package state

import (
	"net/netip"
	"testing"

	"github.com/juanfont/headscale/hscontrol/db"
	"github.com/juanfont/headscale/hscontrol/types"
	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
)

// persistTestSetup pre-creates a sqlite database on disk with a single
// registered node, then constructs a State that loads it. The on-disk
// path is returned so the test can close the State and re-open one
// against the same file to simulate a server restart. The caller owns
// the returned State and must Close it; persistTestReopen handles the
// second State's lifecycle for the restart simulation.
func persistTestSetup(t *testing.T) (string, *State, types.NodeID) {
	t.Helper()

	dbPath := t.TempDir() + "/headscale.db"
	cfg := persistTestConfig(dbPath)

	database, err := db.NewHeadscaleDatabase(cfg)
	require.NoError(t, err)

	user := database.CreateUserForTest("persist-user")
	node := database.CreateRegisteredNodeForTest(user, "persist-node")

	require.NoError(t, database.Close())

	s, err := NewState(cfg)
	require.NoError(t, err)

	return dbPath, s, node.ID
}

// persistTestReopen constructs a fresh State pointed at the same
// sqlite file and registers a cleanup to close it at the end of the
// test. Use it to simulate a server restart after the first State has
// been explicitly closed by the caller.
func persistTestReopen(t *testing.T, dbPath string) *State {
	t.Helper()

	s, err := NewState(persistTestConfig(dbPath))
	require.NoError(t, err)
	t.Cleanup(func() { _ = s.Close() })

	return s
}

func persistTestConfig(dbPath string) *types.Config {
	prefixV4 := netip.MustParsePrefix("100.64.0.0/10")
	prefixV6 := netip.MustParsePrefix("fd7a:115c:a1e0::/48")

	return &types.Config{
		Database: types.DatabaseConfig{
			Type: types.DatabaseSqlite,
			Sqlite: types.SqliteConfig{
				Path: dbPath,
			},
		},
		PrefixV4:     &prefixV4,
		PrefixV6:     &prefixV6,
		IPAllocation: types.IPAllocationStrategySequential,
		BaseDomain:   "headscale.test",
		Policy: types.PolicyConfig{
			Mode: types.PolicyModeDB,
		},
		Tuning: types.Tuning{
			NodeStoreBatchSize:    TestBatchSize,
			NodeStoreBatchTimeout: TestBatchTimeout,
		},
	}
}

// TestPersistEmptyApprovedRoutes covers the State.SetApprovedRoutes
// path. The gRPC handler builds the slice via append from a nil
// declaration, so when the operator passes `-r ""` the persist layer
// receives a nil []netip.Prefix. GORM's struct Updates skips nil
// slices, so the column would stay populated with the previously
// approved routes and a restart would re-apply them.
func TestPersistEmptyApprovedRoutes(t *testing.T) {
	dbPath, s, nodeID := persistTestSetup(t)

	route := netip.MustParsePrefix("10.0.0.0/8")

	_, _, err := s.SetApprovedRoutes(nodeID, []netip.Prefix{route})
	require.NoError(t, err)

	gotAfterApprove, err := s.DB().GetNodeByID(nodeID)
	require.NoError(t, err)
	require.Equal(t, []netip.Prefix{route}, gotAfterApprove.ApprovedRoutes.List(),
		"approved_routes should hold the seeded route")

	var noRoutes []netip.Prefix

	_, _, err = s.SetApprovedRoutes(nodeID, noRoutes)
	require.NoError(t, err)

	gotAfterClear, err := s.DB().GetNodeByID(nodeID)
	require.NoError(t, err)
	assert.Empty(t, gotAfterClear.ApprovedRoutes,
		"approved_routes should be empty after rejecting all routes, got %v",
		gotAfterClear.ApprovedRoutes)

	require.NoError(t, s.Close())

	s2 := persistTestReopen(t, dbPath)

	nv, ok := s2.GetNodeByID(nodeID)
	require.True(t, ok, "node should be loaded from DB after restart")
	assert.Empty(t, nv.AsStruct().ApprovedRoutes,
		"after restart, NodeStore should reflect the cleared routes")
}

// TestPersistEmptyTags exercises the same persist path for the tags
// column. State.SetNodeTags rejects an empty slice at the API level
// (tags are one-way), so the test drives the bug surface directly via
// NodeStore + persistNodeToDB, which is the same code path the public
// SetApprovedRoutes call exercises.
func TestPersistEmptyTags(t *testing.T) {
	dbPath, s, nodeID := persistTestSetup(t)

	_, ok := s.nodeStore.UpdateNode(nodeID, func(n *types.Node) {
		n.Tags = []string{"tag:test"}
	})
	require.True(t, ok)

	seeded, ok := s.nodeStore.GetNode(nodeID)
	require.True(t, ok)

	_, _, err := s.persistNodeToDB(seeded)
	require.NoError(t, err)

	gotAfterSeed, err := s.DB().GetNodeByID(nodeID)
	require.NoError(t, err)
	require.Equal(t, []string{"tag:test"}, gotAfterSeed.Tags.List(),
		"tags should hold the seeded value")

	cleared, ok := s.nodeStore.UpdateNode(nodeID, func(n *types.Node) {
		n.Tags = nil
	})
	require.True(t, ok)

	_, _, err = s.persistNodeToDB(cleared)
	require.NoError(t, err)

	gotAfterClear, err := s.DB().GetNodeByID(nodeID)
	require.NoError(t, err)
	assert.Empty(t, gotAfterClear.Tags,
		"tags should be empty after clear, got %v", gotAfterClear.Tags)

	require.NoError(t, s.Close())

	s2 := persistTestReopen(t, dbPath)

	nv, ok := s2.GetNodeByID(nodeID)
	require.True(t, ok)
	assert.Empty(t, nv.AsStruct().Tags,
		"after restart, NodeStore should reflect the cleared tags")
}

// TestPersistEmptyEndpoints covers the endpoints column. Endpoints
// arrive via MapRequest in production; the test reaches the persist
// layer directly because the bug is in serialization, not in
// upstream parsing.
func TestPersistEmptyEndpoints(t *testing.T) {
	dbPath, s, nodeID := persistTestSetup(t)

	endpoint := netip.MustParseAddrPort("198.51.100.1:41641")

	_, ok := s.nodeStore.UpdateNode(nodeID, func(n *types.Node) {
		n.Endpoints = []netip.AddrPort{endpoint}
	})
	require.True(t, ok)

	seeded, ok := s.nodeStore.GetNode(nodeID)
	require.True(t, ok)

	_, _, err := s.persistNodeToDB(seeded)
	require.NoError(t, err)

	gotAfterSeed, err := s.DB().GetNodeByID(nodeID)
	require.NoError(t, err)
	require.Equal(t, []netip.AddrPort{endpoint}, gotAfterSeed.Endpoints.List(),
		"endpoints should hold the seeded value")

	cleared, ok := s.nodeStore.UpdateNode(nodeID, func(n *types.Node) {
		n.Endpoints = nil
	})
	require.True(t, ok)

	_, _, err = s.persistNodeToDB(cleared)
	require.NoError(t, err)

	gotAfterClear, err := s.DB().GetNodeByID(nodeID)
	require.NoError(t, err)
	assert.Empty(t, gotAfterClear.Endpoints,
		"endpoints should be empty after clear, got %v", gotAfterClear.Endpoints)

	require.NoError(t, s.Close())

	s2 := persistTestReopen(t, dbPath)

	nv, ok := s2.GetNodeByID(nodeID)
	require.True(t, ok)
	assert.Empty(t, nv.AsStruct().Endpoints,
		"after restart, NodeStore should reflect the cleared endpoints")
}