package webserver

import (
	"context"
	"fmt"
	"net"
	"net/http"
	"net/http/httptest"
	"net/url"
	"strings"
	"testing"

	"google.golang.org/grpc"
	"google.golang.org/grpc/codes"
	"google.golang.org/grpc/credentials/insecure"
	"google.golang.org/grpc/status"

	mcrv1 "git.wntrmute.dev/kyle/mcr/gen/mcr/v1"
)

// fakeRegistryService implements RegistryServiceServer for testing.
type fakeRegistryService struct {
	mcrv1.UnimplementedRegistryServiceServer
	repos    []*mcrv1.RepositoryMetadata
	repoResp *mcrv1.GetRepositoryResponse
	repoErr  error
}

func (f *fakeRegistryService) ListRepositories(_ context.Context, _ *mcrv1.ListRepositoriesRequest) (*mcrv1.ListRepositoriesResponse, error) {
	return &mcrv1.ListRepositoriesResponse{Repositories: f.repos}, nil
}

func (f *fakeRegistryService) GetRepository(_ context.Context, req *mcrv1.GetRepositoryRequest) (*mcrv1.GetRepositoryResponse, error) {
	if f.repoErr != nil {
		return nil, f.repoErr
	}
	if f.repoResp != nil {
		return f.repoResp, nil
	}
	return &mcrv1.GetRepositoryResponse{Name: req.GetName()}, nil
}

// fakePolicyService implements PolicyServiceServer for testing.
type fakePolicyService struct {
	mcrv1.UnimplementedPolicyServiceServer
	rules   []*mcrv1.PolicyRule
	created *mcrv1.PolicyRule
}

func (f *fakePolicyService) ListPolicyRules(_ context.Context, _ *mcrv1.ListPolicyRulesRequest) (*mcrv1.ListPolicyRulesResponse, error) {
	return &mcrv1.ListPolicyRulesResponse{Rules: f.rules}, nil
}

func (f *fakePolicyService) CreatePolicyRule(_ context.Context, req *mcrv1.CreatePolicyRuleRequest) (*mcrv1.PolicyRule, error) {
	rule := &mcrv1.PolicyRule{
		Id:           1,
		Priority:     req.GetPriority(),
		Description:  req.GetDescription(),
		Effect:       req.GetEffect(),
		Actions:      req.GetActions(),
		Repositories: req.GetRepositories(),
		Enabled:      req.GetEnabled(),
	}
	f.created = rule
	return rule, nil
}

func (f *fakePolicyService) GetPolicyRule(_ context.Context, req *mcrv1.GetPolicyRuleRequest) (*mcrv1.PolicyRule, error) {
	for _, r := range f.rules {
		if r.GetId() == req.GetId() {
			return r, nil
		}
	}
	return nil, status.Errorf(codes.NotFound, "policy rule not found")
}

func (f *fakePolicyService) UpdatePolicyRule(_ context.Context, req *mcrv1.UpdatePolicyRuleRequest) (*mcrv1.PolicyRule, error) {
	for _, r := range f.rules {
		if r.GetId() == req.GetId() {
			r.Enabled = req.GetEnabled()
			return r, nil
		}
	}
	return nil, status.Errorf(codes.NotFound, "policy rule not found")
}

func (f *fakePolicyService) DeletePolicyRule(_ context.Context, req *mcrv1.DeletePolicyRuleRequest) (*mcrv1.DeletePolicyRuleResponse, error) {
	for i, r := range f.rules {
		if r.GetId() == req.GetId() {
			f.rules = append(f.rules[:i], f.rules[i+1:]...)
			return &mcrv1.DeletePolicyRuleResponse{}, nil
		}
	}
	return nil, status.Errorf(codes.NotFound, "policy rule not found")
}

// fakeAuditService implements AuditServiceServer for testing.
type fakeAuditService struct {
	mcrv1.UnimplementedAuditServiceServer
	events []*mcrv1.AuditEvent
}

func (f *fakeAuditService) ListAuditEvents(_ context.Context, _ *mcrv1.ListAuditEventsRequest) (*mcrv1.ListAuditEventsResponse, error) {
	return &mcrv1.ListAuditEventsResponse{Events: f.events}, nil
}

// fakeAdminService implements AdminServiceServer for testing.
type fakeAdminService struct {
	mcrv1.UnimplementedAdminServiceServer
}

func (f *fakeAdminService) Health(_ context.Context, _ *mcrv1.HealthRequest) (*mcrv1.HealthResponse, error) {
	return &mcrv1.HealthResponse{Status: "ok"}, nil
}

// testEnv holds a test server and its dependencies.
type testEnv struct {
	server     *Server
	grpcServer *grpc.Server
	grpcConn   *grpc.ClientConn
	registry   *fakeRegistryService
	policyFake *fakePolicyService
	auditFake  *fakeAuditService
}

func (e *testEnv) close() {
	_ = e.grpcConn.Close()
	e.grpcServer.Stop()
}

// setupTestEnv creates a test environment with fake gRPC backends.
func setupTestEnv(t *testing.T) *testEnv {
	t.Helper()

	registrySvc := &fakeRegistryService{
		repos: []*mcrv1.RepositoryMetadata{
			{Name: "library/nginx", TagCount: 3, ManifestCount: 2, TotalSize: 1024 * 1024, CreatedAt: "2024-01-15T10:00:00Z"},
			{Name: "library/alpine", TagCount: 1, ManifestCount: 1, TotalSize: 512 * 1024, CreatedAt: "2024-01-16T10:00:00Z"},
		},
	}
	policySvc := &fakePolicyService{
		rules: []*mcrv1.PolicyRule{
			{Id: 1, Priority: 100, Description: "Allow all pulls", Effect: "allow", Actions: []string{"pull"}, Repositories: []string{"*"}, Enabled: true},
		},
	}
	auditSvc := &fakeAuditService{
		events: []*mcrv1.AuditEvent{
			{Id: 1, EventTime: "2024-01-15T12:00:00Z", EventType: "manifest_pushed", ActorId: "user1", Repository: "library/nginx", Digest: "sha256:abc123", IpAddress: "10.0.0.1"},
		},
	}
	adminSvc := &fakeAdminService{}

	// Start in-process gRPC server.
	gs := grpc.NewServer()
	mcrv1.RegisterRegistryServiceServer(gs, registrySvc)
	mcrv1.RegisterPolicyServiceServer(gs, policySvc)
	mcrv1.RegisterAuditServiceServer(gs, auditSvc)
	mcrv1.RegisterAdminServiceServer(gs, adminSvc)

	lis, err := net.Listen("tcp", "127.0.0.1:0")
	if err != nil {
		t.Fatalf("listen: %v", err)
	}

	go func() {
		_ = gs.Serve(lis)
	}()

	// Connect client.
	conn, err := grpc.NewClient(
		lis.Addr().String(),
		grpc.WithTransportCredentials(insecure.NewCredentials()),
		grpc.WithDefaultCallOptions(grpc.ForceCodecV2(mcrv1.JSONCodec{})),
	)
	if err != nil {
		gs.Stop()
		t.Fatalf("dial: %v", err)
	}

	csrfKey := []byte("test-csrf-key-32-bytes-long!1234")

	loginFn := func(username, password string) (string, int, error) {
		if username == "admin" && password == "secret" {
			return "test-token-12345", 3600, nil
		}
		return "", 0, fmt.Errorf("invalid credentials")
	}

	srv, err := New(
		mcrv1.NewRegistryServiceClient(conn),
		mcrv1.NewPolicyServiceClient(conn),
		mcrv1.NewAuditServiceClient(conn),
		mcrv1.NewAdminServiceClient(conn),
		loginFn,
		csrfKey,
	)
	if err != nil {
		_ = conn.Close()
		gs.Stop()
		t.Fatalf("create server: %v", err)
	}

	return &testEnv{
		server:     srv,
		grpcServer: gs,
		grpcConn:   conn,
		registry:   registrySvc,
		policyFake: policySvc,
		auditFake:  auditSvc,
	}
}

func TestLoginPageRenders(t *testing.T) {
	env := setupTestEnv(t)
	defer env.close()

	req := httptest.NewRequest(http.MethodGet, "/login", nil)
	rec := httptest.NewRecorder()

	env.server.Handler().ServeHTTP(rec, req)

	if rec.Code != http.StatusOK {
		t.Fatalf("GET /login: status %d, want %d", rec.Code, http.StatusOK)
	}

	body := rec.Body.String()
	if !strings.Contains(body, "MCR Login") {
		t.Error("login page does not contain 'MCR Login'")
	}
	if !strings.Contains(body, "_csrf") {
		t.Error("login page does not contain CSRF token field")
	}
}

func TestLoginInvalidCredentials(t *testing.T) {
	env := setupTestEnv(t)
	defer env.close()

	// First get a CSRF token.
	getReq := httptest.NewRequest(http.MethodGet, "/login", nil)
	getRec := httptest.NewRecorder()
	env.server.Handler().ServeHTTP(getRec, getReq)

	// Extract CSRF cookie and token.
	var csrfCookie *http.Cookie
	for _, c := range getRec.Result().Cookies() {
		if c.Name == "csrf_token" {
			csrfCookie = c
			break
		}
	}
	if csrfCookie == nil {
		t.Fatal("no csrf_token cookie set")
	}

	// Extract the CSRF token from the cookie value (token.signature).
	parts := strings.SplitN(csrfCookie.Value, ".", 2)
	csrfToken := parts[0]

	// Submit login with wrong credentials.
	form := url.Values{
		"username": {"baduser"},
		"password": {"badpass"},
		"_csrf":    {csrfToken},
	}

	postReq := httptest.NewRequest(http.MethodPost, "/login", strings.NewReader(form.Encode()))
	postReq.Header.Set("Content-Type", "application/x-www-form-urlencoded")
	postReq.AddCookie(csrfCookie)
	postRec := httptest.NewRecorder()

	env.server.Handler().ServeHTTP(postRec, postReq)

	if postRec.Code != http.StatusOK {
		t.Fatalf("POST /login: status %d, want %d", postRec.Code, http.StatusOK)
	}

	body := postRec.Body.String()
	if !strings.Contains(body, "Invalid username or password") {
		t.Error("response does not contain error message for invalid credentials")
	}
}

func TestDashboardRequiresSession(t *testing.T) {
	env := setupTestEnv(t)
	defer env.close()

	req := httptest.NewRequest(http.MethodGet, "/", nil)
	rec := httptest.NewRecorder()

	env.server.Handler().ServeHTTP(rec, req)

	if rec.Code != http.StatusSeeOther {
		t.Fatalf("GET / without session: status %d, want %d", rec.Code, http.StatusSeeOther)
	}

	loc := rec.Header().Get("Location")
	if loc != "/login" {
		t.Fatalf("redirect location: got %q, want /login", loc)
	}
}

func TestDashboardWithSession(t *testing.T) {
	env := setupTestEnv(t)
	defer env.close()

	req := httptest.NewRequest(http.MethodGet, "/", nil)
	req.AddCookie(&http.Cookie{Name: "mcr_session", Value: "test-token"})
	rec := httptest.NewRecorder()

	env.server.Handler().ServeHTTP(rec, req)

	if rec.Code != http.StatusOK {
		t.Fatalf("GET / with session: status %d, want %d", rec.Code, http.StatusOK)
	}

	body := rec.Body.String()
	if !strings.Contains(body, "Dashboard") {
		t.Error("dashboard page does not contain 'Dashboard'")
	}
	if !strings.Contains(body, "Repositories") {
		t.Error("dashboard page does not show repository count")
	}
}

func TestRepositoriesPageRenders(t *testing.T) {
	env := setupTestEnv(t)
	defer env.close()

	req := httptest.NewRequest(http.MethodGet, "/repositories", nil)
	req.AddCookie(&http.Cookie{Name: "mcr_session", Value: "test-token"})
	rec := httptest.NewRecorder()

	env.server.Handler().ServeHTTP(rec, req)

	if rec.Code != http.StatusOK {
		t.Fatalf("GET /repositories: status %d, want %d", rec.Code, http.StatusOK)
	}

	body := rec.Body.String()
	if !strings.Contains(body, "library/nginx") {
		t.Error("repositories page does not contain 'library/nginx'")
	}
	if !strings.Contains(body, "library/alpine") {
		t.Error("repositories page does not contain 'library/alpine'")
	}
}

func TestRepositoryDetailRenders(t *testing.T) {
	env := setupTestEnv(t)
	defer env.close()

	env.registry.repoResp = &mcrv1.GetRepositoryResponse{
		Name:      "library/nginx",
		TotalSize: 2048,
		Tags: []*mcrv1.TagInfo{
			{Name: "latest", Digest: "sha256:abc123def456"},
		},
		Manifests: []*mcrv1.ManifestInfo{
			{Digest: "sha256:abc123def456", MediaType: "application/vnd.oci.image.manifest.v1+json", Size: 2048, CreatedAt: "2024-01-15T10:00:00Z"},
		},
	}

	req := httptest.NewRequest(http.MethodGet, "/repositories/library/nginx", nil)
	req.AddCookie(&http.Cookie{Name: "mcr_session", Value: "test-token"})
	rec := httptest.NewRecorder()

	env.server.Handler().ServeHTTP(rec, req)

	if rec.Code != http.StatusOK {
		t.Fatalf("GET /repositories/library/nginx: status %d, want %d", rec.Code, http.StatusOK)
	}

	body := rec.Body.String()
	if !strings.Contains(body, "library/nginx") {
		t.Error("repository detail page does not contain repo name")
	}
	if !strings.Contains(body, "latest") {
		t.Error("repository detail page does not contain tag 'latest'")
	}
}

func TestCSRFTokenValidation(t *testing.T) {
	env := setupTestEnv(t)
	defer env.close()

	// POST without CSRF token should fail.
	form := url.Values{
		"username": {"admin"},
		"password": {"secret"},
	}

	req := httptest.NewRequest(http.MethodPost, "/login", strings.NewReader(form.Encode()))
	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
	rec := httptest.NewRecorder()

	env.server.Handler().ServeHTTP(rec, req)

	body := rec.Body.String()
	// Should show the error about invalid form submission.
	if !strings.Contains(body, "Invalid or expired form submission") {
		t.Error("POST without CSRF token should show error, got: " + body[:min(200, len(body))])
	}
}

func TestLogout(t *testing.T) {
	env := setupTestEnv(t)
	defer env.close()

	req := httptest.NewRequest(http.MethodGet, "/logout", nil)
	req.AddCookie(&http.Cookie{Name: "mcr_session", Value: "test-token"})
	rec := httptest.NewRecorder()

	env.server.Handler().ServeHTTP(rec, req)

	if rec.Code != http.StatusSeeOther {
		t.Fatalf("GET /logout: status %d, want %d", rec.Code, http.StatusSeeOther)
	}

	loc := rec.Header().Get("Location")
	if loc != "/login" {
		t.Fatalf("redirect location: got %q, want /login", loc)
	}

	// Verify session cookie is cleared.
	var sessionCleared bool
	for _, c := range rec.Result().Cookies() {
		if c.Name == "mcr_session" && c.MaxAge < 0 {
			sessionCleared = true
			break
		}
	}
	if !sessionCleared {
		t.Error("session cookie was not cleared on logout")
	}
}

func TestPoliciesPage(t *testing.T) {
	env := setupTestEnv(t)
	defer env.close()

	req := httptest.NewRequest(http.MethodGet, "/policies", nil)
	req.AddCookie(&http.Cookie{Name: "mcr_session", Value: "test-token"})
	rec := httptest.NewRecorder()

	env.server.Handler().ServeHTTP(rec, req)

	if rec.Code != http.StatusOK {
		t.Fatalf("GET /policies: status %d, want %d", rec.Code, http.StatusOK)
	}

	body := rec.Body.String()
	if !strings.Contains(body, "Allow all pulls") {
		t.Error("policies page does not contain policy description")
	}
}

func TestAuditPage(t *testing.T) {
	env := setupTestEnv(t)
	defer env.close()

	req := httptest.NewRequest(http.MethodGet, "/audit", nil)
	req.AddCookie(&http.Cookie{Name: "mcr_session", Value: "test-token"})
	rec := httptest.NewRecorder()

	env.server.Handler().ServeHTTP(rec, req)

	if rec.Code != http.StatusOK {
		t.Fatalf("GET /audit: status %d, want %d", rec.Code, http.StatusOK)
	}

	body := rec.Body.String()
	if !strings.Contains(body, "manifest_pushed") {
		t.Error("audit page does not contain event type")
	}
}

func TestStaticFiles(t *testing.T) {
	env := setupTestEnv(t)
	defer env.close()

	req := httptest.NewRequest(http.MethodGet, "/static/style.css", nil)
	rec := httptest.NewRecorder()

	env.server.Handler().ServeHTTP(rec, req)

	if rec.Code != http.StatusOK {
		t.Fatalf("GET /static/style.css: status %d, want %d", rec.Code, http.StatusOK)
	}

	body := rec.Body.String()
	if !strings.Contains(body, "font-family") {
		t.Error("style.css does not appear to contain CSS")
	}
}

func TestFormatSize(t *testing.T) {
	tests := []struct {
		input int64
		want  string
	}{
		{0, "0 B"},
		{512, "512 B"},
		{1024, "1.0 KiB"},
		{1048576, "1.0 MiB"},
		{1073741824, "1.0 GiB"},
		{1099511627776, "1.0 TiB"},
	}

	for _, tt := range tests {
		got := formatSize(tt.input)
		if got != tt.want {
			t.Errorf("formatSize(%d) = %q, want %q", tt.input, got, tt.want)
		}
	}
}

func TestFormatTime(t *testing.T) {
	got := formatTime("2024-01-15T10:30:00Z")
	want := "2024-01-15 10:30:00"
	if got != want {
		t.Errorf("formatTime = %q, want %q", got, want)
	}

	// Invalid time returns the input.
	got = formatTime("not-a-time")
	if got != "not-a-time" {
		t.Errorf("formatTime(invalid) = %q, want %q", got, "not-a-time")
	}
}

func TestTruncate(t *testing.T) {
	got := truncate("sha256:abc123def456", 12)
	want := "sha256:abc12..."
	if got != want {
		t.Errorf("truncate = %q, want %q", got, want)
	}

	// Short strings are not truncated.
	got = truncate("short", 10)
	if got != "short" {
		t.Errorf("truncate(short) = %q, want %q", got, "short")
	}
}

func TestLoginSuccessSetsCookie(t *testing.T) {
	env := setupTestEnv(t)
	defer env.close()

	// Get CSRF token.
	getReq := httptest.NewRequest(http.MethodGet, "/login", nil)
	getRec := httptest.NewRecorder()
	env.server.Handler().ServeHTTP(getRec, getReq)

	var csrfCookie *http.Cookie
	for _, c := range getRec.Result().Cookies() {
		if c.Name == "csrf_token" {
			csrfCookie = c
			break
		}
	}
	if csrfCookie == nil {
		t.Fatal("no csrf_token cookie")
	}

	parts := strings.SplitN(csrfCookie.Value, ".", 2)
	csrfToken := parts[0]

	form := url.Values{
		"username": {"admin"},
		"password": {"secret"},
		"_csrf":    {csrfToken},
	}

	postReq := httptest.NewRequest(http.MethodPost, "/login", strings.NewReader(form.Encode()))
	postReq.Header.Set("Content-Type", "application/x-www-form-urlencoded")
	postReq.AddCookie(csrfCookie)
	postRec := httptest.NewRecorder()

	env.server.Handler().ServeHTTP(postRec, postReq)

	if postRec.Code != http.StatusSeeOther {
		t.Fatalf("POST /login: status %d, want %d; body: %s", postRec.Code, http.StatusSeeOther, postRec.Body.String())
	}

	var sessionCookie *http.Cookie
	for _, c := range postRec.Result().Cookies() {
		if c.Name == "mcr_session" {
			sessionCookie = c
			break
		}
	}
	if sessionCookie == nil {
		t.Fatal("no mcr_session cookie set after login")
	}
	if sessionCookie.Value != "test-token-12345" {
		t.Errorf("session cookie value = %q, want %q", sessionCookie.Value, "test-token-12345")
	}
	if !sessionCookie.HttpOnly {
		t.Error("session cookie is not HttpOnly")
	}
	if !sessionCookie.Secure {
		t.Error("session cookie is not Secure")
	}
	if sessionCookie.SameSite != http.SameSiteStrictMode {
		t.Error("session cookie SameSite is not Strict")
	}
}