package web

import (
	"bytes"
	"context"
	"database/sql"
	"image"
	"image/png"
	"mime/multipart"
	"net/http"
	"net/http/httptest"
	"os"
	"strings"
	"testing"

	"github.com/alexedwards/scs/v2"
	"github.com/google/uuid"
	"github.com/joho/godotenv"
	"golang.org/x/crypto/bcrypt"

	"plumber"
	"plumber/internal/blob"
	"plumber/internal/store"
)

func testDBURL() string {
	_ = godotenv.Load()
	return strings.TrimSpace(os.Getenv("TEST_DATABASE_URL"))
}

func newTestServer(t *testing.T, cfg Config) (*Server, *sql.DB) {
	t.Helper()
	url := testDBURL()
	if url == "" {
		t.Skip("set TEST_DATABASE_URL for web tests")
	}
	db, sessions, err := store.OpenPostgres(url, plumber.SchemaSQL)
	if err != nil {
		t.Fatalf("open postgres: %v", err)
	}
	t.Cleanup(func() {
		sessions.Close()
		_ = db.Close()
	})
	if cfg.Blob == nil {
		cfg.Blob = blob.Disabled{}
	}
	srv, err := New(db, sessions.Store(), plumber.TemplateFS, plumber.StaticFS, cfg)
	if err != nil {
		t.Fatal(err)
	}
	return srv, db
}

func uniq(prefix string) string {
	return prefix + "_" + strings.ReplaceAll(uuid.NewString()[:8], "-", "")
}

func seedUser(t *testing.T, db *sql.DB, username, password string, role store.Role) *store.User {
	t.Helper()
	hash, err := bcrypt.GenerateFromPassword([]byte(password), bcrypt.MinCost)
	if err != nil {
		t.Fatal(err)
	}
	u := store.NewUser(db)
	u.Username = username
	u.PasswordHash = string(hash)
	u.Role = role
	if err := u.Create(context.Background()); err != nil {
		t.Fatal(err)
	}
	return u
}

func loginUser(t *testing.T, h http.Handler, username, password string) []*http.Cookie {
	t.Helper()
	rec := httptest.NewRecorder()
	h.ServeHTTP(rec, httptest.NewRequest(http.MethodGet, "/login", nil))
	cookies := rec.Result().Cookies()
	csrf := csrfFrom(rec.Body.String())
	form := strings.NewReader("_csrf=" + csrf + "&username=" + username + "&password=" + password)
	req := httptest.NewRequest(http.MethodPost, "/login", 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("login %s: %d %s", username, rec.Code, rec.Body.String())
	}
	return mergeCookies(cookies, rec.Result().Cookies())
}

func TestHomeEmptyAndViewport(t *testing.T) {
	srv, _ := newTestServer(t, Config{})
	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, "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, Config{})
	h := srv.Handler()
	name := uniq("ask")
	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=" + name + "&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) {
	url := testDBURL()
	if url == "" {
		t.Skip("set TEST_DATABASE_URL for web tests")
	}
	db, sessions, err := store.OpenPostgres(url, plumber.SchemaSQL)
	if err != nil {
		t.Fatal(err)
	}
	t.Cleanup(func() {
		sessions.Close()
		_ = db.Close()
	})
	sessionStore := sessions.Store()

	srv1, err := New(db, sessionStore, plumber.TemplateFS, plumber.StaticFS, Config{})
	if err != nil {
		t.Fatal(err)
	}
	h1 := srv1.Handler()
	name := uniq("sess")

	rec := httptest.NewRecorder()
	h1.ServeHTTP(rec, httptest.NewRequest(http.MethodGet, "/register", nil))
	preCookies := rec.Result().Cookies()
	csrf := csrfFrom(rec.Body.String())
	form := strings.NewReader("_csrf=" + csrf + "&username=" + name + "&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(db, sessionStore, plumber.TemplateFS, plumber.StaticFS, Config{})
	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, db := newTestServer(t, Config{})
	n, err := store.CountAdmins(context.Background(), db)
	if err != nil {
		t.Fatal(err)
	}
	if n > 0 {
		t.Skip("admin already exists in database; bootstrap seed not exercised")
	}
	adminName := uniq("seed")
	srv.cfg.AdminUsername = adminName
	h := srv.Handler()
	registerUser(t, h, adminName, "hunter22")
	u, err := store.UserByUsername(context.Background(), db, adminName)
	if err != nil || !u.Admin() {
		t.Fatalf("first matching registrant should be admin: %+v %v", u, err)
	}
	later := uniq("later")
	srv2, err := New(db, scs.New().Store, plumber.TemplateFS, plumber.StaticFS, Config{AdminUsername: later})
	if err != nil {
		t.Fatal(err)
	}
	registerUser(t, srv2.Handler(), later, "hunter22")
	u2, err := store.UserByUsername(context.Background(), db, later)
	if err != nil {
		t.Fatal(err)
	}
	if u2.Admin() {
		t.Fatal("later admin username must stay user when an admin already exists")
	}
}

func TestAdminUsersPageAccessAndRoles(t *testing.T) {
	srv, db := newTestServer(t, Config{})
	h := srv.Handler()
	hubName := uniq("hub")
	bobName := uniq("bob")
	carolName := uniq("carol")
	seedUser(t, db, hubName, "hunter22", store.RoleAdmin)
	adminCookies := loginUser(t, h, hubName, "hunter22")
	registerUser(t, h, bobName, "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(), bobName) {
		t.Fatal("missing bob on admin page")
	}

	bob, err := store.UserByUsername(context.Background(), db, bobName)
	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, _ = store.UserByUsername(context.Background(), db, bobName)
	if !bob.Admin() {
		t.Fatal("bob should be admin")
	}

	bobCookies := registerUser(t, h, carolName, "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 bob back to user
	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)
	}

	admins, err := store.CountAdmins(context.Background(), db)
	if err != nil {
		t.Fatal(err)
	}
	if admins != 1 {
		t.Skip("shared database has other admins; last-admin demote not isolated")
	}

	hub, err := store.UserByUsername(context.Background(), db, hubName)
	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/"+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, _ = store.UserByUsername(context.Background(), db, hubName)
	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.FileUpload) (string, error) {
	f.calls++
	f.last = obj.Key
	return "https://cdn.example.com/" + obj.Key, nil
}

func TestProfilePageAndState(t *testing.T) {
	srv, db := newTestServer(t, Config{})
	h := srv.Handler()
	name := uniq("alice")
	cookies := registerUser(t, h, name, "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 := store.UserByUsername(context.Background(), db, name)
	if err != nil || u.State != "CA" {
		t.Fatalf("state not saved: %+v %v", u, err)
	}

	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) {
	fb := &fakeBlob{}
	srv, db := newTestServer(t, Config{Blob: fb})
	h := srv.Handler()
	hubName := uniq("hub")
	aliceName := uniq("alice")
	hub := seedUser(t, db, hubName, "hunter22", store.RoleAdmin)
	alice := seedUser(t, db, aliceName, "hunter22", store.RoleUser)
	adminCookies := loginUser(t, h, hubName, "hunter22")

	q := store.NewQuestion(db)
	q.AuthorID = alice.ID
	q.Title = "Drip"
	q.Body = "Under sink"
	q.City = "Oakland"
	if err := q.Create(context.Background()); err != nil {
		t.Fatal(err)
	}
	ans := store.NewAnswer(db)
	ans.QuestionID = q.ID
	ans.AuthorID = hub.ID
	ans.Body = "Replace the cartridge."
	if err := ans.Upsert(context.Background()); 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)
	}
	img := image.NewRGBA(image.Rect(0, 0, 1, 1))
	if err := png.Encode(part, img); err != nil {
		t.Fatal(err)
	}
	_ = 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 fb.calls != 1 {
		t.Fatalf("expected 1 upload, got %d", fb.calls)
	}
	hub, _ = store.UserByUsername(context.Background(), db, hubName)
	if !strings.Contains(hub.AvatarURL, "cdn.example.com/avatars/") {
		t.Fatalf("avatar url %q", hub.AvatarURL)
	}
}

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]
}