package web

import (
	"bytes"
	"context"
	"mime/multipart"
	"net/http"
	"net/http/httptest"
	"strings"
	"testing"

	"github.com/alexedwards/scs/v2"

	"plumber"
	"plumber/internal/blob"
)

func newTestServer(t *testing.T) (*Server, *memDB, scs.Store) {
	t.Helper()
	fake := newMemDB()
	sessions := scs.New()
	srv, err := New(fake, sessions.Store, plumber.TemplateFS, plumber.StaticFS, Config{AdminUsername: "hub"})
	if err != nil {
		t.Fatal(err)
	}
	return srv, fake, sessions.Store
}

func TestHomeEmptyAndViewport(t *testing.T) {
	srv, _, _ := newTestServer(t)
	rec := httptest.NewRecorder()
	req := httptest.NewRequest(http.MethodGet, "/", nil)
	srv.Handler().ServeHTTP(rec, req)
	if rec.Code != 200 {
		t.Fatalf("status %d: %s", rec.Code, rec.Body.String())
	}
	body := rec.Body.String()
	if !strings.Contains(body, "No questions yet") {
		t.Fatal("missing empty state")
	}
	if !strings.Contains(body, "width=device-width") {
		t.Fatal("missing mobile viewport")
	}
	if !strings.Contains(body, "not a substitute for a licensed plumber") {
		t.Fatal("missing disclaimer")
	}
}

func TestRegisterLoginAsk(t *testing.T) {
	srv, _, _ := newTestServer(t)
	h := srv.Handler()
	rec := httptest.NewRecorder()
	h.ServeHTTP(rec, httptest.NewRequest(http.MethodGet, "/register", nil))
	cookie := rec.Result().Cookies()
	csrf := csrfFrom(rec.Body.String())
	if csrf == "" {
		t.Fatal("no csrf")
	}
	form := strings.NewReader("_csrf=" + csrf + "&username=hub&password=hunter22")
	req := httptest.NewRequest(http.MethodPost, "/register", form)
	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
	for _, c := range cookie {
		req.AddCookie(c)
	}
	rec = httptest.NewRecorder()
	h.ServeHTTP(rec, req)
	if rec.Code != http.StatusSeeOther {
		t.Fatalf("register status %d %s", rec.Code, rec.Body.String())
	}
	session := rec.Result().Cookies()
	req = httptest.NewRequest(http.MethodGet, "/submit", nil)
	for _, c := range session {
		req.AddCookie(c)
	}
	rec = httptest.NewRecorder()
	h.ServeHTTP(rec, req)
	if rec.Code != 200 {
		t.Fatalf("submit form %d", rec.Code)
	}
	csrf = csrfFrom(rec.Body.String())
	form = strings.NewReader("_csrf=" + csrf + "&title=Leaky+faucet&body=Drip+all+night.&city=Oakland")
	req = httptest.NewRequest(http.MethodPost, "/submit", form)
	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
	for _, c := range session {
		req.AddCookie(c)
	}
	for _, c := range rec.Result().Cookies() {
		req.AddCookie(c)
	}
	rec2 := httptest.NewRecorder()
	h.ServeHTTP(rec2, req)
	if rec2.Code != http.StatusSeeOther {
		t.Fatalf("submit %d %s", rec2.Code, rec2.Body.String())
	}
}

func TestSessionSurvivesServerRestart(t *testing.T) {
	fake := newMemDB()
	sessionStore := scs.New().Store

	srv1, err := New(fake, sessionStore, plumber.TemplateFS, plumber.StaticFS, Config{AdminUsername: "hub"})
	if err != nil {
		t.Fatal(err)
	}
	h1 := srv1.Handler()

	rec := httptest.NewRecorder()
	h1.ServeHTTP(rec, httptest.NewRequest(http.MethodGet, "/register", nil))
	preCookies := rec.Result().Cookies()
	csrf := csrfFrom(rec.Body.String())
	if csrf == "" {
		t.Fatal("no csrf")
	}
	form := strings.NewReader("_csrf=" + csrf + "&username=hub&password=hunter22")
	req := httptest.NewRequest(http.MethodPost, "/register", form)
	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
	for _, c := range preCookies {
		req.AddCookie(c)
	}
	rec = httptest.NewRecorder()
	h1.ServeHTTP(rec, req)
	if rec.Code != http.StatusSeeOther {
		t.Fatalf("register status %d %s", rec.Code, rec.Body.String())
	}
	sessionCookies := mergeCookies(preCookies, rec.Result().Cookies())

	srv2, err := New(fake, sessionStore, plumber.TemplateFS, plumber.StaticFS, Config{AdminUsername: "hub"})
	if err != nil {
		t.Fatal(err)
	}
	req = httptest.NewRequest(http.MethodGet, "/submit", nil)
	for _, c := range sessionCookies {
		req.AddCookie(c)
	}
	rec = httptest.NewRecorder()
	srv2.Handler().ServeHTTP(rec, req)
	if rec.Code != http.StatusOK {
		t.Fatalf("expected authenticated submit form after restart, got %d: %s", rec.Code, rec.Body.String())
	}
	if !strings.Contains(rec.Body.String(), "Ask a question") {
		t.Fatal("session did not survive restart")
	}
}

func registerUser(t *testing.T, h http.Handler, username, password string) []*http.Cookie {
	t.Helper()
	rec := httptest.NewRecorder()
	h.ServeHTTP(rec, httptest.NewRequest(http.MethodGet, "/register", nil))
	cookies := rec.Result().Cookies()
	csrf := csrfFrom(rec.Body.String())
	form := strings.NewReader("_csrf=" + csrf + "&username=" + username + "&password=" + password)
	req := httptest.NewRequest(http.MethodPost, "/register", form)
	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
	for _, c := range cookies {
		req.AddCookie(c)
	}
	rec = httptest.NewRecorder()
	h.ServeHTTP(rec, req)
	if rec.Code != http.StatusSeeOther {
		t.Fatalf("register %s: %d %s", username, rec.Code, rec.Body.String())
	}
	return mergeCookies(cookies, rec.Result().Cookies())
}

func TestAdminSeedOnlyWhenNoAdmins(t *testing.T) {
	srv, fake, _ := newTestServer(t)
	h := srv.Handler()
	registerUser(t, h, "hub", "hunter22")
	u, err := fake.UserByUsername(context.Background(), "hub")
	if err != nil || !u.Admin() {
		t.Fatalf("hub should be first admin: %+v %v", u, err)
	}
	registerUser(t, h, "hub2", "hunter22")
	// Create another account that also matches AdminUsername after an admin exists — use a fresh server config with AdminUsername hub2 after hub exists
	srv2, err := New(fake, scs.New().Store, plumber.TemplateFS, plumber.StaticFS, Config{AdminUsername: "lateradmin"})
	if err != nil {
		t.Fatal(err)
	}
	registerUser(t, srv2.Handler(), "lateradmin", "hunter22")
	u2, err := fake.UserByUsername(context.Background(), "lateradmin")
	if err != nil {
		t.Fatal(err)
	}
	if u2.Admin() {
		t.Fatal("lateradmin must stay user when an admin already exists")
	}
}

func TestAdminUsersPageAccessAndRoles(t *testing.T) {
	srv, fake, _ := newTestServer(t)
	h := srv.Handler()
	adminCookies := registerUser(t, h, "hub", "hunter22")
	registerUser(t, h, "bob", "hunter22")

	rec := httptest.NewRecorder()
	req := httptest.NewRequest(http.MethodGet, "/admin/users", nil)
	for _, c := range adminCookies {
		req.AddCookie(c)
	}
	h.ServeHTTP(rec, req)
	if rec.Code != 200 {
		t.Fatalf("admin list %d", rec.Code)
	}
	if !strings.Contains(rec.Body.String(), "bob") {
		t.Fatal("missing bob on admin page")
	}

	bob, err := fake.UserByUsername(context.Background(), "bob")
	if err != nil {
		t.Fatal(err)
	}
	csrf := csrfFrom(rec.Body.String())
	form := strings.NewReader("_csrf=" + csrf + "&role=admin")
	req = httptest.NewRequest(http.MethodPost, "/admin/users/"+bob.ID+"/role", form)
	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
	for _, c := range adminCookies {
		req.AddCookie(c)
	}
	rec = httptest.NewRecorder()
	h.ServeHTTP(rec, req)
	if rec.Code != http.StatusSeeOther {
		t.Fatalf("promote %d %s", rec.Code, rec.Body.String())
	}
	bob, _ = fake.UserByUsername(context.Background(), "bob")
	if !bob.Admin() {
		t.Fatal("bob should be admin")
	}

	// Non-admin forbidden
	bobCookies := registerUser(t, h, "carol", "hunter22")
	rec = httptest.NewRecorder()
	req = httptest.NewRequest(http.MethodGet, "/admin/users", nil)
	for _, c := range bobCookies {
		req.AddCookie(c)
	}
	h.ServeHTTP(rec, req)
	if rec.Code != http.StatusForbidden {
		t.Fatalf("non-admin expected 403, got %d", rec.Code)
	}

	// Demote last remaining admin after demoting bob first — leave only hub, then demote hub
	hub, err := fake.UserByUsername(context.Background(), "hub")
	if err != nil {
		t.Fatal(err)
	}
	rec = httptest.NewRecorder()
	req = httptest.NewRequest(http.MethodGet, "/admin/users", nil)
	for _, c := range adminCookies {
		req.AddCookie(c)
	}
	h.ServeHTTP(rec, req)
	csrf = csrfFrom(rec.Body.String())
	form = strings.NewReader("_csrf=" + csrf + "&role=user")
	req = httptest.NewRequest(http.MethodPost, "/admin/users/"+bob.ID+"/role", form)
	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
	for _, c := range adminCookies {
		req.AddCookie(c)
	}
	rec = httptest.NewRecorder()
	h.ServeHTTP(rec, req)
	if rec.Code != http.StatusSeeOther {
		t.Fatalf("demote bob %d", rec.Code)
	}

	rec = httptest.NewRecorder()
	req = httptest.NewRequest(http.MethodGet, "/admin/users", nil)
	for _, c := range adminCookies {
		req.AddCookie(c)
	}
	h.ServeHTTP(rec, req)
	csrf = csrfFrom(rec.Body.String())
	form = strings.NewReader("_csrf=" + csrf + "&role=user")
	req = httptest.NewRequest(http.MethodPost, "/admin/users/"+hub.ID+"/role", form)
	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
	for _, c := range adminCookies {
		req.AddCookie(c)
	}
	rec = httptest.NewRecorder()
	h.ServeHTTP(rec, req)
	if rec.Code != 200 {
		t.Fatalf("demote last admin expected page with error, got %d", rec.Code)
	}
	if !strings.Contains(rec.Body.String(), "Cannot demote the last admin") {
		t.Fatalf("missing last-admin error: %s", rec.Body.String())
	}
	hub, _ = fake.UserByUsername(context.Background(), "hub")
	if !hub.Admin() {
		t.Fatal("hub must remain admin")
	}
}

type fakeBlob struct {
	calls int
	last  string
}

func (f *fakeBlob) Enabled() bool { return true }

func (f *fakeBlob) Upload(_ context.Context, obj blob.Object) (string, error) {
	f.calls++
	f.last = obj.Key
	return "https://cdn.example.com/" + obj.Key, nil
}

func TestProfilePageAndState(t *testing.T) {
	srv, fake, _ := newTestServer(t)
	h := srv.Handler()
	cookies := registerUser(t, h, "alice", "hunter22")

	rec := httptest.NewRecorder()
	req := httptest.NewRequest(http.MethodGet, "/profile", nil)
	for _, c := range cookies {
		req.AddCookie(c)
	}
	h.ServeHTTP(rec, req)
	if rec.Code != 200 {
		t.Fatalf("profile %d", rec.Code)
	}
	if !strings.Contains(rec.Body.String(), "Your questions") {
		t.Fatal("expected user questions label")
	}
	if !strings.Contains(rec.Body.String(), "local plumbing codes") {
		t.Fatal("missing state helper copy")
	}

	csrf := csrfFrom(rec.Body.String())
	var buf bytes.Buffer
	w := multipart.NewWriter(&buf)
	_ = w.WriteField("_csrf", csrf)
	_ = w.WriteField("state", "CA")
	_ = w.Close()
	req = httptest.NewRequest(http.MethodPost, "/profile", &buf)
	req.Header.Set("Content-Type", w.FormDataContentType())
	for _, c := range cookies {
		req.AddCookie(c)
	}
	rec = httptest.NewRecorder()
	h.ServeHTTP(rec, req)
	if rec.Code != http.StatusSeeOther {
		t.Fatalf("save profile %d %s", rec.Code, rec.Body.String())
	}
	u, err := fake.UserByUsername(context.Background(), "alice")
	if err != nil || u.State != "CA" {
		t.Fatalf("state not saved: %+v %v", u, err)
	}

	// invalid state
	rec = httptest.NewRecorder()
	req = httptest.NewRequest(http.MethodGet, "/profile", nil)
	for _, c := range cookies {
		req.AddCookie(c)
	}
	h.ServeHTTP(rec, req)
	csrf = csrfFrom(rec.Body.String())
	buf.Reset()
	w = multipart.NewWriter(&buf)
	_ = w.WriteField("_csrf", csrf)
	_ = w.WriteField("state", "ZZ")
	_ = w.Close()
	req = httptest.NewRequest(http.MethodPost, "/profile", &buf)
	req.Header.Set("Content-Type", w.FormDataContentType())
	for _, c := range cookies {
		req.AddCookie(c)
	}
	rec = httptest.NewRecorder()
	h.ServeHTTP(rec, req)
	if rec.Code != 200 || !strings.Contains(rec.Body.String(), "valid US state") {
		t.Fatalf("expected invalid state error, got %d %s", rec.Code, rec.Body.String())
	}
}

func TestProfileAdminAnsweredListAndAvatarUpload(t *testing.T) {
	fake := newMemDB()
	blob := &fakeBlob{}
	sessions := scs.New()
	srv, err := New(fake, sessions.Store, plumber.TemplateFS, plumber.StaticFS, Config{
		AdminUsername: "hub",
		Blob:          blob,
	})
	if err != nil {
		t.Fatal(err)
	}
	h := srv.Handler()
	adminCookies := registerUser(t, h, "hub", "hunter22")
	userCookies := registerUser(t, h, "alice", "hunter22")

	alice, _ := fake.UserByUsername(context.Background(), "alice")
	hub, _ := fake.UserByUsername(context.Background(), "hub")
	q, err := fake.CreateQuestion(context.Background(), alice.ID, "Drip", "Under sink", "Oakland")
	if err != nil {
		t.Fatal(err)
	}
	if err := fake.UpsertAnswer(context.Background(), q.ID, hub.ID, "Replace the cartridge."); err != nil {
		t.Fatal(err)
	}

	rec := httptest.NewRecorder()
	req := httptest.NewRequest(http.MethodGet, "/profile", nil)
	for _, c := range adminCookies {
		req.AddCookie(c)
	}
	h.ServeHTTP(rec, req)
	if rec.Code != 200 {
		t.Fatalf("admin profile %d", rec.Code)
	}
	body := rec.Body.String()
	if !strings.Contains(body, "Questions you answered") || !strings.Contains(body, "Drip") {
		t.Fatalf("admin answered list missing: %s", body)
	}

	csrf := csrfFrom(body)
	var buf bytes.Buffer
	w := multipart.NewWriter(&buf)
	_ = w.WriteField("_csrf", csrf)
	_ = w.WriteField("state", "OR")
	part, err := w.CreateFormFile("avatar", "pic.png")
	if err != nil {
		t.Fatal(err)
	}
	_, _ = part.Write([]byte("fakepngbytes"))
	_ = w.Close()
	req = httptest.NewRequest(http.MethodPost, "/profile", &buf)
	req.Header.Set("Content-Type", w.FormDataContentType())
	for _, c := range adminCookies {
		req.AddCookie(c)
	}
	rec = httptest.NewRecorder()
	h.ServeHTTP(rec, req)
	if rec.Code != http.StatusSeeOther {
		t.Fatalf("avatar upload %d %s", rec.Code, rec.Body.String())
	}
	if blob.calls != 1 {
		t.Fatalf("expected 1 upload, got %d", blob.calls)
	}
	hub, _ = fake.UserByUsername(context.Background(), "hub")
	if !strings.Contains(hub.AvatarURL, "cdn.example.com/avatars/") {
		t.Fatalf("avatar url %q", hub.AvatarURL)
	}
	_ = userCookies
}

func mergeCookies(sets ...[]*http.Cookie) []*http.Cookie {
	byName := map[string]*http.Cookie{}
	for _, set := range sets {
		for _, c := range set {
			byName[c.Name] = c
		}
	}
	out := make([]*http.Cookie, 0, len(byName))
	for _, c := range byName {
		out = append(out, c)
	}
	return out
}

func csrfFrom(html string) string {
	const needle = `name="_csrf" value="`
	i := strings.Index(html, needle)
	if i < 0 {
		return ""
	}
	html = html[i+len(needle):]
	j := strings.Index(html, `"`)
	if j < 0 {
		return ""
	}
	return html[:j]
}