package service

import (
	"testing"

	"filefast/backend/internal/model"
	"filefast/backend/internal/store"
)

func TestRegisterReusesKnownDeviceOnlyWithValidToken(t *testing.T) {
	memStore := store.NewMemoryStore(model.RuntimeConfig{})
	deviceService := NewDeviceService(memStore, nil, nil)

	device, session := deviceService.Register(RegisterDeviceInput{
		DeviceID: "known-device",
		Name:     "Alpha",
		Type:     "desktop",
	}, "ua/1.0", "")

	if device.ID != "known-device" {
		t.Fatalf("expected first registration to keep requested device id, got %q", device.ID)
	}
	if !deviceService.ValidateSession(device.ID, session.Token) {
		t.Fatal("expected issued device token to validate")
	}

	hijacked, hijackedSession := deviceService.Register(RegisterDeviceInput{
		DeviceID: "known-device",
		Name:     "Mallory",
		Type:     "desktop",
	}, "ua/1.0", "")

	if hijacked.ID == device.ID {
		t.Fatal("expected registration without token to receive a new device id")
	}
	if !deviceService.ValidateSession(hijacked.ID, hijackedSession.Token) {
		t.Fatal("expected replacement device token to validate")
	}

	restored, rotatedSession := deviceService.Register(RegisterDeviceInput{
		DeviceID: "known-device",
		Name:     "Alpha",
		Type:     "desktop",
	}, "ua/1.0", session.Token)

	if restored.ID != device.ID {
		t.Fatalf("expected valid token to reclaim original device id, got %q", restored.ID)
	}
	if rotatedSession.Token == session.Token {
		t.Fatal("expected registration to rotate the device token")
	}
	if deviceService.ValidateSession(restored.ID, session.Token) {
		t.Fatal("expected rotated token to invalidate the old token")
	}
	if !deviceService.ValidateSession(restored.ID, rotatedSession.Token) {
		t.Fatal("expected rotated device token to validate")
	}
}

func TestListCandidatesOnlyReturnsSameNetworkDevices(t *testing.T) {
	memStore := store.NewMemoryStore(model.RuntimeConfig{})
	deviceService := NewDeviceService(memStore, nil, nil)

	current, _ := deviceService.Register(RegisterDeviceInput{
		DeviceID:        "current",
		Name:            "Current",
		Type:            "desktop",
		NetworkGroupKey: "192.168.1.10",
	}, "ua/1.0", "")

	sameNetwork, _ := deviceService.Register(RegisterDeviceInput{
		DeviceID:        "same-network",
		Name:            "Same Network",
		Type:            "phone",
		NetworkGroupKey: "192.168.1.10",
	}, "ua/1.0", "")

	_, _ = deviceService.Register(RegisterDeviceInput{
		DeviceID:        "other-network",
		Name:            "Other Network",
		Type:            "phone",
		NetworkGroupKey: "10.0.0.5",
	}, "ua/1.0", "")

	candidates := deviceService.ListCandidates(current.ID)
	if len(candidates) != 1 {
		t.Fatalf("expected 1 same-network candidate, got %d", len(candidates))
	}
	if candidates[0].ID != sameNetwork.ID {
		t.Fatalf("expected candidate %q, got %q", sameNetwork.ID, candidates[0].ID)
	}
}

func TestListCandidatesReturnsEmptyWithoutNetworkGroupKey(t *testing.T) {
	memStore := store.NewMemoryStore(model.RuntimeConfig{})
	deviceService := NewDeviceService(memStore, nil, nil)

	current, _ := deviceService.Register(RegisterDeviceInput{
		DeviceID: "current",
		Name:     "Current",
		Type:     "desktop",
	}, "ua/1.0", "")

	_, _ = deviceService.Register(RegisterDeviceInput{
		DeviceID:        "same-network",
		Name:            "Same Network",
		Type:            "phone",
		NetworkGroupKey: "192.168.1.10",
	}, "ua/1.0", "")

	candidates := deviceService.ListCandidates(current.ID)
	if len(candidates) != 0 {
		t.Fatalf("expected no candidates without a local network group key, got %d", len(candidates))
	}
}