package api

import (
	"bytes"
	"encoding/base64"
	"encoding/json"
	"io"
	"net/http"
	"net/http/httptest"
	"path/filepath"
	"strings"
	"testing"

	"github.com/gin-gonic/gin"
	"github.com/google/uuid"
	"github.com/rs/zerolog"

	"kereru.forms/internal/database"
)

func newTestRouter(t *testing.T) (*gin.Engine, database.Store) {
	t.Helper()
	path := filepath.Join(t.TempDir(), "api-test.db")
	store, err := database.Open("sqlite", "file:"+path+"?_pragma=foreign_keys(1)")
	if err != nil {
		t.Fatalf("open database: %v", err)
	}
	t.Cleanup(func() { _ = store.Close() })

	server := NewServer(store, zerolog.Nop(), "test-version")
	router := NewRouter(server, zerolog.Nop(), RouterOptions{CORSOrigins: []string{"http://localhost:5173"}})
	return router, store
}

func doRequest(t *testing.T, router *gin.Engine, method, path string, body any) *httptest.ResponseRecorder {
	t.Helper()
	var reader io.Reader
	if body != nil {
		payload, err := json.Marshal(body)
		if err != nil {
			t.Fatalf("marshal request: %v", err)
		}
		reader = bytes.NewReader(payload)
	}
	req := httptest.NewRequest(method, path, reader)
	if body != nil {
		req.Header.Set("Content-Type", "application/json")
	}
	req.Header.Set("User-Agent", "kereru-test-agent")
	w := httptest.NewRecorder()
	router.ServeHTTP(w, req)
	return w
}

func decode[T any](t *testing.T, w *httptest.ResponseRecorder) T {
	t.Helper()
	var out T
	if err := json.Unmarshal(w.Body.Bytes(), &out); err != nil {
		t.Fatalf("decode response %q: %v", w.Body.String(), err)
	}
	return out
}

func boolPtr(b bool) *bool      { return &b }
func f32Ptr(f float32) *float32 { return &f }
func strPtr(s string) *string   { return &s }

func createSampleForm(t *testing.T, router *gin.Engine) Form {
	t.Helper()
	options := []QuestionOption{
		{Value: "red", Label: "Red"},
		{Value: "blue", Label: "Blue"},
	}
	body := CreateFormRequest{
		Title:              "Customer feedback",
		Description:        strPtr("A short survey"),
		Introduction:       strPtr("Thanks for helping us improve."),
		RequiresAccessCode: boolPtr(true),
		LogoUrl:            strPtr("https://example.com/logo.png"),
		Questions: []QuestionInput{
			{Key: "name", Label: "Your name", Type: Text, Required: true},
			{Key: "happy", Label: "Are you happy?", Type: Boolean, Required: true},
			{Key: "score", Label: "Score", Type: Number, MinValue: f32Ptr(1), MaxValue: f32Ptr(10)},
			{Key: "colour", Label: "Favourite colour", Type: Select, Options: &options},
			{Key: "when", Label: "Date", Type: Date},
		},
	}

	w := doRequest(t, router, http.MethodPost, "/forms", body)
	if w.Code != http.StatusCreated {
		t.Fatalf("create form: status %d body %s", w.Code, w.Body.String())
	}
	return decode[Form](t, w)
}

func TestHealth(t *testing.T) {
	router, _ := newTestRouter(t)
	for _, path := range []string{"/health", "/api/health"} {
		w := doRequest(t, router, http.MethodGet, path, nil)
		if w.Code != http.StatusOK {
			t.Fatalf("health %s: status %d", path, w.Code)
		}
		health := decode[Health](t, w)
		if health.Status != "ok" || health.Version != "test-version" {
			t.Fatalf("unexpected health: %+v", health)
		}
		if health.UptimeSeconds == nil {
			t.Fatal("uptimeSeconds should be present")
		}
	}
}

func TestFormLifecycle(t *testing.T) {
	router, _ := newTestRouter(t)
	form := createSampleForm(t, router)

	if form.Version != 1 || !form.IsActive || len(form.Questions) != 5 {
		t.Fatalf("unexpected form: %+v", form)
	}

	w := doRequest(t, router, http.MethodGet, "/forms/"+form.Id.String(), nil)
	if w.Code != http.StatusOK {
		t.Fatalf("get form: %d %s", w.Code, w.Body.String())
	}

	w = doRequest(t, router, http.MethodGet, "/forms", nil)
	if w.Code != http.StatusOK {
		t.Fatalf("list forms: %d", w.Code)
	}
	forms := decode[[]FormSummary](t, w)
	if len(forms) != 1 || forms[0].QuestionCount != 5 {
		t.Fatalf("unexpected forms: %+v", forms)
	}
	if forms[0].LogoUrl == nil || *forms[0].LogoUrl != "https://example.com/logo.png" {
		t.Fatalf("logo url missing from summary: %+v", forms[0])
	}

	w = doRequest(t, router, http.MethodPost, "/forms/"+form.Id.String()+"/access-codes",
		CreateAccessCodesRequest{Count: 2, Prefix: strPtr("demo")})
	if w.Code != http.StatusCreated {
		t.Fatalf("create codes: %d %s", w.Code, w.Body.String())
	}
	codes := decode[[]AccessCode](t, w)
	if len(codes) != 2 || !strings.HasPrefix(codes[0].Code, "DEMO-") {
		t.Fatalf("unexpected codes: %+v", codes)
	}

	w = doRequest(t, router, http.MethodPost, "/forms/"+form.Id.String()+"/inactivate", nil)
	if w.Code != http.StatusOK {
		t.Fatalf("inactivate: %d %s", w.Code, w.Body.String())
	}
	if inactive := decode[Form](t, w); inactive.IsActive {
		t.Fatal("form should be inactive")
	}

	w = doRequest(t, router, http.MethodPost, "/forms/"+form.Id.String()+"/activate", nil)
	if w.Code != http.StatusOK {
		t.Fatalf("activate: %d", w.Code)
	}

	w = doRequest(t, router, http.MethodPost, "/forms/"+form.Id.String()+"/versions", nil)
	if w.Code != http.StatusCreated {
		t.Fatalf("create version: %d %s", w.Code, w.Body.String())
	}
	v2 := decode[Form](t, w)
	if v2.Version != 2 || v2.FormGroupId != form.FormGroupId {
		t.Fatalf("unexpected version: %+v", v2)
	}
	if v2.LogoUrl == nil || *v2.LogoUrl != "https://example.com/logo.png" {
		t.Fatalf("new version should keep the logo: %+v", v2)
	}

	w = doRequest(t, router, http.MethodGet, "/forms/"+form.Id.String(), nil)
	old := decode[Form](t, w)
	if old.IsActive {
		t.Fatal("previous version should be inactive")
	}
}

func TestSubmitFlow(t *testing.T) {
	router, _ := newTestRouter(t)
	form := createSampleForm(t, router)

	byKey := map[string]Question{}
	for _, q := range form.Questions {
		byKey[q.Key] = q
	}
	answers := []Answer{
		{QuestionId: byKey["name"].Id, Value: "Ada"},
		{QuestionId: byKey["happy"].Id, Value: true},
		{QuestionId: byKey["score"].Id, Value: 8},
		{QuestionId: byKey["colour"].Id, Value: "blue"},
		{QuestionId: byKey["when"].Id, Value: "2026-10-23"},
	}

	w := doRequest(t, router, http.MethodPost, "/forms/"+form.Id.String()+"/access-codes",
		CreateAccessCodesRequest{Count: 1})
	if w.Code != http.StatusCreated {
		t.Fatalf("create code: %d", w.Code)
	}
	code := decode[[]AccessCode](t, w)[0].Code

	submit := SubmitFormRequest{
		UserId:     "ada@example.com",
		UserIdType: Email,
		Answers:    answers,
		Tracking:   &ClientTracking{Locale: strPtr("en-NZ")},
	}

	w = doRequest(t, router, http.MethodPost, "/forms/"+form.Id.String()+"/submissions", submit)
	if w.Code != http.StatusBadRequest {
		t.Fatalf("missing access code should be 400, got %d %s", w.Code, w.Body.String())
	}

	submit.AccessCode = &code
	w = doRequest(t, router, http.MethodPost, "/forms/"+form.Id.String()+"/submissions", submit)
	if w.Code != http.StatusCreated {
		t.Fatalf("submit: %d %s", w.Code, w.Body.String())
	}
	submission := decode[Submission](t, w)
	if submission.FormVersion != 1 || len(submission.Answers) != 5 {
		t.Fatalf("unexpected submission: %+v", submission)
	}
	var storedDate string
	for _, answer := range submission.Answers {
		if answer.QuestionKey == "when" {
			storedDate, _ = answer.Value.(string)
		}
	}
	if storedDate != "2026-10-23" {
		t.Fatalf("date answer not stored correctly: %+v", submission.Answers)
	}
	if submission.Tracking == nil || submission.Tracking.UserAgent == nil ||
		*submission.Tracking.UserAgent != "kereru-test-agent" {
		t.Fatalf("server-side tracking missing: %+v", submission.Tracking)
	}

	w = doRequest(t, router, http.MethodPost, "/forms/"+form.Id.String()+"/submissions", submit)
	if w.Code != http.StatusConflict {
		t.Fatalf("reused code should be 409, got %d %s", w.Code, w.Body.String())
	}

	w = doRequest(t, router, http.MethodGet, "/forms/"+form.Id.String()+"/submissions", nil)
	if w.Code != http.StatusOK {
		t.Fatalf("list submissions: %d", w.Code)
	}
	subs := decode[[]SubmissionSummary](t, w)
	if len(subs) != 1 || subs[0].Id != submission.Id {
		t.Fatalf("unexpected submissions: %+v", subs)
	}

	w = doRequest(t, router, http.MethodGet, "/submissions/"+submission.Id.String(), nil)
	if w.Code != http.StatusOK {
		t.Fatalf("get submission: %d", w.Code)
	}

	w = doRequest(t, router, http.MethodPost, "/forms/"+form.Id.String()+"/inactivate", nil)
	if w.Code != http.StatusOK {
		t.Fatalf("inactivate: %d", w.Code)
	}
	second := SubmitFormRequest{
		UserId:     "ada@example.com",
		UserIdType: Email,
		Answers:    answers,
	}
	w = doRequest(t, router, http.MethodPost, "/forms/"+form.Id.String()+"/submissions", second)
	if w.Code != http.StatusGone {
		t.Fatalf("inactive form should be 410, got %d %s", w.Code, w.Body.String())
	}
}

func TestSubmitValidation(t *testing.T) {
	router, _ := newTestRouter(t)
	form := createSampleForm(t, router)
	byKey := map[string]Question{}
	for _, q := range form.Questions {
		byKey[q.Key] = q
	}

	cases := []struct {
		name    string
		answers []Answer
	}{
		{
			name:    "missing required",
			answers: []Answer{{QuestionId: byKey["score"].Id, Value: 5}},
		},
		{
			name: "number out of range",
			answers: []Answer{
				{QuestionId: byKey["name"].Id, Value: "Ada"},
				{QuestionId: byKey["happy"].Id, Value: true},
				{QuestionId: byKey["score"].Id, Value: 42},
			},
		},
		{
			name: "bad select option",
			answers: []Answer{
				{QuestionId: byKey["name"].Id, Value: "Ada"},
				{QuestionId: byKey["happy"].Id, Value: true},
				{QuestionId: byKey["colour"].Id, Value: "green"},
			},
		},
		{
			name: "bad date",
			answers: []Answer{
				{QuestionId: byKey["name"].Id, Value: "Ada"},
				{QuestionId: byKey["happy"].Id, Value: true},
				{QuestionId: byKey["when"].Id, Value: "23/10/2026"},
			},
		},
		{
			name: "wrong type",
			answers: []Answer{
				{QuestionId: byKey["name"].Id, Value: "Ada"},
				{QuestionId: byKey["happy"].Id, Value: "yes"},
			},
		},
	}

	for _, tc := range cases {
		t.Run(tc.name, func(t *testing.T) {
			w := doRequest(t, router, http.MethodPost, "/forms/"+form.Id.String()+"/submissions",
				SubmitFormRequest{UserId: "ada@example.com", UserIdType: Email, Answers: tc.answers})
			if w.Code != http.StatusBadRequest {
				t.Fatalf("expected 400, got %d %s", w.Code, w.Body.String())
			}
		})
	}
}

func TestCreateFormValidation(t *testing.T) {
	router, _ := newTestRouter(t)
	options := []QuestionOption{{Value: "a", Label: "A"}}

	cases := []CreateFormRequest{
		{Title: "", Questions: []QuestionInput{{Key: "a", Label: "A", Type: Text}}},
		{Title: "Test", Questions: []QuestionInput{{Key: "1bad", Label: "A", Type: Text}}},
		{Title: "Test", Questions: []QuestionInput{{Key: "dup", Label: "A", Type: Text}, {Key: "dup", Label: "B", Type: Text}}},
		{Title: "Test", Questions: []QuestionInput{{Key: "a", Label: "A", Type: "datetime"}}},
		{Title: "Test", Questions: []QuestionInput{{Key: "a", Label: "A", Type: Select}}},
		{Title: "Test", Questions: []QuestionInput{{Key: "a", Label: "A", Type: Number, MinValue: f32Ptr(10), MaxValue: f32Ptr(1)}}},
		{Title: "Test", Questions: []QuestionInput{{Key: "a", Label: "A", Type: Select, Options: &options}, {Key: "a", Label: "B", Type: Text}}},
		{Title: "Test", Questions: []QuestionInput{{Key: "a", Label: "A", Type: Text}}, LogoUrl: strPtr("javascript:alert(1)")},
		{Title: "Test", Questions: []QuestionInput{{Key: "a", Label: "A", Type: Text}}, LogoUrl: strPtr("not a url")},
	}

	for i, body := range cases {
		w := doRequest(t, router, http.MethodPost, "/forms", body)
		if w.Code != http.StatusBadRequest {
			t.Fatalf("case %d: expected 400, got %d %s", i, w.Code, w.Body.String())
		}
	}
}

func TestPDFAndCORS(t *testing.T) {
	router, _ := newTestRouter(t)
	form := createSampleForm(t, router)

	w := doRequest(t, router, http.MethodGet, "/forms/"+form.Id.String()+"/pdf", nil)
	if w.Code != http.StatusOK {
		t.Fatalf("pdf: %d %s", w.Code, w.Body.String())
	}
	if ct := w.Header().Get("Content-Type"); ct != "application/pdf" {
		t.Fatalf("content type = %q", ct)
	}
	if !bytes.HasPrefix(w.Body.Bytes(), []byte("%PDF")) {
		t.Fatal("response is not a PDF")
	}

	req := httptest.NewRequest(http.MethodOptions, "/forms", nil)
	req.Header.Set("Origin", "http://localhost:5173")
	req.Header.Set("Access-Control-Request-Method", "POST")
	corsW := httptest.NewRecorder()
	router.ServeHTTP(corsW, req)
	if corsW.Code != http.StatusNoContent {
		t.Fatalf("preflight status = %d", corsW.Code)
	}
	if got := corsW.Header().Get("Access-Control-Allow-Origin"); got != "http://localhost:5173" {
		t.Fatalf("allow origin = %q", got)
	}
}

func TestNotFound(t *testing.T) {
	router, _ := newTestRouter(t)
	missing := uuid.NewString()

	for _, tc := range []struct {
		method string
		path   string
	}{
		{http.MethodGet, "/forms/" + missing},
		{http.MethodDelete, "/forms/" + missing},
		{http.MethodPost, "/forms/" + missing + "/inactivate"},
		{http.MethodGet, "/forms/" + missing + "/submissions"},
		{http.MethodGet, "/submissions/" + missing},
		{http.MethodGet, "/submissions/" + missing + "/offline-pdf"},
	} {
		w := doRequest(t, router, tc.method, tc.path, nil)
		if w.Code != http.StatusNotFound {
			t.Fatalf("%s %s: expected 404, got %d", tc.method, tc.path, w.Code)
		}
	}
}

func createSignatureForm(t *testing.T, router *gin.Engine) Form {
	t.Helper()
	body := CreateFormRequest{
		Title:             "Signed declaration",
		SignatureRequired: boolPtr(true),
		Questions: []QuestionInput{
			{Key: "name", Label: "Your name", Type: Text, Required: true},
		},
	}
	w := doRequest(t, router, http.MethodPost, "/forms", body)
	if w.Code != http.StatusCreated {
		t.Fatalf("create signature form: %d %s", w.Code, w.Body.String())
	}
	return decode[Form](t, w)
}

func pngDataURL() string {
	data := []byte{0x89, 'P', 'N', 'G', 0x0d, 0x0a, 0x1a, 0x0a}
	return "data:image/png;base64," + base64.StdEncoding.EncodeToString(data)
}

func pdfDataURL(data []byte) string {
	return "data:application/pdf;base64," + base64.StdEncoding.EncodeToString(data)
}

func TestUpdateFormCreatesVersion(t *testing.T) {
	router, _ := newTestRouter(t)
	form := createSampleForm(t, router)

	update := UpdateFormRequest{
		Title:                     "Customer feedback v2",
		PdfUrl:                    strPtr("https://example.com/prebuilt.pdf"),
		ExternalReferenceRequired: boolPtr(true),
		Questions: []QuestionInput{
			{Key: "name", Label: "Your name", Type: Text, Required: true},
		},
	}
	w := doRequest(t, router, http.MethodPut, "/forms/"+form.Id.String(), update)
	if w.Code != http.StatusOK {
		t.Fatalf("update form: %d %s", w.Code, w.Body.String())
	}
	updated := decode[Form](t, w)
	if updated.Id == form.Id {
		t.Fatal("editing should create a new form id")
	}
	if updated.Version != 2 || updated.FormGroupId != form.FormGroupId {
		t.Fatalf("unexpected versioned form: %+v", updated)
	}
	if updated.PdfUrl == nil || *updated.PdfUrl != "https://example.com/prebuilt.pdf" {
		t.Fatalf("pdf url not saved: %+v", updated.PdfUrl)
	}
	if updated.SignatureRequired == nil || *updated.SignatureRequired {
		t.Fatalf("signature flag should preserve false: %+v", updated.SignatureRequired)
	}
	if updated.ExternalReferenceRequired == nil || !*updated.ExternalReferenceRequired ||
		updated.ExternalReferenceLabel == nil || *updated.ExternalReferenceLabel != "External reference" {
		t.Fatalf("external reference was not enabled with a default label: %+v", updated)
	}
	if len(updated.Questions) != 1 || updated.Questions[0].Id.String() == "" {
		t.Fatalf("expected a fresh question: %+v", updated.Questions)
	}

	w = doRequest(t, router, http.MethodGet, "/forms/"+form.Id.String(), nil)
	if w.Code != http.StatusOK {
		t.Fatalf("get old form: %d", w.Code)
	}
	old := decode[Form](t, w)
	if old.IsActive {
		t.Fatal("previous version should be inactive")
	}

	w = doRequest(t, router, http.MethodGet, "/forms?includeInactive=true", nil)
	if w.Code != http.StatusOK {
		t.Fatalf("list forms: %d", w.Code)
	}
	forms := decode[[]FormSummary](t, w)
	if len(forms) != 2 {
		t.Fatalf("expected two versions, got %+v", forms)
	}
}

func TestExternalReference(t *testing.T) {
	router, _ := newTestRouter(t)
	body := CreateFormRequest{
		Title:                     "Invoice approval",
		ExternalReferenceRequired: boolPtr(true),
		ExternalReferenceLabel:    strPtr("Invoice number"),
		Questions: []QuestionInput{
			{Key: "note", Label: "Note", Type: Text, Required: true},
		},
	}
	w := doRequest(t, router, http.MethodPost, "/forms", body)
	if w.Code != http.StatusCreated {
		t.Fatalf("create form: %d %s", w.Code, w.Body.String())
	}
	form := decode[Form](t, w)
	if form.ExternalReferenceRequired == nil || !*form.ExternalReferenceRequired ||
		form.ExternalReferenceLabel == nil || *form.ExternalReferenceLabel != "Invoice number" {
		t.Fatalf("unexpected external reference config: %+v", form)
	}

	submit := SubmitFormRequest{
		UserId:     "ada@example.com",
		UserIdType: Email,
		Answers: []Answer{{
			QuestionId: form.Questions[0].Id,
			Value:      "Approved",
		}},
	}
	w = doRequest(t, router, http.MethodPost, "/forms/"+form.Id.String()+"/submissions", submit)
	if w.Code != http.StatusBadRequest {
		t.Fatalf("missing external reference should be 400, got %d %s", w.Code, w.Body.String())
	}

	submit.ExternalReference = strPtr("INV-42")
	w = doRequest(t, router, http.MethodPost, "/forms/"+form.Id.String()+"/submissions", submit)
	if w.Code != http.StatusCreated {
		t.Fatalf("submit with reference: %d %s", w.Code, w.Body.String())
	}
	submission := decode[Submission](t, w)
	if submission.ExternalReference == nil || *submission.ExternalReference != "INV-42" {
		t.Fatalf("external reference not returned: %+v", submission.ExternalReference)
	}

	w = doRequest(t, router, http.MethodGet, "/submissions/"+submission.Id.String(), nil)
	if w.Code != http.StatusOK {
		t.Fatalf("get submission: %d %s", w.Code, w.Body.String())
	}
	stored := decode[Submission](t, w)
	if stored.ExternalReference == nil || *stored.ExternalReference != "INV-42" {
		t.Fatalf("external reference not persisted: %+v", stored.ExternalReference)
	}

	w = doRequest(t, router, http.MethodGet, "/forms/"+form.Id.String()+"/submissions", nil)
	if w.Code != http.StatusOK {
		t.Fatalf("list submissions: %d %s", w.Code, w.Body.String())
	}
	summaries := decode[[]SubmissionSummary](t, w)
	if len(summaries) != 1 || summaries[0].ExternalReference == nil ||
		*summaries[0].ExternalReference != "INV-42" {
		t.Fatalf("reference missing from summary: %+v", summaries)
	}
}

func TestSignatureSubmission(t *testing.T) {
	router, _ := newTestRouter(t)
	form := createSignatureForm(t, router)
	questionID := form.Questions[0].Id

	base := SubmitFormRequest{
		UserId:     "ada@example.com",
		UserIdType: Email,
		Answers:    []Answer{{QuestionId: questionID, Value: "Ada"}},
	}

	w := doRequest(t, router, http.MethodPost, "/forms/"+form.Id.String()+"/submissions", base)
	if w.Code != http.StatusBadRequest {
		t.Fatalf("missing signature should be 400, got %d %s", w.Code, w.Body.String())
	}

	base.Signature = &SignatureInput{
		Type:    Drawn,
		DataUrl: pngDataURL(),
		Name:    "Ada Lovelace",
		Title:   strPtr("Analyst"),
	}
	w = doRequest(t, router, http.MethodPost, "/forms/"+form.Id.String()+"/submissions", base)
	if w.Code != http.StatusCreated {
		t.Fatalf("signed submission: %d %s", w.Code, w.Body.String())
	}
	submission := decode[Submission](t, w)
	if submission.Signature == nil || submission.Signature.Name != "Ada Lovelace" ||
		submission.Signature.Title == nil || *submission.Signature.Title != "Analyst" ||
		submission.Signature.SignedAt.IsZero() {
		t.Fatalf("signature not returned: %+v", submission.Signature)
	}

	w = doRequest(t, router, http.MethodGet, "/submissions/"+submission.Id.String(), nil)
	if w.Code != http.StatusOK {
		t.Fatalf("get submission: %d %s", w.Code, w.Body.String())
	}
	stored := decode[Submission](t, w)
	if stored.Signature == nil || stored.Signature.DataUrl != pngDataURL() {
		t.Fatalf("signature not persisted: %+v", stored.Signature)
	}

	base.Signature = &SignatureInput{Type: Drawn, DataUrl: pngDataURL(), Name: ""}
	w = doRequest(t, router, http.MethodPost, "/forms/"+form.Id.String()+"/submissions", base)
	if w.Code != http.StatusBadRequest {
		t.Fatalf("empty signature name should be 400, got %d %s", w.Code, w.Body.String())
	}
}

func TestOfflinePDFSubmission(t *testing.T) {
	router, _ := newTestRouter(t)
	form := createSignatureForm(t, router)
	pdf := []byte("%PDF-1.4\n1 0 obj\n<<>>\nendobj\ntrailer\n<<>>\n%%EOF\n")

	submit := SubmitFormRequest{
		UserId:         "ada@example.com",
		UserIdType:     Email,
		OfflinePdf:     strPtr(pdfDataURL(pdf)),
		OfflinePdfName: strPtr("signed-declaration.pdf"),
	}

	invalid := submit
	invalid.OfflinePdf = strPtr(pdfDataURL([]byte("not a pdf")))
	w := doRequest(t, router, http.MethodPost, "/forms/"+form.Id.String()+"/submissions", invalid)
	if w.Code != http.StatusBadRequest {
		t.Fatalf("invalid pdf should be 400, got %d %s", w.Code, w.Body.String())
	}

	w = doRequest(t, router, http.MethodPost, "/forms/"+form.Id.String()+"/submissions", submit)
	if w.Code != http.StatusCreated {
		t.Fatalf("offline submission: %d %s", w.Code, w.Body.String())
	}
	submission := decode[Submission](t, w)
	if len(submission.Answers) != 0 || submission.OfflinePdfName == nil ||
		*submission.OfflinePdfName != "signed-declaration.pdf" || submission.Signature != nil {
		t.Fatalf("unexpected offline submission: %+v", submission)
	}

	w = doRequest(t, router, http.MethodGet, "/submissions/"+submission.Id.String()+"/offline-pdf", nil)
	if w.Code != http.StatusOK {
		t.Fatalf("download offline pdf: %d %s", w.Code, w.Body.String())
	}
	if got := w.Header().Get("Content-Type"); got != "application/pdf" {
		t.Fatalf("content type = %q", got)
	}
	if got := w.Header().Get("Content-Disposition"); !strings.Contains(got, "signed-declaration.pdf") {
		t.Fatalf("content disposition = %q", got)
	}
	if !bytes.Equal(w.Body.Bytes(), pdf) {
		t.Fatalf("downloaded pdf differs from upload")
	}
}