// Copyright (c) 2026 Petr Balvín <opensource@petrbalvin.org> (https://petrbalvin.org)
// SPDX-License-Identifier: PolyForm-Noncommercial-1.0.0

package admin

import (
	"net/http"
	"net/http/httptest"
	"net/url"
	"os"
	"path/filepath"
	"regexp"
	"strings"
	"testing"

	"sourcedock.dev/petrbalvin/volumen/internal/audit"
	"sourcedock.dev/petrbalvin/volumen/internal/backup"
	"sourcedock.dev/petrbalvin/volumen/internal/config"
	"sourcedock.dev/petrbalvin/volumen/internal/ratelimit"
	"sourcedock.dev/petrbalvin/volumen/internal/session"
	"sourcedock.dev/petrbalvin/volumen/internal/store"
	"sourcedock.dev/petrbalvin/volumen/internal/templates"
	"sourcedock.dev/petrbalvin/volumen/internal/tokens"
	"sourcedock.dev/petrbalvin/volumen/internal/users"
)

var csrfRe = regexp.MustCompile(`name="_csrf" value="([a-f0-9]+)"`)

type fixture struct {
	handler    http.Handler
	admin      *Admin
	users      *users.Users
	store      *session.Store
	storeObj   *store.Store
	contentDir string
	events     []string
	payloads   []map[string]any
}

func newFixture(t *testing.T) *fixture {
	t.Helper()
	return newFixtureSeeded(t, true)
}

// newFixtureSeeded builds the same handler over an empty users file
// when seeded is false: that is the first-run state, with no account
// and the wizard serving the admin screen.
func newFixtureSeeded(t *testing.T, seeded bool) *fixture {
	t.Helper()
	dir := t.TempDir()
	content := filepath.Join(dir, "posts")
	if err := os.MkdirAll(content, 0o755); err != nil {
		t.Fatalf("mkdir: %v", err)
	}
	cfg, err := config.Load(filepath.Join(dir, "config.toml"), config.Overrides{
		Port:       config.PortUnset,
		ContentDir: content,
		UsersFile:  filepath.Join(dir, "users.toml"),
	})
	// Preview links are signed with the session key, so the fixture sets
	// one the way a real deployment does.
	cfg.Admin.SessionKey = strings.Repeat("k", 64)
	if err != nil {
		t.Fatalf("config: %v", err)
	}
	st := store.New(store.Options{ContentDir: content, DefaultLang: "en", RevisionLimit: 10})
	usersObj := users.New(cfg.UsersFile)
	if seeded {
		if _, err := usersObj.Add("admin", "correct-horse-9", "admin"); err != nil {
			t.Fatalf("seed admin: %v", err)
		}
	}
	f := &fixture{storeObj: st, contentDir: content}
	a, err := New(Deps{
		Config:    cfg,
		Store:     st,
		Users:     usersObj,
		Templates: templates.New(filepath.Join(dir, "templates.toml")),
		Tokens:    tokens.New(filepath.Join(dir, "tokens.toml")),
		Backup: backup.Options{
			ContentDir:    content,
			UsersFile:     cfg.UsersFile,
			TemplatesFile: cfg.TemplatesFile(),
			TokensFile:    cfg.TokensFile(),
		},
		Audit:      audit.New(""),
		LoginLim:   ratelimit.NewLoginLimiter(),
		Sessions:   session.New(strings.Repeat("k", 64), 0, false),
		Version:    "0.0.0-test",
		PreviewKey: strings.Repeat("k", 64),
		OnEvent: func(event string, payload map[string]any) {
			f.events = append(f.events, event)
			f.payloads = append(f.payloads, payload)
		},
	})
	if err != nil {
		t.Fatalf("New: %v", err)
	}
	// Production mounts this handler inside the session middleware; the
	// fixture mirrors that so cookies round-trip.
	f.handler = a.deps.Sessions.Middleware(a.Handler())
	f.admin = a
	f.users = usersObj
	f.store = a.deps.Sessions
	return f
}

func (f *fixture) do(t *testing.T, req *http.Request) *httptest.ResponseRecorder {
	t.Helper()
	rec := httptest.NewRecorder()
	f.handler.ServeHTTP(rec, req)
	return rec
}

func extractCSRF(t *testing.T, body string) string {
	t.Helper()
	m := csrfRe.FindStringSubmatch(body)
	if m == nil {
		t.Fatalf("no CSRF token in body:\n%s", body[:min(len(body), 500)])
	}
	return m[1]
}

func sessionCookie(t *testing.T, rec *httptest.ResponseRecorder) *http.Cookie {
	t.Helper()
	for _, cookie := range rec.Result().Cookies() {
		if cookie.Name == session.CookieName {
			return cookie
		}
	}
	t.Fatal("no session cookie")
	return nil
}

func TestLoginPageRenders(t *testing.T) {
	f := newFixture(t)
	rec := f.do(t, httptest.NewRequest(http.MethodGet, "/admin/login", nil))
	if rec.Code != http.StatusOK {
		t.Fatalf("code = %d", rec.Code)
	}
	body := rec.Body.String()
	for _, want := range []string{"Sign in", "Volumen admin", "0.0.0-test"} {
		if !strings.Contains(body, want) {
			t.Fatalf("missing %q", want)
		}
	}
	if !strings.Contains(rec.Header().Get("Content-Type"), "text/html") {
		t.Fatalf("content-type = %q", rec.Header().Get("Content-Type"))
	}
}

func TestLoginRedirectsAuthenticatedUser(t *testing.T) {
	f := newFixture(t)
	cookie := login(t, f, "admin", "correct-horse-9")

	req := httptest.NewRequest(http.MethodGet, "/admin/login", nil)
	req.AddCookie(cookie)
	rec := f.do(t, req)
	if rec.Code != http.StatusSeeOther || rec.Header().Get("Location") != "/admin/" {
		t.Fatalf("code=%d location=%q", rec.Code, rec.Header().Get("Location"))
	}
}

// login performs the full CSRF + credential flow and returns the
// authenticated session cookie.
func login(t *testing.T, f *fixture, username, secret string) *http.Cookie {
	t.Helper()
	get := f.do(t, httptest.NewRequest(http.MethodGet, "/admin/login", nil))
	csrf := extractCSRF(t, get.Body.String())
	cookie := sessionCookie(t, get)

	form := url.Values{"_csrf": {csrf}, "username": {username}, "password": {secret}}
	req := httptest.NewRequest(http.MethodPost, "/admin/login", strings.NewReader(form.Encode()))
	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
	req.AddCookie(cookie)
	rec := f.do(t, req)
	if rec.Code != http.StatusSeeOther || rec.Header().Get("Location") != "/admin/" {
		t.Fatalf("login failed: code=%d body=%s", rec.Code, rec.Body.String())
	}
	return sessionCookie(t, rec)
}

func TestLoginRejectsWrongPassword(t *testing.T) {
	f := newFixture(t)
	get := f.do(t, httptest.NewRequest(http.MethodGet, "/admin/login", nil))
	csrf := extractCSRF(t, get.Body.String())
	cookie := sessionCookie(t, get)

	form := url.Values{"_csrf": {csrf}, "username": {"admin"}, "password": {"nope"}}
	req := httptest.NewRequest(http.MethodPost, "/admin/login", strings.NewReader(form.Encode()))
	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
	req.AddCookie(cookie)
	rec := f.do(t, req)
	if rec.Code != http.StatusUnauthorized {
		t.Fatalf("code = %d", rec.Code)
	}
	if !strings.Contains(rec.Body.String(), "Invalid username or password.") {
		t.Fatal("error message missing")
	}
}

func TestLoginRejectsMissingCSRF(t *testing.T) {
	f := newFixture(t)
	get := f.do(t, httptest.NewRequest(http.MethodGet, "/admin/login", nil))
	cookie := sessionCookie(t, get)

	form := url.Values{"username": {"admin"}, "password": {"correct-horse-9"}}
	req := httptest.NewRequest(http.MethodPost, "/admin/login", strings.NewReader(form.Encode()))
	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
	req.AddCookie(cookie)
	if rec := f.do(t, req); rec.Code != http.StatusForbidden {
		t.Fatalf("code = %d, want 403", rec.Code)
	}
}

func TestLoginRateLimitRendersCountdown(t *testing.T) {
	f := newFixture(t)
	get := f.do(t, httptest.NewRequest(http.MethodGet, "/admin/login", nil))
	csrf := extractCSRF(t, get.Body.String())
	cookie := sessionCookie(t, get)

	var last *httptest.ResponseRecorder
	for range 12 {
		form := url.Values{"_csrf": {csrf}, "username": {"admin"}, "password": {"wrong"}}
		req := httptest.NewRequest(http.MethodPost, "/admin/login", strings.NewReader(form.Encode()))
		req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
		req.AddCookie(cookie)
		last = f.do(t, req)
	}
	if last.Code != http.StatusTooManyRequests {
		t.Fatalf("code = %d, want 429", last.Code)
	}
	if !strings.Contains(last.Body.String(), "Auto-unlock in") {
		t.Fatal("lockout message missing")
	}
	if !strings.Contains(last.Body.String(), `id="lockout-countdown"`) {
		t.Fatal("countdown element missing")
	}
}

func TestLogout(t *testing.T) {
	f := newFixture(t)
	cookie := login(t, f, "admin", "correct-horse-9")

	// Grab a fresh CSRF token via the session cookie's page.
	req := httptest.NewRequest(http.MethodGet, "/admin/login", nil)
	req.AddCookie(cookie)
	// Authenticated users are redirected; get the CSRF from the session
	// store directly instead.
	sess := f.store.Load(req)
	csrf := CSRFToken(sess)

	form := url.Values{"_csrf": {csrf}}
	logoutReq := httptest.NewRequest(http.MethodPost, "/admin/logout", strings.NewReader(form.Encode()))
	logoutReq.Header.Set("Content-Type", "application/x-www-form-urlencoded")
	logoutReq.AddCookie(cookie)
	rec := f.do(t, logoutReq)
	if rec.Code != http.StatusSeeOther || rec.Header().Get("Location") != "/admin/login" {
		t.Fatalf("code=%d location=%q", rec.Code, rec.Header().Get("Location"))
	}
}

func TestBareAdminRedirects(t *testing.T) {
	f := newFixture(t)
	rec := f.do(t, httptest.NewRequest(http.MethodGet, "/admin", nil))
	if rec.Code != http.StatusSeeOther || rec.Header().Get("Location") != "/admin/" {
		t.Fatalf("code=%d location=%q", rec.Code, rec.Header().Get("Location"))
	}
}

// An /admin path no route claims meets the shell's own 404 page, not the
// engine's bare text, and an anonymous visitor is still sent to the
// sign-in screen first.
func TestAdminNotFound(t *testing.T) {
	f := newFixture(t)

	anon := f.do(t, httptest.NewRequest(http.MethodGet, "/admin/no-such-page", nil))
	if anon.Code != http.StatusSeeOther || anon.Header().Get("Location") != "/admin/login" {
		t.Fatalf("anonymous: code=%d location=%q", anon.Code, anon.Header().Get("Location"))
	}

	cookie := login(t, f, "admin", "correct-horse-9")
	req := httptest.NewRequest(http.MethodGet, "/admin/no-such-page", nil)
	req.AddCookie(cookie)
	rec := f.do(t, req)
	if rec.Code != http.StatusNotFound {
		t.Fatalf("code = %d", rec.Code)
	}
	if ct := rec.Header().Get("Content-Type"); !strings.HasPrefix(ct, "text/html") {
		t.Fatalf("content type = %q", ct)
	}
	body := rec.Body.String()
	if !strings.Contains(body, "Page not found") {
		t.Fatalf("body lacks the 404 heading:\n%s", body[:min(len(body), 500)])
	}
	if !strings.Contains(body, `<html`) || !strings.Contains(body, `class="shell"`) {
		t.Fatalf("body is not rendered in the shell")
	}

	post := httptest.NewRequest(http.MethodPost, "/admin/no-such-page", strings.NewReader(""))
	post.AddCookie(cookie)
	if rec := f.do(t, post); rec.Code != http.StatusNotFound || strings.Contains(rec.Body.String(), "<html") {
		t.Fatalf("POST: code=%d", rec.Code)
	}
}

func TestPasswordError(t *testing.T) {
	if key, n := PasswordError("", 10, 1024); key != "New password cannot be empty." || n != 0 {
		t.Fatalf("empty password = %q, %d", key, n)
	}
	if key, n := PasswordError("short", 10, 1024); key != "password.min" || n != 10 {
		t.Fatalf("short password = %q, %d", key, n)
	}
	if key, n := PasswordError(strings.Repeat("x", 2000), 10, 1024); key != "password.max" || n != 1024 {
		t.Fatalf("long password = %q, %d", key, n)
	}
	if key, n := PasswordError("password123", 10, 1024); key != "This password is too common." || n != 0 {
		t.Fatalf("common password = %q, %d", key, n)
	}
	if key, n := PasswordError("a genuinely unique passphrase", 10, 1024); key != "" || n != 0 {
		t.Fatalf("valid password = %q, %d", key, n)
	}
}

func TestFirstUpper(t *testing.T) {
	if got := firstUpper("petr", "?"); got != "P" {
		t.Fatalf("got = %q", got)
	}
	if got := firstUpper("", "?"); got != "?" {
		t.Fatalf("got = %q", got)
	}
}

func TestHumanSize(t *testing.T) {
	cases := map[int64]string{
		0:           "",
		512:         "1 kB",
		10 * 1024:   "10 kB",
		1024 * 1024: "1.0 MB",
		5 << 20:     "5.0 MB",
		1536 * 1024: "1.5 MB",
	}
	for in, want := range cases {
		if got := humanSize(in); got != want {
			t.Errorf("humanSize(%d) = %q, want %q", in, got, want)
		}
	}
}

// A post-template body containing "</script>" must not be able to end
// the script element the JSON literal is embedded in.
func TestTemplatesJSONEscapesScriptClose(t *testing.T) {
	list := []tplOption{{
		Name: "s", Title: "T", Slug: "s", Tags: []string{},
		Body: `Use <script>document.write("x")</script> carefully`,
	}}
	out := string(templatesJSON(list))
	if strings.Contains(out, "</script>") {
		t.Fatalf("literal script close survived: %s", out)
	}
	if !strings.Contains(out, `\u003c/script>`) {
		t.Fatalf("expected unicode escapes: %s", out)
	}
}