package server

import (
	"bytes"
	"encoding/json"
	"fmt"
	"io"
	"log/slog"
	"mime"
	"mime/multipart"
	"net/http"
	"net/http/httptest"
	"os"
	"path/filepath"
	"strings"
	"testing"
	"time"

	"send/internal/auth"
	"send/internal/config"
	"send/internal/store"
)

// clock is the fixed instant tests start from; s.now is swapped so expiry can
// be exercised without sleeping.
var clock = time.Date(2026, 9, 12, 10, 0, 0, 0, time.UTC)

type harness struct {
	*Server
	ts    *httptest.Server
	dir   string
	now   time.Time
	token string // a token allowing vanity names
	admin string
}

func newHarness(t *testing.T, tweak func(*config.Config)) *harness {
	t.Helper()
	dir := t.TempDir()

	cfg := config.Config{}
	fs := config.NewSet("test", "SEND_TEST_")
	cfg.Register(fs)
	if err := fs.Parse(nil); err != nil {
		t.Fatal(err)
	}
	cfg.DataDir = dir
	cfg.MaxSize = 1 << 20
	cfg.MaxExpiry = 72 * time.Hour
	cfg.DefaultExpiry = 72 * time.Hour
	cfg.MinFreeBytes = 0
	cfg.UploadRate = 100000
	cfg.UploadBurst = 100000
	if tweak != nil {
		tweak(&cfg)
	}
	if err := cfg.Normalise(); err != nil {
		t.Fatal(err)
	}

	st, err := store.Open(cfg.DataDir)
	if err != nil {
		t.Fatal(err)
	}
	tokens, err := auth.Load(cfg.TokensPath)
	if err != nil {
		t.Fatal(err)
	}

	h := &harness{dir: dir, now: clock}
	for _, spec := range []struct {
		name  string
		admin bool
		dst   *string
	}{{"friend", false, &h.token}, {"boss", true, &h.admin}} {
		secret, err := store.NewSecret()
		if err != nil {
			t.Fatal(err)
		}
		if err := tokens.Add(&auth.Token{
			Name: spec.name, Hash: auth.HashSecret(secret),
			AllowVanity: true, Admin: spec.admin,
		}); err != nil {
			t.Fatal(err)
		}
		*spec.dst = secret
	}

	log := slog.New(slog.NewTextHandler(io.Discard, nil))
	srv, err := New(&cfg, st, tokens, log)
	if err != nil {
		t.Fatal(err)
	}
	srv.now = func() time.Time { return h.now }

	h.Server = srv
	h.ts = httptest.NewServer(srv)
	t.Cleanup(h.ts.Close)
	return h
}

// upload posts a raw body, the way curl does.
func (h *harness) upload(t *testing.T, body []byte, headers map[string]string) *http.Response {
	t.Helper()
	return h.uploadReader(t, bytes.NewReader(body), headers)
}

func (h *harness) uploadReader(t *testing.T, body io.Reader, headers map[string]string) *http.Response {
	t.Helper()
	req, err := http.NewRequest("POST", h.ts.URL+"/api/upload", body)
	if err != nil {
		t.Fatal(err)
	}
	req.Header.Set("Accept", "application/json")
	for k, v := range headers {
		req.Header.Set(k, v)
	}
	resp, err := h.ts.Client().Do(req)
	if err != nil {
		t.Fatal(err)
	}
	return resp
}

func decode[T any](t *testing.T, resp *http.Response) T {
	t.Helper()
	defer resp.Body.Close()
	var v T
	if err := json.NewDecoder(resp.Body).Decode(&v); err != nil {
		t.Fatalf("decoding %s response: %v", resp.Status, err)
	}
	return v
}

func TestRoundTrip(t *testing.T) {
	h := newHarness(t, nil)
	payload := bytes.Repeat([]byte("godot"), 4096)

	resp := h.upload(t, payload, map[string]string{
		"Content-Disposition": `attachment; filename="MyGame.zip"`,
	})
	if resp.StatusCode != http.StatusCreated {
		t.Fatalf("upload status = %s", resp.Status)
	}
	res := decode[uploadResult](t, resp)

	if res.Filename != "MyGame.zip" {
		t.Errorf("filename = %q, want MyGame.zip", res.Filename)
	}
	if res.Size != int64(len(payload)) {
		t.Errorf("size = %d, want %d", res.Size, len(payload))
	}
	if res.DeleteToken == "" {
		t.Error("no delete token returned")
	}

	get, err := h.ts.Client().Get(h.ts.URL + "/d/" + res.ID)
	if err != nil {
		t.Fatal(err)
	}
	defer get.Body.Close()
	got, _ := io.ReadAll(get.Body)
	if !bytes.Equal(got, payload) {
		t.Errorf("downloaded %d bytes, want %d", len(got), len(payload))
	}

	// An uploaded file must never come back as something a browser will run.
	if ct := get.Header.Get("Content-Type"); ct != "application/octet-stream" {
		t.Errorf("Content-Type = %q", ct)
	}
	if get.Header.Get("X-Content-Type-Options") != "nosniff" {
		t.Error("missing nosniff")
	}
	if !strings.Contains(get.Header.Get("Content-Security-Policy"), "sandbox") {
		t.Errorf("CSP = %q", get.Header.Get("Content-Security-Policy"))
	}
	disp, params, err := mime.ParseMediaType(get.Header.Get("Content-Disposition"))
	if err != nil || disp != "attachment" || params["filename"] != "MyGame.zip" {
		t.Errorf("Content-Disposition = %q (%v)", get.Header.Get("Content-Disposition"), err)
	}
}

func TestHTMLUploadIsServedInert(t *testing.T) {
	h := newHarness(t, nil)
	resp := h.upload(t, []byte("<script>alert(1)</script>"), map[string]string{
		"Content-Disposition": `attachment; filename="evil.html"`,
	})
	res := decode[uploadResult](t, resp)

	get, err := h.ts.Client().Get(h.ts.URL + "/d/" + res.ID)
	if err != nil {
		t.Fatal(err)
	}
	defer get.Body.Close()
	if ct := get.Header.Get("Content-Type"); ct != "application/octet-stream" {
		t.Errorf("HTML served as %q; it must never be text/html", ct)
	}
	if !strings.HasPrefix(get.Header.Get("Content-Disposition"), "attachment") {
		t.Error("HTML was not served as an attachment")
	}
}

func TestRangeRequest(t *testing.T) {
	h := newHarness(t, nil)
	payload := bytes.Repeat([]byte("abcdefgh"), 1024)
	res := decode[uploadResult](t, h.upload(t, payload, nil))

	req, _ := http.NewRequest("GET", h.ts.URL+"/d/"+res.ID, nil)
	req.Header.Set("Range", "bytes=0-1023")
	get, err := h.ts.Client().Do(req)
	if err != nil {
		t.Fatal(err)
	}
	defer get.Body.Close()
	if get.StatusCode != http.StatusPartialContent {
		t.Fatalf("status = %s, want 206", get.Status)
	}
	body, _ := io.ReadAll(get.Body)
	if len(body) != 1024 || !bytes.Equal(body, payload[:1024]) {
		t.Errorf("got %d bytes, want the first 1024", len(body))
	}
	if cr := get.Header.Get("Content-Range"); cr != fmt.Sprintf("bytes 0-1023/%d", len(payload)) {
		t.Errorf("Content-Range = %q", cr)
	}
}

// An oversized body must be refused on bytes actually written, never on a
// declared length. This sends a chunked body, so there is no Content-Length to
// consult even if the code wanted to.
func TestOversizeChunkedUploadIsRefused(t *testing.T) {
	h := newHarness(t, func(c *config.Config) { c.MaxSize = 4096 })

	// A plain io.Reader (not a *bytes.Buffer) makes the client use chunked
	// encoding with no declared length.
	body := io.LimitReader(zeroes{}, 1<<20)
	resp := h.uploadReader(t, struct{ io.Reader }{body}, nil)
	defer resp.Body.Close()
	if resp.StatusCode != http.StatusRequestEntityTooLarge {
		t.Fatalf("status = %s, want 413", resp.Status)
	}
	if n := h.store.Count(); n != 0 {
		t.Errorf("%d objects stored after a refused upload", n)
	}
	assertNoDebris(t, h.dir)
}

// A body one byte over the cap is refused; exactly at the cap is accepted.
func TestSizeLimitBoundary(t *testing.T) {
	h := newHarness(t, func(c *config.Config) { c.MaxSize = 1000 })

	resp := h.upload(t, bytes.Repeat([]byte("x"), 1000), nil)
	if resp.StatusCode != http.StatusCreated {
		t.Fatalf("exactly at the limit: status = %s, want 201", resp.Status)
	}
	resp.Body.Close()

	resp = h.upload(t, bytes.Repeat([]byte("x"), 1001), nil)
	defer resp.Body.Close()
	if resp.StatusCode != http.StatusRequestEntityTooLarge {
		t.Fatalf("one byte over: status = %s, want 413", resp.Status)
	}
}

type zeroes struct{}

func (zeroes) Read(p []byte) (int, error) { return len(p), nil }

func TestAnonymousCannotClaimVanity(t *testing.T) {
	h := newHarness(t, nil)
	resp := h.upload(t, []byte("hi"), map[string]string{"Vanity": "my-file"})
	defer resp.Body.Close()
	if resp.StatusCode != http.StatusForbidden {
		t.Fatalf("status = %s, want 403", resp.Status)
	}
	if h.store.Exists("my-file") {
		t.Error("the name was claimed despite the refusal")
	}
}

func TestVanityCollision(t *testing.T) {
	h := newHarness(t, nil)
	hdr := map[string]string{
		"Vanity":        "my-file",
		"Authorization": "Bearer " + h.token,
	}
	resp := h.upload(t, []byte("first"), hdr)
	if resp.StatusCode != http.StatusCreated {
		t.Fatalf("first upload: status = %s", resp.Status)
	}
	resp.Body.Close()

	resp = h.upload(t, []byte("second"), hdr)
	defer resp.Body.Close()
	if resp.StatusCode != http.StatusConflict {
		t.Fatalf("second upload: status = %s, want 409", resp.Status)
	}

	// The first object must be untouched.
	get, err := h.ts.Client().Get(h.ts.URL + "/d/my-file")
	if err != nil {
		t.Fatal(err)
	}
	defer get.Body.Close()
	body, _ := io.ReadAll(get.Body)
	if string(body) != "first" {
		t.Errorf("content = %q, want %q", body, "first")
	}
}

func TestUnknownTokenIsRejected(t *testing.T) {
	h := newHarness(t, nil)
	resp := h.upload(t, []byte("hi"), map[string]string{"Authorization": "Bearer nope"})
	defer resp.Body.Close()
	if resp.StatusCode != http.StatusUnauthorized {
		t.Fatalf("status = %s, want 401", resp.Status)
	}
}

// Expiry is enforced on read, not only by the sweeper, which never runs here.
func TestExpiryIsCheckedOnRead(t *testing.T) {
	h := newHarness(t, nil)
	res := decode[uploadResult](t, h.upload(t, []byte("ephemeral"), map[string]string{
		"Expiry": "1h",
	}))

	status := func(when time.Duration) int {
		h.now = clock.Add(when)
		get, err := h.ts.Client().Get(h.ts.URL + "/d/" + res.ID)
		if err != nil {
			t.Fatal(err)
		}
		get.Body.Close()
		return get.StatusCode
	}

	if got := status(59 * time.Minute); got != http.StatusOK {
		t.Fatalf("before expiry: status = %d, want 200", got)
	}
	if got := status(61 * time.Minute); got != http.StatusNotFound {
		t.Fatalf("after expiry: status = %d, want 404", got)
	}
	// The read path also reclaims the space.
	if _, err := os.Stat(filepath.Join(h.dir, "objects", res.ID)); !os.IsNotExist(err) {
		t.Error("expired object was not removed on read")
	}
}

func TestExpiryBeyondLimitIsRefused(t *testing.T) {
	h := newHarness(t, nil) // max 72h for anonymous
	for _, req := range []string{"30d", "never"} {
		resp := h.upload(t, []byte("hi"), map[string]string{"Expiry": req})
		if resp.StatusCode != http.StatusBadRequest {
			t.Errorf("Expiry: %s => status %s, want 400", req, resp.Status)
		}
		resp.Body.Close()
	}
}

func TestTokenMayOutliveTheAnonymousLimit(t *testing.T) {
	h := newHarness(t, nil)
	forever := "never"
	if err := h.tokens.Remove("friend"); err != nil {
		t.Fatal(err)
	}
	secret, _ := store.NewSecret()
	if err := h.tokens.Add(&auth.Token{
		Name: "friend", Hash: auth.HashSecret(secret),
		MaxExpiry: &forever, DefaultExpiry: &forever, AllowVanity: true,
	}); err != nil {
		t.Fatal(err)
	}
	res := decode[uploadResult](t, h.upload(t, []byte("keep me"), map[string]string{
		"Authorization": "Bearer " + secret,
		"Expiry":        "never",
	}))
	if res.Expires != "" {
		t.Errorf("expires = %q, want empty (never)", res.Expires)
	}
}

func TestPathTraversalIsRejected(t *testing.T) {
	h := newHarness(t, nil)

	// As a requested vanity name.
	for _, name := range []string{"../etc/passwd", "..", ".", "/absolute", "a/b", `a\b`, "ok..name"} {
		resp := h.upload(t, []byte("x"), map[string]string{
			"Vanity":        name,
			"Authorization": "Bearer " + h.token,
		})
		if resp.StatusCode == http.StatusCreated {
			t.Errorf("vanity %q was accepted", name)
		}
		resp.Body.Close()
	}

	// As a download path. Some of these are normalised away into a redirect to
	// the index, which is harmless; what matters is that no stored bytes are
	// ever served, so the check is for an object response rather than a status.
	for _, path := range []string{
		"/d/..%2f..%2fetc%2fpasswd", "/d/.", "/d/..", "/d/%2e%2e",
		"/d/../tokens.json", "/d/%2e%2e%2ftokens.json", "/d/objects",
	} {
		get, err := h.ts.Client().Get(h.ts.URL + path)
		if err != nil {
			continue // the client itself may refuse to send it, which is fine
		}
		get.Body.Close()
		if get.Header.Get("Content-Disposition") != "" {
			t.Errorf("GET %s served an object", path)
		}
	}
}

func TestReservedNamesAreRejected(t *testing.T) {
	h := newHarness(t, nil)
	for _, name := range []string{"api", "static", "d", "i", "robots.txt"} {
		resp := h.upload(t, []byte("x"), map[string]string{
			"Vanity":        name,
			"Authorization": "Bearer " + h.token,
		})
		if resp.StatusCode != http.StatusBadRequest {
			t.Errorf("vanity %q => %s, want 400", name, resp.Status)
		}
		resp.Body.Close()
	}
}

func TestDeleteRequiresTheRightToken(t *testing.T) {
	h := newHarness(t, nil)
	res := decode[uploadResult](t, h.upload(t, []byte("delete me"), nil))

	del := func(token string) int {
		form := strings.NewReader("token=" + token)
		req, _ := http.NewRequest("POST", h.ts.URL+"/api/d/"+res.ID+"/delete", form)
		req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
		req.Header.Set("Accept", "application/json")
		resp, err := h.ts.Client().Do(req)
		if err != nil {
			t.Fatal(err)
		}
		resp.Body.Close()
		return resp.StatusCode
	}

	if got := del("wrong-token"); got != http.StatusForbidden {
		t.Errorf("wrong token => %d, want 403", got)
	}
	if got := del(h.token); got != http.StatusForbidden {
		t.Errorf("a non-owning, non-admin token => %d, want 403", got)
	}
	if got := del(res.DeleteToken); got != http.StatusOK {
		t.Errorf("correct token => %d, want 200", got)
	}
	// The token is single-use because the object it names is gone.
	if got := del(res.DeleteToken); got != http.StatusNotFound {
		t.Errorf("reused token => %d, want 404", got)
	}
	assertNoDebris(t, h.dir)
}

func TestAdminMayDeleteAnything(t *testing.T) {
	h := newHarness(t, nil)
	res := decode[uploadResult](t, h.upload(t, []byte("someone else's"), nil))

	req, _ := http.NewRequest("POST", h.ts.URL+"/api/d/"+res.ID+"/delete", nil)
	req.Header.Set("Authorization", "Bearer "+h.admin)
	req.Header.Set("Accept", "application/json")
	resp, err := h.ts.Client().Do(req)
	if err != nil {
		t.Fatal(err)
	}
	resp.Body.Close()
	if resp.StatusCode != http.StatusOK {
		t.Fatalf("admin delete => %s, want 200", resp.Status)
	}
}

func TestMultipartUpload(t *testing.T) {
	h := newHarness(t, nil)

	var body bytes.Buffer
	mw := multipart.NewWriter(&body)
	// Order matters: the server needs these before the file part arrives.
	mw.WriteField("token", h.token)
	mw.WriteField("expiry", "2h")
	mw.WriteField("vanity", "from-the-form")
	fw, err := mw.CreateFormFile("file", "notes (draft).txt")
	if err != nil {
		t.Fatal(err)
	}
	fw.Write([]byte("hello from a browser"))
	mw.Close()

	req, _ := http.NewRequest("POST", h.ts.URL+"/api/upload", &body)
	req.Header.Set("Content-Type", mw.FormDataContentType())
	req.Header.Set("Accept", "application/json")
	resp, err := h.ts.Client().Do(req)
	if err != nil {
		t.Fatal(err)
	}
	if resp.StatusCode != http.StatusCreated {
		t.Fatalf("status = %s", resp.Status)
	}
	res := decode[uploadResult](t, resp)
	if res.ID != "from-the-form" {
		t.Errorf("id = %q, want from-the-form", res.ID)
	}
	if res.Filename != "notes (draft).txt" {
		t.Errorf("filename = %q", res.Filename)
	}
}

// A form post with no Accept: application/json gets the HTML success page, so
// the no-JS path works.
func TestFormPostRendersHTML(t *testing.T) {
	h := newHarness(t, nil)
	var body bytes.Buffer
	mw := multipart.NewWriter(&body)
	fw, _ := mw.CreateFormFile("file", "thing.bin")
	fw.Write([]byte("data"))
	mw.Close()

	req, _ := http.NewRequest("POST", h.ts.URL+"/api/upload", &body)
	req.Header.Set("Content-Type", mw.FormDataContentType())
	req.Header.Set("Accept", "text/html,application/xhtml+xml")
	resp, err := h.ts.Client().Do(req)
	if err != nil {
		t.Fatal(err)
	}
	defer resp.Body.Close()
	if ct := resp.Header.Get("Content-Type"); !strings.HasPrefix(ct, "text/html") {
		t.Fatalf("Content-Type = %q, want HTML", ct)
	}
	page, _ := io.ReadAll(resp.Body)
	if !strings.Contains(string(page), "Delete token") {
		t.Error("the success page does not show the delete token")
	}
}

func TestBasePathMounting(t *testing.T) {
	h := newHarness(t, func(c *config.Config) { c.BasePath = "/send" })

	get, err := h.ts.Client().Get(h.ts.URL + "/send/")
	if err != nil {
		t.Fatal(err)
	}
	defer get.Body.Close()
	if get.StatusCode != http.StatusOK {
		t.Fatalf("GET /send/ => %s", get.Status)
	}
	page, _ := io.ReadAll(get.Body)
	if !strings.Contains(string(page), `href="/send/static/style.css"`) {
		t.Error("page links do not carry the base path")
	}

	// The bare prefix redirects to the slashed form.
	noRedirect := *h.ts.Client()
	noRedirect.CheckRedirect = func(*http.Request, []*http.Request) error {
		return http.ErrUseLastResponse
	}
	resp, err := noRedirect.Get(h.ts.URL + "/send")
	if err != nil {
		t.Fatal(err)
	}
	resp.Body.Close()
	if resp.StatusCode != http.StatusMovedPermanently {
		t.Errorf("GET /send => %s, want 301", resp.Status)
	}
}

// An upload that dies mid-flight must leave nothing visible behind, and the
// sweeper must eventually reclaim the directory.
func TestAbandonedUploadIsInvisibleAndSwept(t *testing.T) {
	h := newHarness(t, nil)

	up, err := h.store.Reserve("half-done")
	if err != nil {
		t.Fatal(err)
	}
	up.Write([]byte("partial"))
	// Deliberately no Commit and no Abort: this is what a killed process leaves.

	get, err := h.ts.Client().Get(h.ts.URL + "/d/half-done")
	if err != nil {
		t.Fatal(err)
	}
	get.Body.Close()
	if get.StatusCode != http.StatusNotFound {
		t.Errorf("an uncommitted object was visible: %s", get.Status)
	}

	dir := filepath.Join(h.dir, "objects", "half-done")
	old := clock.Add(-48 * time.Hour)
	if err := os.Chtimes(dir, old, old); err != nil {
		t.Fatal(err)
	}
	h.store.Sweep(clock)
	if _, err := os.Stat(dir); !os.IsNotExist(err) {
		t.Error("abandoned upload directory was not swept")
	}
}

func TestQuotaRefusesUploads(t *testing.T) {
	h := newHarness(t, func(c *config.Config) { c.MaxTotalBytes = 100 })

	resp := h.upload(t, bytes.Repeat([]byte("x"), 80), nil)
	if resp.StatusCode != http.StatusCreated {
		t.Fatalf("first upload => %s", resp.Status)
	}
	resp.Body.Close()

	// Only 20 bytes of quota remain, so this is truncated to the remainder and
	// refused rather than allowed to overshoot.
	resp = h.upload(t, bytes.Repeat([]byte("x"), 80), nil)
	defer resp.Body.Close()
	if resp.StatusCode != http.StatusRequestEntityTooLarge {
		t.Fatalf("over quota => %s, want 413", resp.Status)
	}
}

func TestRateLimit(t *testing.T) {
	h := newHarness(t, func(c *config.Config) {
		c.UploadRate = 1
		c.UploadBurst = 2
	})
	var last *http.Response
	for range 3 {
		if last != nil {
			last.Body.Close()
		}
		last = h.upload(t, []byte("x"), nil)
	}
	defer last.Body.Close()
	if last.StatusCode != http.StatusTooManyRequests {
		t.Fatalf("third upload => %s, want 429", last.Status)
	}
}

// assertNoDebris checks that no object directory was left behind.
func assertNoDebris(t *testing.T, dir string) {
	t.Helper()
	entries, err := os.ReadDir(filepath.Join(dir, "objects"))
	if err != nil {
		t.Fatal(err)
	}
	for _, e := range entries {
		t.Errorf("leftover object directory: %s", e.Name())
	}
}

// --- remembered tokens ---------------------------------------------------

// A browser form post that carries a token and the remember box gets a cookie
// back, and that cookie then authenticates later uploads on its own.
func TestTokenIsRememberedInACookie(t *testing.T) {
	h := newHarness(t, nil)

	resp := h.formUpload(t, map[string]string{"token": h.token, "remember": "1"}, "a.bin", "one")
	if resp.StatusCode != http.StatusCreated {
		t.Fatalf("status = %s", resp.Status)
	}
	resp.Body.Close()

	cookie := findCookie(resp, tokenCookie)
	if cookie == nil {
		t.Fatal("no token cookie was set")
	}
	if cookie.Value != h.token {
		t.Error("the cookie does not hold the token")
	}
	if !cookie.HttpOnly {
		t.Error("the token cookie is readable by scripts")
	}
	if cookie.SameSite != http.SameSiteStrictMode {
		t.Error("the token cookie is not SameSite=Strict, so it is CSRF-exposed")
	}

	// The cookie alone is now enough to claim a vanity name, which anonymous
	// callers cannot do.
	req, _ := http.NewRequest("POST", h.ts.URL+"/api/upload", strings.NewReader("two"))
	req.Header.Set("Accept", "application/json")
	req.Header.Set("Vanity", "remembered")
	req.AddCookie(cookie)
	resp, err := h.ts.Client().Do(req)
	if err != nil {
		t.Fatal(err)
	}
	if resp.StatusCode != http.StatusCreated {
		t.Fatalf("upload with only the cookie: status = %s", resp.Status)
	}
	if res := decode[uploadResult](t, resp); res.ID != "remembered" {
		t.Errorf("id = %q, want remembered", res.ID)
	}
}

// A typed token wins over whatever the browser remembered.
func TestExplicitTokenBeatsTheCookie(t *testing.T) {
	h := newHarness(t, nil)
	resp := h.formUpload(t, map[string]string{"token": h.token, "remember": "1"}, "a.bin", "x")
	cookie := findCookie(resp, tokenCookie)
	resp.Body.Close()

	resp = h.formUploadWith(t, cookie, map[string]string{"token": h.admin, "remember": "1"}, "b.bin", "y")
	defer resp.Body.Close()
	res := decode[uploadResult](t, resp)

	m, err := h.store.Get(res.ID, h.now)
	if err != nil {
		t.Fatal(err)
	}
	if m.Owner != "boss" {
		t.Errorf("owner = %q, want boss: the cookie shadowed the typed token", m.Owner)
	}
}

// Leaving the box unchecked clears a token the browser had remembered.
func TestUncheckingRememberForgetsTheCookie(t *testing.T) {
	h := newHarness(t, nil)
	resp := h.formUpload(t, map[string]string{"token": h.token, "remember": "1"}, "a.bin", "x")
	cookie := findCookie(resp, tokenCookie)
	resp.Body.Close()

	resp = h.formUploadWith(t, cookie, map[string]string{}, "b.bin", "y")
	defer resp.Body.Close()
	cleared := findCookie(resp, tokenCookie)
	if cleared == nil || cleared.MaxAge >= 0 {
		t.Fatalf("the cookie was not cleared: %v", cleared)
	}
}

func TestForgetEndpointClearsTheCookie(t *testing.T) {
	h := newHarness(t, nil)
	req, _ := http.NewRequest("POST", h.ts.URL+"/api/forget", nil)
	req.Header.Set("Accept", "application/json")
	req.AddCookie(&http.Cookie{Name: tokenCookie, Value: h.token})
	resp, err := h.ts.Client().Do(req)
	if err != nil {
		t.Fatal(err)
	}
	defer resp.Body.Close()
	c := findCookie(resp, tokenCookie)
	if c == nil || c.MaxAge >= 0 || c.Value != "" {
		t.Fatalf("the cookie was not cleared: %v", c)
	}
}

// A revoked token left in a cookie must not wedge the page.
func TestStaleCookieIsDropped(t *testing.T) {
	h := newHarness(t, nil)
	req, _ := http.NewRequest("GET", h.ts.URL+"/", nil)
	req.AddCookie(&http.Cookie{Name: tokenCookie, Value: "a-token-that-was-revoked"})
	resp, err := h.ts.Client().Do(req)
	if err != nil {
		t.Fatal(err)
	}
	defer resp.Body.Close()
	if resp.StatusCode != http.StatusOK {
		t.Fatalf("status = %s, want the page to still render", resp.Status)
	}
	if c := findCookie(resp, tokenCookie); c == nil || c.MaxAge >= 0 {
		t.Error("a stale cookie was not dropped")
	}
	page, _ := io.ReadAll(resp.Body)
	if strings.Contains(string(page), "Uploading as") {
		t.Error("the page claims an identity it could not resolve")
	}
}

// The index page resolves a remembered token server-side, so the limits shown
// are the caller's real ones even though the cookie is unreadable by script.
func TestIndexShowsTheRememberedIdentity(t *testing.T) {
	h := newHarness(t, nil)
	req, _ := http.NewRequest("GET", h.ts.URL+"/", nil)
	req.AddCookie(&http.Cookie{Name: tokenCookie, Value: h.token})
	resp, err := h.ts.Client().Do(req)
	if err != nil {
		t.Fatal(err)
	}
	defer resp.Body.Close()
	page, _ := io.ReadAll(resp.Body)
	if !strings.Contains(string(page), "Uploading as <strong>friend</strong>") {
		t.Error("the page does not show the remembered identity")
	}
	if strings.Contains(string(page), h.token) {
		t.Error("the page echoes the token back into the HTML")
	}
}

// The per-object delete token must still work when a cookie is also present.
func TestCookieDoesNotShadowTheDeleteToken(t *testing.T) {
	h := newHarness(t, nil)
	// Uploaded anonymously, so the remembered token owns nothing here.
	res := decode[uploadResult](t, h.upload(t, []byte("x"), nil))

	form := strings.NewReader("token=" + res.DeleteToken)
	req, _ := http.NewRequest("POST", h.ts.URL+"/api/d/"+res.ID+"/delete", form)
	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
	req.Header.Set("Accept", "application/json")
	req.AddCookie(&http.Cookie{Name: tokenCookie, Value: h.token})
	resp, err := h.ts.Client().Do(req)
	if err != nil {
		t.Fatal(err)
	}
	defer resp.Body.Close()
	if resp.StatusCode != http.StatusOK {
		t.Fatalf("status = %s, want 200: the cookie shadowed the delete token", resp.Status)
	}
}

// An API caller sending a bearer token manages its own credentials and should
// not be handed a cookie it never asked for.
func TestBearerCallersAreNotGivenACookie(t *testing.T) {
	h := newHarness(t, nil)
	resp := h.upload(t, []byte("x"), map[string]string{"Authorization": "Bearer " + h.token})
	defer resp.Body.Close()
	if c := findCookie(resp, tokenCookie); c != nil {
		t.Errorf("a cookie was set for a bearer-token upload: %v", c)
	}
}

func findCookie(resp *http.Response, name string) *http.Cookie {
	for _, c := range resp.Cookies() {
		if c.Name == name {
			return c
		}
	}
	return nil
}

// formUpload posts the multipart form the browser would, with fields ordered
// ahead of the file part.
func (h *harness) formUpload(t *testing.T, fields map[string]string, filename, content string) *http.Response {
	t.Helper()
	return h.formUploadWith(t, nil, fields, filename, content)
}

func (h *harness) formUploadWith(t *testing.T, cookie *http.Cookie, fields map[string]string, filename, content string) *http.Response {
	t.Helper()
	var body bytes.Buffer
	mw := multipart.NewWriter(&body)
	for k, v := range fields {
		mw.WriteField(k, v)
	}
	fw, err := mw.CreateFormFile("file", filename)
	if err != nil {
		t.Fatal(err)
	}
	fw.Write([]byte(content))
	mw.Close()

	req, _ := http.NewRequest("POST", h.ts.URL+"/api/upload", &body)
	req.Header.Set("Content-Type", mw.FormDataContentType())
	req.Header.Set("Accept", "application/json")
	if cookie != nil {
		req.AddCookie(cookie)
	}
	resp, err := h.ts.Client().Do(req)
	if err != nil {
		t.Fatal(err)
	}
	return resp
}

// --- content security policy ---------------------------------------------

// The page's own behaviour and its CSP have to agree, and nothing in a Go test
// or a curl invocation enforces CSP — only a browser does. This reads the
// script that is actually shipped, works out which fetch directives the page
// needs, and checks the policy grants them.
//
// It exists because omitting connect-src once made the browser block every
// upload while every server-side test still passed.
func TestAppCSPAllowsWhatThePageDoes(t *testing.T) {
	h := newHarness(t, nil)

	resp, err := h.ts.Client().Get(h.ts.URL + "/static/app.js")
	if err != nil {
		t.Fatal(err)
	}
	defer resp.Body.Close()
	script, err := io.ReadAll(resp.Body)
	if err != nil {
		t.Fatal(err)
	}

	// Which directive each capability the script might use depends on. Every
	// fetch directive falls back to default-src when unlisted, and default-src
	// here is 'none', so anything the script does must be granted explicitly.
	needs := []struct {
		directive string
		used      bool
		because   string
	}{
		{"connect-src", bytes.Contains(script, []byte("XMLHttpRequest")) ||
			bytes.Contains(script, []byte("fetch(")), "the page makes XHR or fetch calls"},
		{"script-src", true, "the page loads an external script"},
		{"style-src", true, "the page loads an external stylesheet"},
		{"form-action", true, "the page posts a form"},
	}

	page, err := h.ts.Client().Get(h.ts.URL + "/")
	if err != nil {
		t.Fatal(err)
	}
	page.Body.Close()
	csp := page.Header.Get("Content-Security-Policy")
	if csp == "" {
		t.Fatal("the upload page carries no Content-Security-Policy")
	}

	directives := map[string]string{}
	for _, d := range strings.Split(csp, ";") {
		name, value, _ := strings.Cut(strings.TrimSpace(d), " ")
		directives[strings.ToLower(name)] = strings.TrimSpace(value)
	}
	if directives["default-src"] != "'none'" {
		t.Errorf("default-src = %q, want 'none': the checks below assume it denies by default",
			directives["default-src"])
	}

	for _, n := range needs {
		if !n.used {
			continue
		}
		value, ok := directives[n.directive]
		if !ok {
			t.Errorf("CSP has no %s, but %s; the browser will fall back to default-src and block it",
				n.directive, n.because)
			continue
		}
		if !strings.Contains(value, "'self'") {
			t.Errorf("CSP %s = %q, which does not allow this origin, but %s",
				n.directive, value, n.because)
		}
	}
}

// The download policy is the opposite case: it must stay maximally restrictive,
// since it governs bytes a stranger uploaded.
func TestDownloadCSPStaysInert(t *testing.T) {
	h := newHarness(t, nil)
	res := decode[uploadResult](t, h.upload(t, []byte("<script>alert(1)</script>"), nil))

	get, err := h.ts.Client().Get(h.ts.URL + "/d/" + res.ID)
	if err != nil {
		t.Fatal(err)
	}
	get.Body.Close()

	csp := get.Header.Get("Content-Security-Policy")
	if !strings.Contains(csp, "default-src 'none'") || !strings.Contains(csp, "sandbox") {
		t.Errorf("download CSP = %q, want default-src 'none' and sandbox", csp)
	}
	for _, forbidden := range []string{"connect-src", "script-src 'self'", "'unsafe-inline'"} {
		if strings.Contains(csp, forbidden) {
			t.Errorf("download CSP contains %q; uploaded bytes must be granted nothing", forbidden)
		}
	}
}