package setup

import (
	"errors"
	"fmt"
	"net"
	"strings"
	"time"
)

// remoteServicesInjection is appended to the marge URL in the envswitch
// command. When the speaker next reads its boseurls (within ~60s), the device
// runs these shell commands: it touches the remote_services marker and starts
// sshd. This is the #471 bootstrap — it enables SSH on firmware with no prior
// SSH access and without a USB recovery stick. The whole marge value is
// double-quoted in the telnet command because it now contains spaces and
// semicolons.
const remoteServicesInjection = ";touch /tmp/remote_services;/etc/init.d/sshd start"

// EnableSSHViaTelnet bootstraps SSH on a speaker over its port-17000 shell by
// setting boseurls to an injected value (see remoteServicesInjection). It needs
// no existing SSH and no USB recovery. The injected commands run on the
// speaker's next boseurls check (up to ~60s), so callers should WaitForSSHPort
// afterwards, then ResetBoseURLs (to restore a usable marge URL) and
// EnsureRemoteServices (to persist SSH across reboots).
//
// serviceURL is the AfterTouch service base the speaker should point at
// (e.g. https://192.0.2.10:8443). It must not contain a double quote.
func (m *Manager) EnableSSHViaTelnet(deviceIP, serviceURL string) (string, error) {
	return m.setBoseURLsViaTelnet(deviceIP, serviceURL+remoteServicesInjection, serviceURL+"/update")
}

// ResetBoseURLs restores clean boseurls (no injected commands) after SSH has
// been enabled, so the speaker's marge URL is usable again.
func (m *Manager) ResetBoseURLs(deviceIP, serviceURL string) (string, error) {
	return m.setBoseURLsViaTelnet(deviceIP, serviceURL, serviceURL+"/update")
}

// DefaultTelnetCommandDelay is the pause between successive commands in
// EnableSSHViaTelnetFullConfig's sequence. Originally set based on #515
// comment 5228449448 (same six commands, back-to-back left sshd down after
// reboot but succeeded with ~7s gaps). That inter-command-delay theory was
// RETRACTED by the same reporter after a controlled A/B on three variants
// (issue comment 5231931569): back-to-back and 5s-gapped runs produced
// identical results (all writes applied, confirmed via verified reboots),
// so the delay itself does not appear to be the mechanism — the likely real
// gate was the account-pairing precondition (see EnsureMargeAccountPaired),
// fixed independently. The flag is kept at a small non-zero default (3s)
// as a low-cost hedge for firmware variants nobody has A/B-tested yet
// (only lisa/mojo/spotty/ginger/taigan are confirmed); 0 sends everything
// back-to-back.
const DefaultTelnetCommandDelay = 3 * time.Second

// EnableSSHViaTelnetFullConfig is the #515 variant of EnableSSHViaTelnet for
// devices where the single-envswitch injection is accepted and persisted but
// sshd never starts (ST Portable, CineMate 520; see also memory note #471). It
// replicates the sequence @Henri-be confirmed by hand over telnet :17000: it
// writes all four `sys configuration` URL keys with the remote_services
// injection on margeServerUrl (the runtime layer, not just the envswitch
// persistence layer), mirrors the injection into `envswitch boseurls set`, and
// verifies with getpdo. The caller should pause commandDelay again, reboot
// (the injection fires on the speaker's next full config re-parse at boot),
// and then WaitForSSHPort.
//
// serviceURL is the AfterTouch service base the speaker should point at
// (e.g. https://192.0.2.10:8443). It must not contain a double quote.
// commandDelay is the pause between each command (see
// DefaultTelnetCommandDelay); 0 sends them back-to-back.
func (m *Manager) EnableSSHViaTelnetFullConfig(deviceIP, serviceURL string, commandDelay time.Duration) (string, error) {
	u := defaultTelnetURLs(serviceURL)
	margeInjected := serviceURL + remoteServicesInjection

	// All values are double-quoted: margeInjected contains spaces and
	// semicolons, so the device's command parser needs the quotes to keep it
	// one argument (the unquoted telnetURLs.Commands() is only safe for clean
	// migration URLs).
	cmds := []string{
		`sys configuration bmxRegistryUrl "` + u.BmxRegistry + `"`,
		`sys configuration statsServerUrl "` + u.Stats + `"`,
		`sys configuration margeServerUrl "` + margeInjected + `"`,
		`sys configuration swUpdateUrl "` + u.SwUpdate + `"`,
		`envswitch boseurls set "` + margeInjected + `" "` + u.SwUpdate + `"`,
	}

	return m.runTelnetInjection(deviceIP, []string{serviceURL, u.SwUpdate}, cmds, commandDelay)
}

// runTelnetInjection opens the port-17000 shell, runs an ordered list of
// commands (aborting on the first transport error or "command not found"
// rejection), pausing commandDelay after each one (see
// DefaultTelnetCommandDelay), then logs a getpdo verification. forbidQuote
// values are checked for an embedded double quote, which would break the
// command parsing. Verification is best-effort (logged, never fatal) to
// match enable-ssh's forgiving philosophy and tolerate the
// aftertouch.invalid placeholder.
func (m *Manager) runTelnetInjection(deviceIP string, forbidQuote, cmds []string, commandDelay time.Duration) (string, error) {
	if m.NewTelnet == nil {
		return "", errors.New("telnet not configured: Manager.NewTelnet is nil")
	}

	for _, v := range forbidQuote {
		if strings.Contains(v, `"`) {
			return "", errors.New("boseurls values must not contain a double quote")
		}
	}

	var logs strings.Builder

	t := m.NewTelnet(deviceIP)
	if err := t.Dial(); err != nil {
		return logs.String(), fmt.Errorf("telnet dial %s:17000: %w", deviceIP, err)
	}

	defer func() { _ = t.Close() }()

	if banner, _ := t.Probe(); banner != "" {
		fmt.Fprintf(&logs, "Telnet banner: %q\n", strings.TrimSpace(banner))
	}

	for _, cmd := range cmds {
		resp, err := t.SendCommand(cmd)
		if err != nil {
			return logs.String(), fmt.Errorf("telnet command %q failed: %w", cmd, err)
		}

		fmt.Fprintf(&logs, "→ %s\n%s\n", cmd, strings.TrimRight(resp, "\r\n"))

		if isCommandNotFound(resp) {
			return logs.String(), fmt.Errorf("device rejected %q (firmware does not expose this command)", cmd)
		}

		if commandDelay > 0 {
			time.Sleep(commandDelay)
		}
	}

	if verify, err := t.SendCommand("getpdo CurrentSystemConfiguration"); err == nil {
		fmt.Fprintf(&logs, "→ getpdo CurrentSystemConfiguration (runtime layer only — confirms the writes were accepted, not that they'll survive a reboot)\n%s\n", strings.TrimRight(verify, "\r\n"))
	}

	return logs.String(), nil
}

// setBoseURLsViaTelnet runs `envswitch boseurls set "<marge>" "<swUpdate>"`
// over the port-17000 shell. Both arguments are double-quoted so values
// containing spaces or semicolons (the SSH-enable injection) survive the
// device's command parser.
func (m *Manager) setBoseURLsViaTelnet(deviceIP, marge, swUpdate string) (string, error) {
	if m.NewTelnet == nil {
		return "", errors.New("telnet not configured: Manager.NewTelnet is nil")
	}

	if strings.Contains(marge, `"`) || strings.Contains(swUpdate, `"`) {
		return "", errors.New("boseurls values must not contain a double quote")
	}

	var logs strings.Builder

	t := m.NewTelnet(deviceIP)
	if err := t.Dial(); err != nil {
		return logs.String(), fmt.Errorf("telnet dial %s:17000: %w", deviceIP, err)
	}

	defer func() { _ = t.Close() }()

	if banner, _ := t.Probe(); banner != "" {
		fmt.Fprintf(&logs, "Telnet banner: %q\n", strings.TrimSpace(banner))
	}

	cmd := `envswitch boseurls set "` + marge + `" "` + swUpdate + `"`

	resp, err := t.SendCommand(cmd)
	if err != nil {
		return logs.String(), fmt.Errorf("telnet command %q failed: %w", cmd, err)
	}

	fmt.Fprintf(&logs, "→ %s\n%s\n", cmd, strings.TrimRight(resp, "\r\n"))

	if isCommandNotFound(resp) {
		return logs.String(), fmt.Errorf("device rejected %q (firmware does not expose envswitch)", cmd)
	}

	return logs.String(), nil
}

// setAllBoseURLsViaTelnet writes all four boseurls (bmx, stats, marge,
// swUpdate) to the runtime layer via `sys configuration ...`, then commits
// them with `envswitch boseurls set`, over the port-17000 shell. Unlike
// setBoseURLsViaTelnet (which only issues the envswitch commit, used by the
// #471 SSH-bootstrap/reset flows that need that specific two-argument
// injection), this mirrors telnetURLs.Commands()'s full sequence so the
// envswitch commit captures fresh values for all four fields, not just two.
func (m *Manager) setAllBoseURLsViaTelnet(deviceIP string, urls telnetURLs) (string, error) {
	if m.NewTelnet == nil {
		return "", errors.New("telnet not configured: Manager.NewTelnet is nil")
	}

	var logs strings.Builder

	t := m.NewTelnet(deviceIP)
	if err := t.Dial(); err != nil {
		return logs.String(), fmt.Errorf("telnet dial %s:17000: %w", deviceIP, err)
	}

	defer func() { _ = t.Close() }()

	if banner, _ := t.Probe(); banner != "" {
		fmt.Fprintf(&logs, "Telnet banner: %q\n", strings.TrimSpace(banner))
	}

	for _, cmd := range urls.Commands() {
		resp, err := t.SendCommand(cmd)
		if err != nil {
			return logs.String(), fmt.Errorf("telnet command %q failed: %w", cmd, err)
		}

		fmt.Fprintf(&logs, "→ %s\n%s\n", cmd, strings.TrimRight(resp, "\r\n"))

		if isCommandNotFound(resp) {
			return logs.String(), fmt.Errorf("device rejected %q (firmware does not expose this command)", cmd)
		}
	}

	return logs.String(), nil
}

// fwScript is the speaker's persistent iptables script; appending here makes a
// rule survive reboot (it is re-applied on boot).
const fwScript = "/etc/init.d/Firewalls/update_iptables"

// block17000Marker guards the appended rule so Close17000 is idempotent.
const block17000Marker = "# Block 17000 (added by AfterTouch)"

// Close17000 blocks the port-17000 diagnostic shell from the LAN over SSH:
// it persists an iptables rule in the firewall script (idempotent, keyed on
// block17000Marker) and applies the rule immediately, keeping loopback access.
// Opt-in — the caller decides whether to harden. Needs SSH already enabled.
func (m *Manager) Close17000(deviceIP string) (string, error) {
	if m.NewSSH == nil {
		return "", errors.New("ssh not configured: Manager.NewSSH is nil")
	}

	persist := "grep -q '" + block17000Marker + "' " + fwScript + " 2>/dev/null || cat >> " + fwScript + " <<'AFTEREOF'\n\n" +
		block17000Marker + "\n" +
		"iptables -I INPUT -p tcp --dport 17000 -j DROP\n" +
		"iptables -I INPUT -p tcp --dport 17000 -i lo -j ACCEPT\n" +
		"AFTEREOF"

	steps := []struct{ desc, cmd string }{
		{"remount / read-write", "mount / -o rw,remount"},
		{"persist firewall rule", persist},
		{"apply firewall rule now", "iptables -I INPUT -p tcp --dport 17000 -j DROP; iptables -I INPUT -p tcp --dport 17000 -i lo -j ACCEPT"},
	}

	return m.runSSHSteps(deviceIP, steps)
}

// InstallAuthorizedKey installs an SSH public key for root so access no longer
// relies on the empty-password login. Opt-in. Needs SSH already enabled.
func (m *Manager) InstallAuthorizedKey(deviceIP, publicKey string) (string, error) {
	if m.NewSSH == nil {
		return "", errors.New("ssh not configured: Manager.NewSSH is nil")
	}

	key := strings.TrimSpace(publicKey)
	if key == "" {
		return "", errors.New("public key is empty")
	}

	c := m.NewSSH(deviceIP)

	var logs strings.Builder

	if out, err := c.Run("mount / -o rw,remount && mkdir -p -m 700 /home/root/.ssh"); err != nil {
		fmt.Fprintf(&logs, "→ prepare /home/root/.ssh\n%s\n", strings.TrimSpace(out))
		return logs.String(), fmt.Errorf("prepare /home/root/.ssh: %w", err)
	}

	if err := c.UploadContent([]byte(key+"\n"), "/home/root/.ssh/authorized_keys"); err != nil {
		return logs.String(), fmt.Errorf("upload authorized_keys: %w", err)
	}

	if out, err := c.Run("chmod 600 /home/root/.ssh/authorized_keys"); err != nil {
		fmt.Fprintf(&logs, "→ chmod authorized_keys\n%s\n", strings.TrimSpace(out))
		return logs.String(), fmt.Errorf("chmod authorized_keys: %w", err)
	}

	logs.WriteString("Installed authorized_keys for root.\n")

	return logs.String(), nil
}

// runSSHSteps runs an ordered list of shell commands over a single-shot SSH
// client, aborting on the first failure. Commands MUST be service-controlled
// literals, never built from untrusted HTTP input.
func (m *Manager) runSSHSteps(deviceIP string, steps []struct{ desc, cmd string }) (string, error) {
	c := m.NewSSH(deviceIP)

	var logs strings.Builder

	for _, s := range steps {
		out, err := c.Run(s.cmd)

		fmt.Fprintf(&logs, "→ %s\n%s\n", s.desc, strings.TrimSpace(out))

		if err != nil {
			return logs.String(), fmt.Errorf("%s: %w", s.desc, err)
		}
	}

	return logs.String(), nil
}

// WaitForSSHPort polls TCP :22 on the speaker until it accepts a connection or
// timeout elapses. Used after EnableSSHViaTelnet, since sshd starts only when
// the speaker next reads its boseurls (up to ~60s later).
func WaitForSSHPort(deviceIP string, timeout time.Duration) error {
	deadline := time.Now().Add(timeout)
	addr := net.JoinHostPort(deviceIP, "22")

	for {
		conn, err := net.DialTimeout("tcp", addr, 3*time.Second)
		if err == nil {
			_ = conn.Close()
			return nil
		}

		if time.Now().After(deadline) {
			return fmt.Errorf("ssh (:22) on %s not reachable within %s: %w", deviceIP, timeout, err)
		}

		time.Sleep(3 * time.Second)
	}
}