package ws

import (
	"context"
	"sync"
	"testing"
	"time"

	"github.com/oklog/ulid/v2"

	"gitea.dcglab.co.uk/steve/restic-manager/internal/api"
	"gitea.dcglab.co.uk/steve/restic-manager/internal/store"
)

type fakeAlerts struct {
	mu       sync.Mutex
	raised   []string // hostIDs
	resolved []string
	reasons  []string
}

func (f *fakeAlerts) RaiseUpdateFailed(_ context.Context, hostID, _ /*jobID*/, reason string, _ time.Time) {
	f.mu.Lock()
	defer f.mu.Unlock()
	f.raised = append(f.raised, hostID)
	f.reasons = append(f.reasons, reason)
}

func (f *fakeAlerts) ResolveUpdateFailed(_ context.Context, hostID string, _ time.Time) {
	f.mu.Lock()
	defer f.mu.Unlock()
	f.resolved = append(f.resolved, hostID)
}

func seedJob(t *testing.T, st *store.Store, hostID string) string {
	t.Helper()
	jobID := ulid.Make().String()
	if err := st.CreateJob(context.Background(), store.Job{
		ID: jobID, HostID: hostID, Kind: "update",
		ActorKind: "user", CreatedAt: time.Now().UTC(),
	}); err != nil {
		t.Fatalf("create job: %v", err)
	}
	return jobID
}

func TestUpdateWatcherOnHelloSuccess(t *testing.T) {
	st := openWSTestStore(t)
	hostID := ulid.Make().String()
	seedHostWS(t, st, hostID)
	jobID := seedJob(t, st, hostID)

	a := &fakeAlerts{}
	w := NewUpdateWatcher(st, a, nil)
	w.Track(jobID, hostID)

	w.OnHello(context.Background(), hostID, "v2", "v2")

	job, err := st.GetJob(context.Background(), jobID)
	if err != nil {
		t.Fatalf("get job: %v", err)
	}
	if job.Status != "succeeded" {
		t.Fatalf("status: got %q want succeeded", job.Status)
	}
	a.mu.Lock()
	defer a.mu.Unlock()
	if len(a.resolved) != 1 || a.resolved[0] != hostID {
		t.Fatalf("resolve calls: %v", a.resolved)
	}
	if len(a.raised) != 0 {
		t.Fatalf("unexpected raises: %v", a.raised)
	}
}

func TestUpdateWatcherTimeout(t *testing.T) {
	prev := updateTimeout
	updateTimeout = 50 * time.Millisecond
	t.Cleanup(func() { updateTimeout = prev })

	st := openWSTestStore(t)
	hostID := ulid.Make().String()
	seedHostWS(t, st, hostID)
	jobID := seedJob(t, st, hostID)

	a := &fakeAlerts{}
	w := NewUpdateWatcher(st, a, nil)
	w.Track(jobID, hostID)

	time.Sleep(80 * time.Millisecond)
	w.sweep(context.Background(), time.Now())

	job, err := st.GetJob(context.Background(), jobID)
	if err != nil {
		t.Fatalf("get job: %v", err)
	}
	if job.Status != "failed" {
		t.Fatalf("status: got %q want failed", job.Status)
	}
	a.mu.Lock()
	defer a.mu.Unlock()
	if len(a.raised) != 1 || a.raised[0] != hostID {
		t.Fatalf("raise calls: %v", a.raised)
	}
	if len(a.reasons) == 0 || a.reasons[0] == "" {
		t.Fatalf("missing reason")
	}
}

func TestUpdateWatcherMismatchedVersionNoOp(t *testing.T) {
	st := openWSTestStore(t)
	hostID := ulid.Make().String()
	seedHostWS(t, st, hostID)
	jobID := seedJob(t, st, hostID)

	a := &fakeAlerts{}
	w := NewUpdateWatcher(st, a, nil)
	w.Track(jobID, hostID)

	w.OnHello(context.Background(), hostID, "v1", "v2")

	job, _ := st.GetJob(context.Background(), jobID)
	if job.Status == "succeeded" || job.Status == "failed" {
		t.Fatalf("status flipped on mismatched hello: %q", job.Status)
	}
	a.mu.Lock()
	defer a.mu.Unlock()
	if len(a.raised) != 0 || len(a.resolved) != 0 {
		t.Fatalf("unexpected alert calls raised=%v resolved=%v", a.raised, a.resolved)
	}
}

func TestUpdateWatcherHelloAfterTimeoutIsNoOp(t *testing.T) {
	prev := updateTimeout
	updateTimeout = 50 * time.Millisecond
	t.Cleanup(func() { updateTimeout = prev })

	st := openWSTestStore(t)
	hostID := ulid.Make().String()
	seedHostWS(t, st, hostID)
	jobID := seedJob(t, st, hostID)

	a := &fakeAlerts{}
	w := NewUpdateWatcher(st, a, nil)
	w.Track(jobID, hostID)

	time.Sleep(80 * time.Millisecond)
	w.sweep(context.Background(), time.Now())

	// Hello arrives after sweep — entry already gone, must be no-op.
	w.OnHello(context.Background(), hostID, "v2", "v2")

	job, _ := st.GetJob(context.Background(), jobID)
	if job.Status != "failed" {
		t.Fatalf("status flipped from failed → %q", job.Status)
	}
	a.mu.Lock()
	defer a.mu.Unlock()
	if len(a.resolved) != 0 {
		t.Fatalf("late hello triggered ResolveUpdateFailed: %v", a.resolved)
	}
}

func TestUpdateWatcherOnHelloBroadcastsJobFinished(t *testing.T) {
	st := openWSTestStore(t)
	hostID := ulid.Make().String()
	seedHostWS(t, st, hostID)
	jobID := seedJob(t, st, hostID)

	hub := NewJobHub()
	sub := hub.Register(jobID)
	defer sub.unregister()

	w := NewUpdateWatcher(st, &fakeAlerts{}, hub)
	w.Track(jobID, hostID)
	w.OnHello(context.Background(), hostID, "v2", "v2")

	select {
	case env := <-sub.ch:
		if env.Type != api.MsgJobFinished {
			t.Fatalf("envelope type: got %q want %q", env.Type, api.MsgJobFinished)
		}
		var p api.JobFinishedPayload
		if err := env.UnmarshalPayload(&p); err != nil {
			t.Fatalf("unmarshal payload: %v", err)
		}
		if p.JobID != jobID || p.Status != api.JobSucceeded {
			t.Fatalf("payload: got %+v", p)
		}
	case <-time.After(time.Second):
		t.Fatal("expected synthetic job.finished broadcast, got nothing")
	}
}

func TestUpdateWatcherTimeoutBroadcastsJobFinished(t *testing.T) {
	prev := updateTimeout
	updateTimeout = 50 * time.Millisecond
	t.Cleanup(func() { updateTimeout = prev })

	st := openWSTestStore(t)
	hostID := ulid.Make().String()
	seedHostWS(t, st, hostID)
	jobID := seedJob(t, st, hostID)

	hub := NewJobHub()
	sub := hub.Register(jobID)
	defer sub.unregister()

	w := NewUpdateWatcher(st, &fakeAlerts{}, hub)
	w.Track(jobID, hostID)

	time.Sleep(80 * time.Millisecond)
	w.sweep(context.Background(), time.Now())

	select {
	case env := <-sub.ch:
		if env.Type != api.MsgJobFinished {
			t.Fatalf("envelope type: got %q want %q", env.Type, api.MsgJobFinished)
		}
		var p api.JobFinishedPayload
		if err := env.UnmarshalPayload(&p); err != nil {
			t.Fatalf("unmarshal payload: %v", err)
		}
		if p.JobID != jobID || p.Status != api.JobFailed {
			t.Fatalf("payload: got %+v", p)
		}
	case <-time.After(time.Second):
		t.Fatal("expected synthetic job.finished broadcast, got nothing")
	}
}