package backup

import (
	"io"
	"log"
	"path/filepath"
	"strings"
	"testing"

	"gitea.dooplex.hu/admin/felhom-controller/internal/appbackup"
)

// R-158 / R-167 (D-c, operator half) — a per-app Tier-1 recovery-unit capture failure must reach a
// hub channel.
//
// THE GAP THESE CLOSE. `captureAllRecoveryUnits` logged `[WARN] Recovery unit capture failed for %s`
// and stopped there. The manager carried three notify seams — tier2Notify, offboxNotify,
// offboxEnlargeBlockedNotify — and none for the unit capture, so the one page a person opens to ask
// whether ONE app is backed up (`/backups/apps`) was the one page that never said. Fifth instance in
// this project of a mechanism built and left disconnected.

// unitFailProvider lists a fixed set of stacks and refuses GetStackRecoveryInfo for the named ones,
// which is the earliest real failure inside CaptureRecoveryUnit ("stack %q not found").
type unitFailProvider struct {
	stacks []string
	fail   map[string]bool
	dir    string
}

func (p *unitFailProvider) GetStackComposePath(string) (string, bool) { return "", false }
func (p *unitFailProvider) ListDeployedStacks() []StackSummary {
	out := make([]StackSummary, 0, len(p.stacks))
	for _, s := range p.stacks {
		out = append(out, StackSummary{Name: s})
	}
	return out
}
func (p *unitFailProvider) GetStackHDDMounts(string) []string { return nil }
func (p *unitFailProvider) GetStackHDDPath(string) string     { return "" }
func (p *unitFailProvider) GetImportRoot() string             { return "" }
func (p *unitFailProvider) GetDockerVolumes(string) []string  { return nil }
func (p *unitFailProvider) StopStack(string) error            { return nil }
func (p *unitFailProvider) StartStack(string) error           { return nil }
func (p *unitFailProvider) RefreshAndIsRunning(string) bool   { return true }
func (p *unitFailProvider) GetStackRecoveryInfo(name string) (RecoveryInfo, bool) {
	if p.fail[name] {
		return RecoveryInfo{}, false
	}
	return RecoveryInfo{StackDir: filepath.Join(p.dir, "stacks", name)}, true
}
func (p *unitFailProvider) RecoverStackSecrets(string, []string) map[string]string { return nil }
func (p *unitFailProvider) RecreateStackDefinitionFromUnit(string, string, map[string]string) error {
	return nil
}
func (p *unitFailProvider) StartStackServices(string, []string) error { return nil }
func (p *unitFailProvider) GetStackClassifiedBinds(string) ([]appbackup.ClassifiedBind, bool) {
	return nil, false
}

var _ appbackup.StackDataProvider = (*unitFailProvider)(nil)

type unitEvent struct {
	app   string
	err   string
	usage *UnitSpace
}

func newUnitNotifyManager(t *testing.T, stacks []string, fail map[string]bool) (*Manager, *[]unitEvent) {
	t.Helper()
	dir := t.TempDir()
	m := &Manager{
		logger:         log.New(io.Discard, "", 0),
		systemDataPath: dir,
		stackProvider:  &unitFailProvider{stacks: stacks, fail: fail, dir: dir},
	}
	var got []unitEvent
	m.SetUnitNotify(func(name string, err error, usage *UnitSpace) {
		got = append(got, unitEvent{app: name, err: err.Error(), usage: usage})
	})
	return m, &got
}

// --- Scenario C — a local unit capture failure reaches the operator ------------------------------

func TestCaptureAll_FailureNotifiesOnceWithTheSpaceFigures(t *testing.T) {
	m, got := newUnitNotifyManager(t, []string{"immich"}, map[string]bool{"immich": true})

	m.captureAllRecoveryUnits()

	if len(*got) != 1 {
		t.Fatalf("got %d unit-failure events, want exactly 1 — a per-app Tier-1 capture failure "+
			"reached no hub channel, which is the R-158 gap un-fixed", len(*got))
	}
	e := (*got)[0]
	if e.app != "immich" {
		t.Fatalf("event names app %q, want immich — an operator cannot act on an unnamed app", e.app)
	}
	if e.err == "" {
		t.Fatal("the event carries no error — the operator is told a capture failed but not why")
	}
	// The space figures are the point: the overwhelmingly likely cause is a full filesystem, and
	// these answer "why" without an operator logging in.
	if e.usage == nil {
		t.Fatal("the event carries no space figures for a readable target filesystem — this is the " +
			"pair of numbers that makes the alert actionable, and the same pair the customer fill " +
			"warning reports (which is why the two ship together)")
	}
	if e.usage.Path == "" || e.usage.TotalGB <= 0 {
		t.Fatalf("space figures are not populated: %+v", e.usage)
	}
}

// --- Scenario D — one failing app does not silence the others ------------------------------------

func TestCaptureAll_OneFailureDoesNotAbortOrDuplicate(t *testing.T) {
	m, got := newUnitNotifyManager(t,
		[]string{"homebox", "immich", "nextcloud"},
		map[string]bool{"immich": true})

	m.captureAllRecoveryUnits()

	if len(*got) != 1 {
		t.Fatalf("got %d events, want exactly 1 — either the loop ABORTED on the middle app "+
			"(and its siblings were never captured), or one failure produced several events: %+v",
			len(*got), *got)
	}
	if (*got)[0].app != "immich" {
		t.Fatalf("event names %q, want immich", (*got)[0].app)
	}

	// The siblings must have been ATTEMPTED after the failure — a positive observable, not the
	// absence of an event. The provider records nothing, so assert via the failure set instead:
	// flip the LAST app to failing and require both events.
	m2, got2 := newUnitNotifyManager(t,
		[]string{"homebox", "immich", "nextcloud"},
		map[string]bool{"immich": true, "nextcloud": true})
	m2.captureAllRecoveryUnits()
	if len(*got2) != 2 {
		t.Fatalf("got %d events, want 2 — the app AFTER the first failure was never reached, so the "+
			"loop is aborting rather than continuing: %+v", len(*got2), *got2)
	}
	if (*got2)[0].app != "immich" || (*got2)[1].app != "nextcloud" {
		t.Fatalf("events %+v, want immich then nextcloud in loop order", *got2)
	}
}

// A successful capture must be SILENT. An alert that fires on success is an alert an operator learns
// to ignore.
func TestCaptureAll_SuccessIsSilent(t *testing.T) {
	m, got := newUnitNotifyManager(t, []string{"homebox"}, nil)
	m.captureAllRecoveryUnits()
	if len(*got) != 0 {
		t.Fatalf("a successful capture fired %d event(s): %+v", len(*got), *got)
	}
}

// The seam must be nil-safe: an unwired notify is the pre-v0.191.0 behaviour (a WARN line), never a
// panic that takes the whole nightly backup down with it.
func TestCaptureAll_UnwiredNotifyDoesNotPanic(t *testing.T) {
	dir := t.TempDir()
	m := &Manager{
		logger:         log.New(io.Discard, "", 0),
		systemDataPath: dir,
		stackProvider:  &unitFailProvider{stacks: []string{"immich"}, fail: map[string]bool{"immich": true}, dir: dir},
	}
	m.captureAllRecoveryUnits() // no SetUnitNotify — must not panic
}

// §8.4 in the failure direction: an unreadable target filesystem is reported as UNKNOWN, never as
// zeros. "0 GB free" and "we could not look" are opposite diagnoses, and rendering the second as the
// first is the presence-is-not-success trap pointing the other way.
func TestUnitSpace_NilRendersAsUnavailableNotZero(t *testing.T) {
	var u *UnitSpace
	s := u.String()
	if !strings.Contains(s, "unavailable") {
		t.Fatalf("nil UnitSpace renders as %q — it must say the reading is unavailable", s)
	}
	if strings.Contains(s, "0.0") {
		t.Fatalf("nil UnitSpace renders zeros (%q) — an operator would read \"the disk is full\" "+
			"from a filesystem nobody could read", s)
	}
}