package storage

import (
	"context"
	"os"
	"path/filepath"
	"runtime"
	"strings"
	"testing"
)

// The §8 decision table, encoded exactly (RCA AUDIT-nas-cwa-rca-2026-07-11 fix 1).
func TestNetReassertAction_Table(t *testing.T) {
	cases := []struct {
		fstype string
		want   string
	}{
		{"nfs4", NetReassertSkipActive},  // real mount — inherited by fresh namespaces
		{"nfs", NetReassertSkipActive},   // real mount
		{"cifs", NetReassertSkipActive},  // real mount
		{"autofs", NetReassertRearmed},   // idle trigger — NOT inherited, re-arm to propagate
		{"", NetReassertSkipNone},        // nothing at the path — removed/orphan, owned elsewhere
		{"ext4", NetReassertSkipNone},    // a local fs at the path is not a network state we own
		{"tmpfs", NetReassertSkipNone},   //
	}
	for _, c := range cases {
		if got := netReassertAction(c.fstype); got != c.want {
			t.Errorf("netReassertAction(%q) = %q, want %q", c.fstype, got, c.want)
		}
	}
}

// installNetUnitFile writes a rendered network .mount unit straight into unitDir (bypassing the
// runner-mediated install — the reassert only READS unit files).
func installNetUnitFile(t *testing.T, unitDir string, spec NetworkMountSpec) (where, automountUnit string) {
	t.Helper()
	where = spec.Where()
	mountUnit, err := UnitNameForMount(where)
	if err != nil {
		t.Fatalf("unit name: %v", err)
	}
	if err := os.WriteFile(filepath.Join(unitDir, mountUnit), []byte(renderNetworkMountUnit(spec)), 0o644); err != nil {
		t.Fatalf("write unit: %v", err)
	}
	return where, strings.TrimSuffix(mountUnit, ".mount") + ".automount"
}

func netReassertOps(t *testing.T, unitDir string, mounts []Mount) (*SudoHostOps, *recordingRunner) {
	t.Helper()
	rr := &recordingRunner{}
	ops := NewSudoHostOps(SudoHostOpsConfig{
		Runner: rr, Bins: Binaries{}.withDefaults(), UnitDir: unitDir, StageDir: t.TempDir(),
		Host: &fakeHostReader{mounts: mounts}, Logger: quietLogger(),
	})
	return ops, rr
}

// An idle trigger (autofs at the mountpoint) must be re-armed with EXACTLY the granted verbs:
// `systemctl stop -- <unit>.automount` then `systemctl enable --now -- <unit>.automount`.
func TestReassertNetworkAutomounts_RearmsIdleTrigger(t *testing.T) {
	if runtime.GOOS == "windows" {
		t.Skip("systemd-escaped unit filename contains a backslash; exercised on the Linux build server")
	}
	unitDir := t.TempDir()
	spec := NetworkMountSpec{Name: "media", Protocol: ProtocolNFS, Server: "10.0.0.5", Export: "/srv/media", MappedUID: 1000, MappedGID: 1000}
	where, autoUnit := installNetUnitFile(t, unitDir, spec)
	ops, rr := netReassertOps(t, unitDir, []Mount{{MountPoint: where, FSType: "autofs"}})

	results := ops.ReassertNetworkAutomounts(context.Background())
	if len(results) != 1 || results[0].Action != NetReassertRearmed || results[0].Err != nil {
		t.Fatalf("want one rearmed result, got %+v", results)
	}
	if results[0].Where != where || results[0].Name != "media" {
		t.Fatalf("result identity wrong: %+v", results[0])
	}
	if len(rr.calls) != 2 {
		t.Fatalf("want exactly stop + enable --now, got %d calls: %v", len(rr.calls), rr.calls)
	}
	stop, enable := strings.Join(rr.calls[0], " "), strings.Join(rr.calls[1], " ")
	if !strings.Contains(stop, "systemctl stop -- "+autoUnit) {
		t.Errorf("first call must be `systemctl stop -- %s`, got: %s", autoUnit, stop)
	}
	if !strings.Contains(enable, "systemctl enable --now -- "+autoUnit) {
		t.Errorf("second call must be `systemctl enable --now -- %s`, got: %s", autoUnit, enable)
	}
}

// An ACTIVE real mount must not be touched — stopping the automount of a live mount would churn it.
// (Red-proof companion: a naive always-rearm implementation fails this with 2 recorded calls.)
func TestReassertNetworkAutomounts_ActiveMountUntouched(t *testing.T) {
	if runtime.GOOS == "windows" {
		t.Skip("systemd-escaped unit filename contains a backslash; exercised on the Linux build server")
	}
	unitDir := t.TempDir()
	spec := NetworkMountSpec{Name: "media", Protocol: ProtocolNFS, Server: "10.0.0.5", Export: "/srv/media", MappedUID: 1000, MappedGID: 1000}
	where, _ := installNetUnitFile(t, unitDir, spec)
	ops, rr := netReassertOps(t, unitDir, []Mount{{MountPoint: where, FSType: "nfs4"}})

	results := ops.ReassertNetworkAutomounts(context.Background())
	if len(results) != 1 || results[0].Action != NetReassertSkipActive {
		t.Fatalf("want one skip-active result, got %+v", results)
	}
	if len(rr.calls) != 0 {
		t.Fatalf("an actively-mounted share must trigger ZERO systemctl calls, got: %v", rr.calls)
	}
}

// Neither a mount nor an armed trigger → skip (removed/orphan state, owned by add/remove flows).
func TestReassertNetworkAutomounts_NoTriggerSkips(t *testing.T) {
	if runtime.GOOS == "windows" {
		t.Skip("systemd-escaped unit filename contains a backslash; exercised on the Linux build server")
	}
	unitDir := t.TempDir()
	spec := NetworkMountSpec{Name: "media", Protocol: ProtocolNFS, Server: "10.0.0.5", Export: "/srv/media", MappedUID: 1000, MappedGID: 1000}
	installNetUnitFile(t, unitDir, spec)
	ops, rr := netReassertOps(t, unitDir, nil) // nothing at the mountpoint

	results := ops.ReassertNetworkAutomounts(context.Background())
	if len(results) != 1 || results[0].Action != NetReassertSkipNone {
		t.Fatalf("want one skip-none result, got %+v", results)
	}
	if len(rr.calls) != 0 {
		t.Fatalf("a unit with no trigger must not be acted on, got: %v", rr.calls)
	}
}

// Idempotency: two consecutive passes over an idle trigger both succeed with the same action and no
// error (re-arming a fresh trigger is harmless — same end state).
func TestReassertNetworkAutomounts_Idempotent(t *testing.T) {
	if runtime.GOOS == "windows" {
		t.Skip("systemd-escaped unit filename contains a backslash; exercised on the Linux build server")
	}
	unitDir := t.TempDir()
	spec := NetworkMountSpec{Name: "media", Protocol: ProtocolNFS, Server: "10.0.0.5", Export: "/srv/media", MappedUID: 1000, MappedGID: 1000}
	where, _ := installNetUnitFile(t, unitDir, spec)
	ops, rr := netReassertOps(t, unitDir, []Mount{{MountPoint: where, FSType: "autofs"}})

	first := ops.ReassertNetworkAutomounts(context.Background())
	second := ops.ReassertNetworkAutomounts(context.Background())
	if first[0].Action != NetReassertRearmed || second[0].Action != NetReassertRearmed {
		t.Fatalf("both passes must re-arm: first=%+v second=%+v", first, second)
	}
	if first[0].Err != nil || second[0].Err != nil {
		t.Fatalf("idempotent passes must not error: first=%v second=%v", first[0].Err, second[0].Err)
	}
	if len(rr.calls) != 4 {
		t.Fatalf("two passes = 2×(stop+enable), got %d: %v", len(rr.calls), rr.calls)
	}
}

// Zero configured network units → empty pass, zero commands.
func TestReassertNetworkAutomounts_NoUnitsNoOp(t *testing.T) {
	ops, rr := netReassertOps(t, t.TempDir(), nil)
	if results := ops.ReassertNetworkAutomounts(context.Background()); len(results) != 0 {
		t.Fatalf("no units must yield no results, got %+v", results)
	}
	if len(rr.calls) != 0 {
		t.Fatalf("no units must construct zero commands, got: %v", rr.calls)
	}
}