package api_test

import (
	"bytes"
	"encoding/json"
	"io"
	"net/http"
	"net/http/cookiejar"
	"net/http/httptest"
	"strings"
	"testing"

	"git.ryuvia.com/niklas/terdut-server/internal/api"
)

const adminPassword = "correct horse battery"

// browser is an HTTP client with its own cookie jar, standing in for one
// signed-in browser.
type browser struct {
	*http.Client
	base string
}

func newBrowser(t *testing.T, base string) *browser {
	t.Helper()
	jar, _ := cookiejar.New(nil)
	return &browser{Client: &http.Client{Jar: jar}, base: base}
}

// do sends a request the way the web UI's own fetch would: same-origin, with
// the cookie from the jar.
func (b *browser) do(t *testing.T, method, path string, body any, header ...string) *http.Response {
	t.Helper()
	var r io.Reader
	if body != nil {
		data, _ := json.Marshal(body)
		r = bytes.NewReader(data)
	}
	req, _ := http.NewRequest(method, b.base+path, r)
	if body != nil {
		req.Header.Set("Content-Type", "application/json")
	}
	req.Header.Set("Sec-Fetch-Site", "same-origin")
	for i := 0; i+1 < len(header); i += 2 {
		req.Header.Set(header[i], header[i+1])
	}
	resp, err := b.Do(req)
	if err != nil {
		t.Fatalf("%s %s: %v", method, path, err)
	}
	return resp
}

func (b *browser) login(t *testing.T, username, password string) *http.Response {
	t.Helper()
	return b.do(t, http.MethodPost, "/api/login", map[string]string{"username": username, "password": password})
}

// setAdminPassword gives the bootstrapped admin a password over its API key.
func setAdminPassword(t *testing.T, s *ts) {
	t.Helper()
	resp := s.req(t, http.MethodPut, "/api/users/1/password", map[string]string{"password": adminPassword})
	defer resp.Body.Close()
	if resp.StatusCode != http.StatusNoContent {
		t.Fatalf("set password: %d", resp.StatusCode)
	}
}

func signedIn(t *testing.T, s *ts) *browser {
	t.Helper()
	setAdminPassword(t, s)
	b := newBrowser(t, s.URL)
	resp := b.login(t, "admin", adminPassword)
	defer resp.Body.Close()
	if resp.StatusCode != http.StatusOK {
		t.Fatalf("login: %d", resp.StatusCode)
	}
	return b
}

func status(t *testing.T, resp *http.Response) int {
	t.Helper()
	resp.Body.Close()
	return resp.StatusCode
}

func TestLogin_SetsSessionCookie(t *testing.T) {
	s := newTS(t)
	setAdminPassword(t, s)
	b := newBrowser(t, s.URL)

	resp := b.login(t, "admin", adminPassword)
	if resp.StatusCode != http.StatusOK {
		t.Fatalf("login: %d", resp.StatusCode)
	}
	var cookie *http.Cookie
	for _, c := range resp.Cookies() {
		if c.Name == "terdut_session" {
			cookie = c
		}
	}
	if cookie == nil || !cookie.HttpOnly || cookie.SameSite != http.SameSiteLaxMode {
		t.Fatalf("expected an HttpOnly, SameSite=Lax session cookie, got %+v", cookie)
	}
	if cookie.Secure {
		t.Error("cookie is Secure on a plain-HTTP server with no https public URL")
	}
	var me struct {
		User struct {
			Username string `json:"username"`
		} `json:"user"`
		HasPassword bool `json:"has_password"`
	}
	decode(t, resp, &me)
	if me.User.Username != "admin" || !me.HasPassword {
		t.Errorf("unexpected login response %+v", me)
	}
}

func TestLogin_CookieAuthenticatesAPI(t *testing.T) {
	s := newTS(t)
	b := signedIn(t, s)

	if code := status(t, b.do(t, http.MethodGet, "/api/incidents", nil)); code != http.StatusOK {
		t.Errorf("GET /api/incidents with cookie: %d", code)
	}
	resp := b.do(t, http.MethodGet, "/api/me", nil)
	var me struct {
		User struct {
			ID int64 `json:"id"`
		} `json:"user"`
	}
	decode(t, resp, &me)
	if me.User.ID != 1 {
		t.Errorf("/api/me returned user %d", me.User.ID)
	}
}

func TestLogin_SecureCookieBehindHTTPSPublicURL(t *testing.T) {
	s := newTS(t, api.NotifyConfig{PublicURL: "https://terdut.example.com"})
	setAdminPassword(t, s)
	resp := newBrowser(t, s.URL).login(t, "admin", adminPassword)
	resp.Body.Close()
	for _, c := range resp.Cookies() {
		if c.Name == "terdut_session" && !c.Secure {
			t.Error("cookie should be Secure when the public URL is https")
		}
	}
}

func TestLogin_WrongPasswordAndUnknownUser(t *testing.T) {
	s := newTS(t)
	setAdminPassword(t, s)
	b := newBrowser(t, s.URL)

	if code := status(t, b.login(t, "admin", "not the password")); code != http.StatusUnauthorized {
		t.Errorf("wrong password: %d", code)
	}
	if code := status(t, b.login(t, "nobody", adminPassword)); code != http.StatusUnauthorized {
		t.Errorf("unknown user: %d", code)
	}
}

func TestLogin_UserWithoutPasswordCannotSignIn(t *testing.T) {
	s := newTS(t)
	b := newBrowser(t, s.URL)
	// The empty password must not match a user that has none.
	if code := status(t, b.login(t, "admin", "")); code != http.StatusUnauthorized {
		t.Errorf("login without a password set: %d", code)
	}
}

func TestLogin_RateLimitedPerUsername(t *testing.T) {
	s := newTS(t)
	setAdminPassword(t, s)
	b := newBrowser(t, s.URL)

	for i := range 10 {
		if code := status(t, b.login(t, "admin", "wrong")); code != http.StatusUnauthorized {
			t.Fatalf("attempt %d: %d", i+1, code)
		}
	}
	// Even the right password is refused once the limit is reached.
	resp := b.login(t, "admin", adminPassword)
	if resp.StatusCode != http.StatusTooManyRequests {
		t.Fatalf("expected 429, got %d", resp.StatusCode)
	}
	if resp.Header.Get("Retry-After") == "" {
		t.Error("429 without Retry-After")
	}
	resp.Body.Close()
}

func TestSession_CrossOriginWriteRejected(t *testing.T) {
	s := newTS(t)
	b := signedIn(t, s)

	code := status(t, b.do(t, http.MethodPost, "/api/incidents/999/acknowledge", nil,
		"Sec-Fetch-Site", "cross-site", "Origin", "https://evil.example"))
	if code != http.StatusForbidden {
		t.Errorf("cross-origin POST with cookie: %d, want 403", code)
	}

	// The same request from the page itself gets through to the handler.
	code = status(t, b.do(t, http.MethodPost, "/api/incidents/999/acknowledge", nil))
	if code != http.StatusNotFound {
		t.Errorf("same-origin POST with cookie: %d, want 404 from the handler", code)
	}
}

func TestSession_BearerIgnoresOriginChecks(t *testing.T) {
	s := newTS(t)
	req, _ := http.NewRequest(http.MethodPost, s.URL+"/api/incidents/999/acknowledge", nil)
	req.Header.Set("Authorization", "Bearer "+s.key)
	req.Header.Set("Sec-Fetch-Site", "cross-site")
	resp, err := http.DefaultClient.Do(req)
	if err != nil {
		t.Fatal(err)
	}
	if code := status(t, resp); code != http.StatusNotFound {
		t.Errorf("Bearer request: %d, want 404 from the handler", code)
	}
}

func TestLogout_EndsSession(t *testing.T) {
	s := newTS(t)
	b := signedIn(t, s)

	if code := status(t, b.do(t, http.MethodPost, "/api/logout", nil)); code != http.StatusNoContent {
		t.Fatalf("logout: %d", code)
	}
	if code := status(t, b.do(t, http.MethodGet, "/api/me", nil)); code != http.StatusUnauthorized {
		t.Errorf("after logout: %d", code)
	}
	var n int
	s.db.QueryRow("SELECT COUNT(*) FROM sessions").Scan(&n)
	if n != 0 {
		t.Errorf("%d session(s) left after logout", n)
	}
}

func TestSession_ExpiredIsRejected(t *testing.T) {
	s := newTS(t)
	b := signedIn(t, s)
	s.exec(t, "UPDATE sessions SET expires_at = 1")

	if code := status(t, b.do(t, http.MethodGet, "/api/me", nil)); code != http.StatusUnauthorized {
		t.Errorf("expired session: %d", code)
	}
	api.Sweep(t.Context(), s.db, 0, 0, api.NotifyConfig{})
	var n int
	s.db.QueryRow("SELECT COUNT(*) FROM sessions").Scan(&n)
	if n != 0 {
		t.Errorf("sweep left %d expired session(s)", n)
	}
}

func TestSetPassword_OwnNeedsCurrent(t *testing.T) {
	s := newTS(t)
	b := signedIn(t, s)

	code := status(t, b.do(t, http.MethodPut, "/api/users/1/password",
		map[string]string{"password": "a brand new secret", "current_password": "wrong"}))
	if code != http.StatusForbidden {
		t.Errorf("wrong current password: %d", code)
	}
	code = status(t, b.do(t, http.MethodPut, "/api/users/1/password",
		map[string]string{"password": "short", "current_password": adminPassword}))
	if code != http.StatusBadRequest {
		t.Errorf("too-short password: %d", code)
	}
	code = status(t, b.do(t, http.MethodPut, "/api/users/1/password",
		map[string]string{"password": "a brand new secret", "current_password": adminPassword}))
	if code != http.StatusNoContent {
		t.Fatalf("change password: %d", code)
	}
	if code := status(t, newBrowser(t, s.URL).login(t, "admin", "a brand new secret")); code != http.StatusOK {
		t.Errorf("login with the new password: %d", code)
	}
}

func TestSetPassword_EndsOtherSessionsButNotThisOne(t *testing.T) {
	s := newTS(t)
	phone := signedIn(t, s)
	laptop := newBrowser(t, s.URL)
	status(t, laptop.login(t, "admin", adminPassword))

	code := status(t, phone.do(t, http.MethodPut, "/api/users/1/password",
		map[string]string{"password": "a brand new secret", "current_password": adminPassword}))
	if code != http.StatusNoContent {
		t.Fatalf("change password: %d", code)
	}
	if code := status(t, phone.do(t, http.MethodGet, "/api/me", nil)); code != http.StatusOK {
		t.Errorf("the session that changed the password: %d", code)
	}
	if code := status(t, laptop.do(t, http.MethodGet, "/api/me", nil)); code != http.StatusUnauthorized {
		t.Errorf("the other session: %d", code)
	}
}

func TestBootstrap_WithPassword(t *testing.T) {
	database := newTestDB(t)
	srv := httptest.NewServer(api.NewRouter(database, api.NotifyConfig{}))
	t.Cleanup(srv.Close)

	body := `{"username":"admin","email":"a@test.com","password":"` + adminPassword + `"}`
	resp, err := http.Post(srv.URL+"/api/bootstrap", "application/json", strings.NewReader(body))
	if err != nil {
		t.Fatal(err)
	}
	if code := status(t, resp); code != http.StatusCreated {
		t.Fatalf("bootstrap: %d", code)
	}
	if code := status(t, newBrowser(t, srv.URL).login(t, "admin", adminPassword)); code != http.StatusOK {
		t.Errorf("login after bootstrap: %d", code)
	}
}

func TestRouter_UnknownAPIPathIsJSON404(t *testing.T) {
	s := newTS(t)
	resp, err := http.Get(s.URL + "/api/nope")
	if err != nil {
		t.Fatal(err)
	}
	defer resp.Body.Close()
	if resp.StatusCode != http.StatusNotFound || !strings.HasPrefix(resp.Header.Get("Content-Type"), "application/json") {
		t.Errorf("GET /api/nope: %d %s", resp.StatusCode, resp.Header.Get("Content-Type"))
	}
}

func TestRouter_DeepLinkServesWebUI(t *testing.T) {
	s := newTS(t)
	resp, err := http.Get(s.URL + "/incidents/1")
	if err != nil {
		t.Fatal(err)
	}
	defer resp.Body.Close()
	if resp.StatusCode != http.StatusOK || !strings.HasPrefix(resp.Header.Get("Content-Type"), "text/html") {
		t.Errorf("GET /incidents/1: %d %s", resp.StatusCode, resp.Header.Get("Content-Type"))
	}
	if resp.Header.Get("Content-Security-Policy") == "" {
		t.Error("web UI served without a CSP")
	}

	resp2, err := http.Get(s.URL + "/js/missing.js")
	if err != nil {
		t.Fatal(err)
	}
	if code := status(t, resp2); code != http.StatusNotFound {
		t.Errorf("missing asset: %d", code)
	}
}