// 外部測試套件（與 helpers_test.go 同理）：oidc 模型由 store 遷移，內部
// 測試套件匯入 testdb 會形成循環。涵蓋 RP-Initiated Logout 1.0 的
// /logout：id_token_hint 驗證、確認頁、post_logout_redirect_uri 註冊比對
// 與 state 回填，及不帶 RP 參數時對既有登出行為的委派。
package oidc_test

import (
	"net/http"
	"net/http/httptest"
	"net/url"
	"strings"
	"testing"
	"time"

	"alterminal/internal/application"
	"alterminal/internal/auth"
	"alterminal/internal/oidc"
)

// postLogoutURI 為測試應用程式註冊的登出後返回 URI。
const postLogoutURI = "https://rp.example/logged-out"

// newLogoutEnv 建立已註冊登出後返回 URI 的測試環境。
func newLogoutEnv(t *testing.T) *testEnv {
	t.Helper()
	e := newTestEnv(t)
	e.app.PostLogoutRedirectURIs = application.RedirectURIs{postLogoutURI}
	if err := e.db.Save(e.app).Error; err != nil {
		t.Fatal("註冊登出後返回 URI: ", err)
	}
	return e
}

// idTokenHint 為環境使用者簽發 ID token 供 id_token_hint 用。
func idTokenHint(t *testing.T, e *testEnv) string {
	t.Helper()
	tok, err := oidc.IssueIDToken(e.db, testIssuer, e.user, e.app, "openid", "", e.session.CreatedAt)
	if err != nil {
		t.Fatal("簽發 ID token: ", err)
	}
	return tok
}

// getLogout 對 GET /logout 發出請求（query 含前導 ?，可選帶 Cookie）。
func getLogout(h http.HandlerFunc, query string, cookies ...*http.Cookie) *httptest.ResponseRecorder {
	req := httptest.NewRequest(http.MethodGet, "/logout"+query, nil)
	for _, c := range cookies {
		req.AddCookie(c)
	}
	rec := httptest.NewRecorder()
	h(rec, req)
	return rec
}

// postLogoutForm 以表單送出 POST /logout（可選帶 Cookie）。
func postLogoutForm(h http.HandlerFunc, form url.Values, cookies ...*http.Cookie) *httptest.ResponseRecorder {
	req := httptest.NewRequest(http.MethodPost, "/logout", strings.NewReader(form.Encode()))
	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
	for _, c := range cookies {
		req.AddCookie(c)
	}
	rec := httptest.NewRecorder()
	h(rec, req)
	return rec
}

// sessionCookieCleared 檢查回應是否清除 Session Cookie（Max-Age<0）。
func sessionCookieCleared(rec *httptest.ResponseRecorder) bool {
	for _, c := range rec.Result().Cookies() {
		if c.Name == auth.CookieName && c.MaxAge < 0 {
			return true
		}
	}
	return false
}

// sessionAlive 回傳環境 Session 是否仍有效。
func sessionAlive(t *testing.T, e *testEnv) bool {
	t.Helper()
	_, err := auth.GetSession(e.db, e.session.ID)
	return err == nil
}

// logoutQuery 組出 RP-Initiated Logout 的 GET query（含前導 ?）。
func logoutQuery(hint, redirectURI, clientID, state string) string {
	v := url.Values{}
	set := func(k, s string) {
		if s != "" {
			v.Set(k, s)
		}
	}
	set("id_token_hint", hint)
	set("post_logout_redirect_uri", redirectURI)
	set("client_id", clientID)
	set("state", state)
	return "?" + v.Encode()
}

func TestLogoutDiscoveryEndSessionEndpoint(t *testing.T) {
	rec := httptest.NewRecorder()
	oidc.DiscoveryHandler(testIssuer)(rec, httptest.NewRequest(http.MethodGet, "/.well-known/openid-configuration", nil))
	if rec.Code != http.StatusOK {
		t.Fatalf("status = %d, want 200", rec.Code)
	}
	// RP-Initiated Logout 1.0 §2.1：支援 Discovery 時須發佈 end_session_endpoint。
	if !strings.Contains(rec.Body.String(), `"end_session_endpoint":"`+testIssuer+`/logout"`) {
		t.Fatalf("Discovery 應發佈 end_session_endpoint: %s", rec.Body.String())
	}
}

func TestRPLogoutHintMatchingSessionRedirects(t *testing.T) {
	e := newLogoutEnv(t)
	h := oidc.LogoutHandler(e.db, testIssuer)
	hint := idTokenHint(t, e)

	rec := getLogout(h, logoutQuery(hint, postLogoutURI, "", "st-123"), e.sessionCookie())
	if rec.Code != http.StatusSeeOther {
		t.Fatalf("status = %d, want 303, body = %s", rec.Code, rec.Body.String())
	}
	// RP-Initiated Logout 1.0 §2：重導 post_logout_redirect_uri 並以 state
	// 回填原值。
	loc := redirectLocation(t, rec)
	if loc.String() != postLogoutURI+"?state=st-123" {
		t.Fatalf("Location = %q, want %q?state=st-123", loc.String(), postLogoutURI)
	}
	if !sessionCookieCleared(rec) {
		t.Fatal("應清除 Session Cookie")
	}
	if sessionAlive(t, e) {
		t.Fatal("登出後 Session 應已刪除")
	}
}

func TestRPLogoutExpiredHintAccepted(t *testing.T) {
	e := newLogoutEnv(t)
	h := oidc.LogoutHandler(e.db, testIssuer)
	// 過期的 ID token：登出提示常在效期外送達，RP-Initiated Logout 1.0
	// §2 要求 RP 對應 session 存在（或近期存在）時應接受。
	past := time.Now().Add(-time.Hour).Unix()
	hint := forgeJWT(t, e.key,
		map[string]string{"alg": "RS256", "kid": e.key.Kid, "typ": "JWT"},
		map[string]any{"iss": testIssuer, "sub": subjectOf(e.user.ID), "aud": e.app.ClientID, "exp": past, "iat": past})

	rec := getLogout(h, logoutQuery(hint, postLogoutURI, "", ""), e.sessionCookie())
	if rec.Code != http.StatusSeeOther {
		t.Fatalf("status = %d, want 303, body = %s", rec.Code, rec.Body.String())
	}
	if got := redirectLocation(t, rec).String(); got != postLogoutURI {
		t.Fatalf("Location = %q, want %q", got, postLogoutURI)
	}
}

func TestRPLogoutHintOfOtherUserRequiresConfirmation(t *testing.T) {
	e := newLogoutEnv(t)
	h := oidc.LogoutHandler(e.db, testIssuer)

	other := &auth.User{Username: "logout-other", Email: "logout-other@example.com", Name: "他人"}
	if err := e.db.Create(other).Error; err != nil {
		t.Fatal(err)
	}
	t.Cleanup(func() {
		e.db.Delete(&auth.Session{}, "user_id = ?", other.ID)
		e.db.Delete(&auth.User{}, other.ID)
	})
	otherHint, err := oidc.IssueIDToken(e.db, testIssuer, other, e.app, "openid", "", time.Now())
	if err != nil {
		t.Fatal(err)
	}

	rec := getLogout(h, logoutQuery(otherHint, postLogoutURI, "", ""), e.sessionCookie())
	if rec.Code != http.StatusOK {
		t.Fatalf("status = %d, want 200（確認頁）, body = %s", rec.Code, rec.Body.String())
	}
	if !strings.Contains(rec.Body.String(), "您確定要登出嗎") {
		t.Fatal("應顯示登出確認頁")
	}
	if !sessionAlive(t, e) {
		t.Fatal("未確認前不應登出")
	}
}

func TestRPLogoutWithoutHintConfirmationFlow(t *testing.T) {
	e := newLogoutEnv(t)
	h := oidc.LogoutHandler(e.db, testIssuer)

	// 無 id_token_hint：RP-Initiated Logout 1.0 §2 MUST 先詢問 End-User。
	rec := getLogout(h, logoutQuery("", postLogoutURI, e.app.ClientID, "st-9"), e.sessionCookie())
	if rec.Code != http.StatusOK {
		t.Fatalf("status = %d, want 200（確認頁）, body = %s", rec.Code, rec.Body.String())
	}
	body := rec.Body.String()
	if !strings.Contains(body, "您確定要登出嗎") || !strings.Contains(body, e.app.Name) {
		t.Fatalf("確認頁應顯示標題與應用程式名稱: %s", body)
	}
	// 原始參數以隱藏欄位帶回。
	if got := hiddenFieldValue(t, body, "post_logout_redirect_uri"); got != postLogoutURI {
		t.Fatalf("隱藏欄位 post_logout_redirect_uri = %q, want %q", got, postLogoutURI)
	}
	if got := hiddenFieldValue(t, body, "state"); got != "st-9" {
		t.Fatalf("隱藏欄位 state = %q, want st-9", got)
	}
	csrf := csrfCookieOf(t, rec)

	form := url.Values{
		"decision":                 {"logout"},
		"csrf_token":               {csrf.Value},
		"client_id":                {e.app.ClientID},
		"post_logout_redirect_uri": {postLogoutURI},
		"state":                    {"st-9"},
	}
	rec = postLogoutForm(h, form, e.sessionCookie(), csrf)
	if rec.Code != http.StatusSeeOther {
		t.Fatalf("確認後 status = %d, want 303, body = %s", rec.Code, rec.Body.String())
	}
	loc := redirectLocation(t, rec)
	if loc.String() != postLogoutURI+"?state=st-9" {
		t.Fatalf("Location = %q, want %q?state=st-9", loc.String(), postLogoutURI)
	}
	if sessionAlive(t, e) {
		t.Fatal("確認後 Session 應已刪除")
	}

	// 取消：維持登入，返回帳號首頁。
	s, err := auth.CreateSession(e.db, e.user.ID)
	if err != nil {
		t.Fatal(err)
	}
	e.session = s
	rec2 := getLogout(h, logoutQuery("", postLogoutURI, e.app.ClientID, ""), e.sessionCookie())
	csrf2 := csrfCookieOf(t, rec2)
	form2 := url.Values{
		"decision":                 {"cancel"},
		"csrf_token":               {csrf2.Value},
		"client_id":                {e.app.ClientID},
		"post_logout_redirect_uri": {postLogoutURI},
	}
	rec2 = postLogoutForm(h, form2, e.sessionCookie(), csrf2)
	if rec2.Code != http.StatusSeeOther {
		t.Fatalf("取消 status = %d, want 303", rec2.Code)
	}
	if loc := redirectLocation(t, rec2).String(); loc != "/" {
		t.Fatalf("取消後 Location = %q, want /", loc)
	}
	if !sessionAlive(t, e) {
		t.Fatal("取消登出後 Session 應保持有效")
	}
}

func TestRPLogoutConfirmCSRFRequired(t *testing.T) {
	e := newLogoutEnv(t)
	h := oidc.LogoutHandler(e.db, testIssuer)

	form := url.Values{
		"decision":                 {"logout"},
		"csrf_token":               {"wrong"},
		"client_id":                {e.app.ClientID},
		"post_logout_redirect_uri": {postLogoutURI},
	}
	rec := postLogoutForm(h, form, e.sessionCookie(), &http.Cookie{Name: auth.CSRFCookieName, Value: "right"})
	if rec.Code != http.StatusForbidden {
		t.Fatalf("status = %d, want 403, body = %s", rec.Code, rec.Body.String())
	}
	if !strings.Contains(rec.Body.String(), "表單驗證失敗") {
		t.Fatal("應重繪確認頁並顯示錯誤")
	}
	if !sessionAlive(t, e) {
		t.Fatal("CSRF 失敗時不應登出")
	}
}

func TestRPLogoutUnregisteredRedirectRejected(t *testing.T) {
	e := newLogoutEnv(t)
	h := oidc.LogoutHandler(e.db, testIssuer)
	hint := idTokenHint(t, e)

	// 未註冊的返回 URI（含湊巧是 redirect URI 者）：RP-Initiated Logout
	// 1.0 §3 MUST NOT 重導；登出仍完成並顯示說明。
	for _, uri := range []string{"https://evil.example/gotcha", e.app.RedirectURIs[0]} {
		rec := getLogout(h, logoutQuery(hint, uri, "", ""), e.sessionCookie())
		if rec.Code != http.StatusOK {
			t.Fatalf("uri = %s: status = %d, want 200（已登出頁）, body = %s", uri, rec.Code, rec.Body.String())
		}
		if loc := rec.Header().Get("Location"); loc != "" {
			t.Fatalf("uri = %s: 不應重導，得到 Location = %s", uri, loc)
		}
		if !strings.Contains(rec.Body.String(), "您已登出") || !strings.Contains(rec.Body.String(), "未經應用程式註冊") {
			t.Fatalf("uri = %s: 應顯示已登出頁與說明: %s", uri, rec.Body.String())
		}
		if sessionAlive(t, e) {
			t.Fatal("登出仍應執行")
		}
		// 下一輪以新 Session 測試（前輪已登出）。
		s, err := auth.CreateSession(e.db, e.user.ID)
		if err != nil {
			t.Fatal(err)
		}
		e.session = s
	}
}

func TestRPLogoutInvalidHintRejected(t *testing.T) {
	e := newLogoutEnv(t)
	h := oidc.LogoutHandler(e.db, testIssuer)

	// 以未註冊於本服務的金鑰簽署：kid 查無 → hint 無效（§2 OP MUST 驗證
	// 為本 OP 簽發；§4 錯誤時 MUST 不重導）。
	other := mustNewKey(t, false)
	forged := forgeJWT(t, other,
		map[string]string{"alg": "RS256", "kid": other.Kid, "typ": "JWT"},
		map[string]any{"iss": testIssuer, "sub": subjectOf(e.user.ID), "aud": e.app.ClientID})

	rec := getLogout(h, logoutQuery(forged, postLogoutURI, "", ""), e.sessionCookie())
	if rec.Code != http.StatusBadRequest {
		t.Fatalf("status = %d, want 400, body = %s", rec.Code, rec.Body.String())
	}
	if loc := rec.Header().Get("Location"); loc != "" {
		t.Fatalf("錯誤時不應重導，得到 Location = %s", loc)
	}
	if !sessionAlive(t, e) {
		t.Fatal("無效 hint 不應執行登出")
	}

	// client_id 與 hint 的 aud 不符（§2 MUST 驗證相符）。
	hint := idTokenHint(t, e)
	rec = getLogout(h, logoutQuery(hint, postLogoutURI, e.pub.ClientID, ""), e.sessionCookie())
	if rec.Code != http.StatusBadRequest {
		t.Fatalf("status = %d, want 400, body = %s", rec.Code, rec.Body.String())
	}
	if !sessionAlive(t, e) {
		t.Fatal("client_id 不符時不應執行登出")
	}
}

func TestRPLogoutIdempotentWithoutSession(t *testing.T) {
	e := newLogoutEnv(t)
	h := oidc.LogoutHandler(e.db, testIssuer)
	hint := idTokenHint(t, e)

	// 無 Session：冪等完成，仍重導至已註冊的返回 URI。
	rec := getLogout(h, logoutQuery(hint, postLogoutURI, "", "s"))
	if rec.Code != http.StatusSeeOther {
		t.Fatalf("status = %d, want 303, body = %s", rec.Code, rec.Body.String())
	}
	if got := redirectLocation(t, rec).String(); got != postLogoutURI+"?state=s" {
		t.Fatalf("Location = %q, want %q?state=s", got, postLogoutURI)
	}
	if !sessionCookieCleared(rec) {
		t.Fatal("仍應清除（失效的）Session Cookie")
	}
}

func TestLogoutDirectVisit(t *testing.T) {
	e := newLogoutEnv(t)
	h := oidc.LogoutHandler(e.db, testIssuer)

	// 已登入直接造訪：無 hint，須先確認。
	rec := getLogout(h, "", e.sessionCookie())
	if rec.Code != http.StatusOK || !strings.Contains(rec.Body.String(), "您確定要登出嗎") {
		t.Fatalf("已登入直接造訪應顯示確認頁, status = %d", rec.Code)
	}
	if !sessionAlive(t, e) {
		t.Fatal("未確認前不應登出")
	}

	// 未登入直接造訪：冪等，導向 /login（與既有登出行為一致）。
	rec = getLogout(h, "")
	if rec.Code != http.StatusSeeOther {
		t.Fatalf("status = %d, want 303", rec.Code)
	}
	if loc := redirectLocation(t, rec).String(); loc != "/login" {
		t.Fatalf("Location = %q, want /login", loc)
	}
}

func TestLogoutPostDelegatesLegacyBehavior(t *testing.T) {
	e := newLogoutEnv(t)
	h := oidc.LogoutHandler(e.db, testIssuer)

	// 側欄登出表單（僅 csrf_token）：委由 auth.LogoutHandler，303 /login。
	rec := postLogoutForm(h, url.Values{"csrf_token": {"t"}},
		e.sessionCookie(), &http.Cookie{Name: auth.CSRFCookieName, Value: "t"})
	if rec.Code != http.StatusSeeOther {
		t.Fatalf("status = %d, want 303, body = %s", rec.Code, rec.Body.String())
	}
	if loc := redirectLocation(t, rec).String(); loc != "/login" {
		t.Fatalf("Location = %q, want /login", loc)
	}
	if sessionAlive(t, e) {
		t.Fatal("表單登出應刪除 Session")
	}

	// JSON API 登出：204。
	req := httptest.NewRequest(http.MethodPost, "/logout", nil)
	req.Header.Set("Content-Type", "application/json")
	rec2 := httptest.NewRecorder()
	h(rec2, req)
	if rec2.Code != http.StatusNoContent {
		t.Fatalf("status = %d, want 204", rec2.Code)
	}
	if !sessionCookieCleared(rec2) {
		t.Fatal("JSON 登出應清除 Session Cookie")
	}

	// 不支援的 Content-Type：415（沿 auth.LogoutHandler 的檢查）。
	req = httptest.NewRequest(http.MethodPost, "/logout", strings.NewReader("x=1"))
	req.Header.Set("Content-Type", "text/plain")
	rec3 := httptest.NewRecorder()
	h(rec3, req)
	if rec3.Code != http.StatusUnsupportedMediaType {
		t.Fatalf("status = %d, want 415", rec3.Code)
	}
}

func TestRPLogoutClientIDWithoutHintSoftFailsRedirect(t *testing.T) {
	e := newLogoutEnv(t)
	h := oidc.LogoutHandler(e.db, testIssuer)

	// 僅帶查無對應的 client_id：請求仍可進行（經確認頁），但不接受重導
	// ——無法確認返回網址的歸屬（RP-Initiated Logout 1.0 §3）。
	rec := getLogout(h, logoutQuery("", postLogoutURI, "no-such-client", ""), e.sessionCookie())
	if rec.Code != http.StatusOK || !strings.Contains(rec.Body.String(), "您確定要登出嗎") {
		t.Fatalf("應顯示確認頁, status = %d, body = %s", rec.Code, rec.Body.String())
	}
	csrf := csrfCookieOf(t, rec)
	form := url.Values{
		"decision":                 {"logout"},
		"csrf_token":               {csrf.Value},
		"client_id":                {"no-such-client"},
		"post_logout_redirect_uri": {postLogoutURI},
	}
	rec = postLogoutForm(h, form, e.sessionCookie(), csrf)
	if rec.Code != http.StatusOK {
		t.Fatalf("status = %d, want 200（已登出頁）, body = %s", rec.Code, rec.Body.String())
	}
	if loc := rec.Header().Get("Location"); loc != "" {
		t.Fatalf("查無 client 不得重導，得到 Location = %s", loc)
	}
	if sessionAlive(t, e) {
		t.Fatal("確認後應完成登出")
	}
}