package alert

import (
	"context"
	"log/slog"
	"strings"
	"testing"
	"time"

	"gitea.lab.audasmedia.com.au/sam/internet_use_control/internal/store"
)

type fakeStore struct {
	devices []store.Device
	eff     map[int64]store.EffectiveState
	states  map[int64]store.AlertState
	alerts  []*store.Alert
	nextID  int64
}

func newFakeStore(devices ...store.Device) *fakeStore {
	return &fakeStore{
		devices: devices,
		eff:     map[int64]store.EffectiveState{},
		states:  map[int64]store.AlertState{},
	}
}

func (f *fakeStore) ListDevices(context.Context) ([]store.Device, error) { return f.devices, nil }

func (f *fakeStore) EffectiveState(_ context.Context, dev store.Device, _ time.Time) (store.EffectiveState, error) {
	return f.eff[dev.ID], nil
}

func (f *fakeStore) AlertStates(context.Context) (map[int64]store.AlertState, error) {
	out := make(map[int64]store.AlertState, len(f.states))
	for k, v := range f.states {
		out[k] = v
	}
	return out, nil
}

func (f *fakeStore) SetAlertState(_ context.Context, deviceID int64, locked, offline bool) error {
	f.states[deviceID] = store.AlertState{Locked: locked, Offline: offline}
	return nil
}

func (f *fakeStore) CreateAlert(_ context.Context, deviceID *int64, kind, message string) (*store.Alert, error) {
	f.nextID++
	a := &store.Alert{ID: f.nextID, DeviceID: deviceID, Kind: kind, Message: message}
	f.alerts = append(f.alerts, a)
	return a, nil
}

func (f *fakeStore) MarkAlertDelivered(_ context.Context, id int64, errMsg string) error {
	for _, a := range f.alerts {
		if a.ID == id {
			a.Delivered = errMsg == ""
			a.Error = errMsg
		}
	}
	return nil
}

type fakeNotifier struct {
	configured bool
	sent       []string
	err        error
}

func (f *fakeNotifier) Configured() bool { return f.configured }

func (f *fakeNotifier) SendType(_ context.Context, _, body, _ string) error {
	if f.err != nil {
		return f.err
	}
	f.sent = append(f.sent, body)
	return nil
}

func newEngine(st *fakeStore, n *fakeNotifier, now time.Time) *Engine {
	e := New(st, n, slog.New(slog.DiscardHandler), 30*time.Minute, time.UTC)
	e.Now = func() time.Time { return now }
	return e
}

func TestSeedThenLimitTransition(t *testing.T) {
	now := time.Date(2026, 10, 13, 20, 30, 0, 0, time.UTC)
	until := now.Add(30 * time.Minute)
	fs := newFakeStore(store.Device{ID: 1, Name: "Harry's phone", Child: "Harry"})
	fs.eff[1] = store.EffectiveState{DeviceID: 1, Locked: false, Reason: ""}
	fn := &fakeNotifier{configured: true}
	e := newEngine(fs, fn, now)

	// First observation seeds the state and raises nothing.
	e.Evaluate(context.Background())
	if len(fs.alerts) != 0 {
		t.Fatalf("seed raised %d alerts, want 0", len(fs.alerts))
	}
	if st := fs.states[1]; st.Locked {
		t.Fatalf("seeded state = %#v, want unlocked", st)
	}

	// A schedule turns on: exactly one limit alert.
	fs.eff[1] = store.EffectiveState{DeviceID: 1, Locked: true, Reason: "schedule", Until: &until}
	e.Evaluate(context.Background())
	if len(fs.alerts) != 1 {
		t.Fatalf("alerts = %d, want 1", len(fs.alerts))
	}
	if fs.alerts[0].Kind != store.AlertLimit {
		t.Errorf("kind = %q, want limit", fs.alerts[0].Kind)
	}
	if !fs.alerts[0].Delivered {
		t.Error("alert was not marked delivered")
	}
	if len(fn.sent) != 1 {
		t.Fatalf("notifier sent %d, want 1", len(fn.sent))
	}

	// No new alert while the condition stays true.
	e.Evaluate(context.Background())
	if len(fs.alerts) != 1 {
		t.Fatalf("repeat evaluation raised %d alerts, want 1", len(fs.alerts))
	}
}

func TestOfflineTransition(t *testing.T) {
	now := time.Date(2026, 10, 13, 15, 0, 0, 0, time.UTC)
	old := now.Add(-2 * time.Hour)
	fs := newFakeStore(store.Device{ID: 2, Name: "Finn's computer", Child: "Finn", Online: true})
	fs.eff[2] = store.EffectiveState{DeviceID: 2}
	fn := &fakeNotifier{configured: true}
	e := newEngine(fs, fn, now)
	e.Evaluate(context.Background()) // seed online

	fs.devices[0].Online = false
	fs.devices[0].LastSeen = &old
	e.Evaluate(context.Background())

	if len(fs.alerts) != 1 || fs.alerts[0].Kind != store.AlertOffline {
		t.Fatalf("alerts = %#v, want one offline alert", fs.alerts)
	}
	if len(fn.sent) != 1 {
		t.Fatalf("notifier sent %d, want 1", len(fn.sent))
	}
}

func TestNeverSeenDeviceIsNotOffline(t *testing.T) {
	now := time.Date(2026, 10, 13, 15, 0, 0, 0, time.UTC)
	fs := newFakeStore(store.Device{ID: 3, Name: "New device", Child: "Harry", Online: false})
	fs.eff[3] = store.EffectiveState{DeviceID: 3}
	e := newEngine(fs, &fakeNotifier{configured: true}, now)

	e.Evaluate(context.Background()) // seed
	e.Evaluate(context.Background()) // still no last_seen
	if len(fs.alerts) != 0 {
		t.Fatalf("alerts = %d, want 0 for a never-seen device", len(fs.alerts))
	}
}

func TestUndeliveredWhenNotConfigured(t *testing.T) {
	now := time.Date(2026, 10, 13, 20, 30, 0, 0, time.UTC)
	until := now.Add(30 * time.Minute)
	fs := newFakeStore(store.Device{ID: 1, Name: "Harry's phone", Child: "Harry"})
	fs.eff[1] = store.EffectiveState{DeviceID: 1}
	fn := &fakeNotifier{configured: false}
	e := newEngine(fs, fn, now)
	e.Evaluate(context.Background())

	fs.eff[1] = store.EffectiveState{DeviceID: 1, Locked: true, Reason: "schedule", Until: &until}
	e.Evaluate(context.Background())

	if len(fs.alerts) != 1 {
		t.Fatalf("alerts = %d, want 1", len(fs.alerts))
	}
	if fs.alerts[0].Delivered {
		t.Error("alert marked delivered with an unconfigured notifier")
	}
}

func TestRaiseTamperDeliversOnce(t *testing.T) {
	now := time.Date(2026, 10, 13, 20, 30, 0, 0, time.UTC)
	fs := newFakeStore(store.Device{ID: 1, Name: "Harry's phone", Child: "Harry"})
	fn := &fakeNotifier{configured: true}
	e := newEngine(fs, fn, now)

	dev := store.Device{ID: 1, Name: "Harry's phone"}
	e.Raise(context.Background(), dev, store.AlertTamper,
		TamperMessage(dev, "accessibility_disabled", "service turned off"))

	if len(fs.alerts) != 1 {
		t.Fatalf("alerts = %d, want 1", len(fs.alerts))
	}
	a := fs.alerts[0]
	if a.Kind != store.AlertTamper {
		t.Errorf("kind = %q, want %q", a.Kind, store.AlertTamper)
	}
	if !a.Delivered {
		t.Error("tamper alert was not delivered")
	}
	if len(fn.sent) != 1 || !strings.Contains(fn.sent[0], "Harry's phone") {
		t.Errorf("delivered bodies = %v", fn.sent)
	}
}

func TestTamperMessagePhrases(t *testing.T) {
	dev := store.Device{ID: 1, Name: "Finn's computer"}
	for kind, want := range map[string]string{
		"accessibility_disabled": "the Accessibility Service was disabled",
		"overlay_revoked":        "the overlay permission was revoked",
		"force_stopped":          "the app was force stopped",
		"something_new":          "the client enforcement was bypassed",
	} {
		got := TamperMessage(dev, kind, "")
		if !strings.Contains(got, want) {
			t.Errorf("TamperMessage(%q) = %q, want it to contain %q", kind, got, want)
		}
	}
}