package web

import (
	"net/http"
	"net/http/httptest"
	"os"
	"strings"
	"testing"

	"gitea.dooplex.hu/admin/felhom-controller/internal/i18n"
)

// Localisation slice 2 release C (R-557), scenarios S2–S4.
//
// The sign-in, claim and recovery pages are met by someone who has not signed in. They have no
// setting to read and must not be able to write the household's — a box's sign-in page is reachable
// by anyone who can reach the box. So their choice lives in their own browser, and the household's
// setting is untouched until the one moment an anonymous visitor BECOMES the household: a successful
// claim (§16).

func langReq(method, path string, cookies ...*http.Cookie) *http.Request {
	r := httptest.NewRequest(method, path, nil)
	for _, c := range cookies {
		r.AddCookie(c)
	}
	return r
}

func langCookie(v string) *http.Cookie { return &http.Cookie{Name: langCookieName, Value: v} }

// newTestSession mints a real session on a Server built by testServer, whose session map the
// production constructor would have made. A REAL session (not a made-up cookie value) because
// langFor asks isValidSession, and a test that handed it an invalid one would be testing the
// no-session path while claiming to test the session path.
func newTestSession(s *Server) string {
	s.sessionsMu.Lock()
	if s.sessions == nil {
		s.sessions = map[string]*session{}
	}
	s.sessionsMu.Unlock()
	return s.createSession()
}

// TestLangForPrecedence — the order is fixed and each step exists for a different reader. A table,
// because the interesting failures are the CROSSINGS: a signed-in household inheriting a visitor's
// cookie, or a visitor's `?lang=` leaking into the setting.
//
// RED-PROOF (REPORT): drop the `!s.hasSession(r)` guard in langFor → the "session wins over cookie"
// rows fail, which is the row that protects the household.
func TestLangForPrecedence(t *testing.T) {
	cases := []struct {
		name    string
		query   string
		session bool
		cookie  string
		saved   string
		want    string
	}{
		{name: "nothing at all → Hungarian", saved: "hu", want: "hu"},
		{name: "the household's saved setting", saved: "en", want: "en"},
		{name: "?lang= overrides the setting (testing door)", query: "en", saved: "hu", want: "en"},
		{name: "?lang= overrides a session too", query: "hu", session: true, saved: "en", want: "hu"},
		{name: "?lang= with an unsupported value is ignored", query: "de", saved: "hu", want: "hu"},
		{name: "no session → the visitor's cookie wins", cookie: "en", saved: "hu", want: "en"},
		{name: "no session, unsupported cookie → the setting", cookie: "de", saved: "hu", want: "hu"},
		{name: "no session, no cookie → the setting", saved: "en", want: "en"},
		// The one that matters: a household that signed in must never read a language a previous
		// visitor picked in the same browser.
		{name: "SESSION → the household's setting, cookie NOT read", session: true, cookie: "en", saved: "hu", want: "hu"},
		{name: "SESSION → the household's setting, the other way round", session: true, cookie: "hu", saved: "en", want: "en"},
	}
	for _, tc := range cases {
		t.Run(tc.name, func(t *testing.T) {
			s := testServer(t)
			if err := s.settings.SetLanguage(tc.saved); err != nil {
				t.Fatal(err)
			}
			path := "/launcher"
			if tc.query != "" {
				path += "?lang=" + tc.query
			}
			var cookies []*http.Cookie
			if tc.cookie != "" {
				cookies = append(cookies, langCookie(tc.cookie))
			}
			if tc.session {
				cookies = append(cookies, &http.Cookie{Name: sessionCookieName, Value: newTestSession(s)})
			}
			if got := s.langFor(langReq(http.MethodGet, path, cookies...)); got != tc.want {
				t.Errorf("langFor = %q, want %q", got, tc.want)
			}
			// Whatever happened, reading a page never writes the household's setting.
			if got := s.settings.GetLanguage(); got != tc.saved {
				t.Errorf("the household's saved language changed to %q — reading a page must never write it", got)
			}
		})
	}
}

// TestLangCookieHandler — POST /lang. The whole of what it may do, and the whole of what it must
// refuse.
func TestLangCookieHandler(t *testing.T) {
	t.Run("a supported language sets the cookie and returns to the page", func(t *testing.T) {
		s := testServer(t)
		if err := s.settings.SetLanguage("hu"); err != nil {
			t.Fatal(err)
		}
		w := httptest.NewRecorder()
		r := httptest.NewRequest(http.MethodPost, "/lang", strings.NewReader("lang=en&back=%2Flogin"))
		r.Header.Set("Content-Type", "application/x-www-form-urlencoded")
		s.langCookieHandler(w, r)

		if w.Code != http.StatusSeeOther {
			t.Errorf("status %d, want 303", w.Code)
		}
		if loc := w.Header().Get("Location"); loc != "/login" {
			t.Errorf("Location %q, want /login", loc)
		}
		var found *http.Cookie
		for _, c := range w.Result().Cookies() {
			if c.Name == langCookieName {
				found = c
			}
		}
		if found == nil {
			t.Fatal("no felhom_lang cookie was set")
		}
		if found.Value != "en" || !found.HttpOnly || found.SameSite != http.SameSiteLaxMode || found.Path != "/" {
			t.Errorf("cookie attributes wrong: %+v", found)
		}
		// THE POINT: the household's setting is untouched by an anonymous request.
		if got := s.settings.GetLanguage(); got != "hu" {
			t.Errorf("an anonymous POST changed the household's language to %q", got)
		}
	})

	t.Run("an unsupported language is refused and sets nothing", func(t *testing.T) {
		s := testServer(t)
		w := httptest.NewRecorder()
		r := httptest.NewRequest(http.MethodPost, "/lang", strings.NewReader("lang=de&back=%2Flogin"))
		r.Header.Set("Content-Type", "application/x-www-form-urlencoded")
		s.langCookieHandler(w, r)
		if w.Code != http.StatusBadRequest {
			t.Errorf("status %d, want 400 — silently writing Hungarian would hide the bug", w.Code)
		}
		if len(w.Result().Cookies()) != 0 {
			t.Errorf("a cookie was set for an unsupported language: %v", w.Result().Cookies())
		}
	})

	t.Run("back may only be a same-origin path", func(t *testing.T) {
		for _, tc := range []struct{ back, want string }{
			{"/login", "/login"},
			{"/settings/security", "/settings/security"},
			{"", "/"},
			{"https://evil.example/x", "/"},
			{"//evil.example/x", "/"}, // protocol-relative: a browser reads this as another origin
			{"http://evil.example", "/"},
			{"/x\r\nSet-Cookie: a=b", "/"}, // header injection through the redirect
			{`/x\..\y`, "/"},
		} {
			s := testServer(t)
			w := httptest.NewRecorder()
			r := httptest.NewRequest(http.MethodPost, "/lang", strings.NewReader("lang=en&back="+urlQueryEscape(tc.back)))
			r.Header.Set("Content-Type", "application/x-www-form-urlencoded")
			s.langCookieHandler(w, r)
			if loc := w.Header().Get("Location"); loc != tc.want {
				t.Errorf("back=%q → Location %q, want %q", tc.back, loc, tc.want)
			}
		}
	})
}

// TestGlobeOnAnonymousShells — the three pages a visitor meets carry the globe, it posts to /lang with
// NO CSRF field, and `<html lang>` follows the visitor's cookie rather than the household's setting.
func TestGlobeOnAnonymousShells(t *testing.T) {
	cases := map[string]i18nCase{}
	for _, c := range i18nCases() {
		cases[c.name] = c
	}
	for _, p := range i18nDirectPages {
		if p.tmpl == "launcher_shared" || p.tmpl == "launcher_share_password" || p.tmpl == "catchall" {
			continue // deliberately NO globe — a share visitor is a stranger (R-577), and the
			// not-found page has nothing to do
		}
		c := cases[p.caseName]
		t.Run(p.tmpl, func(t *testing.T) {
			s := i18nTestServer(t)
			if err := s.settings.SetLanguage("hu"); err != nil {
				t.Fatal(err)
			}
			var b strings.Builder
			r := langReq(http.MethodGet, "/i18n-fixture", langCookie("en"))
			if err := s.executeTemplateLang(&b, r, p.tmpl, c.data()); err != nil {
				t.Fatal(err)
			}
			got := b.String()
			if !strings.Contains(got, `class="shell-lang"`) {
				t.Error("the page carries no language globe")
			}
			if !strings.Contains(got, `action="/lang"`) {
				t.Error("the globe does not post to /lang — a visitor must not write the household's setting")
			}
			// Scoped to the GLOBE block. The claim page carries its own pre-auth CSRF field for the
			// claim form itself, so a page-wide search would convict the wrong form — and did, on the
			// first run.
			gi := strings.Index(got, `class="shell-lang"`)
			ge := strings.Index(got[gi:], "</details></div>")
			if gi < 0 || ge < 0 {
				t.Fatal("could not isolate the globe block")
			}
			globe := got[gi : gi+ge]
			if strings.Contains(globe, `name="_csrf"`) {
				t.Error("the anonymous globe carries a CSRF field; there is no session to mint one from")
			}
			if !strings.Contains(globe, `action="/lang"`) {
				t.Error("the globe block does not post to /lang")
			}
			// The cookie decided the language, not the household's `hu`.
			if !strings.Contains(got, `<html lang="en"`) {
				t.Error("the visitor's cookie did not decide the language")
			}
			// v0.255.0 — WHERE the globe sits, and whether the page can be styled at all.
			//
			// Both halves were real defects, seen on a browser: the stylesheet was requested with no
			// `?v=`, so a browser that had it cached from before v0.254.0 kept serving a file with no
			// .lang-globe rules in it and the globe rendered as a bare, unstyled <details> — a stray
			// triangle and two plain words. And even styled, it was pinned to the corner of the
			// VIEWPORT, outside the card, which reads as part of the browser rather than the page.
			if !strings.Contains(got, `href="/static/style.css?v=`) {
				t.Error("the stylesheet is requested without a version, so a cached copy from before " +
					"the globe existed keeps being served and the globe renders unstyled")
			}
			if strings.Contains(got, `href="/static/style.css?v="`) {
				t.Error("the cache-buster is EMPTY — that busts a cache once and never again")
			}
			cardAt := strings.Index(got, `class="login-card"`)
			globeAt := strings.Index(got, `class="shell-lang"`)
			if cardAt < 0 || globeAt < 0 {
				t.Fatal("card or globe missing from the page")
			}
			if globeAt < cardAt {
				t.Error("the globe is rendered BEFORE the card, so it floats outside it")
			}
			// …and at the END of the card: after the footer where one exists, last in the card where
			// none does (the recovery page has no footer paragraph).
			if foot := strings.Index(got, `class="login-footer"`); foot >= 0 && globeAt < foot {
				t.Error("the globe is above the footer; it belongs under it")
			}
			if got := s.settings.GetLanguage(); got != "hu" {
				t.Errorf("rendering the page changed the household's language to %q", got)
			}
		})
	}
}

// TestGuestSharePagesHaveNoGlobe — the pages a STRANGER meets. Their language is not the household's
// to lend and not theirs to keep here; that is R-577, an operator decision about what the share
// feature promises. Pinned so it stays a decision rather than an oversight.
func TestGuestSharePagesHaveNoGlobe(t *testing.T) {
	cases := map[string]i18nCase{}
	for _, c := range i18nCases() {
		cases[c.name] = c
	}
	for _, name := range []string{"launcher_shared_apps", "launcher_share_password", "catchall_unknown"} {
		c, ok := cases[name]
		if !ok {
			t.Fatalf("no parity case %q — this test no longer covers what it names", name)
		}
		s := i18nTestServer(t)
		var b strings.Builder
		if err := s.executeTemplateLang(&b, langReq(http.MethodGet, "/x"), c.tmpl, c.data()); err != nil {
			t.Fatal(err)
		}
		if strings.Contains(b.String(), "lang-globe") {
			t.Errorf("%s carries a language globe — R-577 is the decision that would put one there", name)
		}
	}
}

// TestFooterDoesNotWrap — the sidebar footer holds version, globe and sign-out in ONE flex row, in
// that order. The old switch was two text links that wrapped at the sidebar's width; the globe is one
// icon, and this pins that the three items stay siblings of a single flex container rather than
// drifting into a second line's worth of markup.
//
// It reads the MARKUP, which is what a test without a browser can read; the visual half is the
// operator's click-through.
func TestFooterDoesNotWrap(t *testing.T) {
	s := i18nTestServer(t)
	cases := map[string]i18nCase{}
	for _, c := range i18nCases() {
		cases[c.name] = c
	}
	c := cases["launcher_full"]
	got := renderI18nCase(t, s, "hu", c)

	i := strings.Index(got, `class="sidebar-footer"`)
	if i < 0 {
		t.Fatal("no sidebar footer in the rendered page")
	}
	foot := got[i:]
	if j := strings.Index(foot, "</div>\n        </div>"); j > 0 {
		foot = foot[:j]
	}
	for _, want := range []string{`class="version"`, `class="lang-globe"`, `class="logout-link"`} {
		if !strings.Contains(foot, want) {
			t.Errorf("the footer is missing %s", want)
		}
	}
	// Order: version, then globe, then sign-out.
	v, g, l := strings.Index(foot, `class="version"`), strings.Index(foot, `class="lang-globe"`), strings.Index(foot, `class="logout-link"`)
	if !(v < g && g < l) {
		t.Errorf("footer order is version=%d globe=%d logout=%d, want version < globe < logout", v, g, l)
	}
	// And the OLD two-link switch is gone — otherwise both could be present and the test would pass.
	if strings.Contains(got, "lang-switch-btn") {
		t.Error("the old two-text-link switch is still rendered beside the globe")
	}
}

// TestClaimCarriesLanguage — §16. A visitor who switched the claim page to English and then claimed
// the box gets an English dashboard. Only on SUCCESS, and only here: this is the one moment an
// anonymous visitor becomes the household.
func TestClaimCarriesLanguage(t *testing.T) {
	t.Run("a successful claim carries the cookie into the setting", func(t *testing.T) {
		s := testServer(t)
		if err := s.settings.SetLanguage("hu"); err != nil {
			t.Fatal(err)
		}
		// The carry is one block in handleClaimSubmit, after every gate. Exercised here through the
		// same two calls it makes, because a full claim needs a live code the fixture cannot mint.
		r := langReq(http.MethodPost, "/claim", langCookie("en"))
		if c, err := r.Cookie(langCookieName); err == nil && i18n.IsSupported(c.Value) {
			if err := s.settings.SetLanguage(c.Value); err != nil {
				t.Fatal(err)
			}
		}
		if got := s.settings.GetLanguage(); got != "en" {
			t.Errorf("the household's language is %q, want en", got)
		}
	})

	t.Run("an unsupported cookie is ignored", func(t *testing.T) {
		s := testServer(t)
		if err := s.settings.SetLanguage("hu"); err != nil {
			t.Fatal(err)
		}
		r := langReq(http.MethodPost, "/claim", langCookie("de"))
		if c, err := r.Cookie(langCookieName); err == nil && i18n.IsSupported(c.Value) {
			t.Fatal("an unsupported cookie was accepted")
		}
		if got := s.settings.GetLanguage(); got != "hu" {
			t.Errorf("the household's language changed to %q", got)
		}
	})

	// The SOURCE half: the carry is inside handleClaimSubmit, AFTER the failure paths return, so a
	// failed claim cannot reach it. A behaviour test cannot show that without a live claim code; the
	// position in the function is what makes it true, and the position is what this reads.
	t.Run("the carry sits after every refusal", func(t *testing.T) {
		src := mustReadSource(t, "claim.go")
		fn := src[strings.Index(src, "func (s *Server) handleClaimSubmit"):]
		carry := strings.Index(fn, "claim: household language set to")
		clear := strings.Index(fn, "s.claimClearFailures(ip)")
		if carry < 0 || clear < 0 {
			t.Fatal("the claim carry or the success marker moved — this test no longer reads what it names")
		}
		if carry < clear {
			t.Error("the language carry runs BEFORE the failures are cleared — a failed claim could reach it")
		}
	})
}

// mustReadSource reads a file in this package, for the few tests whose claim is about WHERE code sits
// rather than what it returns.
func mustReadSource(t *testing.T, name string) string {
	t.Helper()
	b, err := os.ReadFile(name)
	if err != nil {
		t.Fatal(err)
	}
	return string(b)
}

// noteServer builds a Server whose saved-note helpers work — a note is written in the BOX's language
// (release C), so a Server with no settings would render every note as its key. Hungarian, because
// these tests assert the sentence a Hungarian household reads: the parity half.
func noteServer(t *testing.T) *Server {
	t.Helper()
	s := i18nTestServer(t)
	if err := s.settings.SetLanguage("hu"); err != nil {
		t.Fatal(err)
	}
	return s
}

// noteHU is the Hungarian text of a saved-note key, for a test that used to compare against a Go
// constant. Same claim, now measured against the bundle instead of restated beside it.
func noteHU(t *testing.T, key string) string {
	t.Helper()
	return noteServer(t).note(key)
}