package main

import (
	"bytes"
	"io"
	"log"
	"net/http"
	"net/http/httptest"
	"net/url"
	"os"
	"strings"
	"sync"
	"testing"
)

// recorder is a Mailer that remembers instead of sending.
type recorder struct {
	mu   sync.Mutex
	sent []Message
	fail bool
}

func (m *recorder) Send(msg Message) error {
	m.mu.Lock()
	defer m.mu.Unlock()
	if m.fail {
		return io.ErrUnexpectedEOF
	}
	m.sent = append(m.sent, msg)
	return nil
}

func (m *recorder) messages() []Message {
	m.mu.Lock()
	defer m.mu.Unlock()
	return append([]Message(nil), m.sent...)
}

func TestSpoolDrainsOldestFirst(t *testing.T) {
	dir := t.TempDir()
	driver := &recorder{}
	spool := &Mail{dir: dir, driver: driver, wake: make(chan struct{}, 1)}

	for _, to := range []string{"one@example.com", "two@example.com", "three@example.com"} {
		spool.Enqueue(Message{To: to, Subject: "hello", Body: "body"})
	}
	if entries, _ := os.ReadDir(dir); len(entries) != 3 {
		t.Fatalf("expected three spooled messages, got %d", len(entries))
	}
	if spool.drainOnce() {
		t.Fatal("draining reported a failure")
	}
	sent := driver.messages()
	if len(sent) != 3 || sent[0].To != "one@example.com" || sent[2].To != "three@example.com" {
		t.Errorf("sent out of order: %v", sent)
	}
	if entries, _ := os.ReadDir(dir); len(entries) != 0 {
		t.Errorf("the spool still holds %d messages", len(entries))
	}
	// A message with no recipient is not a message.
	spool.Enqueue(Message{Subject: "nobody"})
	if entries, _ := os.ReadDir(dir); len(entries) != 0 {
		t.Error("a message with no recipient was spooled")
	}
}

// The line that says a message was dropped has to name it without carrying it:
// the body of one of these is a capability.
func TestSpoolGivesUpLoudly(t *testing.T) {
	dir := t.TempDir()
	spool := &Mail{dir: dir, driver: &recorder{fail: true}, wake: make(chan struct{}, 1)}
	spool.Enqueue(Message{To: "one@example.com", Subject: "set a new password",
		Body: "https://forge.example/set-password?name=bob&t=the-capability\n"})

	var buf bytes.Buffer
	old := log.Writer()
	log.SetOutput(&buf)
	for i := 0; i < mailAttempts; i++ {
		if !spool.drainOnce() {
			log.SetOutput(old)
			t.Fatalf("attempt %d: a failing driver reported success", i)
		}
	}
	log.SetOutput(old)

	if entries, _ := os.ReadDir(dir); len(entries) != 0 {
		t.Errorf("a message that will never send is still queued after %d attempts", mailAttempts)
	}
	for _, want := range []string{"giving up", "set a new password", "one@example.com"} {
		if !strings.Contains(buf.String(), want) {
			t.Errorf("the log does not say %q:\n%s", want, buf.String())
		}
	}
	if strings.Contains(buf.String(), "the-capability") {
		t.Errorf("a one time link reached the log:\n%s", buf.String())
	}
}

// The none driver is off: the log names what was not sent and never carries
// it, since the body of one of these is a capability.
func TestNoneDriverNamesWhatItDrops(t *testing.T) {
	if _, ok := newMail(&Config{Mail: MailConfig{Driver: "log"}}, t.TempDir()).driver.(logMailer); !ok {
		t.Error("the log driver is not the one that logs")
	}
	if _, ok := newMail(defaultConfig(), t.TempDir()).driver.(dropMailer); !ok {
		t.Error("the default driver sends somewhere")
	}

	var buf bytes.Buffer
	old := log.Writer()
	log.SetOutput(&buf)
	err := dropMailer{}.Send(Message{To: "bob@example.com", Subject: "set a new password",
		Body: "https://forge.example/set-password?name=bob&t=the-capability\n"})
	log.SetOutput(old)
	if err != nil {
		t.Fatal(err)
	}
	for _, want := range []string{"set a new password", "bob@example.com"} {
		if !strings.Contains(buf.String(), want) {
			t.Errorf("the log does not say %q:\n%s", want, buf.String())
		}
	}
	if strings.Contains(buf.String(), "the-capability") {
		t.Errorf("a one time link reached the log:\n%s", buf.String())
	}
}

func TestMailgunDriver(t *testing.T) {
	var got url.Values
	var user, key string
	var ok bool
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		user, key, ok = r.BasicAuth()
		r.ParseForm()
		got = r.PostForm
		if r.URL.Path != "/v3/mg.example.com/messages" {
			t.Errorf("posted to %s", r.URL.Path)
		}
	}))
	defer srv.Close()

	driver := &mailgunMailer{
		from: "git-forge <forge@example.com>", base: srv.URL + "/v3", domain: "mg.example.com",
		key: "secret", list: "https://git.example.com/settings", client: srv.Client(),
	}
	err := driver.Send(Message{To: "bob@example.com", Subject: "hello", Body: "body", Unsubscribe: true})
	if err != nil {
		t.Fatal(err)
	}
	if !ok || user != "api" || key != "secret" {
		t.Errorf("basic auth was %q %q %v", user, key, ok)
	}
	for field, want := range map[string]string{
		"from": "git-forge <forge@example.com>", "to": "bob@example.com",
		"subject": "hello", "text": "body",
		"h:List-Unsubscribe": "<https://git.example.com/settings>",
	} {
		if got.Get(field) != want {
			t.Errorf("%s was %q, wanted %q", field, got.Get(field), want)
		}
	}

	// A message that ignores the toggle carries no unsubscribe header.
	if err := driver.Send(Message{To: "bob@example.com", Subject: "hello", Body: "body"}); err != nil {
		t.Fatal(err)
	}
	if got.Has("h:List-Unsubscribe") {
		t.Error("a notice about the account itself carried List-Unsubscribe")
	}
}

func TestIssueNotifiesGranteesOnly(t *testing.T) {
	f := testForge(t)
	driver := &recorder{}
	f.mail.driver = driver
	addUser(t, f, "alice", "hunter2hunter2")
	addUser(t, f, "bob", "hunter2hunter2")
	addUser(t, f, "carol", "hunter2hunter2")
	confirm(t, f, "alice", "alice@example.com", true)
	confirm(t, f, "bob", "bob@example.com", true)
	confirm(t, f, "carol", "carol@example.com", false) // notify off
	addRepo(t, f, "notes", Repo{
		Visibility: visPublic, Issues: featUsers, Wiki: featDisabled,
		Grants: map[string]string{"alice": grantWrite, "bob": grantRead, "carol": grantRead},
	})

	h := f.routes()
	session := signIn(t, f, h, "alice")
	form := url.Values{"csrf": {f.csrf(withCookies("/", session))}, "title": {"A bug"}, "body": {"Details."}}
	if code := post(h, "/notes/issues", form, session).Code; code != http.StatusSeeOther {
		t.Fatalf("opening an issue: status %d", code)
	}
	f.mail.drainOnce()

	sent := driver.messages()
	if len(sent) != 1 {
		t.Fatalf("expected one message, got %v", sent)
	}
	if sent[0].To != "bob@example.com" {
		t.Errorf("mailed %s: alice caused it and carol has notifications off", sent[0].To)
	}
	if !sent[0].Unsubscribe {
		t.Error("an activity message did not carry the unsubscribe flag")
	}
	if !strings.Contains(sent[0].Body, "/notes/issues/1") {
		t.Errorf("the message does not link to the issue: %q", sent[0].Body)
	}
}

// An address receives nothing until a link sent to it has been followed, and
// changing it again unproves it and spends the link sent to the old one.
func TestAddressIsProvedByALink(t *testing.T) {
	f := testForge(t)
	driver := &recorder{}
	f.mail.driver = driver
	addUser(t, f, "bob", "hunter2hunter2")
	h := f.routes()
	session := signIn(t, f, h, "bob")
	token := f.csrf(withCookies("/", session))

	set := func(email string) {
		t.Helper()
		w := post(h, "/settings/email", url.Values{
			"csrf": {token}, "email": {email}, "notify": {"yes"}}, session)
		if w.Code != http.StatusOK {
			t.Fatalf("setting %q: status %d", email, w.Code)
		}
		f.mail.drainOnce()
	}

	set("bob@example.com")
	if u, _ := f.store.User("bob"); u.EmailConfirmed {
		t.Fatal("an address was confirmed without the link being followed")
	}
	sent := driver.messages()
	if len(sent) != 1 || sent[0].To != "bob@example.com" {
		t.Fatalf("expected one message to the address, got %v", sent)
	}
	link := between(sent[0].Body, f.cfg.BaseURL, "\n")
	if !strings.HasPrefix(link, "/confirm-email?") {
		t.Fatalf("no confirmation link in %q", sent[0].Body)
	}
	if code := get(h, link, session).Code; code != http.StatusOK {
		t.Fatalf("following the link: status %d", code)
	}
	if u, _ := f.store.User("bob"); !u.EmailConfirmed {
		t.Error("the address is still unconfirmed after the link was followed")
	}

	set("other@example.com")
	if u, _ := f.store.User("bob"); u.EmailConfirmed {
		t.Error("a changed address kept the old one's confirmation")
	}
	if code := get(h, link, session).Code; code != http.StatusNotFound {
		t.Errorf("the link to the old address still works: status %d", code)
	}
}

// The one unauthenticated path that sends a capability. The answer is the same
// either way, or the form is a list of which names are taken.
func TestResetTellsNobodyWhichAccountsExist(t *testing.T) {
	f := testForge(t)
	driver := &recorder{}
	f.mail.driver = driver
	addUser(t, f, "bob", "hunter2hunter2")
	confirm(t, f, "bob", "bob@example.com", true)
	h := f.routes()

	ask := func(name string) string {
		t.Helper()
		w := post(h, "/reset", url.Values{
			"csrf": {f.csrf(withCookies("/", nil))}, "name": {name}}, nil)
		if w.Code != http.StatusOK {
			t.Fatalf("asking for %q: status %d", name, w.Code)
		}
		f.mail.drainOnce()
		return w.Body.String()
	}

	const same = "if that account exists"
	if page := ask("bob"); !strings.Contains(page, same) {
		t.Error("the answer for an account that exists does not carry the notice")
	}
	sent := driver.messages()
	if len(sent) != 1 || sent[0].To != "bob@example.com" {
		t.Fatalf("no link went to the account: %v", sent)
	}
	if page := ask("nobody"); !strings.Contains(page, same) {
		t.Error("the answer for an account that does not exist reads differently")
	}
	if n := len(driver.messages()); n != 1 {
		t.Errorf("a reset for an account that does not exist sent mail: %d", n)
	}

	// And the link it did send sets a password once.
	link := between(sent[0].Body, f.cfg.BaseURL, "\n")
	page := get(h, link, nil)
	if page.Code != http.StatusOK {
		t.Fatalf("following the link: status %d", page.Code)
	}
	body := page.Body.String()
	form := url.Values{
		"csrf":    {f.csrf(withCookies("/", nil))},
		"name":    {between(body, `name="name" value="`, `"`)},
		"expires": {between(body, `name="expires" value="`, `"`)},
		"t":       {between(body, `name="t" value="`, `"`)},
		"new":     {"opensesame1"}, "again": {"opensesame1"},
	}
	if w := post(h, "/set-password", form, nil); w.Code != http.StatusSeeOther {
		t.Fatalf("setting the password: status %d", w.Code)
	}
	if u, _ := f.store.User("bob"); !passwordOK(u.Password, "opensesame1") {
		t.Error("the new password was not stored")
	}
	if w := post(h, "/set-password", form, nil); w.Code != http.StatusNotFound {
		t.Errorf("the link worked twice: status %d", w.Code)
	}
}

func confirm(t *testing.T, f *Forge, name, email string, notify bool) {
	t.Helper()
	err := f.store.UpdateUsers("users: address", f.store.forgeAuthor(), func(m map[string]User) error {
		u := m[name]
		u.Email, u.EmailConfirmed, u.Notify = email, true, notify
		m[name] = u
		return nil
	})
	if err != nil {
		t.Fatal(err)
	}
}