrapperFlags{Forwards: host.Forwards, Tunnel: true}
	}

	var args []string
	// User override from TUI edit mode takes priority, then static host and config defaults.
	defaultUser, defaultPort := hostDefaults(cfg, resolvedHost{Name: host.Name, Kind: host.Kind})
	user := host.User
	if user == "" {
		user = defaultUser
	}
	if user != "" {
		args = append(args, client.UserArgs(user)...)
	}
	port := host.Port
	if port == "" && defaultPort > 0 {
		port = strconv.Itoa(defaultPort)
	}
	if port != "" {
		args = append(args, client.PortArgs(port)...)
	}
	// Apply replaces the destination; a bare name cannot be mistaken for
	// host:path by sftp, unlike an IPv6 address.
	_, name := netbox.SplitTarget(host.Name)
	return client, flags, append(args, name)
}

// forwardNames lists the forwards configured for a host, sorted.
func forwardNames(opts config.SSHOptions) []string {
	names := make([]string, 0, len(opts.Forwards))
	for name := range opts.Forwards {
		names = append(names, name)
	}
	sort.Strings(names)
	return names
}

// --- cobra root + subcommands ---

func rootCmd() *cobra.Command {
	root := &cobra.Command{
		Use:                "netssh",
		Short:              "SSH wrapper with NetBox hostname resolution",
		DisableFlagParsing: true,
		ValidArgsFunction: func(cmd *cobra.Command, args []string, toComplete string) ([]cobra.Completion, cobra.ShellCompDirective) {
			if len(args) > 0 && args[len(args)-1] == "--forward" {
				cfg, err := config.Load()
				if err != nil {
					return nil, cobra.ShellCompDirectiveError
				}
				return filterPrefix(allForwardNames(cfg), toComplete, nil), cobra.ShellCompDirectiveNoFileComp
			}
			hosts := completeHosts(toComplete)
			completions := make([]cobra.Completion, 0, len(hosts))
			for _, host := range hosts {
				completions = append(completions, cobra.Completion(host))
			}
			// Subcommands at the end, after all hostnames.
			for _, sub := range cmd.Commands() {
				if sub.IsAvailableCommand() && strings.HasPrefix(sub.Name(), toComplete) {
					completions = append(completions, cobra.Completion(sub.Name()+"\t"+sub.Short))
				}
			}
			return completions, cobra.ShellCompDirectiveNoFileComp | cobra.ShellCompDirectiveKeepOrder
		},
	}

	root.AddCommand(notesCmd(), configureCmd(), searchCmd(), cacheCmd(), aliasCmd(), hookCmd(), shellInitCmd(), versionCmd(), uninstallCmd(), sftpCmd(), scpCmd(), tunnelCmd(), hostsCmd(), multiCmd(), syncCmd())

	// cobra builds the "completion" command lazily; force init so we can extend it.
	root.InitDefaultCompletionCmd()
	for _, cmd := range root.Commands() {
		if cmd.Name() == "completion" {
			cmd.AddCommand(completionInstallCmd(root))
			// Cobra's zsh script spawns a subshell per line and sends every host
			// through _describe, which hangs with thousands of cached hosts.
			for _, sub := range cmd.Commands() {
				if sub.Name() == "zsh" {
					sub.RunE = func(cmd *cobra.Command, args []string) error {
						_, err := io.WriteString(cmd.OutOrStdout(), hook.ZshCompletionScript)
						return err
					}
					sub.Run = nil
				}
			}
			break
		}
	}

	return root
}

func completionInstallCmd(root *cobra.Command) *cobra.Command {
	var shell string
	cmd := &cobra.Command{
		Use:   "install",
		Short: "Install shell completion for the current user (no sudo required)",
		RunE: func(cmd *cobra.Command, args []string) error {
			if shell == "" {
				shell = filepath.Base(os.Getenv("SHELL"))
			}

			var (
				dir  string
				file string
				gen  func() ([]byte, error)
				note string
			)

			switch shell {
			case "bash":
				dir = filepath.Join(os.Getenv("HOME"), ".local", "share", "bash-completion", "completions")
				file = filepath.Join(dir, "netssh")
				gen = func() ([]byte, error) {
					var buf strings.Builder
					err := root.GenBashCompletionV2(&buf, true)
					return []byte(buf.String()), err
				}
				note = "Reload your shell or run: source " + file
			case "zsh":
				dir = filepath.Join(os.Getenv("HOME"), ".zfunc")
				file = filepath.Join(dir, "_netssh")
				gen = func() ([]byte, error) { return []byte(hook.ZshCompletionScript), nil }
				note = hook.ZshCompletionNote(dir)
			case "fish":
				dir = filepath.Join(hook.FishConfigDir(), "completions")
				file = filepath.Join(dir, "netssh.fish")
				gen = func() ([]byte, error) {
					var buf strings.Builder
					err := root.GenFishCompletion(&buf, true)
					return []byte(buf.String()), err
				}
				note = "Reload your shell or start a new fish session."
			default:
				return fmt.Errorf("unsupported shell %q — use --shell bash|zsh|fish", shell)
			}

			script, err := gen()
			if err != nil {
				return fmt.Errorf("generating completion: %w", err)
			}
			if err := os.MkdirAll(dir, 0o755); err != nil {
				return fmt.Errorf("creating %s: %w", dir, err)
			}
			if err := os.WriteFile(file, script, 0o644); err != nil {
				return fmt.Errorf("writing %s: %w", file, err)
			}
			cfg, err := config.Load()
			if err != nil {
				return err
			}
			if err := hook.SyncCommandCompletion(cfg.Shell.Alias); err != nil {
				return err
			}
			fmt.Printf("Completion installed → %s\n%s\n", file, note)
			if cfg.Shell.Alias != "" {
				fmt.Printf("Completion also enabled for alias %q.\n", cfg.Shell.Alias)
			}
			return nil
		},
	}
	cmd.Flags().StringVar(&shell, "shell", "", "Shell to install for (default: $SHELL). Supported: bash, zsh, fish")
	return cmd
}

func configureCmd() *cobra.Command {
	return &cobra.Command{
		Use:   "configure",
		Short: "Interactively configure netssh",
		RunE: func(cmd *cobra.Command, args []string) error {
			cfg, err := config.Load()
			if err != nil {
				return err
			}
			return setup.RunWizard(cfg)
		},
	}
}

func searchCmd() *cobra.Command {
	return &cobra.Command{
		Use:   "search <query>",
		Short: "Print hostnames from the cache (used for shell completion)",
		Args:  cobra.MaximumNArgs(1),
		RunE: func(cmd *cobra.Command, args []string) error {
			cfg, err := config.Load()
			if err != nil {
				return err
			}
			c := newCache(cfg)
			if err := c.Load(); err != nil {
				return err
			}
			q := ""
			if len(args) > 0 {
				q = args[0]
			}
			for _, e := range c.Search(q) {
				fmt.Println(e.Name)
			}
			return nil
		},
	}
}

func cacheCmd() *cobra.Command {
	cmd := &cobra.Command{
		Use:   "cache",
		Short: "Manage the local host cache",
	}
	cmd.AddCommand(cacheListCmd(), cacheClearCmd(), cacheRefreshCmd())
	return cmd
}

func cacheListCmd() *cobra.Command {
	return &cobra.Command{
		Use:   "list",
		Short: "Show all cached entries",
		RunE: func(cmd *cobra.Command, args []string) error {
			cfg, err := config.Load()
			if err != nil {
				return err
			}
			c := newCache(cfg)
			if err := c.Load(); err != nil {
				return err
			}
			entries := c.All()
			sort.Slice(entries, func(i, j int) bool { return entries[i].Name < entries[j].Name })

			w := tabwriter.NewWriter(os.Stdout, 0, 0, 2, ' ', 0)
			fmt.Fprintln(w, "NAME\tIP\tKIND\tCACHED AT")
			for _, e := range entries {
				fmt.Fprintf(w, "%s\t%s\t%s\t%s\n", e.Name, e.IP, e.Kind, e.CachedAt.Format(time.RFC3339))
			}
			return w.Flush()
		},
	}
}

func cacheClearCmd() *cobra.Command {
	return &cobra.Command{
		Use:   "clear",
		Short: "Remove all cached entries",
		RunE: func(cmd *cobra.Command, args []string) error {
			cfg, err := config.Load()
			if err != nil {
				return err
			}
			c := newCache(cfg)
			c.Clear()
			if err := c.Save(); err != nil {
				return err
			}
			fmt.Println("Cache cleared.")
			return nil
		},
	}
}

func cacheRefreshCmd() *cobra.Command {
	var filterTag, filterKind, filterInstance string
	cmd := &cobra.Command{
		Use:   "refresh",
		Short: "Re-fetch all known hosts from NetBox",
		RunE: func(cmd *cobra.Command, args []string) error {
			cfg, err := config.Load()
			if err != nil {
				return err
			}
			if !cfg.HasNetBox() {
				return fmt.Errorf("netbox.url is not configured")
			}

			nbClient := newNetBoxClient(cfg)
			ctx, cancel := context.WithTimeout(context.Background(), 60*time.Second)
			defer cancel()

			opts := netbox.SearchOptions{Tag: filterTag, Kind: filterKind}
			query := ""
			if filterInstance != "" {
				if !nbClient.MultipleSources() {
					return fmt.Errorf("--instance requires named netboxes configuration")
				}
				query = filterInstance + "/"
			}
			entries, err := nbClient.SearchAll(ctx, query, opts)
			if err != nil {
				return fmt.Errorf("NetBox: %w", err)
			}

			c := newCache(cfg)
			_ = c.Load()

			chain, err := resolver.New(cfg.Resolver)
			if err != nil {
				return fmt.Errorf("resolver: %w", err)
			}
			written := 0
			nameCounts := make(map[string]int)
			for _, e := range entries {
				nameCounts[strings.ToLower(e.Target())]++
			}
			for i := range entries {
				e := &entries[i]
				if nameCounts[strings.ToLower(e.Target())] > 1 {
					c.Delete(e.Target())
					fmt.Fprintf(os.Stderr, "warning: skipping ambiguous hostname %q\n", e.Name)
					continue
				}

				ip, err := chain.Resolve(ctx, e, nbClient)
				if err != nil {
					// Do not turn a failed configured strategy into a fresh
					// primary-IP cache hit that bypasses the resolver.
					if ctx.Err() != nil {
						return ctx.Err()
					}
					c.Delete(e.Target())
					fmt.Fprintf(os.Stderr, "warning: skipping %s: %v\n", e.Name, err)
					continue
				}
				c.Upsert(cache.Entry{Name: e.Target(), IP: ip, Kind: e.Kind, Tags: e.Tags, Cluster: e.Cluster})
				written++
			}

			if err := c.Save(); err != nil {
				return err
			}
			if filterTag == "" && filterKind == "" && filterInstance == "" {
				if err := c.SetRefreshed(); err != nil {
					fmt.Fprintf(os.Stderr, "warning: could not update refresh timestamp: %v\n", err)
				}
			}
			if aliasEntries := buildAliasEntries(c, *cfg); len(aliasEntries) > 0 {
				if err := hook.WriteAliasFiles(aliasEntries); err != nil {
					fmt.Fprintf(os.Stderr, "warning: could not write alias files: %v\n", err)
				}
			}
			fmt.Printf("%d entries written to cache.\n", written)
			return nil
		},
	}
	cmd.Flags().StringVar(&filterTag, "tag", "", "Filter by NetBox tag slug (e.g. prod)")
	cmd.Flags().StringVar(&filterKind, "kind", "", "Filter by kind: device or vm")
	cmd.Flags().StringVar(&filterInstance, "instance", "", "Refresh only this named NetBox instance")
	return cmd
}

// buildAliasEntries computes the sorted, deduplicated alias list from the cache.
func buildAliasEntries(c *cache.Cache, cfg config.Config) []hook.AliasEntry {
	return hook.BuildAliasEntries(c.All(), cfg)
}

func aliasCmd() *cobra.Command {
	var shell, test string
	cmd := &cobra.Command{
		Use:   "alias",
		Short: "Print shell aliases for all cached hosts",
		Long: `Print shell alias definitions for all cached hosts.
The alias name is the shortened form derived from the configured shortcuts
(domain suffixes stripped, rewrite rules applied, hyphens optionally stripped).

Check a rule with: netssh alias --test fsn1-bx1.example.com

Source the output in your shell profile:
  bash/zsh:  eval "$(netssh alias)"
  fish:      netssh alias --shell fish | source

Or use in a script:
  source <(netssh alias)`,
		RunE: func(cmd *cobra.Command, args []string) error {
			cfg, err := config.Load()
			if err != nil {
				return err
			}
			c := newCache(cfg)
			if err := c.Load(); err != nil {
				return err
			}
			if test != "" {
				printShortcutTest(os.Stdout, test, c.All(), cfg.Shortcuts)
				return nil
			}
			if shell == "" {
				shell = filepath.Base(os.Getenv("SHELL"))
			}

			entries := buildAliasEntries(c, *cfg)
			if len(entries) == 0 {
				fmt.Fprintln(os.Stderr, "netssh: cache is empty — run 'netssh cache refresh' first")
				return nil
			}

			switch shell {
			case "fish":
				fmt.Printf("# netssh aliases (%d hosts) — source with: netssh alias --shell fish | source\n", len(entries))
				for _, e := range entries {
					fmt.Println(e.Definition("fish"))
				}
			default:
				fmt.Printf("# netssh aliases (%d hosts) — source with: eval \"$(netssh alias)\"\n", len(entries))
				for _, e := range entries {
					fmt.Println(e.Definition("bash"))
				}
			}
			return nil
		},
	}
	cmd.Flags().StringVar(&shell, "shell", "", "Output format: bash, zsh, fish (default: $SHELL)")
	cmd.Flags().StringVar(&test, "test", "", "Show the shortcut for a hostname and the cached hosts it matches")
	return cmd
}

// printShortcutTest helps writing shortcut rules: it shows what a name is
// shortened to and which cached hosts share that shortcut.
func printShortcutTest(w io.Writer, name string, entries []cache.Entry, sc config.ShortcutsConfig) {
	normalize := normalizeTarget(sc, strings.Contains(name, "/"))
	short := normalize(name)
	fmt.Fprintf(w, "%s → %s\n", name, short)
	var matches []string
	for _, e := range entries {
		if normalize(e.Name) == short {
			matches = append(matches, e.Name)
		}
	}
	sort.Strings(matches)
	switch len(matches) {
	case 0:
		fmt.Fprintln(w, "no cached host has this shortcut")
	case 1:
		fmt.Fprintf(w, "matches %s\n", matches[0])
	default:
		fmt.Fprintf(w, "ambiguous, matches %d hosts:\n", len(matches))
		for _, m := range matches {
			fmt.Fprintf(w, "  %s\n", m)
		}
	}
}

// shellInitCmd is called at shell startup to update alias files and trigger a
// background cache refresh when stale. Intentionally silent — never disrupts the prompt.
func shellInitCmd() *cobra.Command {
	return &cobra.Command{
		Use:    "shell-init",
		Short:  "Regenerate alias files and trigger a background cache refresh if stale",
		Hidden: true,
		RunE: func(cmd *cobra.Command, args []string) error {
			cfg, err := config.Load()
			if err != nil {
				return nil
			}
			c := newCache(cfg)
			_ = c.Load()

			// Regenerate alias files from the current cache every shell start
			// so aliases are always up-to-date even before a refresh completes.
			_ = hook.WriteAliasFiles(buildAliasEntries(c, *cfg))

			maybeBackgroundRefresh(cfg, c)
			return nil
		},
	}
}

func hookCmd() *cobra.Command {
	cmd := &cobra.Command{
		Use:   "hook",
		Short: "Manage shell hooks for automatic cache refresh at shell startup",
	}
	cmd.AddCommand(hookInstallCmd(), hookUninstallCmd())
	return cmd
}

func hookInstallCmd() *cobra.Command {
	var shell string
	cmd := &cobra.Command{
		Use:   "install",
		Short: "Add netssh shell-init to your shell profile",
		Long: `Adds a marked block (# >>> netssh >>> … # <<< netssh <<<) to your shell
profile that runs 'netssh shell-init' on every new shell session and, for zsh,
registers the completion. Unmarked entries from older versions are replaced.
shell-init checks whether the cache is older than 24 hours and, if so, starts
a background refresh — no delay to your prompt.

After installation, reload your profile or open a new shell.`,
		RunE: func(cmd *cobra.Command, args []string) error {
			if shell == "" {
				shell = filepath.Base(os.Getenv("SHELL"))
			}
			profile, err := hook.ProfilePath(shell)
			if err != nil {
				return err
			}

			// The managed block also sources the aliases (bash/zsh) and registers
			// zsh completion; fish uses conf.d auto-sourcing instead.
			installed, err := hook.Install(profile, shell)
			if err != nil {
				return err
			}

			if !installed {
				fmt.Printf("Hook already installed in %s\n", profile)
			} else {
				fmt.Printf("Hook installed → %s\n%s\n", profile, hook.ReloadNote(profile))
			}

			// Generate the aliases file immediately so it is ready on the next shell start.
			cfg, cfgErr := config.Load()
			if cfgErr == nil && cfg.HasNetBox() {
				c := newCache(cfg)
				if _ = c.Load(); true {
					if entries := buildAliasEntries(c, *cfg); len(entries) > 0 {
						if err := hook.WriteAliasFiles(entries); err != nil {
							fmt.Fprintf(os.Stderr, "warning: could not write alias files: %v\n", err)
						} else {
							fmt.Printf("%d aliases written to %s\n", len(entries), hook.AliasesPath())
						}
					} else {
						fmt.Println("Cache is empty — run 'netssh cache refresh' to populate aliases.")
					}
				}
			}
			return nil
		},
	}
	cmd.Flags().StringVar(&shell, "shell", "", "Shell to install for (default: $SHELL). Supported: bash, zsh, fish")
	return cmd
}

func hookUninstallCmd() *cobra.Command {
	var shell string
	cmd := &cobra.Command{
		Use:   "uninstall",
		Short: "Remove netssh shell-init from your shell profile",
		RunE: func(cmd *cobra.Command, args []string) error {
			if shell == "" {
				shell = filepath.Base(os.Getenv("SHELL"))
			}
			profile, err := hook.ProfilePath(shell)
			if err != nil {
				return err
			}
			removed, err := hook.Uninstall(profile)
			if err != nil {
				return err
			}
			if !removed {
				fmt.Printf("No hook found in %s\n", profile)
				return nil
			}
			fmt.Printf("Hook removed from %s\n", profile)
			return nil
		},
	}
	cmd.Flags().StringVar(&shell, "shell", "", "Shell to uninstall from (default: $SHELL). Supported: bash, zsh, fish")
	return cmd
}

// maybeBackgroundRefresh starts a background `netssh cache refresh` if the cache
// has not been fully refreshed within the last 24 hours.
func maybeBackgroundRefresh(cfg *config.Config, c *cache.Cache) {
	// netssh multi checks once and starts its panes with NETSSH_NO_REFRESH.
	if !cfg.HasNetBox() || os.Getenv("NETSSH_NO_REFRESH") != "" {
		return
	}
	if !c.NeedsRefresh(24 * time.Hour) {
		return
	}
	self, err := os.Executable()
	if err != nil {
		return
	}
	cmd := exec.Command(self, "cache", "refresh")
	cmd.Stdout = nil
	cmd.Stderr = nil
	cmd.Stdin = nil
	_ = cmd.Start() // fire and forget — becomes orphan after parent execs ssh
}

func fatalf(format string, args ...any) {
	fmt.Fprintf(os.Stderr, "netssh: "+format+"\n", args...)
	os.Exit(1)
}