package bouncer

import (
	"context"
	"testing"
	"time"

	"github.com/golang-jwt/jwt/v5"
)

// TestAuthTime pins the auth_time claim of plan 07 (P-29, C-CR-02's
// framework half): every sign-in mint stamps it equal to iat for both
// audiences, every refresh path copies it unchanged across rotations, a
// token without it refreshes without it, and VerifyAuthTime keeps the
// checks of VerifyClaims and VerifyClaimsAudience.
func TestAuthTime(t *testing.T) {
	const iss = "https://app.test/_user/api/v1/login"
	const refreshIss = "https://app.test/_user/api/v1/refresh"

	if ClaimAuthTime != "auth_time" {
		t.Fatalf("ClaimAuthTime = %q, want auth_time", ClaimAuthTime)
	}

	t.Run("mint stamps auth_time equal to iat for both audiences", func(t *testing.T) {
		for _, aud := range []string{AudienceUser, AudienceBackend} {
			tok, _, err := MintAudience(secret, "42", iss, time.Hour, aud)
			if err != nil {
				t.Fatal(err)
			}
			claims := decodeClaims(t, tok, secret)
			at := claimUnix(t, claims, ClaimAuthTime)
			iat := claimUnix(t, claims, "iat")
			if at.Unix() != iat.Unix() {
				t.Fatalf("%s: auth_time %d != iat %d", aud, at.Unix(), iat.Unix())
			}
			_, got, ok, err := VerifyAuthTime(tok, secret, aud)
			if err != nil || !ok || got.Unix() != iat.Unix() {
				t.Fatalf("%s: VerifyAuthTime = %v, %v, %v", aud, got, ok, err)
			}
		}
		tok, _, err := Mint(secret, "42", iss, time.Hour)
		if err != nil {
			t.Fatal(err)
		}
		if _, _, ok, err := VerifyAuthTime(tok, secret, AudienceUser); err != nil || !ok {
			t.Fatalf("Mint: ok=%v err=%v", ok, err)
		}
	})

	signedAt := time.Now().Add(-90 * time.Minute).Truncate(time.Second)
	users := memUsers{byID: map[uint]*Principal{42: {ID: 42, Backend: true}}}
	refreshers := []struct {
		name     string
		audience string
		refresh  func(tok string) (string, error)
	}{
		{"Refresh", AudienceUser, func(tok string) (string, error) {
			return Refresh(secret, tok, 4*time.Hour, NewMemoryBlacklist(), 0, refreshIss)
		}},
		{"RefreshAudience", AudienceBackend, func(tok string) (string, error) {
			return RefreshAudience(secret, tok, AudienceBackend, 4*time.Hour, NewMemoryBlacklist(), 0, refreshIss)
		}},
		{"RefreshAudienceFor", AudienceBackend, func(tok string) (string, error) {
			return RefreshAudienceFor(context.Background(), users, secret, tok, AudienceBackend, 4*time.Hour, NewMemoryBlacklist(), 0, refreshIss)
		}},
	}
	for _, r := range refreshers {
		t.Run(r.name+" carries auth_time unchanged across two rotations", func(t *testing.T) {
			tok, _, err := mintAudience(secret, "42", iss, 30*time.Minute, r.audience, signedAt, signedAt)
			if err != nil {
				t.Fatal(err)
			}
			prevIat := signedAt
			for i := 1; i <= 2; i++ {
				next, err := r.refresh(tok)
				if err != nil {
					t.Fatalf("rotation %d: %v", i, err)
				}
				_, at, ok, err := VerifyAuthTime(next, secret, r.audience)
				if err != nil || !ok {
					t.Fatalf("rotation %d: ok=%v err=%v", i, ok, err)
				}
				if at.Unix() != signedAt.Unix() {
					t.Fatalf("rotation %d: auth_time %d, want %d", i, at.Unix(), signedAt.Unix())
				}
				iat := claimUnix(t, decodeClaims(t, next, secret), "iat")
				if !iat.After(prevIat) && i == 1 {
					t.Fatalf("rotation %d: iat %s did not move past %s", i, iat, prevIat)
				}
				prevIat = iat
				tok = next
			}
		})
	}

	t.Run("a legacy token without auth_time refreshes without one", func(t *testing.T) {
		legacy := sign(t, jwt.SigningMethodHS256, jwt.MapClaims{
			"sub": "42", "aud": AudienceBackend, "jti": "legacy-backend",
			"iat": time.Now().Add(-10 * time.Minute).Unix(),
			"exp": time.Now().Add(time.Minute).Unix(),
		}, []byte(secret))
		for name, refresh := range map[string]func(string) (string, error){
			"RefreshAudience": func(tok string) (string, error) {
				return RefreshAudience(secret, tok, AudienceBackend, time.Hour, NewMemoryBlacklist(), 0, refreshIss)
			},
			"RefreshAudienceFor": func(tok string) (string, error) {
				return RefreshAudienceFor(context.Background(), users, secret, tok, AudienceBackend, time.Hour, NewMemoryBlacklist(), 0, refreshIss)
			},
		} {
			next, err := refresh(legacy)
			if err != nil {
				t.Fatalf("%s: %v", name, err)
			}
			if _, has := decodeClaims(t, next, secret)[ClaimAuthTime]; has {
				t.Fatalf("%s stamped auth_time on a legacy token", name)
			}
			if _, _, ok, err := VerifyAuthTime(next, secret, AudienceBackend); err != nil || ok {
				t.Fatalf("%s: VerifyAuthTime ok=%v err=%v, want ok=false and no error", name, ok, err)
			}
		}
		user := sign(t, jwt.SigningMethodHS256, jwt.MapClaims{
			"sub": "42", "jti": "legacy-user",
			"iat": time.Now().Add(-10 * time.Minute).Unix(),
			"exp": time.Now().Add(time.Minute).Unix(),
		}, []byte(secret))
		next, err := Refresh(secret, user, time.Hour, NewMemoryBlacklist(), 0, refreshIss)
		if err != nil {
			t.Fatal(err)
		}
		if _, has := decodeClaims(t, next, secret)[ClaimAuthTime]; has {
			t.Fatal("Refresh stamped auth_time on a legacy token")
		}
	})

	t.Run("VerifyAuthTime refuses what VerifyClaims refuses", func(t *testing.T) {
		good, _, err := MintAudience(secret, "42", iss, time.Hour, AudienceUser)
		if err != nil {
			t.Fatal(err)
		}
		if _, _, _, err := VerifyAuthTime(good, "another-secret", AudienceUser); err == nil {
			t.Fatal("bad signature accepted")
		}
		if _, _, _, err := VerifyAuthTime(good, secret, AudienceBackend); err == nil {
			t.Fatal("wrong audience accepted")
		}
		backend, _, err := MintAudience(secret, "42", iss, time.Hour, AudienceBackend)
		if err != nil {
			t.Fatal(err)
		}
		if _, _, _, err := VerifyAuthTime(backend, secret, AudienceUser); err == nil {
			t.Fatal("a backend token accepted for the frontend audience")
		}
		past := time.Now().Add(-time.Hour)
		expired, _, err := mintAudience(secret, "42", iss, time.Minute, AudienceUser, past, past)
		if err != nil {
			t.Fatal(err)
		}
		if _, _, _, err := VerifyAuthTime(expired, secret, AudienceUser); err == nil {
			t.Fatal("expired token accepted")
		}
		if _, _, _, err := VerifyAuthTime(good, secret, " "); err == nil {
			t.Fatal("empty audience accepted")
		}
	})

	t.Run("a frontend token without aud is accepted as VerifyClaims does", func(t *testing.T) {
		at := time.Now().Add(-5 * time.Minute).Unix()
		noAud := sign(t, jwt.SigningMethodHS256, jwt.MapClaims{
			"sub": "42", "jti": "no-aud",
			"iat":         time.Now().Unix(),
			"exp":         time.Now().Add(time.Hour).Unix(),
			ClaimAuthTime: at,
		}, []byte(secret))
		if _, _, _, _, err := VerifyClaims(noAud, secret); err != nil {
			t.Fatalf("VerifyClaims refused the no-aud token: %v", err)
		}
		sub, got, ok, err := VerifyAuthTime(noAud, secret, AudienceUser)
		if err != nil || !ok || sub != "42" || got.Unix() != at {
			t.Fatalf("VerifyAuthTime(no aud) = %q, %v, %v, %v", sub, got, ok, err)
		}
	})
}