package auth

import (
	"context"
	"encoding/json"
	"io"
	"log/slog"
	"net/http"
	"net/http/httptest"
	"strings"
	"testing"
	"time"
)

func bearerHeader(token string) string {
	return "Bearer " + token
}

func claimsHandler(t *testing.T) http.Handler {
	t.Helper()
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		claims, ok := ClaimsFromContext(r.Context())
		if !ok {
			http.Error(w, "no claims in context", http.StatusInternalServerError)
			return
		}
		w.Header().Set("X-Claims-Sub", claims.Sub)
		w.Header().Set("X-Claims-Role", string(claims.Role))
		w.WriteHeader(http.StatusOK)
	})
}

func doAuth(h http.Handler, tok string) *httptest.ResponseRecorder {
	req := httptest.NewRequest(http.MethodGet, "/", nil)
	if tok != "" {
		req.Header.Set("Authorization", bearerHeader(tok))
	}
	rr := httptest.NewRecorder()
	h.ServeHTTP(rr, req)
	return rr
}

func responseCode(t *testing.T, rr *httptest.ResponseRecorder, want int) {
	t.Helper()
	if rr.Code != want {
		t.Fatalf("status = %d, want %d (body: %s)", rr.Code, want, rr.Body.String())
	}
}

func assertErrorCode(t *testing.T, rr *httptest.ResponseRecorder, want string) {
	t.Helper()
	var body struct {
		Error struct {
			Code    string `json:"code"`
			Message string `json:"message"`
		} `json:"error"`
	}
	if err := json.NewDecoder(strings.NewReader(rr.Body.String())).Decode(&body); err != nil {
		t.Fatalf("decode error body: %v", err)
	}
	if body.Error.Code != want {
		t.Errorf("error.code = %q, want %q", body.Error.Code, want)
	}
}

func TestAuthorize_NoBearer(t *testing.T) {
	t.Parallel()
	svc := New(testConfig(""))
	rr := doAuth(svc.Authorize(RoleViewer)(claimsHandler(t)), "")
	responseCode(t, rr, http.StatusUnauthorized)
	assertErrorCode(t, rr, "unauthorized")
}

func TestAuthorize_InvalidToken(t *testing.T) {
	t.Parallel()
	svc := New(testConfig(""))
	rr := doAuth(svc.Authorize(RoleViewer)(claimsHandler(t)), "not-a-jwt")
	responseCode(t, rr, http.StatusUnauthorized)
	assertErrorCode(t, rr, "unauthorized")
}

func TestAuthorize_ExpiredToken(t *testing.T) {
	t.Parallel()
	svc := New(testConfig(""))
	tok, err := svc.Sign("u", RoleViewer, -time.Minute)
	if err != nil {
		t.Fatalf("Sign error: %v", err)
	}
	rr := doAuth(svc.Authorize(RoleViewer)(claimsHandler(t)), tok)
	responseCode(t, rr, http.StatusUnauthorized)
	assertErrorCode(t, rr, "unauthorized")
}

func TestAuthorize_OwnerSatisfiesAdminAndViewer(t *testing.T) {
	t.Parallel()
	svc := New(testConfig(""))
	tok, err := svc.Sign("u", RoleOwner, time.Hour)
	if err != nil {
		t.Fatalf("Sign error: %v", err)
	}
	rr := doAuth(svc.Authorize(RoleAdmin, RoleViewer)(claimsHandler(t)), tok)
	responseCode(t, rr, http.StatusOK)
	if rr.Header().Get("X-Claims-Sub") != "u" {
		t.Errorf("X-Claims-Sub = %q, want u", rr.Header().Get("X-Claims-Sub"))
	}
	if rr.Header().Get("X-Claims-Role") != "owner" {
		t.Errorf("X-Claims-Role = %q, want owner", rr.Header().Get("X-Claims-Role"))
	}
}

func TestAuthorize_AdminSatisfiesViewer(t *testing.T) {
	t.Parallel()
	svc := New(testConfig(""))
	tok, err := svc.Sign("u", RoleAdmin, time.Hour)
	if err != nil {
		t.Fatalf("Sign error: %v", err)
	}
	rr := doAuth(svc.Authorize(RoleViewer)(claimsHandler(t)), tok)
	responseCode(t, rr, http.StatusOK)
}

func TestAuthorize_AdminFailsOwner(t *testing.T) {
	t.Parallel()
	svc := New(testConfig(""))
	tok, err := svc.Sign("u", RoleAdmin, time.Hour)
	if err != nil {
		t.Fatalf("Sign error: %v", err)
	}
	rr := doAuth(svc.Authorize(RoleOwner)(claimsHandler(t)), tok)
	responseCode(t, rr, http.StatusForbidden)
	assertErrorCode(t, rr, "forbidden")
}

func TestAuthorize_ViewerFailsAdmin(t *testing.T) {
	t.Parallel()
	svc := New(testConfig(""))
	tok, err := svc.Sign("u", RoleViewer, time.Hour)
	if err != nil {
		t.Fatalf("Sign error: %v", err)
	}
	rr := doAuth(svc.Authorize(RoleAdmin)(claimsHandler(t)), tok)
	responseCode(t, rr, http.StatusForbidden)
	assertErrorCode(t, rr, "forbidden")
}

func TestAuthorize_AnyAuthenticated(t *testing.T) {
	t.Parallel()
	svc := New(testConfig(""))
	tok, err := svc.Sign("u", RoleViewer, time.Hour)
	if err != nil {
		t.Fatalf("Sign error: %v", err)
	}
	rr := doAuth(svc.Authorize()(claimsHandler(t)), tok)
	responseCode(t, rr, http.StatusOK)
}

func TestAuthorize_BearerPrefixRequired(t *testing.T) {
	t.Parallel()
	svc := New(testConfig(""))
	tok, err := svc.Sign("u", RoleViewer, time.Hour)
	if err != nil {
		t.Fatalf("Sign error: %v", err)
	}
	req := httptest.NewRequest(http.MethodGet, "/", nil)
	req.Header.Set("Authorization", tok) // no "Bearer " prefix
	rr := httptest.NewRecorder()
	svc.Authorize(RoleViewer)(claimsHandler(t)).ServeHTTP(rr, req)
	responseCode(t, rr, http.StatusUnauthorized)
}

func TestClaimsFromContext_Missing(t *testing.T) {
	t.Parallel()
	if _, ok := ClaimsFromContext(context.Background()); ok {
		t.Fatal("ClaimsFromContext on empty ctx should return ok=false")
	}
}

// --- X-API-Key 分支（裁决 15.4.2 / 15.4.3）-----------------------------------

// discardLog 是中间件测试用的丢弃型 logger（不产出日志噪声）。
func discardLog() *slog.Logger {
	return slog.New(slog.NewTextHandler(io.Discard, nil))
}

// keyDoor 构建「Bearer + X-API-Key」双凭据门。
func keyDoor(keys KeyTable, required ...Role) func(http.Handler) http.Handler {
	return WithAPIKey(keys, New(testConfig("")).Authorize(required...), discardLog(), required...)
}

// doAPIKey 发一个只带 `X-API-Key` 头的请求。
func doAPIKey(h http.Handler, key string) *httptest.ResponseRecorder {
	req := httptest.NewRequest(http.MethodGet, "/", nil)
	req.Header.Set(apiKeyHeader, key)
	rr := httptest.NewRecorder()
	h.ServeHTTP(rr, req)
	return rr
}

// TestWithAPIKey_ValidKeyPassesOwnerGate 是 15.4.2 的核心断言：签发出去的 key
// 真的能用，并且拿到 owner 级（15.4.3），Sub 是脱敏 id 而不是密钥明文。
func TestWithAPIKey_ValidKeyPassesOwnerGate(t *testing.T) {
	t.Parallel()
	keys := newTestAPIKey()
	key, err := keys.Generate()
	if err != nil {
		t.Fatalf("Generate error: %v", err)
	}
	rr := doAPIKey(keyDoor(keys, RoleOwner)(claimsHandler(t)), key)
	responseCode(t, rr, http.StatusOK)
	if got := rr.Header().Get("X-Claims-Role"); got != string(RoleOwner) {
		t.Errorf("X-Claims-Role = %q, want owner", got)
	}
	if got := rr.Header().Get("X-Claims-Sub"); got != apiKeySubPrefix+MaskKey(key) {
		t.Errorf("X-Claims-Sub = %q, want masked id %q", got, apiKeySubPrefix+MaskKey(key))
	}
	if strings.Contains(rr.Header().Get("X-Claims-Sub"), key) {
		t.Error("claims Sub leaked the key material")
	}
}

// TestWithAPIKey_UnknownKeyRejected 断言未知 key 一律 401，且**即使同时带着一份
// 合法 Bearer 也不回落** —— fail-closed，坏 key 不能借道另一份凭据混过门。
func TestWithAPIKey_UnknownKeyRejected(t *testing.T) {
	t.Parallel()
	keys := newTestAPIKey()
	door := keyDoor(keys, RoleOwner)
	rr := doAPIKey(door(claimsHandler(t)), "not-a-key")
	responseCode(t, rr, http.StatusUnauthorized)
	assertErrorCode(t, rr, "unauthorized")

	svc := New(testConfig(""))
	tok, err := svc.Sign("u", RoleOwner, time.Hour)
	if err != nil {
		t.Fatalf("Sign error: %v", err)
	}
	req := httptest.NewRequest(http.MethodGet, "/", nil)
	req.Header.Set(apiKeyHeader, "not-a-key")
	req.Header.Set("Authorization", bearerHeader(tok))
	rec := httptest.NewRecorder()
	WithAPIKey(keys, svc.Authorize(RoleOwner), discardLog(), RoleOwner)(claimsHandler(t)).ServeHTTP(rec, req)
	responseCode(t, rec, http.StatusUnauthorized)
}

// TestWithAPIKey_RevokedKeyRejected 断言吊销后的 key 立即失效（能发也能废）。
func TestWithAPIKey_RevokedKeyRejected(t *testing.T) {
	t.Parallel()
	keys := newTestAPIKey()
	key, err := keys.Generate()
	if err != nil {
		t.Fatalf("Generate error: %v", err)
	}
	door := keyDoor(keys, RoleOwner)
	responseCode(t, doAPIKey(door(claimsHandler(t)), key), http.StatusOK)
	keys.Revoke(key)
	responseCode(t, doAPIKey(door(claimsHandler(t)), key), http.StatusUnauthorized)
}

// TestWithAPIKey_EmptyHeaderValueRejected 断言该头出现但值为空时按无效凭据拒绝，
// 而不是被当成「没带 key」悄悄回落到 Bearer。
func TestWithAPIKey_EmptyHeaderValueRejected(t *testing.T) {
	t.Parallel()
	keys := newTestAPIKey()
	if _, err := keys.Generate(); err != nil {
		t.Fatalf("Generate error: %v", err)
	}
	rr := doAPIKey(keyDoor(keys, RoleOwner)(claimsHandler(t)), "")
	responseCode(t, rr, http.StatusUnauthorized)
}

// TestWithAPIKey_NilTableRejectsKeyHeader 断言 key 表未注入时带 key 的请求一律
// 拒绝（表不在 = 表为空），不带 key 的请求则照旧走 Bearer。
func TestWithAPIKey_NilTableRejectsKeyHeader(t *testing.T) {
	t.Parallel()
	svc := New(testConfig(""))
	door := WithAPIKey(nil, svc.Authorize(RoleOwner), discardLog(), RoleOwner)
	responseCode(t, doAPIKey(door(claimsHandler(t)), "any-key"), http.StatusUnauthorized)

	tok, err := svc.Sign("u", RoleOwner, time.Hour)
	if err != nil {
		t.Fatalf("Sign error: %v", err)
	}
	rr := doAuth(door(claimsHandler(t)), tok)
	responseCode(t, rr, http.StatusOK)
}

// TestWithAPIKey_BearerPathUnchanged 断言不带该头时行为与纯 Bearer 门逐字一致：
// 角色不足仍 403、缺凭据仍 401。
func TestWithAPIKey_BearerPathUnchanged(t *testing.T) {
	t.Parallel()
	svc := New(testConfig(""))
	keys := newTestAPIKey()
	door := WithAPIKey(keys, svc.Authorize(RoleOwner), discardLog(), RoleOwner)

	admin, err := svc.Sign("u", RoleAdmin, time.Hour)
	if err != nil {
		t.Fatalf("Sign error: %v", err)
	}
	responseCode(t, doAuth(door(claimsHandler(t)), admin), http.StatusForbidden)
	responseCode(t, doAuth(door(claimsHandler(t)), ""), http.StatusUnauthorized)

	owner, err := svc.Sign("u", RoleOwner, time.Hour)
	if err != nil {
		t.Fatalf("Sign error: %v", err)
	}
	responseCode(t, doAuth(door(claimsHandler(t)), owner), http.StatusOK)
}